linux/fs/btrfs/extent_io.c

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 14:07:57 +00:00
// SPDX-License-Identifier: GPL-2.0
#include <linux/bitops.h>
#include <linux/slab.h>
#include <linux/bio.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/page-flags.h>
#include <linux/spinlock.h>
#include <linux/blkdev.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/pagevec.h>
#include <linux/prefetch.h>
#include <linux/cleancache.h>
#include "misc.h"
#include "extent_io.h"
#include "extent-io-tree.h"
#include "extent_map.h"
#include "ctree.h"
#include "btrfs_inode.h"
#include "volumes.h"
#include "check-integrity.h"
#include "locking.h"
#include "rcu-string.h"
#include "backref.h"
#include "disk-io.h"
#include "subpage.h"
#include "zoned.h"
#include "block-group.h"
static struct kmem_cache *extent_state_cache;
static struct kmem_cache *extent_buffer_cache;
static struct bio_set btrfs_bioset;
static inline bool extent_state_in_tree(const struct extent_state *state)
{
return !RB_EMPTY_NODE(&state->rb_node);
}
#ifdef CONFIG_BTRFS_DEBUG
static LIST_HEAD(states);
static DEFINE_SPINLOCK(leak_lock);
static inline void btrfs_leak_debug_add(spinlock_t *lock,
struct list_head *new,
struct list_head *head)
{
unsigned long flags;
spin_lock_irqsave(lock, flags);
list_add(new, head);
spin_unlock_irqrestore(lock, flags);
}
static inline void btrfs_leak_debug_del(spinlock_t *lock,
struct list_head *entry)
{
unsigned long flags;
spin_lock_irqsave(lock, flags);
list_del(entry);
spin_unlock_irqrestore(lock, flags);
}
void btrfs_extent_buffer_leak_debug_check(struct btrfs_fs_info *fs_info)
{
struct extent_buffer *eb;
unsigned long flags;
/*
* If we didn't get into open_ctree our allocated_ebs will not be
* initialized, so just skip this.
*/
if (!fs_info->allocated_ebs.next)
return;
spin_lock_irqsave(&fs_info->eb_leak_lock, flags);
while (!list_empty(&fs_info->allocated_ebs)) {
eb = list_first_entry(&fs_info->allocated_ebs,
struct extent_buffer, leak_list);
pr_err(
"BTRFS: buffer leak start %llu len %lu refs %d bflags %lu owner %llu\n",
eb->start, eb->len, atomic_read(&eb->refs), eb->bflags,
btrfs_header_owner(eb));
list_del(&eb->leak_list);
kmem_cache_free(extent_buffer_cache, eb);
}
spin_unlock_irqrestore(&fs_info->eb_leak_lock, flags);
}
static inline void btrfs_extent_state_leak_debug_check(void)
{
struct extent_state *state;
while (!list_empty(&states)) {
state = list_entry(states.next, struct extent_state, leak_list);
pr_err("BTRFS: state leak: start %llu end %llu state %u in tree %d refs %d\n",
state->start, state->end, state->state,
extent_state_in_tree(state),
refcount_read(&state->refs));
list_del(&state->leak_list);
kmem_cache_free(extent_state_cache, state);
}
}
#define btrfs_debug_check_extent_io_range(tree, start, end) \
__btrfs_debug_check_extent_io_range(__func__, (tree), (start), (end))
static inline void __btrfs_debug_check_extent_io_range(const char *caller,
struct extent_io_tree *tree, u64 start, u64 end)
{
struct inode *inode = tree->private_data;
u64 isize;
if (!inode || !is_data_inode(inode))
return;
isize = i_size_read(inode);
if (end >= PAGE_SIZE && (end % 2) == 0 && end != isize - 1) {
btrfs_debug_rl(BTRFS_I(inode)->root->fs_info,
"%s: ino %llu isize %llu odd range [%llu,%llu]",
caller, btrfs_ino(BTRFS_I(inode)), isize, start, end);
}
}
#else
#define btrfs_leak_debug_add(lock, new, head) do {} while (0)
#define btrfs_leak_debug_del(lock, entry) do {} while (0)
#define btrfs_extent_state_leak_debug_check() do {} while (0)
#define btrfs_debug_check_extent_io_range(c, s, e) do {} while (0)
#endif
struct tree_entry {
u64 start;
u64 end;
struct rb_node rb_node;
};
struct extent_page_data {
struct bio *bio;
/* tells writepage not to lock the state bits for this range
* it still does the unlocking
*/
unsigned int extent_locked:1;
/* tells the submit_bio code to use REQ_SYNC */
unsigned int sync_io:1;
};
static int add_extent_changeset(struct extent_state *state, u32 bits,
struct extent_changeset *changeset,
int set)
{
int ret;
if (!changeset)
return 0;
if (set && (state->state & bits) == bits)
return 0;
if (!set && (state->state & bits) == 0)
return 0;
changeset->bytes_changed += state->end - state->start + 1;
ret = ulist_add(&changeset->range_changed, state->start, state->end,
GFP_ATOMIC);
return ret;
}
int __must_check submit_one_bio(struct bio *bio, int mirror_num,
unsigned long bio_flags)
{
blk_status_t ret = 0;
struct extent_io_tree *tree = bio->bi_private;
bio->bi_private = NULL;
if (is_data_inode(tree->private_data))
ret = btrfs_submit_data_bio(tree->private_data, bio, mirror_num,
bio_flags);
else
ret = btrfs_submit_metadata_bio(tree->private_data, bio,
mirror_num, bio_flags);
return blk_status_to_errno(ret);
}
/* Cleanup unsubmitted bios */
static void end_write_bio(struct extent_page_data *epd, int ret)
{
if (epd->bio) {
epd->bio->bi_status = errno_to_blk_status(ret);
bio_endio(epd->bio);
epd->bio = NULL;
}
}
/*
* Submit bio from extent page data via submit_one_bio
*
* Return 0 if everything is OK.
* Return <0 for error.
*/
static int __must_check flush_write_bio(struct extent_page_data *epd)
{
int ret = 0;
if (epd->bio) {
ret = submit_one_bio(epd->bio, 0, 0);
/*
* Clean up of epd->bio is handled by its endio function.
* And endio is either triggered by successful bio execution
* or the error handler of submit bio hook.
* So at this point, no matter what happened, we don't need
* to clean up epd->bio.
*/
epd->bio = NULL;
}
return ret;
}
int __init extent_state_cache_init(void)
{
extent_state_cache = kmem_cache_create("btrfs_extent_state",
sizeof(struct extent_state), 0,
SLAB_MEM_SPREAD, NULL);
if (!extent_state_cache)
return -ENOMEM;
return 0;
}
int __init extent_io_init(void)
{
extent_buffer_cache = kmem_cache_create("btrfs_extent_buffer",
sizeof(struct extent_buffer), 0,
SLAB_MEM_SPREAD, NULL);
if (!extent_buffer_cache)
return -ENOMEM;
if (bioset_init(&btrfs_bioset, BIO_POOL_SIZE,
offsetof(struct btrfs_io_bio, bio),
BIOSET_NEED_BVECS))
goto free_buffer_cache;
btrfs: Fix crash due to not allocating integrity data for a bioset When btrfs creates a bioset, we must also allocate the integrity data pool. Otherwise btrfs will crash when it tries to submit a bio to a checksumming disk: BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 IP: [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150 PGD 2305e4067 PUD 23063d067 PMD 0 Oops: 0000 [#1] PREEMPT SMP Modules linked in: btrfs scsi_debug xfs ext4 jbd2 ext3 jbd mbcache sch_fq_codel eeprom lpc_ich mfd_core nfsd exportfs auth_rpcgss af_packet raid6_pq xor zlib_deflate libcrc32c [last unloaded: scsi_debug] CPU: 1 PID: 4486 Comm: mount Not tainted 3.12.0-rc1-mcsum #2 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 task: ffff8802451c9720 ti: ffff880230698000 task.ti: ffff880230698000 RIP: 0010:[<ffffffff8111e28a>] [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150 RSP: 0018:ffff880230699688 EFLAGS: 00010286 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 00000000005f8445 RDX: 0000000000000001 RSI: 0000000000000010 RDI: 0000000000000000 RBP: ffff8802306996f8 R08: 0000000000011200 R09: 0000000000000008 R10: 0000000000000020 R11: ffff88009d6e8000 R12: 0000000000011210 R13: 0000000000000030 R14: ffff8802306996b8 R15: ffff8802451c9720 FS: 00007f25b8a16800(0000) GS:ffff88024fc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000018 CR3: 0000000230576000 CR4: 00000000000007e0 Stack: ffff8802451c9720 0000000000000002 ffffffff81a97100 0000000000281250 ffffffff81a96480 ffff88024fc99150 ffff880228d18200 0000000000000000 0000000000000000 0000000000000040 ffff880230e8c2e8 ffff8802459dc900 Call Trace: [<ffffffff811b2208>] bio_integrity_alloc+0x48/0x1b0 [<ffffffff811b26fc>] bio_integrity_prep+0xac/0x360 [<ffffffff8111e298>] ? mempool_alloc+0x58/0x150 [<ffffffffa03e8041>] ? alloc_extent_state+0x31/0x110 [btrfs] [<ffffffff81241579>] blk_queue_bio+0x1c9/0x460 [<ffffffff8123e58a>] generic_make_request+0xca/0x100 [<ffffffff8123e639>] submit_bio+0x79/0x160 [<ffffffffa03f865e>] btrfs_map_bio+0x48e/0x5b0 [btrfs] [<ffffffffa03c821a>] btree_submit_bio_hook+0xda/0x110 [btrfs] [<ffffffffa03e7eba>] submit_one_bio+0x6a/0xa0 [btrfs] [<ffffffffa03ef450>] read_extent_buffer_pages+0x250/0x310 [btrfs] [<ffffffff8125eef6>] ? __radix_tree_preload+0x66/0xf0 [<ffffffff8125f1c5>] ? radix_tree_insert+0x95/0x260 [<ffffffffa03c66f6>] btree_read_extent_buffer_pages.constprop.128+0xb6/0x120 [btrfs] [<ffffffffa03c8c1a>] read_tree_block+0x3a/0x60 [btrfs] [<ffffffffa03caefd>] open_ctree+0x139d/0x2030 [btrfs] [<ffffffffa03a282a>] btrfs_mount+0x53a/0x7d0 [btrfs] [<ffffffff8113ab0b>] ? pcpu_alloc+0x8eb/0x9f0 [<ffffffff81167305>] ? __kmalloc_track_caller+0x35/0x1e0 [<ffffffff81176ba0>] mount_fs+0x20/0xd0 [<ffffffff81191096>] vfs_kern_mount+0x76/0x120 [<ffffffff81193320>] do_mount+0x200/0xa40 [<ffffffff81135cdb>] ? strndup_user+0x5b/0x80 [<ffffffff81193bf0>] SyS_mount+0x90/0xe0 [<ffffffff8156d31d>] system_call_fastpath+0x1a/0x1f Code: 4c 8d 75 a8 4c 89 6d e8 45 89 e0 4c 8d 6f 30 48 89 5d d8 41 83 e0 af 48 89 fb 49 83 c6 18 4c 89 7d f8 65 4c 8b 3c 25 c0 b8 00 00 <48> 8b 73 18 44 89 c7 44 89 45 98 ff 53 20 48 85 c0 48 89 c2 74 RIP [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150 RSP <ffff880230699688> CR2: 0000000000000018 ---[ end trace 7a96042017ed21e2 ]--- Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-09-20 03:37:07 +00:00
if (bioset_integrity_create(&btrfs_bioset, BIO_POOL_SIZE))
btrfs: Fix crash due to not allocating integrity data for a bioset When btrfs creates a bioset, we must also allocate the integrity data pool. Otherwise btrfs will crash when it tries to submit a bio to a checksumming disk: BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 IP: [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150 PGD 2305e4067 PUD 23063d067 PMD 0 Oops: 0000 [#1] PREEMPT SMP Modules linked in: btrfs scsi_debug xfs ext4 jbd2 ext3 jbd mbcache sch_fq_codel eeprom lpc_ich mfd_core nfsd exportfs auth_rpcgss af_packet raid6_pq xor zlib_deflate libcrc32c [last unloaded: scsi_debug] CPU: 1 PID: 4486 Comm: mount Not tainted 3.12.0-rc1-mcsum #2 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 task: ffff8802451c9720 ti: ffff880230698000 task.ti: ffff880230698000 RIP: 0010:[<ffffffff8111e28a>] [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150 RSP: 0018:ffff880230699688 EFLAGS: 00010286 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 00000000005f8445 RDX: 0000000000000001 RSI: 0000000000000010 RDI: 0000000000000000 RBP: ffff8802306996f8 R08: 0000000000011200 R09: 0000000000000008 R10: 0000000000000020 R11: ffff88009d6e8000 R12: 0000000000011210 R13: 0000000000000030 R14: ffff8802306996b8 R15: ffff8802451c9720 FS: 00007f25b8a16800(0000) GS:ffff88024fc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000018 CR3: 0000000230576000 CR4: 00000000000007e0 Stack: ffff8802451c9720 0000000000000002 ffffffff81a97100 0000000000281250 ffffffff81a96480 ffff88024fc99150 ffff880228d18200 0000000000000000 0000000000000000 0000000000000040 ffff880230e8c2e8 ffff8802459dc900 Call Trace: [<ffffffff811b2208>] bio_integrity_alloc+0x48/0x1b0 [<ffffffff811b26fc>] bio_integrity_prep+0xac/0x360 [<ffffffff8111e298>] ? mempool_alloc+0x58/0x150 [<ffffffffa03e8041>] ? alloc_extent_state+0x31/0x110 [btrfs] [<ffffffff81241579>] blk_queue_bio+0x1c9/0x460 [<ffffffff8123e58a>] generic_make_request+0xca/0x100 [<ffffffff8123e639>] submit_bio+0x79/0x160 [<ffffffffa03f865e>] btrfs_map_bio+0x48e/0x5b0 [btrfs] [<ffffffffa03c821a>] btree_submit_bio_hook+0xda/0x110 [btrfs] [<ffffffffa03e7eba>] submit_one_bio+0x6a/0xa0 [btrfs] [<ffffffffa03ef450>] read_extent_buffer_pages+0x250/0x310 [btrfs] [<ffffffff8125eef6>] ? __radix_tree_preload+0x66/0xf0 [<ffffffff8125f1c5>] ? radix_tree_insert+0x95/0x260 [<ffffffffa03c66f6>] btree_read_extent_buffer_pages.constprop.128+0xb6/0x120 [btrfs] [<ffffffffa03c8c1a>] read_tree_block+0x3a/0x60 [btrfs] [<ffffffffa03caefd>] open_ctree+0x139d/0x2030 [btrfs] [<ffffffffa03a282a>] btrfs_mount+0x53a/0x7d0 [btrfs] [<ffffffff8113ab0b>] ? pcpu_alloc+0x8eb/0x9f0 [<ffffffff81167305>] ? __kmalloc_track_caller+0x35/0x1e0 [<ffffffff81176ba0>] mount_fs+0x20/0xd0 [<ffffffff81191096>] vfs_kern_mount+0x76/0x120 [<ffffffff81193320>] do_mount+0x200/0xa40 [<ffffffff81135cdb>] ? strndup_user+0x5b/0x80 [<ffffffff81193bf0>] SyS_mount+0x90/0xe0 [<ffffffff8156d31d>] system_call_fastpath+0x1a/0x1f Code: 4c 8d 75 a8 4c 89 6d e8 45 89 e0 4c 8d 6f 30 48 89 5d d8 41 83 e0 af 48 89 fb 49 83 c6 18 4c 89 7d f8 65 4c 8b 3c 25 c0 b8 00 00 <48> 8b 73 18 44 89 c7 44 89 45 98 ff 53 20 48 85 c0 48 89 c2 74 RIP [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150 RSP <ffff880230699688> CR2: 0000000000000018 ---[ end trace 7a96042017ed21e2 ]--- Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-09-20 03:37:07 +00:00
goto free_bioset;
return 0;
btrfs: Fix crash due to not allocating integrity data for a bioset When btrfs creates a bioset, we must also allocate the integrity data pool. Otherwise btrfs will crash when it tries to submit a bio to a checksumming disk: BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 IP: [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150 PGD 2305e4067 PUD 23063d067 PMD 0 Oops: 0000 [#1] PREEMPT SMP Modules linked in: btrfs scsi_debug xfs ext4 jbd2 ext3 jbd mbcache sch_fq_codel eeprom lpc_ich mfd_core nfsd exportfs auth_rpcgss af_packet raid6_pq xor zlib_deflate libcrc32c [last unloaded: scsi_debug] CPU: 1 PID: 4486 Comm: mount Not tainted 3.12.0-rc1-mcsum #2 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 task: ffff8802451c9720 ti: ffff880230698000 task.ti: ffff880230698000 RIP: 0010:[<ffffffff8111e28a>] [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150 RSP: 0018:ffff880230699688 EFLAGS: 00010286 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 00000000005f8445 RDX: 0000000000000001 RSI: 0000000000000010 RDI: 0000000000000000 RBP: ffff8802306996f8 R08: 0000000000011200 R09: 0000000000000008 R10: 0000000000000020 R11: ffff88009d6e8000 R12: 0000000000011210 R13: 0000000000000030 R14: ffff8802306996b8 R15: ffff8802451c9720 FS: 00007f25b8a16800(0000) GS:ffff88024fc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000018 CR3: 0000000230576000 CR4: 00000000000007e0 Stack: ffff8802451c9720 0000000000000002 ffffffff81a97100 0000000000281250 ffffffff81a96480 ffff88024fc99150 ffff880228d18200 0000000000000000 0000000000000000 0000000000000040 ffff880230e8c2e8 ffff8802459dc900 Call Trace: [<ffffffff811b2208>] bio_integrity_alloc+0x48/0x1b0 [<ffffffff811b26fc>] bio_integrity_prep+0xac/0x360 [<ffffffff8111e298>] ? mempool_alloc+0x58/0x150 [<ffffffffa03e8041>] ? alloc_extent_state+0x31/0x110 [btrfs] [<ffffffff81241579>] blk_queue_bio+0x1c9/0x460 [<ffffffff8123e58a>] generic_make_request+0xca/0x100 [<ffffffff8123e639>] submit_bio+0x79/0x160 [<ffffffffa03f865e>] btrfs_map_bio+0x48e/0x5b0 [btrfs] [<ffffffffa03c821a>] btree_submit_bio_hook+0xda/0x110 [btrfs] [<ffffffffa03e7eba>] submit_one_bio+0x6a/0xa0 [btrfs] [<ffffffffa03ef450>] read_extent_buffer_pages+0x250/0x310 [btrfs] [<ffffffff8125eef6>] ? __radix_tree_preload+0x66/0xf0 [<ffffffff8125f1c5>] ? radix_tree_insert+0x95/0x260 [<ffffffffa03c66f6>] btree_read_extent_buffer_pages.constprop.128+0xb6/0x120 [btrfs] [<ffffffffa03c8c1a>] read_tree_block+0x3a/0x60 [btrfs] [<ffffffffa03caefd>] open_ctree+0x139d/0x2030 [btrfs] [<ffffffffa03a282a>] btrfs_mount+0x53a/0x7d0 [btrfs] [<ffffffff8113ab0b>] ? pcpu_alloc+0x8eb/0x9f0 [<ffffffff81167305>] ? __kmalloc_track_caller+0x35/0x1e0 [<ffffffff81176ba0>] mount_fs+0x20/0xd0 [<ffffffff81191096>] vfs_kern_mount+0x76/0x120 [<ffffffff81193320>] do_mount+0x200/0xa40 [<ffffffff81135cdb>] ? strndup_user+0x5b/0x80 [<ffffffff81193bf0>] SyS_mount+0x90/0xe0 [<ffffffff8156d31d>] system_call_fastpath+0x1a/0x1f Code: 4c 8d 75 a8 4c 89 6d e8 45 89 e0 4c 8d 6f 30 48 89 5d d8 41 83 e0 af 48 89 fb 49 83 c6 18 4c 89 7d f8 65 4c 8b 3c 25 c0 b8 00 00 <48> 8b 73 18 44 89 c7 44 89 45 98 ff 53 20 48 85 c0 48 89 c2 74 RIP [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150 RSP <ffff880230699688> CR2: 0000000000000018 ---[ end trace 7a96042017ed21e2 ]--- Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-09-20 03:37:07 +00:00
free_bioset:
bioset_exit(&btrfs_bioset);
btrfs: Fix crash due to not allocating integrity data for a bioset When btrfs creates a bioset, we must also allocate the integrity data pool. Otherwise btrfs will crash when it tries to submit a bio to a checksumming disk: BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 IP: [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150 PGD 2305e4067 PUD 23063d067 PMD 0 Oops: 0000 [#1] PREEMPT SMP Modules linked in: btrfs scsi_debug xfs ext4 jbd2 ext3 jbd mbcache sch_fq_codel eeprom lpc_ich mfd_core nfsd exportfs auth_rpcgss af_packet raid6_pq xor zlib_deflate libcrc32c [last unloaded: scsi_debug] CPU: 1 PID: 4486 Comm: mount Not tainted 3.12.0-rc1-mcsum #2 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 task: ffff8802451c9720 ti: ffff880230698000 task.ti: ffff880230698000 RIP: 0010:[<ffffffff8111e28a>] [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150 RSP: 0018:ffff880230699688 EFLAGS: 00010286 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 00000000005f8445 RDX: 0000000000000001 RSI: 0000000000000010 RDI: 0000000000000000 RBP: ffff8802306996f8 R08: 0000000000011200 R09: 0000000000000008 R10: 0000000000000020 R11: ffff88009d6e8000 R12: 0000000000011210 R13: 0000000000000030 R14: ffff8802306996b8 R15: ffff8802451c9720 FS: 00007f25b8a16800(0000) GS:ffff88024fc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000018 CR3: 0000000230576000 CR4: 00000000000007e0 Stack: ffff8802451c9720 0000000000000002 ffffffff81a97100 0000000000281250 ffffffff81a96480 ffff88024fc99150 ffff880228d18200 0000000000000000 0000000000000000 0000000000000040 ffff880230e8c2e8 ffff8802459dc900 Call Trace: [<ffffffff811b2208>] bio_integrity_alloc+0x48/0x1b0 [<ffffffff811b26fc>] bio_integrity_prep+0xac/0x360 [<ffffffff8111e298>] ? mempool_alloc+0x58/0x150 [<ffffffffa03e8041>] ? alloc_extent_state+0x31/0x110 [btrfs] [<ffffffff81241579>] blk_queue_bio+0x1c9/0x460 [<ffffffff8123e58a>] generic_make_request+0xca/0x100 [<ffffffff8123e639>] submit_bio+0x79/0x160 [<ffffffffa03f865e>] btrfs_map_bio+0x48e/0x5b0 [btrfs] [<ffffffffa03c821a>] btree_submit_bio_hook+0xda/0x110 [btrfs] [<ffffffffa03e7eba>] submit_one_bio+0x6a/0xa0 [btrfs] [<ffffffffa03ef450>] read_extent_buffer_pages+0x250/0x310 [btrfs] [<ffffffff8125eef6>] ? __radix_tree_preload+0x66/0xf0 [<ffffffff8125f1c5>] ? radix_tree_insert+0x95/0x260 [<ffffffffa03c66f6>] btree_read_extent_buffer_pages.constprop.128+0xb6/0x120 [btrfs] [<ffffffffa03c8c1a>] read_tree_block+0x3a/0x60 [btrfs] [<ffffffffa03caefd>] open_ctree+0x139d/0x2030 [btrfs] [<ffffffffa03a282a>] btrfs_mount+0x53a/0x7d0 [btrfs] [<ffffffff8113ab0b>] ? pcpu_alloc+0x8eb/0x9f0 [<ffffffff81167305>] ? __kmalloc_track_caller+0x35/0x1e0 [<ffffffff81176ba0>] mount_fs+0x20/0xd0 [<ffffffff81191096>] vfs_kern_mount+0x76/0x120 [<ffffffff81193320>] do_mount+0x200/0xa40 [<ffffffff81135cdb>] ? strndup_user+0x5b/0x80 [<ffffffff81193bf0>] SyS_mount+0x90/0xe0 [<ffffffff8156d31d>] system_call_fastpath+0x1a/0x1f Code: 4c 8d 75 a8 4c 89 6d e8 45 89 e0 4c 8d 6f 30 48 89 5d d8 41 83 e0 af 48 89 fb 49 83 c6 18 4c 89 7d f8 65 4c 8b 3c 25 c0 b8 00 00 <48> 8b 73 18 44 89 c7 44 89 45 98 ff 53 20 48 85 c0 48 89 c2 74 RIP [<ffffffff8111e28a>] mempool_alloc+0x4a/0x150 RSP <ffff880230699688> CR2: 0000000000000018 ---[ end trace 7a96042017ed21e2 ]--- Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-09-20 03:37:07 +00:00
free_buffer_cache:
kmem_cache_destroy(extent_buffer_cache);
extent_buffer_cache = NULL;
return -ENOMEM;
}
void __cold extent_state_cache_exit(void)
{
btrfs_extent_state_leak_debug_check();
kmem_cache_destroy(extent_state_cache);
}
void __cold extent_io_exit(void)
{
/*
* Make sure all delayed rcu free are flushed before we
* destroy caches.
*/
rcu_barrier();
kmem_cache_destroy(extent_buffer_cache);
bioset_exit(&btrfs_bioset);
}
/*
* For the file_extent_tree, we want to hold the inode lock when we lookup and
* update the disk_i_size, but lockdep will complain because our io_tree we hold
* the tree lock and get the inode lock when setting delalloc. These two things
* are unrelated, so make a class for the file_extent_tree so we don't get the
* two locking patterns mixed up.
*/
static struct lock_class_key file_extent_tree_class;
void extent_io_tree_init(struct btrfs_fs_info *fs_info,
struct extent_io_tree *tree, unsigned int owner,
void *private_data)
{
tree->fs_info = fs_info;
tree->state = RB_ROOT;
tree->dirty_bytes = 0;
spin_lock_init(&tree->lock);
tree->private_data = private_data;
tree->owner = owner;
if (owner == IO_TREE_INODE_FILE_EXTENT)
lockdep_set_class(&tree->lock, &file_extent_tree_class);
}
void extent_io_tree_release(struct extent_io_tree *tree)
{
spin_lock(&tree->lock);
/*
* Do a single barrier for the waitqueue_active check here, the state
* of the waitqueue should not change once extent_io_tree_release is
* called.
*/
smp_mb();
while (!RB_EMPTY_ROOT(&tree->state)) {
struct rb_node *node;
struct extent_state *state;
node = rb_first(&tree->state);
state = rb_entry(node, struct extent_state, rb_node);
rb_erase(&state->rb_node, &tree->state);
RB_CLEAR_NODE(&state->rb_node);
/*
* btree io trees aren't supposed to have tasks waiting for
* changes in the flags of extent states ever.
*/
ASSERT(!waitqueue_active(&state->wq));
free_extent_state(state);
cond_resched_lock(&tree->lock);
}
spin_unlock(&tree->lock);
}
static struct extent_state *alloc_extent_state(gfp_t mask)
{
struct extent_state *state;
/*
* The given mask might be not appropriate for the slab allocator,
* drop the unsupported bits
*/
mask &= ~(__GFP_DMA32|__GFP_HIGHMEM);
state = kmem_cache_alloc(extent_state_cache, mask);
if (!state)
return state;
state->state = 0;
state->failrec = NULL;
RB_CLEAR_NODE(&state->rb_node);
btrfs_leak_debug_add(&leak_lock, &state->leak_list, &states);
refcount_set(&state->refs, 1);
init_waitqueue_head(&state->wq);
trace_alloc_extent_state(state, mask, _RET_IP_);
return state;
}
void free_extent_state(struct extent_state *state)
{
if (!state)
return;
if (refcount_dec_and_test(&state->refs)) {
WARN_ON(extent_state_in_tree(state));
btrfs_leak_debug_del(&leak_lock, &state->leak_list);
trace_free_extent_state(state, _RET_IP_);
kmem_cache_free(extent_state_cache, state);
}
}
static struct rb_node *tree_insert(struct rb_root *root,
struct rb_node *search_start,
u64 offset,
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
struct rb_node *node,
struct rb_node ***p_in,
struct rb_node **parent_in)
{
struct rb_node **p;
struct rb_node *parent = NULL;
struct tree_entry *entry;
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
if (p_in && parent_in) {
p = *p_in;
parent = *parent_in;
goto do_insert;
}
p = search_start ? &search_start : &root->rb_node;
while (*p) {
parent = *p;
entry = rb_entry(parent, struct tree_entry, rb_node);
if (offset < entry->start)
p = &(*p)->rb_left;
else if (offset > entry->end)
p = &(*p)->rb_right;
else
return parent;
}
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
do_insert:
rb_link_node(node, parent, p);
rb_insert_color(node, root);
return NULL;
}
/**
btrfs: fix parameter description for functions in extent_io.c This makes the file W=1 clean and fixes the following warnings: fs/btrfs/extent_io.c:414: warning: Function parameter or member 'tree' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'offset' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'next_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'prev_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'p_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'parent_ret' not described in '__etree_search' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'tree' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start_ret' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'end_ret' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'bits' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'tree' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start_ret' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'end_ret' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'bits' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:4187: warning: Function parameter or member 'epd' not described in 'extent_write_cache_pages' fs/btrfs/extent_io.c:4187: warning: Excess function parameter 'data' description in 'extent_write_cache_pages' Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-22 09:58:03 +00:00
* Search @tree for an entry that contains @offset. Such entry would have
* entry->start <= offset && entry->end >= offset.
*
btrfs: fix parameter description for functions in extent_io.c This makes the file W=1 clean and fixes the following warnings: fs/btrfs/extent_io.c:414: warning: Function parameter or member 'tree' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'offset' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'next_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'prev_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'p_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'parent_ret' not described in '__etree_search' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'tree' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start_ret' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'end_ret' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'bits' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'tree' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start_ret' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'end_ret' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'bits' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:4187: warning: Function parameter or member 'epd' not described in 'extent_write_cache_pages' fs/btrfs/extent_io.c:4187: warning: Excess function parameter 'data' description in 'extent_write_cache_pages' Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-22 09:58:03 +00:00
* @tree: the tree to search
* @offset: offset that should fall within an entry in @tree
* @next_ret: pointer to the first entry whose range ends after @offset
* @prev_ret: pointer to the first entry whose range begins before @offset
* @p_ret: pointer where new node should be anchored (used when inserting an
* entry in the tree)
* @parent_ret: points to entry which would have been the parent of the entry,
* containing @offset
*
* This function returns a pointer to the entry that contains @offset byte
* address. If no such entry exists, then NULL is returned and the other
* pointer arguments to the function are filled, otherwise the found entry is
* returned and other pointers are left untouched.
*/
static struct rb_node *__etree_search(struct extent_io_tree *tree, u64 offset,
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
struct rb_node **next_ret,
struct rb_node **prev_ret,
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
struct rb_node ***p_ret,
struct rb_node **parent_ret)
{
struct rb_root *root = &tree->state;
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
struct rb_node **n = &root->rb_node;
struct rb_node *prev = NULL;
struct rb_node *orig_prev = NULL;
struct tree_entry *entry;
struct tree_entry *prev_entry = NULL;
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
while (*n) {
prev = *n;
entry = rb_entry(prev, struct tree_entry, rb_node);
prev_entry = entry;
if (offset < entry->start)
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
n = &(*n)->rb_left;
else if (offset > entry->end)
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
n = &(*n)->rb_right;
else
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
return *n;
}
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
if (p_ret)
*p_ret = n;
if (parent_ret)
*parent_ret = prev;
if (next_ret) {
orig_prev = prev;
while (prev && offset > prev_entry->end) {
prev = rb_next(prev);
prev_entry = rb_entry(prev, struct tree_entry, rb_node);
}
*next_ret = prev;
prev = orig_prev;
}
if (prev_ret) {
prev_entry = rb_entry(prev, struct tree_entry, rb_node);
while (prev && offset < prev_entry->start) {
prev = rb_prev(prev);
prev_entry = rb_entry(prev, struct tree_entry, rb_node);
}
*prev_ret = prev;
}
return NULL;
}
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
static inline struct rb_node *
tree_search_for_insert(struct extent_io_tree *tree,
u64 offset,
struct rb_node ***p_ret,
struct rb_node **parent_ret)
{
struct rb_node *next= NULL;
struct rb_node *ret;
ret = __etree_search(tree, offset, &next, NULL, p_ret, parent_ret);
if (!ret)
return next;
return ret;
}
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
static inline struct rb_node *tree_search(struct extent_io_tree *tree,
u64 offset)
{
return tree_search_for_insert(tree, offset, NULL, NULL);
}
/*
* utility function to look for merge candidates inside a given range.
* Any extents with matching state are merged together into a single
* extent in the tree. Extents with EXTENT_IO in their state field
* are not merged because the end_io handlers need to be able to do
* operations on them without sleeping (or doing allocations/splits).
*
* This should be called with the tree lock held.
*/
static void merge_state(struct extent_io_tree *tree,
struct extent_state *state)
{
struct extent_state *other;
struct rb_node *other_node;
if (state->state & (EXTENT_LOCKED | EXTENT_BOUNDARY))
return;
other_node = rb_prev(&state->rb_node);
if (other_node) {
other = rb_entry(other_node, struct extent_state, rb_node);
if (other->end == state->start - 1 &&
other->state == state->state) {
if (tree->private_data &&
is_data_inode(tree->private_data))
btrfs_merge_delalloc_extent(tree->private_data,
state, other);
state->start = other->start;
rb_erase(&other->rb_node, &tree->state);
RB_CLEAR_NODE(&other->rb_node);
free_extent_state(other);
}
}
other_node = rb_next(&state->rb_node);
if (other_node) {
other = rb_entry(other_node, struct extent_state, rb_node);
if (other->start == state->end + 1 &&
other->state == state->state) {
if (tree->private_data &&
is_data_inode(tree->private_data))
btrfs_merge_delalloc_extent(tree->private_data,
state, other);
state->end = other->end;
rb_erase(&other->rb_node, &tree->state);
RB_CLEAR_NODE(&other->rb_node);
free_extent_state(other);
}
}
}
static void set_state_bits(struct extent_io_tree *tree,
struct extent_state *state, u32 *bits,
struct extent_changeset *changeset);
/*
* insert an extent_state struct into the tree. 'bits' are set on the
* struct before it is inserted.
*
* This may return -EEXIST if the extent is already there, in which case the
* state struct is freed.
*
* The tree lock is not taken internally. This is a utility function and
* probably isn't what you want to call (see set/clear_extent_bit).
*/
static int insert_state(struct extent_io_tree *tree,
struct extent_state *state, u64 start, u64 end,
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
struct rb_node ***p,
struct rb_node **parent,
u32 *bits, struct extent_changeset *changeset)
{
struct rb_node *node;
if (end < start) {
btrfs_err(tree->fs_info,
"insert state: end < start %llu %llu", end, start);
WARN_ON(1);
}
state->start = start;
state->end = end;
Btrfs: proper -ENOSPC handling At the start of a transaction we do a btrfs_reserve_metadata_space() and specify how many items we plan on modifying. Then once we've done our modifications and such, just call btrfs_unreserve_metadata_space() for the same number of items we reserved. For keeping track of metadata needed for data I've had to add an extent_io op for when we merge extents. This lets us track space properly when we are doing sequential writes, so we don't end up reserving way more metadata space than what we need. The only place where the metadata space accounting is not done is in the relocation code. This is because Yan is going to be reworking that code in the near future, so running btrfs-vol -b could still possibly result in a ENOSPC related panic. This patch also turns off the metadata_ratio stuff in order to allow users to more efficiently use their disk space. This patch makes it so we track how much metadata we need for an inode's delayed allocation extents by tracking how many extents are currently waiting for allocation. It introduces two new callbacks for the extent_io tree's, merge_extent_hook and split_extent_hook. These help us keep track of when we merge delalloc extents together and split them up. Reservations are handled prior to any actually dirty'ing occurs, and then we unreserve after we dirty. btrfs_unreserve_metadata_for_delalloc() will make the appropriate unreservations as needed based on the number of reservations we currently have and the number of extents we currently have. Doing the reservation outside of doing any of the actual dirty'ing lets us do things like filemap_flush() the inode to try and force delalloc to happen, or as a last resort actually start allocation on all delalloc inodes in the fs. This has survived dbench, fs_mark and an fsx torture test. Signed-off-by: Josef Bacik <jbacik@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:12:44 +00:00
set_state_bits(tree, state, bits, changeset);
node = tree_insert(&tree->state, NULL, end, &state->rb_node, p, parent);
if (node) {
struct extent_state *found;
found = rb_entry(node, struct extent_state, rb_node);
btrfs_err(tree->fs_info,
"found node %llu %llu on insert of %llu %llu",
found->start, found->end, start, end);
return -EEXIST;
}
merge_state(tree, state);
return 0;
}
/*
* split a given extent state struct in two, inserting the preallocated
* struct 'prealloc' as the newly created second half. 'split' indicates an
* offset inside 'orig' where it should be split.
*
* Before calling,
* the tree has 'orig' at [orig->start, orig->end]. After calling, there
* are two extent state structs in the tree:
* prealloc: [orig->start, split - 1]
* orig: [ split, orig->end ]
*
* The tree locks are not taken by this function. They need to be held
* by the caller.
*/
static int split_state(struct extent_io_tree *tree, struct extent_state *orig,
struct extent_state *prealloc, u64 split)
{
struct rb_node *node;
Btrfs: proper -ENOSPC handling At the start of a transaction we do a btrfs_reserve_metadata_space() and specify how many items we plan on modifying. Then once we've done our modifications and such, just call btrfs_unreserve_metadata_space() for the same number of items we reserved. For keeping track of metadata needed for data I've had to add an extent_io op for when we merge extents. This lets us track space properly when we are doing sequential writes, so we don't end up reserving way more metadata space than what we need. The only place where the metadata space accounting is not done is in the relocation code. This is because Yan is going to be reworking that code in the near future, so running btrfs-vol -b could still possibly result in a ENOSPC related panic. This patch also turns off the metadata_ratio stuff in order to allow users to more efficiently use their disk space. This patch makes it so we track how much metadata we need for an inode's delayed allocation extents by tracking how many extents are currently waiting for allocation. It introduces two new callbacks for the extent_io tree's, merge_extent_hook and split_extent_hook. These help us keep track of when we merge delalloc extents together and split them up. Reservations are handled prior to any actually dirty'ing occurs, and then we unreserve after we dirty. btrfs_unreserve_metadata_for_delalloc() will make the appropriate unreservations as needed based on the number of reservations we currently have and the number of extents we currently have. Doing the reservation outside of doing any of the actual dirty'ing lets us do things like filemap_flush() the inode to try and force delalloc to happen, or as a last resort actually start allocation on all delalloc inodes in the fs. This has survived dbench, fs_mark and an fsx torture test. Signed-off-by: Josef Bacik <jbacik@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:12:44 +00:00
if (tree->private_data && is_data_inode(tree->private_data))
btrfs_split_delalloc_extent(tree->private_data, orig, split);
Btrfs: proper -ENOSPC handling At the start of a transaction we do a btrfs_reserve_metadata_space() and specify how many items we plan on modifying. Then once we've done our modifications and such, just call btrfs_unreserve_metadata_space() for the same number of items we reserved. For keeping track of metadata needed for data I've had to add an extent_io op for when we merge extents. This lets us track space properly when we are doing sequential writes, so we don't end up reserving way more metadata space than what we need. The only place where the metadata space accounting is not done is in the relocation code. This is because Yan is going to be reworking that code in the near future, so running btrfs-vol -b could still possibly result in a ENOSPC related panic. This patch also turns off the metadata_ratio stuff in order to allow users to more efficiently use their disk space. This patch makes it so we track how much metadata we need for an inode's delayed allocation extents by tracking how many extents are currently waiting for allocation. It introduces two new callbacks for the extent_io tree's, merge_extent_hook and split_extent_hook. These help us keep track of when we merge delalloc extents together and split them up. Reservations are handled prior to any actually dirty'ing occurs, and then we unreserve after we dirty. btrfs_unreserve_metadata_for_delalloc() will make the appropriate unreservations as needed based on the number of reservations we currently have and the number of extents we currently have. Doing the reservation outside of doing any of the actual dirty'ing lets us do things like filemap_flush() the inode to try and force delalloc to happen, or as a last resort actually start allocation on all delalloc inodes in the fs. This has survived dbench, fs_mark and an fsx torture test. Signed-off-by: Josef Bacik <jbacik@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:12:44 +00:00
prealloc->start = orig->start;
prealloc->end = split - 1;
prealloc->state = orig->state;
orig->start = split;
node = tree_insert(&tree->state, &orig->rb_node, prealloc->end,
&prealloc->rb_node, NULL, NULL);
if (node) {
free_extent_state(prealloc);
return -EEXIST;
}
return 0;
}
static struct extent_state *next_state(struct extent_state *state)
{
struct rb_node *next = rb_next(&state->rb_node);
if (next)
return rb_entry(next, struct extent_state, rb_node);
else
return NULL;
}
/*
* utility function to clear some bits in an extent state struct.
* it will optionally wake up anyone waiting on this state (wake == 1).
*
* If no bits are set on the state struct after clearing things, the
* struct is freed and removed from the tree
*/
static struct extent_state *clear_state_bit(struct extent_io_tree *tree,
struct extent_state *state,
u32 *bits, int wake,
struct extent_changeset *changeset)
{
struct extent_state *next;
u32 bits_to_clear = *bits & ~EXTENT_CTLBITS;
int ret;
if ((bits_to_clear & EXTENT_DIRTY) && (state->state & EXTENT_DIRTY)) {
u64 range = state->end - state->start + 1;
WARN_ON(range > tree->dirty_bytes);
tree->dirty_bytes -= range;
}
if (tree->private_data && is_data_inode(tree->private_data))
btrfs_clear_delalloc_extent(tree->private_data, state, bits);
ret = add_extent_changeset(state, bits_to_clear, changeset, 0);
BUG_ON(ret < 0);
state->state &= ~bits_to_clear;
if (wake)
wake_up(&state->wq);
if (state->state == 0) {
next = next_state(state);
if (extent_state_in_tree(state)) {
rb_erase(&state->rb_node, &tree->state);
RB_CLEAR_NODE(&state->rb_node);
free_extent_state(state);
} else {
WARN_ON(1);
}
} else {
merge_state(tree, state);
next = next_state(state);
}
return next;
}
static struct extent_state *
alloc_extent_state_atomic(struct extent_state *prealloc)
{
if (!prealloc)
prealloc = alloc_extent_state(GFP_ATOMIC);
return prealloc;
}
static void extent_io_tree_panic(struct extent_io_tree *tree, int err)
{
btrfs_panic(tree->fs_info, err,
"locking error: extent tree was modified by another thread while locked");
}
/*
* clear some bits on a range in the tree. This may require splitting
* or inserting elements in the tree, so the gfp mask is used to
* indicate which allocations or sleeping are allowed.
*
* pass 'wake' == 1 to kick any sleepers, and 'delete' == 1 to remove
* the given range from the tree regardless of state (ie for truncate).
*
* the range [start, end] is inclusive.
*
* This takes the tree lock, and returns 0 on success and < 0 on error.
*/
int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
u32 bits, int wake, int delete,
struct extent_state **cached_state,
gfp_t mask, struct extent_changeset *changeset)
{
struct extent_state *state;
struct extent_state *cached;
struct extent_state *prealloc = NULL;
struct rb_node *node;
u64 last_end;
int err;
int clear = 0;
btrfs_debug_check_extent_io_range(tree, start, end);
btrfs: tracepoints: Add trace events for extent_io_tree Although btrfs heavily relies on extent_io_tree, we don't really have any good trace events for them. This patch will add the folowing trace events: - trace_btrfs_set_extent_bit() - trace_btrfs_clear_extent_bit() - trace_btrfs_convert_extent_bit() Since selftests could create temporary extent_io_tree without fs_info, modify TP_fast_assign_fsid() to accept NULL as fs_info. NULL fs_info will lead to all zero fsid. The output would be: btrfs_set_extent_bit: <FDID>: io_tree=INODE_IO ino=1 root=1 start=22036480 len=4096 set_bits=LOCKED btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22040576 len=4096 set_bits=LOCKED btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22044672 len=4096 set_bits=LOCKED btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22048768 len=4096 set_bits=LOCKED btrfs_clear_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22036480 len=16384 clear_bits=LOCKED ^^^ Extent buffer 22036480 read from disk, the locking progress btrfs_set_extent_bit: <FSID>: io_tree=TRANS_DIRTY_PAGES ino=1 root=1 start=30425088 len=16384 set_bits=DIRTY btrfs_set_extent_bit: <FSID>: io_tree=TRANS_DIRTY_PAGES ino=1 root=1 start=30441472 len=16384 set_bits=DIRTY ^^^ 2 new tree blocks allocated in one transaction btrfs_set_extent_bit: <FSID>: io_tree=FREED_EXTENTS0 ino=0 root=0 start=30523392 len=16384 set_bits=DIRTY btrfs_set_extent_bit: <FSID>: io_tree=FREED_EXTENTS0 ino=0 root=0 start=30556160 len=16384 set_bits=DIRTY ^^^ 2 old tree blocks get pinned down There is one point which need attention: 1) Those trace events can be pretty heavy: The following workload would generate over 400 trace events. mkfs.btrfs -f $dev start_trace mount $dev $mnt -o enospc_debug sync touch $mnt/file1 touch $mnt/file2 touch $mnt/file3 xfs_io -f -c "pwrite 0 16k" $mnt/file4 umount $mnt end_trace It's not recommended to use them in real world environment. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ rename enums ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-03-01 02:48:00 +00:00
trace_btrfs_clear_extent_bit(tree, start, end - start + 1, bits);
if (bits & EXTENT_DELALLOC)
bits |= EXTENT_NORESERVE;
if (delete)
bits |= ~EXTENT_CTLBITS;
if (bits & (EXTENT_LOCKED | EXTENT_BOUNDARY))
clear = 1;
again:
mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd __GFP_WAIT has been used to identify atomic context in callers that hold spinlocks or are in interrupts. They are expected to be high priority and have access one of two watermarks lower than "min" which can be referred to as the "atomic reserve". __GFP_HIGH users get access to the first lower watermark and can be called the "high priority reserve". Over time, callers had a requirement to not block when fallback options were available. Some have abused __GFP_WAIT leading to a situation where an optimisitic allocation with a fallback option can access atomic reserves. This patch uses __GFP_ATOMIC to identify callers that are truely atomic, cannot sleep and have no alternative. High priority users continue to use __GFP_HIGH. __GFP_DIRECT_RECLAIM identifies callers that can sleep and are willing to enter direct reclaim. __GFP_KSWAPD_RECLAIM to identify callers that want to wake kswapd for background reclaim. __GFP_WAIT is redefined as a caller that is willing to enter direct reclaim and wake kswapd for background reclaim. This patch then converts a number of sites o __GFP_ATOMIC is used by callers that are high priority and have memory pools for those requests. GFP_ATOMIC uses this flag. o Callers that have a limited mempool to guarantee forward progress clear __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall into this category where kswapd will still be woken but atomic reserves are not used as there is a one-entry mempool to guarantee progress. o Callers that are checking if they are non-blocking should use the helper gfpflags_allow_blocking() where possible. This is because checking for __GFP_WAIT as was done historically now can trigger false positives. Some exceptions like dm-crypt.c exist where the code intent is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to flag manipulations. o Callers that built their own GFP flags instead of starting with GFP_KERNEL and friends now also need to specify __GFP_KSWAPD_RECLAIM. The first key hazard to watch out for is callers that removed __GFP_WAIT and was depending on access to atomic reserves for inconspicuous reasons. In some cases it may be appropriate for them to use __GFP_HIGH. The second key hazard is callers that assembled their own combination of GFP flags instead of starting with something like GFP_KERNEL. They may now wish to specify __GFP_KSWAPD_RECLAIM. It's almost certainly harmless if it's missed in most cases as other activity will wake kswapd. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-07 00:28:21 +00:00
if (!prealloc && gfpflags_allow_blocking(mask)) {
/*
* Don't care for allocation failure here because we might end
* up not needing the pre-allocated extent state at all, which
* is the case if we only have in the tree extent states that
* cover our input range and don't cover too any other range.
* If we end up needing a new extent state we allocate it later.
*/
prealloc = alloc_extent_state(mask);
}
spin_lock(&tree->lock);
if (cached_state) {
cached = *cached_state;
if (clear) {
*cached_state = NULL;
cached_state = NULL;
}
if (cached && extent_state_in_tree(cached) &&
cached->start <= start && cached->end > start) {
if (clear)
refcount_dec(&cached->refs);
state = cached;
goto hit_next;
}
if (clear)
free_extent_state(cached);
}
/*
* this search will find the extents that end after
* our range starts
*/
node = tree_search(tree, start);
if (!node)
goto out;
state = rb_entry(node, struct extent_state, rb_node);
hit_next:
if (state->start > end)
goto out;
WARN_ON(state->end < start);
last_end = state->end;
/* the state doesn't have the wanted bits, go ahead */
if (!(state->state & bits)) {
state = next_state(state);
goto next;
}
/*
* | ---- desired range ---- |
* | state | or
* | ------------- state -------------- |
*
* We need to split the extent we found, and may flip
* bits on second half.
*
* If the extent we found extends past our range, we
* just split and search again. It'll get split again
* the next time though.
*
* If the extent we found is inside our range, we clear
* the desired bit on it.
*/
if (state->start < start) {
prealloc = alloc_extent_state_atomic(prealloc);
BUG_ON(!prealloc);
err = split_state(tree, state, prealloc, start);
if (err)
extent_io_tree_panic(tree, err);
prealloc = NULL;
if (err)
goto out;
if (state->end <= end) {
state = clear_state_bit(tree, state, &bits, wake,
changeset);
goto next;
}
goto search_again;
}
/*
* | ---- desired range ---- |
* | state |
* We need to split the extent, and clear the bit
* on the first half
*/
if (state->start <= end && state->end > end) {
prealloc = alloc_extent_state_atomic(prealloc);
BUG_ON(!prealloc);
err = split_state(tree, state, prealloc, end + 1);
if (err)
extent_io_tree_panic(tree, err);
if (wake)
wake_up(&state->wq);
clear_state_bit(tree, prealloc, &bits, wake, changeset);
Btrfs: proper -ENOSPC handling At the start of a transaction we do a btrfs_reserve_metadata_space() and specify how many items we plan on modifying. Then once we've done our modifications and such, just call btrfs_unreserve_metadata_space() for the same number of items we reserved. For keeping track of metadata needed for data I've had to add an extent_io op for when we merge extents. This lets us track space properly when we are doing sequential writes, so we don't end up reserving way more metadata space than what we need. The only place where the metadata space accounting is not done is in the relocation code. This is because Yan is going to be reworking that code in the near future, so running btrfs-vol -b could still possibly result in a ENOSPC related panic. This patch also turns off the metadata_ratio stuff in order to allow users to more efficiently use their disk space. This patch makes it so we track how much metadata we need for an inode's delayed allocation extents by tracking how many extents are currently waiting for allocation. It introduces two new callbacks for the extent_io tree's, merge_extent_hook and split_extent_hook. These help us keep track of when we merge delalloc extents together and split them up. Reservations are handled prior to any actually dirty'ing occurs, and then we unreserve after we dirty. btrfs_unreserve_metadata_for_delalloc() will make the appropriate unreservations as needed based on the number of reservations we currently have and the number of extents we currently have. Doing the reservation outside of doing any of the actual dirty'ing lets us do things like filemap_flush() the inode to try and force delalloc to happen, or as a last resort actually start allocation on all delalloc inodes in the fs. This has survived dbench, fs_mark and an fsx torture test. Signed-off-by: Josef Bacik <jbacik@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:12:44 +00:00
prealloc = NULL;
goto out;
}
state = clear_state_bit(tree, state, &bits, wake, changeset);
next:
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
if (start <= end && state && !need_resched())
goto hit_next;
search_again:
if (start > end)
goto out;
spin_unlock(&tree->lock);
mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd __GFP_WAIT has been used to identify atomic context in callers that hold spinlocks or are in interrupts. They are expected to be high priority and have access one of two watermarks lower than "min" which can be referred to as the "atomic reserve". __GFP_HIGH users get access to the first lower watermark and can be called the "high priority reserve". Over time, callers had a requirement to not block when fallback options were available. Some have abused __GFP_WAIT leading to a situation where an optimisitic allocation with a fallback option can access atomic reserves. This patch uses __GFP_ATOMIC to identify callers that are truely atomic, cannot sleep and have no alternative. High priority users continue to use __GFP_HIGH. __GFP_DIRECT_RECLAIM identifies callers that can sleep and are willing to enter direct reclaim. __GFP_KSWAPD_RECLAIM to identify callers that want to wake kswapd for background reclaim. __GFP_WAIT is redefined as a caller that is willing to enter direct reclaim and wake kswapd for background reclaim. This patch then converts a number of sites o __GFP_ATOMIC is used by callers that are high priority and have memory pools for those requests. GFP_ATOMIC uses this flag. o Callers that have a limited mempool to guarantee forward progress clear __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall into this category where kswapd will still be woken but atomic reserves are not used as there is a one-entry mempool to guarantee progress. o Callers that are checking if they are non-blocking should use the helper gfpflags_allow_blocking() where possible. This is because checking for __GFP_WAIT as was done historically now can trigger false positives. Some exceptions like dm-crypt.c exist where the code intent is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to flag manipulations. o Callers that built their own GFP flags instead of starting with GFP_KERNEL and friends now also need to specify __GFP_KSWAPD_RECLAIM. The first key hazard to watch out for is callers that removed __GFP_WAIT and was depending on access to atomic reserves for inconspicuous reasons. In some cases it may be appropriate for them to use __GFP_HIGH. The second key hazard is callers that assembled their own combination of GFP flags instead of starting with something like GFP_KERNEL. They may now wish to specify __GFP_KSWAPD_RECLAIM. It's almost certainly harmless if it's missed in most cases as other activity will wake kswapd. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-07 00:28:21 +00:00
if (gfpflags_allow_blocking(mask))
cond_resched();
goto again;
out:
spin_unlock(&tree->lock);
if (prealloc)
free_extent_state(prealloc);
return 0;
}
static void wait_on_state(struct extent_io_tree *tree,
struct extent_state *state)
__releases(tree->lock)
__acquires(tree->lock)
{
DEFINE_WAIT(wait);
prepare_to_wait(&state->wq, &wait, TASK_UNINTERRUPTIBLE);
spin_unlock(&tree->lock);
schedule();
spin_lock(&tree->lock);
finish_wait(&state->wq, &wait);
}
/*
* waits for one or more bits to clear on a range in the state tree.
* The range [start, end] is inclusive.
* The tree lock is taken by this function
*/
static void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
u32 bits)
{
struct extent_state *state;
struct rb_node *node;
btrfs_debug_check_extent_io_range(tree, start, end);
spin_lock(&tree->lock);
again:
while (1) {
/*
* this search will find all the extents that end after
* our range starts
*/
node = tree_search(tree, start);
process_node:
if (!node)
break;
state = rb_entry(node, struct extent_state, rb_node);
if (state->start > end)
goto out;
if (state->state & bits) {
start = state->start;
refcount_inc(&state->refs);
wait_on_state(tree, state);
free_extent_state(state);
goto again;
}
start = state->end + 1;
if (start > end)
break;
if (!cond_resched_lock(&tree->lock)) {
node = rb_next(node);
goto process_node;
}
}
out:
spin_unlock(&tree->lock);
}
static void set_state_bits(struct extent_io_tree *tree,
struct extent_state *state,
u32 *bits, struct extent_changeset *changeset)
{
u32 bits_to_set = *bits & ~EXTENT_CTLBITS;
int ret;
Btrfs: proper -ENOSPC handling At the start of a transaction we do a btrfs_reserve_metadata_space() and specify how many items we plan on modifying. Then once we've done our modifications and such, just call btrfs_unreserve_metadata_space() for the same number of items we reserved. For keeping track of metadata needed for data I've had to add an extent_io op for when we merge extents. This lets us track space properly when we are doing sequential writes, so we don't end up reserving way more metadata space than what we need. The only place where the metadata space accounting is not done is in the relocation code. This is because Yan is going to be reworking that code in the near future, so running btrfs-vol -b could still possibly result in a ENOSPC related panic. This patch also turns off the metadata_ratio stuff in order to allow users to more efficiently use their disk space. This patch makes it so we track how much metadata we need for an inode's delayed allocation extents by tracking how many extents are currently waiting for allocation. It introduces two new callbacks for the extent_io tree's, merge_extent_hook and split_extent_hook. These help us keep track of when we merge delalloc extents together and split them up. Reservations are handled prior to any actually dirty'ing occurs, and then we unreserve after we dirty. btrfs_unreserve_metadata_for_delalloc() will make the appropriate unreservations as needed based on the number of reservations we currently have and the number of extents we currently have. Doing the reservation outside of doing any of the actual dirty'ing lets us do things like filemap_flush() the inode to try and force delalloc to happen, or as a last resort actually start allocation on all delalloc inodes in the fs. This has survived dbench, fs_mark and an fsx torture test. Signed-off-by: Josef Bacik <jbacik@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:12:44 +00:00
if (tree->private_data && is_data_inode(tree->private_data))
btrfs_set_delalloc_extent(tree->private_data, state, bits);
if ((bits_to_set & EXTENT_DIRTY) && !(state->state & EXTENT_DIRTY)) {
u64 range = state->end - state->start + 1;
tree->dirty_bytes += range;
}
ret = add_extent_changeset(state, bits_to_set, changeset, 1);
BUG_ON(ret < 0);
state->state |= bits_to_set;
}
static void cache_state_if_flags(struct extent_state *state,
struct extent_state **cached_ptr,
unsigned flags)
{
if (cached_ptr && !(*cached_ptr)) {
if (!flags || (state->state & flags)) {
*cached_ptr = state;
refcount_inc(&state->refs);
}
}
}
static void cache_state(struct extent_state *state,
struct extent_state **cached_ptr)
{
return cache_state_if_flags(state, cached_ptr,
EXTENT_LOCKED | EXTENT_BOUNDARY);
}
/*
* set some bits on a range in the tree. This may require allocations or
* sleeping, so the gfp mask is used to indicate what is allowed.
*
* If any of the exclusive bits are set, this will fail with -EEXIST if some
* part of the range already has the desired bits set. The start of the
* existing range is returned in failed_start in this case.
*
* [start, end] is inclusive This takes the tree lock.
*/
int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, u32 bits,
u32 exclusive_bits, u64 *failed_start,
struct extent_state **cached_state, gfp_t mask,
struct extent_changeset *changeset)
{
struct extent_state *state;
struct extent_state *prealloc = NULL;
struct rb_node *node;
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
struct rb_node **p;
struct rb_node *parent;
int err = 0;
u64 last_start;
u64 last_end;
btrfs_debug_check_extent_io_range(tree, start, end);
btrfs: tracepoints: Add trace events for extent_io_tree Although btrfs heavily relies on extent_io_tree, we don't really have any good trace events for them. This patch will add the folowing trace events: - trace_btrfs_set_extent_bit() - trace_btrfs_clear_extent_bit() - trace_btrfs_convert_extent_bit() Since selftests could create temporary extent_io_tree without fs_info, modify TP_fast_assign_fsid() to accept NULL as fs_info. NULL fs_info will lead to all zero fsid. The output would be: btrfs_set_extent_bit: <FDID>: io_tree=INODE_IO ino=1 root=1 start=22036480 len=4096 set_bits=LOCKED btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22040576 len=4096 set_bits=LOCKED btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22044672 len=4096 set_bits=LOCKED btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22048768 len=4096 set_bits=LOCKED btrfs_clear_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22036480 len=16384 clear_bits=LOCKED ^^^ Extent buffer 22036480 read from disk, the locking progress btrfs_set_extent_bit: <FSID>: io_tree=TRANS_DIRTY_PAGES ino=1 root=1 start=30425088 len=16384 set_bits=DIRTY btrfs_set_extent_bit: <FSID>: io_tree=TRANS_DIRTY_PAGES ino=1 root=1 start=30441472 len=16384 set_bits=DIRTY ^^^ 2 new tree blocks allocated in one transaction btrfs_set_extent_bit: <FSID>: io_tree=FREED_EXTENTS0 ino=0 root=0 start=30523392 len=16384 set_bits=DIRTY btrfs_set_extent_bit: <FSID>: io_tree=FREED_EXTENTS0 ino=0 root=0 start=30556160 len=16384 set_bits=DIRTY ^^^ 2 old tree blocks get pinned down There is one point which need attention: 1) Those trace events can be pretty heavy: The following workload would generate over 400 trace events. mkfs.btrfs -f $dev start_trace mount $dev $mnt -o enospc_debug sync touch $mnt/file1 touch $mnt/file2 touch $mnt/file3 xfs_io -f -c "pwrite 0 16k" $mnt/file4 umount $mnt end_trace It's not recommended to use them in real world environment. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ rename enums ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-03-01 02:48:00 +00:00
trace_btrfs_set_extent_bit(tree, start, end - start + 1, bits);
if (exclusive_bits)
ASSERT(failed_start);
else
ASSERT(failed_start == NULL);
again:
mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd __GFP_WAIT has been used to identify atomic context in callers that hold spinlocks or are in interrupts. They are expected to be high priority and have access one of two watermarks lower than "min" which can be referred to as the "atomic reserve". __GFP_HIGH users get access to the first lower watermark and can be called the "high priority reserve". Over time, callers had a requirement to not block when fallback options were available. Some have abused __GFP_WAIT leading to a situation where an optimisitic allocation with a fallback option can access atomic reserves. This patch uses __GFP_ATOMIC to identify callers that are truely atomic, cannot sleep and have no alternative. High priority users continue to use __GFP_HIGH. __GFP_DIRECT_RECLAIM identifies callers that can sleep and are willing to enter direct reclaim. __GFP_KSWAPD_RECLAIM to identify callers that want to wake kswapd for background reclaim. __GFP_WAIT is redefined as a caller that is willing to enter direct reclaim and wake kswapd for background reclaim. This patch then converts a number of sites o __GFP_ATOMIC is used by callers that are high priority and have memory pools for those requests. GFP_ATOMIC uses this flag. o Callers that have a limited mempool to guarantee forward progress clear __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall into this category where kswapd will still be woken but atomic reserves are not used as there is a one-entry mempool to guarantee progress. o Callers that are checking if they are non-blocking should use the helper gfpflags_allow_blocking() where possible. This is because checking for __GFP_WAIT as was done historically now can trigger false positives. Some exceptions like dm-crypt.c exist where the code intent is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to flag manipulations. o Callers that built their own GFP flags instead of starting with GFP_KERNEL and friends now also need to specify __GFP_KSWAPD_RECLAIM. The first key hazard to watch out for is callers that removed __GFP_WAIT and was depending on access to atomic reserves for inconspicuous reasons. In some cases it may be appropriate for them to use __GFP_HIGH. The second key hazard is callers that assembled their own combination of GFP flags instead of starting with something like GFP_KERNEL. They may now wish to specify __GFP_KSWAPD_RECLAIM. It's almost certainly harmless if it's missed in most cases as other activity will wake kswapd. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-07 00:28:21 +00:00
if (!prealloc && gfpflags_allow_blocking(mask)) {
/*
* Don't care for allocation failure here because we might end
* up not needing the pre-allocated extent state at all, which
* is the case if we only have in the tree extent states that
* cover our input range and don't cover too any other range.
* If we end up needing a new extent state we allocate it later.
*/
prealloc = alloc_extent_state(mask);
}
spin_lock(&tree->lock);
if (cached_state && *cached_state) {
state = *cached_state;
if (state->start <= start && state->end > start &&
extent_state_in_tree(state)) {
node = &state->rb_node;
goto hit_next;
}
}
/*
* this search will find all the extents that end after
* our range starts.
*/
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
node = tree_search_for_insert(tree, start, &p, &parent);
if (!node) {
prealloc = alloc_extent_state_atomic(prealloc);
BUG_ON(!prealloc);
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
err = insert_state(tree, prealloc, start, end,
&p, &parent, &bits, changeset);
if (err)
extent_io_tree_panic(tree, err);
cache_state(prealloc, cached_state);
prealloc = NULL;
goto out;
}
state = rb_entry(node, struct extent_state, rb_node);
hit_next:
last_start = state->start;
last_end = state->end;
/*
* | ---- desired range ---- |
* | state |
*
* Just lock what we found and keep going
*/
if (state->start == start && state->end <= end) {
if (state->state & exclusive_bits) {
*failed_start = state->start;
err = -EEXIST;
goto out;
}
set_state_bits(tree, state, &bits, changeset);
cache_state(state, cached_state);
merge_state(tree, state);
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
state = next_state(state);
if (start < end && state && state->start == start &&
!need_resched())
goto hit_next;
goto search_again;
}
/*
* | ---- desired range ---- |
* | state |
* or
* | ------------- state -------------- |
*
* We need to split the extent we found, and may flip bits on
* second half.
*
* If the extent we found extends past our
* range, we just split and search again. It'll get split
* again the next time though.
*
* If the extent we found is inside our range, we set the
* desired bit on it.
*/
if (state->start < start) {
if (state->state & exclusive_bits) {
*failed_start = start;
err = -EEXIST;
goto out;
}
Btrfs: avoid unnecessary splits when setting bits on an extent io tree When attempting to set bits on a range of an exent io tree that already has those bits set we can end up splitting an extent state record, use the preallocated extent state record, insert it into the red black tree, do another search on the red black tree, merge the preallocated extent state record with the previous extent state record, remove that previous record from the red black tree and then free it. This is all unnecessary work that consumes time. This happens specifically at the following case at __set_extent_bit(): $ cat -n fs/btrfs/extent_io.c 957 static int __must_check 958 __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, (...) 1044 /* 1045 * | ---- desired range ---- | 1046 * | state | 1047 * or 1048 * | ------------- state -------------- | 1049 * (...) 1060 if (state->start < start) { 1061 if (state->state & exclusive_bits) { 1062 *failed_start = start; 1063 err = -EEXIST; 1064 goto out; 1065 } 1066 1067 prealloc = alloc_extent_state_atomic(prealloc); 1068 BUG_ON(!prealloc); 1069 err = split_state(tree, state, prealloc, start); 1070 if (err) 1071 extent_io_tree_panic(tree, err); 1072 1073 prealloc = NULL; So if our extent state represents a range from 0 to 1MiB for example, and we want to set bits in the range 128KiB to 256KiB for example, and that extent state record already has all those bits set, we end up splitting that record, so we end up with extent state records in the tree which represent the ranges from 0 to 128KiB and from 128KiB to 1MiB. This is temporary because a subsequent iteration in that function will end up merging the records. The splitting requires using the preallocated extent state record, so a future iteration that needs to do another split will need to allocate another extent state record in an atomic context, something not ideal that we try to avoid as much as possible. The splitting also requires an insertion in the red black tree, and a subsequent merge will require a deletion from the red black tree and freeing an extent state record. This change just skips the splitting of an extent state record when it already has all the bits the we need to set. Setting a bit that is already set for a range is very common in the inode's 'file_extent_tree' extent io tree for example, where we keep setting the EXTENT_DIRTY bit every time we replace an extent. This change also fixes a bug that happens after the recent patchset from Josef that avoids having implicit holes after a power failure when not using the NO_HOLES feature, more specifically the patch with the subject: "btrfs: introduce the inode->file_extent_tree" This patch introduced an extent io tree per inode to keep track of completed ordered extents and figure out at any time what is the safe value for the inode's disk_i_size. This assumes that for contiguous ranges in a file we always end up with a single extent state record in the io tree, but that is not the case, as there is a short time window where we can have two extent state records representing contiguous ranges. When this happens we end setting up an incorrect value for the inode's disk_i_size, resulting in data loss after a clean unmount of the filesystem. The following example explains how this can happen. Suppose we have an inode with an i_size and a disk_i_size of 1MiB, so in the inode's file_extent_tree we have a single extent state record that represents the range [0, 1MiB) with the EXTENT_DIRTY bit set. Then the following steps happen: 1) A buffered write against file range [512KiB, 768KiB) is made. At this point delalloc was not flushed yet; 2) Deduplication from some other inode into this inode's range [128KiB, 256KiB) is made. This causes btrfs_inode_set_file_extent_range() to be called, from btrfs_insert_clone_extent(), to mark the range [128KiB, 256KiB) with EXTENT_DIRTY in the inode's file_extent_tree; 3) When btrfs_inode_set_file_extent_range() calls set_extent_bits(), we end up at __set_extent_bit(). In the first iteration of that function's loop we end up in the following branch: $ cat -n fs/btrfs/extent_io.c 957 static int __must_check 958 __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, (...) 1044 /* 1045 * | ---- desired range ---- | 1046 * | state | 1047 * or 1048 * | ------------- state -------------- | 1049 * (...) 1060 if (state->start < start) { 1061 if (state->state & exclusive_bits) { 1062 *failed_start = start; 1063 err = -EEXIST; 1064 goto out; 1065 } 1066 1067 prealloc = alloc_extent_state_atomic(prealloc); 1068 BUG_ON(!prealloc); 1069 err = split_state(tree, state, prealloc, start); 1070 if (err) 1071 extent_io_tree_panic(tree, err); 1072 1073 prealloc = NULL; (...) 1089 goto search_again; This splits the state record into two, one for range [0, 128KiB) and another for the range [128KiB, 1MiB). Both already have the EXTENT_DIRTY bit set. Then we jump to the 'search_again' label, where we unlock the the spinlock protecting the extent io tree before jumping to the 'again' label to perform the next iteration; 4) In the meanwhile, delalloc is flushed, the ordered extent for the range [512KiB, 768KiB) is created and when it completes, at btrfs_finish_ordered_io(), it calls btrfs_inode_safe_disk_i_size_write() with a value of 0 for its 'new_size' argument; 5) Before the deduplication task currently at __set_extent_bit() moves to the next iteration, the task finishing the ordered extent calls find_first_extent_bit() through btrfs_inode_safe_disk_i_size_write() and gets 'start' set to 0 and 'end' set to 128KiB - because at this moment the io tree has two extent state records, one representing the range [0, 128KiB) and another representing the range [128KiB, 1MiB), both with EXTENT_DIRTY set. Then we set 'isize' to: isize = min(isize, end + 1) = min(1MiB, 128KiB - 1 + 1) = 128KiB Then we set the inode's disk_i_size to 128KiB (isize). After a clean unmount of the filesystem and mounting it again, we have the file with a size of 128KiB, and effectively lost all the data it had before in the range from 128KiB to 1MiB. This change fixes that issue too, as we never end up splitting extent state records when they already have all the bits we want set. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-02-13 10:20:02 +00:00
/*
* If this extent already has all the bits we want set, then
* skip it, not necessary to split it or do anything with it.
*/
if ((state->state & bits) == bits) {
start = state->end + 1;
cache_state(state, cached_state);
goto search_again;
}
prealloc = alloc_extent_state_atomic(prealloc);
BUG_ON(!prealloc);
err = split_state(tree, state, prealloc, start);
if (err)
extent_io_tree_panic(tree, err);
prealloc = NULL;
if (err)
goto out;
if (state->end <= end) {
set_state_bits(tree, state, &bits, changeset);
cache_state(state, cached_state);
merge_state(tree, state);
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
state = next_state(state);
if (start < end && state && state->start == start &&
!need_resched())
goto hit_next;
}
goto search_again;
}
/*
* | ---- desired range ---- |
* | state | or | state |
*
* There's a hole, we need to insert something in it and
* ignore the extent we found.
*/
if (state->start > start) {
u64 this_end;
if (end < last_start)
this_end = end;
else
this_end = last_start - 1;
prealloc = alloc_extent_state_atomic(prealloc);
BUG_ON(!prealloc);
/*
* Avoid to free 'prealloc' if it can be merged with
* the later extent.
*/
err = insert_state(tree, prealloc, start, this_end,
NULL, NULL, &bits, changeset);
if (err)
extent_io_tree_panic(tree, err);
Btrfs: proper -ENOSPC handling At the start of a transaction we do a btrfs_reserve_metadata_space() and specify how many items we plan on modifying. Then once we've done our modifications and such, just call btrfs_unreserve_metadata_space() for the same number of items we reserved. For keeping track of metadata needed for data I've had to add an extent_io op for when we merge extents. This lets us track space properly when we are doing sequential writes, so we don't end up reserving way more metadata space than what we need. The only place where the metadata space accounting is not done is in the relocation code. This is because Yan is going to be reworking that code in the near future, so running btrfs-vol -b could still possibly result in a ENOSPC related panic. This patch also turns off the metadata_ratio stuff in order to allow users to more efficiently use their disk space. This patch makes it so we track how much metadata we need for an inode's delayed allocation extents by tracking how many extents are currently waiting for allocation. It introduces two new callbacks for the extent_io tree's, merge_extent_hook and split_extent_hook. These help us keep track of when we merge delalloc extents together and split them up. Reservations are handled prior to any actually dirty'ing occurs, and then we unreserve after we dirty. btrfs_unreserve_metadata_for_delalloc() will make the appropriate unreservations as needed based on the number of reservations we currently have and the number of extents we currently have. Doing the reservation outside of doing any of the actual dirty'ing lets us do things like filemap_flush() the inode to try and force delalloc to happen, or as a last resort actually start allocation on all delalloc inodes in the fs. This has survived dbench, fs_mark and an fsx torture test. Signed-off-by: Josef Bacik <jbacik@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:12:44 +00:00
cache_state(prealloc, cached_state);
prealloc = NULL;
start = this_end + 1;
goto search_again;
}
/*
* | ---- desired range ---- |
* | state |
* We need to split the extent, and set the bit
* on the first half
*/
if (state->start <= end && state->end > end) {
if (state->state & exclusive_bits) {
*failed_start = start;
err = -EEXIST;
goto out;
}
prealloc = alloc_extent_state_atomic(prealloc);
BUG_ON(!prealloc);
err = split_state(tree, state, prealloc, end + 1);
if (err)
extent_io_tree_panic(tree, err);
set_state_bits(tree, prealloc, &bits, changeset);
cache_state(prealloc, cached_state);
merge_state(tree, prealloc);
prealloc = NULL;
goto out;
}
search_again:
if (start > end)
goto out;
spin_unlock(&tree->lock);
if (gfpflags_allow_blocking(mask))
cond_resched();
goto again;
out:
spin_unlock(&tree->lock);
if (prealloc)
free_extent_state(prealloc);
return err;
}
/**
* convert_extent_bit - convert all bits in a given range from one bit to
* another
* @tree: the io tree to search
* @start: the start offset in bytes
* @end: the end offset in bytes (inclusive)
* @bits: the bits to set in this range
* @clear_bits: the bits to clear in this range
* @cached_state: state that we're going to cache
*
* This will go through and set bits for the given range. If any states exist
* already in this range they are set with the given bit and cleared of the
* clear_bits. This is only meant to be used by things that are mergeable, ie
* converting from say DELALLOC to DIRTY. This is not meant to be used with
* boundary bits like LOCK.
*
* All allocations are done with GFP_NOFS.
*/
int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
u32 bits, u32 clear_bits,
struct extent_state **cached_state)
{
struct extent_state *state;
struct extent_state *prealloc = NULL;
struct rb_node *node;
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
struct rb_node **p;
struct rb_node *parent;
int err = 0;
u64 last_start;
u64 last_end;
bool first_iteration = true;
btrfs_debug_check_extent_io_range(tree, start, end);
btrfs: tracepoints: Add trace events for extent_io_tree Although btrfs heavily relies on extent_io_tree, we don't really have any good trace events for them. This patch will add the folowing trace events: - trace_btrfs_set_extent_bit() - trace_btrfs_clear_extent_bit() - trace_btrfs_convert_extent_bit() Since selftests could create temporary extent_io_tree without fs_info, modify TP_fast_assign_fsid() to accept NULL as fs_info. NULL fs_info will lead to all zero fsid. The output would be: btrfs_set_extent_bit: <FDID>: io_tree=INODE_IO ino=1 root=1 start=22036480 len=4096 set_bits=LOCKED btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22040576 len=4096 set_bits=LOCKED btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22044672 len=4096 set_bits=LOCKED btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22048768 len=4096 set_bits=LOCKED btrfs_clear_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22036480 len=16384 clear_bits=LOCKED ^^^ Extent buffer 22036480 read from disk, the locking progress btrfs_set_extent_bit: <FSID>: io_tree=TRANS_DIRTY_PAGES ino=1 root=1 start=30425088 len=16384 set_bits=DIRTY btrfs_set_extent_bit: <FSID>: io_tree=TRANS_DIRTY_PAGES ino=1 root=1 start=30441472 len=16384 set_bits=DIRTY ^^^ 2 new tree blocks allocated in one transaction btrfs_set_extent_bit: <FSID>: io_tree=FREED_EXTENTS0 ino=0 root=0 start=30523392 len=16384 set_bits=DIRTY btrfs_set_extent_bit: <FSID>: io_tree=FREED_EXTENTS0 ino=0 root=0 start=30556160 len=16384 set_bits=DIRTY ^^^ 2 old tree blocks get pinned down There is one point which need attention: 1) Those trace events can be pretty heavy: The following workload would generate over 400 trace events. mkfs.btrfs -f $dev start_trace mount $dev $mnt -o enospc_debug sync touch $mnt/file1 touch $mnt/file2 touch $mnt/file3 xfs_io -f -c "pwrite 0 16k" $mnt/file4 umount $mnt end_trace It's not recommended to use them in real world environment. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ rename enums ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-03-01 02:48:00 +00:00
trace_btrfs_convert_extent_bit(tree, start, end - start + 1, bits,
clear_bits);
again:
if (!prealloc) {
/*
* Best effort, don't worry if extent state allocation fails
* here for the first iteration. We might have a cached state
* that matches exactly the target range, in which case no
* extent state allocations are needed. We'll only know this
* after locking the tree.
*/
prealloc = alloc_extent_state(GFP_NOFS);
if (!prealloc && !first_iteration)
return -ENOMEM;
}
spin_lock(&tree->lock);
if (cached_state && *cached_state) {
state = *cached_state;
if (state->start <= start && state->end > start &&
extent_state_in_tree(state)) {
node = &state->rb_node;
goto hit_next;
}
}
/*
* this search will find all the extents that end after
* our range starts.
*/
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
node = tree_search_for_insert(tree, start, &p, &parent);
if (!node) {
prealloc = alloc_extent_state_atomic(prealloc);
if (!prealloc) {
err = -ENOMEM;
goto out;
}
Btrfs: more efficient extent state insertions Currently we do 2 traversals of an inode's extent_io_tree before inserting an extent state structure: 1 to see if a matching extent state already exists and 1 to do the insertion if the fist traversal didn't found such extent state. This change just combines those tree traversals into a single one. While running sysbench tests (random writes) I captured the number of elements in extent_io_tree trees for a while (into a procfs file backed by a seq_list from seq_file module) and got this histogram: Count: 9310 Range: 51.000 - 21386.000; Mean: 11785.243; Median: 18743.500; Stddev: 8923.688 Percentiles: 90th: 20985.000; 95th: 21155.000; 99th: 21369.000 51.000 - 93.933: 693 ######## 93.933 - 172.314: 938 ########## 172.314 - 315.408: 856 ######### 315.408 - 576.646: 95 # 576.646 - 6415.830: 888 ########## 6415.830 - 11713.809: 1024 ########### 11713.809 - 21386.000: 4816 ##################################################### So traversing such trees can take some significant time that can easily be avoided. Ran the following sysbench tests, 5 times each, for sequential and random writes, and got the following results: sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=seqwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync sysbench --test=fileio --file-num=1 --file-total-size=2G \ --file-test-mode=rndwr --num-threads=16 --file-block-size=65536 \ --max-requests=0 --max-time=60 --file-io-mode=sync Before this change: sequential writes: 69.28Mb/sec (average of 5 runs) random writes: 4.14Mb/sec (average of 5 runs) After this change: sequential writes: 69.91Mb/sec (average of 5 runs) random writes: 5.69Mb/sec (average of 5 runs) Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-26 15:41:47 +00:00
err = insert_state(tree, prealloc, start, end,
&p, &parent, &bits, NULL);
if (err)
extent_io_tree_panic(tree, err);
cache_state(prealloc, cached_state);
prealloc = NULL;
goto out;
}
state = rb_entry(node, struct extent_state, rb_node);
hit_next:
last_start = state->start;
last_end = state->end;
/*
* | ---- desired range ---- |
* | state |
*
* Just lock what we found and keep going
*/
if (state->start == start && state->end <= end) {
set_state_bits(tree, state, &bits, NULL);
cache_state(state, cached_state);
state = clear_state_bit(tree, state, &clear_bits, 0, NULL);
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
if (start < end && state && state->start == start &&
!need_resched())
goto hit_next;
goto search_again;
}
/*
* | ---- desired range ---- |
* | state |
* or
* | ------------- state -------------- |
*
* We need to split the extent we found, and may flip bits on
* second half.
*
* If the extent we found extends past our
* range, we just split and search again. It'll get split
* again the next time though.
*
* If the extent we found is inside our range, we set the
* desired bit on it.
*/
if (state->start < start) {
prealloc = alloc_extent_state_atomic(prealloc);
if (!prealloc) {
err = -ENOMEM;
goto out;
}
err = split_state(tree, state, prealloc, start);
if (err)
extent_io_tree_panic(tree, err);
prealloc = NULL;
if (err)
goto out;
if (state->end <= end) {
set_state_bits(tree, state, &bits, NULL);
cache_state(state, cached_state);
state = clear_state_bit(tree, state, &clear_bits, 0,
NULL);
if (last_end == (u64)-1)
goto out;
start = last_end + 1;
if (start < end && state && state->start == start &&
!need_resched())
goto hit_next;
}
goto search_again;
}
/*
* | ---- desired range ---- |
* | state | or | state |
*
* There's a hole, we need to insert something in it and
* ignore the extent we found.
*/
if (state->start > start) {
u64 this_end;
if (end < last_start)
this_end = end;
else
this_end = last_start - 1;
prealloc = alloc_extent_state_atomic(prealloc);
if (!prealloc) {
err = -ENOMEM;
goto out;
}
/*
* Avoid to free 'prealloc' if it can be merged with
* the later extent.
*/
err = insert_state(tree, prealloc, start, this_end,
NULL, NULL, &bits, NULL);
if (err)
extent_io_tree_panic(tree, err);
cache_state(prealloc, cached_state);
prealloc = NULL;
start = this_end + 1;
goto search_again;
}
/*
* | ---- desired range ---- |
* | state |
* We need to split the extent, and set the bit
* on the first half
*/
if (state->start <= end && state->end > end) {
prealloc = alloc_extent_state_atomic(prealloc);
if (!prealloc) {
err = -ENOMEM;
goto out;
}
err = split_state(tree, state, prealloc, end + 1);
if (err)
extent_io_tree_panic(tree, err);
set_state_bits(tree, prealloc, &bits, NULL);
cache_state(prealloc, cached_state);
clear_state_bit(tree, prealloc, &clear_bits, 0, NULL);
prealloc = NULL;
goto out;
}
search_again:
if (start > end)
goto out;
spin_unlock(&tree->lock);
cond_resched();
first_iteration = false;
goto again;
out:
spin_unlock(&tree->lock);
if (prealloc)
free_extent_state(prealloc);
return err;
}
/* wrappers around set/clear extent bit */
int set_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
u32 bits, struct extent_changeset *changeset)
{
/*
* We don't support EXTENT_LOCKED yet, as current changeset will
* record any bits changed, so for EXTENT_LOCKED case, it will
* either fail with -EEXIST or changeset will record the whole
* range.
*/
BUG_ON(bits & EXTENT_LOCKED);
return set_extent_bit(tree, start, end, bits, 0, NULL, NULL, GFP_NOFS,
changeset);
}
int set_extent_bits_nowait(struct extent_io_tree *tree, u64 start, u64 end,
u32 bits)
{
return set_extent_bit(tree, start, end, bits, 0, NULL, NULL,
GFP_NOWAIT, NULL);
}
int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
u32 bits, int wake, int delete,
struct extent_state **cached)
{
return __clear_extent_bit(tree, start, end, bits, wake, delete,
cached, GFP_NOFS, NULL);
}
int clear_record_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
u32 bits, struct extent_changeset *changeset)
{
/*
* Don't support EXTENT_LOCKED case, same reason as
* set_record_extent_bits().
*/
BUG_ON(bits & EXTENT_LOCKED);
return __clear_extent_bit(tree, start, end, bits, 0, 0, NULL, GFP_NOFS,
changeset);
}
/*
* either insert or lock state struct between start and end use mask to tell
* us if waiting is desired.
*/
int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
struct extent_state **cached_state)
{
int err;
u64 failed_start;
while (1) {
err = set_extent_bit(tree, start, end, EXTENT_LOCKED,
EXTENT_LOCKED, &failed_start,
cached_state, GFP_NOFS, NULL);
if (err == -EEXIST) {
wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
start = failed_start;
} else
break;
WARN_ON(start > end);
}
return err;
}
int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end)
{
int err;
u64 failed_start;
err = set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
&failed_start, NULL, GFP_NOFS, NULL);
if (err == -EEXIST) {
if (failed_start > start)
clear_extent_bit(tree, start, failed_start - 1,
EXTENT_LOCKED, 1, 0, NULL);
return 0;
}
return 1;
}
void extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end)
{
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
unsigned long index = start >> PAGE_SHIFT;
unsigned long end_index = end >> PAGE_SHIFT;
struct page *page;
while (index <= end_index) {
page = find_get_page(inode->i_mapping, index);
BUG_ON(!page); /* Pages should be in the extent_io_tree */
clear_page_dirty_for_io(page);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
put_page(page);
index++;
}
}
void extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end)
{
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
unsigned long index = start >> PAGE_SHIFT;
unsigned long end_index = end >> PAGE_SHIFT;
struct page *page;
while (index <= end_index) {
page = find_get_page(inode->i_mapping, index);
BUG_ON(!page); /* Pages should be in the extent_io_tree */
__set_page_dirty_nobuffers(page);
account_page_redirty(page);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
put_page(page);
index++;
}
}
/* find the first state struct with 'bits' set after 'start', and
* return it. tree->lock must be held. NULL will returned if
* nothing was found after 'start'
*/
static struct extent_state *
find_first_extent_bit_state(struct extent_io_tree *tree, u64 start, u32 bits)
{
struct rb_node *node;
struct extent_state *state;
/*
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(tree, start);
if (!node)
goto out;
while (1) {
state = rb_entry(node, struct extent_state, rb_node);
if (state->end >= start && (state->state & bits))
return state;
node = rb_next(node);
if (!node)
break;
}
out:
return NULL;
}
/*
* Find the first offset in the io tree with one or more @bits set.
*
* Note: If there are multiple bits set in @bits, any of them will match.
*
* Return 0 if we find something, and update @start_ret and @end_ret.
* Return 1 if we found nothing.
*/
int find_first_extent_bit(struct extent_io_tree *tree, u64 start,
u64 *start_ret, u64 *end_ret, u32 bits,
struct extent_state **cached_state)
{
struct extent_state *state;
int ret = 1;
spin_lock(&tree->lock);
if (cached_state && *cached_state) {
state = *cached_state;
if (state->end == start - 1 && extent_state_in_tree(state)) {
while ((state = next_state(state)) != NULL) {
if (state->state & bits)
goto got_it;
}
free_extent_state(*cached_state);
*cached_state = NULL;
goto out;
}
free_extent_state(*cached_state);
*cached_state = NULL;
}
state = find_first_extent_bit_state(tree, start, bits);
got_it:
if (state) {
cache_state_if_flags(state, cached_state, 0);
*start_ret = state->start;
*end_ret = state->end;
ret = 0;
}
out:
spin_unlock(&tree->lock);
return ret;
}
/**
btrfs: fix parameter description for functions in extent_io.c This makes the file W=1 clean and fixes the following warnings: fs/btrfs/extent_io.c:414: warning: Function parameter or member 'tree' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'offset' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'next_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'prev_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'p_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'parent_ret' not described in '__etree_search' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'tree' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start_ret' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'end_ret' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'bits' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'tree' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start_ret' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'end_ret' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'bits' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:4187: warning: Function parameter or member 'epd' not described in 'extent_write_cache_pages' fs/btrfs/extent_io.c:4187: warning: Excess function parameter 'data' description in 'extent_write_cache_pages' Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-22 09:58:03 +00:00
* Find a contiguous area of bits
*
* @tree: io tree to check
* @start: offset to start the search from
* @start_ret: the first offset we found with the bits set
* @end_ret: the final contiguous range of the bits that were set
* @bits: bits to look for
*
* set_extent_bit and clear_extent_bit can temporarily split contiguous ranges
* to set bits appropriately, and then merge them again. During this time it
* will drop the tree->lock, so use this helper if you want to find the actual
* contiguous area for given bits. We will search to the first bit we find, and
* then walk down the tree until we find a non-contiguous area. The area
* returned will be the full contiguous area with the bits set.
*/
int find_contiguous_extent_bit(struct extent_io_tree *tree, u64 start,
u64 *start_ret, u64 *end_ret, u32 bits)
{
struct extent_state *state;
int ret = 1;
spin_lock(&tree->lock);
state = find_first_extent_bit_state(tree, start, bits);
if (state) {
*start_ret = state->start;
*end_ret = state->end;
while ((state = next_state(state)) != NULL) {
if (state->start > (*end_ret + 1))
break;
*end_ret = state->end;
}
ret = 0;
}
spin_unlock(&tree->lock);
return ret;
}
/**
btrfs: fix parameter description for functions in extent_io.c This makes the file W=1 clean and fixes the following warnings: fs/btrfs/extent_io.c:414: warning: Function parameter or member 'tree' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'offset' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'next_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'prev_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'p_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'parent_ret' not described in '__etree_search' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'tree' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start_ret' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'end_ret' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'bits' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'tree' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start_ret' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'end_ret' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'bits' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:4187: warning: Function parameter or member 'epd' not described in 'extent_write_cache_pages' fs/btrfs/extent_io.c:4187: warning: Excess function parameter 'data' description in 'extent_write_cache_pages' Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-22 09:58:03 +00:00
* Find the first range that has @bits not set. This range could start before
* @start.
*
btrfs: fix parameter description for functions in extent_io.c This makes the file W=1 clean and fixes the following warnings: fs/btrfs/extent_io.c:414: warning: Function parameter or member 'tree' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'offset' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'next_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'prev_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'p_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'parent_ret' not described in '__etree_search' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'tree' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start_ret' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'end_ret' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'bits' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'tree' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start_ret' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'end_ret' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'bits' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:4187: warning: Function parameter or member 'epd' not described in 'extent_write_cache_pages' fs/btrfs/extent_io.c:4187: warning: Excess function parameter 'data' description in 'extent_write_cache_pages' Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-22 09:58:03 +00:00
* @tree: the tree to search
* @start: offset at/after which the found extent should start
* @start_ret: records the beginning of the range
* @end_ret: records the end of the range (inclusive)
* @bits: the set of bits which must be unset
*
* Since unallocated range is also considered one which doesn't have the bits
* set it's possible that @end_ret contains -1, this happens in case the range
* spans (last_range_end, end of device]. In this case it's up to the caller to
* trim @end_ret to the appropriate size.
*/
void find_first_clear_extent_bit(struct extent_io_tree *tree, u64 start,
u64 *start_ret, u64 *end_ret, u32 bits)
{
struct extent_state *state;
struct rb_node *node, *prev = NULL, *next;
spin_lock(&tree->lock);
/* Find first extent with bits cleared */
while (1) {
node = __etree_search(tree, start, &next, &prev, NULL, NULL);
btrfs: Correctly handle empty trees in find_first_clear_extent_bit Raviu reported that running his regular fs_trim segfaulted with the following backtrace: [ 237.525947] assertion failed: prev, in ../fs/btrfs/extent_io.c:1595 [ 237.525984] ------------[ cut here ]------------ [ 237.525985] kernel BUG at ../fs/btrfs/ctree.h:3117! [ 237.525992] invalid opcode: 0000 [#1] SMP PTI [ 237.525998] CPU: 4 PID: 4423 Comm: fstrim Tainted: G U OE 5.4.14-8-vanilla #1 [ 237.526001] Hardware name: ASUSTeK COMPUTER INC. [ 237.526044] RIP: 0010:assfail.constprop.58+0x18/0x1a [btrfs] [ 237.526079] Call Trace: [ 237.526120] find_first_clear_extent_bit+0x13d/0x150 [btrfs] [ 237.526148] btrfs_trim_fs+0x211/0x3f0 [btrfs] [ 237.526184] btrfs_ioctl_fitrim+0x103/0x170 [btrfs] [ 237.526219] btrfs_ioctl+0x129a/0x2ed0 [btrfs] [ 237.526227] ? filemap_map_pages+0x190/0x3d0 [ 237.526232] ? do_filp_open+0xaf/0x110 [ 237.526238] ? _copy_to_user+0x22/0x30 [ 237.526242] ? cp_new_stat+0x150/0x180 [ 237.526247] ? do_vfs_ioctl+0xa4/0x640 [ 237.526278] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs] [ 237.526283] do_vfs_ioctl+0xa4/0x640 [ 237.526288] ? __do_sys_newfstat+0x3c/0x60 [ 237.526292] ksys_ioctl+0x70/0x80 [ 237.526297] __x64_sys_ioctl+0x16/0x20 [ 237.526303] do_syscall_64+0x5a/0x1c0 [ 237.526310] entry_SYSCALL_64_after_hwframe+0x49/0xbe That was due to btrfs_fs_device::aloc_tree being empty. Initially I thought this wasn't possible and as a percaution have put the assert in find_first_clear_extent_bit. Turns out this is indeed possible and could happen when a file system with SINGLE data/metadata profile has a 2nd device added. Until balance is run or a new chunk is allocated on this device it will be completely empty. In this case find_first_clear_extent_bit should return the full range [0, -1ULL] and let the caller handle this i.e for trim the end will be capped at the size of actual device. Link: https://lore.kernel.org/linux-btrfs/izW2WNyvy1dEDweBICizKnd2KDwDiDyY2EYQr4YCwk7pkuIpthx-JRn65MPBde00ND6V0_Lh8mW0kZwzDiLDv25pUYWxkskWNJnVP0kgdMA=@protonmail.com/ Fixes: 45bfcfc168f8 ("btrfs: Implement find_first_clear_extent_bit") CC: stable@vger.kernel.org # 5.2+ Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-27 09:59:26 +00:00
if (!node && !next && !prev) {
/*
* Tree is completely empty, send full range and let
* caller deal with it
*/
*start_ret = 0;
*end_ret = -1;
goto out;
} else if (!node && !next) {
/*
* We are past the last allocated chunk, set start at
* the end of the last extent.
*/
state = rb_entry(prev, struct extent_state, rb_node);
*start_ret = state->end + 1;
*end_ret = -1;
goto out;
} else if (!node) {
node = next;
}
/*
* At this point 'node' either contains 'start' or start is
* before 'node'
*/
state = rb_entry(node, struct extent_state, rb_node);
if (in_range(start, state->start, state->end - state->start + 1)) {
if (state->state & bits) {
/*
* |--range with bits sets--|
* |
* start
*/
start = state->end + 1;
} else {
/*
* 'start' falls within a range that doesn't
* have the bits set, so take its start as
* the beginning of the desired range
*
* |--range with bits cleared----|
* |
* start
*/
*start_ret = state->start;
break;
}
} else {
/*
* |---prev range---|---hole/unset---|---node range---|
* |
* start
*
* or
*
* |---hole/unset--||--first node--|
* 0 |
* start
*/
if (prev) {
state = rb_entry(prev, struct extent_state,
rb_node);
*start_ret = state->end + 1;
} else {
*start_ret = 0;
}
break;
}
}
/*
* Find the longest stretch from start until an entry which has the
* bits set
*/
while (1) {
state = rb_entry(node, struct extent_state, rb_node);
if (state->end >= start && !(state->state & bits)) {
*end_ret = state->end;
} else {
*end_ret = state->start - 1;
break;
}
node = rb_next(node);
if (!node)
break;
}
out:
spin_unlock(&tree->lock);
}
/*
* find a contiguous range of bytes in the file marked as delalloc, not
* more than 'max_bytes'. start and end are used to return the range,
*
* true is returned if we find something, false if nothing was in the tree
*/
bool btrfs_find_delalloc_range(struct extent_io_tree *tree, u64 *start,
u64 *end, u64 max_bytes,
struct extent_state **cached_state)
{
struct rb_node *node;
struct extent_state *state;
u64 cur_start = *start;
bool found = false;
u64 total_bytes = 0;
spin_lock(&tree->lock);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
/*
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(tree, cur_start);
if (!node) {
*end = (u64)-1;
goto out;
}
while (1) {
state = rb_entry(node, struct extent_state, rb_node);
if (found && (state->start != cur_start ||
(state->state & EXTENT_BOUNDARY))) {
goto out;
}
if (!(state->state & EXTENT_DELALLOC)) {
if (!found)
*end = state->end;
goto out;
}
if (!found) {
*start = state->start;
*cached_state = state;
refcount_inc(&state->refs);
}
found = true;
*end = state->end;
cur_start = state->end + 1;
node = rb_next(node);
total_bytes += state->end - state->start + 1;
if (total_bytes >= max_bytes)
break;
if (!node)
break;
}
out:
spin_unlock(&tree->lock);
return found;
}
static int __process_pages_contig(struct address_space *mapping,
struct page *locked_page,
pgoff_t start_index, pgoff_t end_index,
unsigned long page_ops, pgoff_t *index_ret);
static noinline void __unlock_for_delalloc(struct inode *inode,
struct page *locked_page,
u64 start, u64 end)
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
{
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
unsigned long index = start >> PAGE_SHIFT;
unsigned long end_index = end >> PAGE_SHIFT;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
ASSERT(locked_page);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
if (index == locked_page->index && end_index == index)
return;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
__process_pages_contig(inode->i_mapping, locked_page, index, end_index,
PAGE_UNLOCK, NULL);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
}
static noinline int lock_delalloc_pages(struct inode *inode,
struct page *locked_page,
u64 delalloc_start,
u64 delalloc_end)
{
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
unsigned long index = delalloc_start >> PAGE_SHIFT;
unsigned long index_ret = index;
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
unsigned long end_index = delalloc_end >> PAGE_SHIFT;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
int ret;
ASSERT(locked_page);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
if (index == locked_page->index && index == end_index)
return 0;
ret = __process_pages_contig(inode->i_mapping, locked_page, index,
end_index, PAGE_LOCK, &index_ret);
if (ret == -EAGAIN)
__unlock_for_delalloc(inode, locked_page, delalloc_start,
(u64)index_ret << PAGE_SHIFT);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
return ret;
}
/*
* Find and lock a contiguous range of bytes in the file marked as delalloc, no
* more than @max_bytes. @Start and @end are used to return the range,
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
*
* Return: true if we find something
* false if nothing was in the tree
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
*/
EXPORT_FOR_TESTS
noinline_for_stack bool find_lock_delalloc_range(struct inode *inode,
struct page *locked_page, u64 *start,
u64 *end)
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
{
struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
u64 max_bytes = BTRFS_MAX_EXTENT_SIZE;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
u64 delalloc_start;
u64 delalloc_end;
bool found;
struct extent_state *cached_state = NULL;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
int ret;
int loops = 0;
again:
/* step one, find a bunch of delalloc bytes starting at start */
delalloc_start = *start;
delalloc_end = 0;
found = btrfs_find_delalloc_range(tree, &delalloc_start, &delalloc_end,
max_bytes, &cached_state);
if (!found || delalloc_end <= *start) {
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
*start = delalloc_start;
*end = delalloc_end;
free_extent_state(cached_state);
return false;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
}
/*
* start comes from the offset of locked_page. We have to lock
* pages in order, so we can't process delalloc bytes before
* locked_page
*/
if (delalloc_start < *start)
delalloc_start = *start;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
/*
* make sure to limit the number of pages we try to lock down
*/
if (delalloc_end + 1 - delalloc_start > max_bytes)
delalloc_end = delalloc_start + max_bytes - 1;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
/* step two, lock all the pages after the page that has start */
ret = lock_delalloc_pages(inode, locked_page,
delalloc_start, delalloc_end);
ASSERT(!ret || ret == -EAGAIN);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
if (ret == -EAGAIN) {
/* some of the pages are gone, lets avoid looping by
* shortening the size of the delalloc range we're searching
*/
free_extent_state(cached_state);
cached_state = NULL;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
if (!loops) {
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
max_bytes = PAGE_SIZE;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
loops = 1;
goto again;
} else {
found = false;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
goto out_failed;
}
}
/* step three, lock the state bits for the whole range */
lock_extent_bits(tree, delalloc_start, delalloc_end, &cached_state);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
/* then test to make sure it is all still delalloc */
ret = test_range_bit(tree, delalloc_start, delalloc_end,
EXTENT_DELALLOC, 1, cached_state);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
if (!ret) {
unlock_extent_cached(tree, delalloc_start, delalloc_end,
&cached_state);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
__unlock_for_delalloc(inode, locked_page,
delalloc_start, delalloc_end);
cond_resched();
goto again;
}
free_extent_state(cached_state);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
*start = delalloc_start;
*end = delalloc_end;
out_failed:
return found;
}
static int __process_pages_contig(struct address_space *mapping,
struct page *locked_page,
pgoff_t start_index, pgoff_t end_index,
unsigned long page_ops, pgoff_t *index_ret)
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
{
unsigned long nr_pages = end_index - start_index + 1;
unsigned long pages_processed = 0;
pgoff_t index = start_index;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
struct page *pages[16];
unsigned ret;
int err = 0;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
int i;
if (page_ops & PAGE_LOCK) {
ASSERT(page_ops == PAGE_LOCK);
ASSERT(index_ret && *index_ret == start_index);
}
if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
mapping_set_error(mapping, -EIO);
while (nr_pages > 0) {
ret = find_get_pages_contig(mapping, index,
min_t(unsigned long,
nr_pages, ARRAY_SIZE(pages)), pages);
if (ret == 0) {
/*
* Only if we're going to lock these pages,
* can we find nothing at @index.
*/
ASSERT(page_ops & PAGE_LOCK);
err = -EAGAIN;
goto out;
}
for (i = 0; i < ret; i++) {
if (page_ops & PAGE_SET_PRIVATE2)
SetPagePrivate2(pages[i]);
Btrfs: only associate the locked page with one async_chunk struct The btrfs writepages function collects a large range of pages flagged for delayed allocation, and then sends them down through the COW code for processing. When compression is on, we allocate one async_chunk structure for every 512K, and then run those pages through the compression code for IO submission. writepages starts all of this off with a single page, locked by the original call to extent_write_cache_pages(), and it's important to keep track of this page because it has already been through clear_page_dirty_for_io(). The btrfs async_chunk struct has a pointer to the locked_page, and when we're redirtying the page because compression had to fallback to uncompressed IO, we use page->index to decide if a given async_chunk struct really owns that page. But, this is racey. If a given delalloc range is broken up into two async_chunks (chunkA and chunkB), we can end up with something like this: compress_file_range(chunkA) submit_compress_extents(chunkA) submit compressed bios(chunkA) put_page(locked_page) compress_file_range(chunkB) ... Or: async_cow_submit submit_compressed_extents <--- falls back to buffered writeout cow_file_range extent_clear_unlock_delalloc __process_pages_contig put_page(locked_pages) async_cow_submit The end result is that chunkA is completed and cleaned up before chunkB even starts processing. This means we can free locked_page() and reuse it elsewhere. If we get really lucky, it'll have the same page->index in its new home as it did before. While we're processing chunkB, we might decide we need to fall back to uncompressed IO, and so compress_file_range() will call __set_page_dirty_nobufers() on chunkB->locked_page. Without cgroups in use, this creates as a phantom dirty page, which isn't great but isn't the end of the world. What can happen, it can go through the fixup worker and the whole COW machinery again: in submit_compressed_extents(): while (async extents) { ... cow_file_range if (!page_started ...) extent_write_locked_range else if (...) unlock_page continue; This hasn't been observed in practice but is still possible. With cgroups in use, we might crash in the accounting code because page->mapping->i_wb isn't set. BUG: unable to handle kernel NULL pointer dereference at 00000000000000d0 IP: percpu_counter_add_batch+0x11/0x70 PGD 66534e067 P4D 66534e067 PUD 66534f067 PMD 0 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC CPU: 16 PID: 2172 Comm: rm Not tainted RIP: 0010:percpu_counter_add_batch+0x11/0x70 RSP: 0018:ffffc9000a97bbe0 EFLAGS: 00010286 RAX: 0000000000000005 RBX: 0000000000000090 RCX: 0000000000026115 RDX: 0000000000000030 RSI: ffffffffffffffff RDI: 0000000000000090 RBP: 0000000000000000 R08: fffffffffffffff5 R09: 0000000000000000 R10: 00000000000260c0 R11: ffff881037fc26c0 R12: ffffffffffffffff R13: ffff880fe4111548 R14: ffffc9000a97bc90 R15: 0000000000000001 FS: 00007f5503ced480(0000) GS:ffff880ff7200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000d0 CR3: 00000001e0459005 CR4: 0000000000360ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: account_page_cleaned+0x15b/0x1f0 __cancel_dirty_page+0x146/0x200 truncate_cleanup_page+0x92/0xb0 truncate_inode_pages_range+0x202/0x7d0 btrfs_evict_inode+0x92/0x5a0 evict+0xc1/0x190 do_unlinkat+0x176/0x280 do_syscall_64+0x63/0x1a0 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The fix here is to make asyc_chunk->locked_page NULL everywhere but the one async_chunk struct that's allowed to do things to the locked page. Link: https://lore.kernel.org/linux-btrfs/c2419d01-5c84-3fb4-189e-4db519d08796@suse.com/ Fixes: 771ed689d2cd ("Btrfs: Optimize compressed writeback and reads") Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Chris Mason <clm@fb.com> [ update changelog from mail thread discussion ] Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-10 19:28:16 +00:00
if (locked_page && pages[i] == locked_page) {
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
put_page(pages[i]);
pages_processed++;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
continue;
}
if (page_ops & PAGE_START_WRITEBACK) {
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
clear_page_dirty_for_io(pages[i]);
set_page_writeback(pages[i]);
}
if (page_ops & PAGE_SET_ERROR)
SetPageError(pages[i]);
if (page_ops & PAGE_END_WRITEBACK)
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
end_page_writeback(pages[i]);
if (page_ops & PAGE_UNLOCK)
unlock_page(pages[i]);
if (page_ops & PAGE_LOCK) {
lock_page(pages[i]);
if (!PageDirty(pages[i]) ||
pages[i]->mapping != mapping) {
unlock_page(pages[i]);
for (; i < ret; i++)
put_page(pages[i]);
err = -EAGAIN;
goto out;
}
}
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
put_page(pages[i]);
pages_processed++;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
}
nr_pages -= ret;
index += ret;
cond_resched();
}
out:
if (err && index_ret)
*index_ret = start_index + pages_processed - 1;
return err;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
}
void extent_clear_unlock_delalloc(struct btrfs_inode *inode, u64 start, u64 end,
struct page *locked_page,
u32 clear_bits, unsigned long page_ops)
{
clear_extent_bit(&inode->io_tree, start, end, clear_bits, 1, 0, NULL);
__process_pages_contig(inode->vfs_inode.i_mapping, locked_page,
start >> PAGE_SHIFT, end >> PAGE_SHIFT,
page_ops, NULL);
}
/*
* count the number of bytes in the tree that have a given bit(s)
* set. This can be fairly slow, except for EXTENT_DIRTY which is
* cached. The total number found is returned.
*/
u64 count_range_bits(struct extent_io_tree *tree,
u64 *start, u64 search_end, u64 max_bytes,
u32 bits, int contig)
{
struct rb_node *node;
struct extent_state *state;
u64 cur_start = *start;
u64 total_bytes = 0;
u64 last = 0;
int found = 0;
if (WARN_ON(search_end <= cur_start))
return 0;
spin_lock(&tree->lock);
if (cur_start == 0 && bits == EXTENT_DIRTY) {
total_bytes = tree->dirty_bytes;
goto out;
}
/*
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(tree, cur_start);
if (!node)
goto out;
while (1) {
state = rb_entry(node, struct extent_state, rb_node);
if (state->start > search_end)
break;
if (contig && found && state->start > last + 1)
break;
if (state->end >= cur_start && (state->state & bits) == bits) {
total_bytes += min(search_end, state->end) + 1 -
max(cur_start, state->start);
if (total_bytes >= max_bytes)
break;
if (!found) {
*start = max(cur_start, state->start);
found = 1;
}
last = state->end;
} else if (contig && found) {
break;
}
node = rb_next(node);
if (!node)
break;
}
out:
spin_unlock(&tree->lock);
return total_bytes;
}
/*
* set the private field for a given byte offset in the tree. If there isn't
* an extent_state there already, this does nothing.
*/
int set_state_failrec(struct extent_io_tree *tree, u64 start,
struct io_failure_record *failrec)
{
struct rb_node *node;
struct extent_state *state;
int ret = 0;
spin_lock(&tree->lock);
/*
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(tree, start);
if (!node) {
ret = -ENOENT;
goto out;
}
state = rb_entry(node, struct extent_state, rb_node);
if (state->start != start) {
ret = -ENOENT;
goto out;
}
state->failrec = failrec;
out:
spin_unlock(&tree->lock);
return ret;
}
struct io_failure_record *get_state_failrec(struct extent_io_tree *tree, u64 start)
{
struct rb_node *node;
struct extent_state *state;
struct io_failure_record *failrec;
spin_lock(&tree->lock);
/*
* this search will find all the extents that end after
* our range starts.
*/
node = tree_search(tree, start);
if (!node) {
failrec = ERR_PTR(-ENOENT);
goto out;
}
state = rb_entry(node, struct extent_state, rb_node);
if (state->start != start) {
failrec = ERR_PTR(-ENOENT);
goto out;
}
failrec = state->failrec;
out:
spin_unlock(&tree->lock);
return failrec;
}
/*
* searches a range in the state tree for a given mask.
* If 'filled' == 1, this returns 1 only if every extent in the tree
* has the bits set. Otherwise, 1 is returned if any bit in the
* range is found set.
*/
int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
u32 bits, int filled, struct extent_state *cached)
{
struct extent_state *state = NULL;
struct rb_node *node;
int bitset = 0;
spin_lock(&tree->lock);
if (cached && extent_state_in_tree(cached) && cached->start <= start &&
cached->end > start)
node = &cached->rb_node;
else
node = tree_search(tree, start);
while (node && start <= end) {
state = rb_entry(node, struct extent_state, rb_node);
if (filled && state->start > start) {
bitset = 0;
break;
}
if (state->start > end)
break;
if (state->state & bits) {
bitset = 1;
if (!filled)
break;
} else if (filled) {
bitset = 0;
break;
}
if (state->end == (u64)-1)
break;
start = state->end + 1;
if (start > end)
break;
node = rb_next(node);
if (!node) {
if (filled)
bitset = 0;
break;
}
}
spin_unlock(&tree->lock);
return bitset;
}
/*
* helper function to set a given page up to date if all the
* extents in the tree for that page are up to date
*/
static void check_page_uptodate(struct extent_io_tree *tree, struct page *page)
{
u64 start = page_offset(page);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
u64 end = start + PAGE_SIZE - 1;
if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
SetPageUptodate(page);
}
int free_io_failure(struct extent_io_tree *failure_tree,
struct extent_io_tree *io_tree,
struct io_failure_record *rec)
{
int ret;
int err = 0;
set_state_failrec(failure_tree, rec->start, NULL);
ret = clear_extent_bits(failure_tree, rec->start,
rec->start + rec->len - 1,
EXTENT_LOCKED | EXTENT_DIRTY);
if (ret)
err = ret;
ret = clear_extent_bits(io_tree, rec->start,
rec->start + rec->len - 1,
EXTENT_DAMAGED);
if (ret && !err)
err = ret;
kfree(rec);
return err;
}
/*
* this bypasses the standard btrfs submit functions deliberately, as
* the standard behavior is to write all copies in a raid setup. here we only
* want to write the one bad copy. so we do the mapping for ourselves and issue
* submit_bio directly.
* to avoid any synchronization issues, wait for the data after writing, which
* actually prevents the read that triggered the error from finishing.
* currently, there can be no more than two copies of every data bit. thus,
* exactly one rewrite is required.
*/
int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
u64 length, u64 logical, struct page *page,
unsigned int pg_offset, int mirror_num)
{
struct bio *bio;
struct btrfs_device *dev;
u64 map_length = 0;
u64 sector;
struct btrfs_bio *bbio = NULL;
int ret;
Rename superblock flags (MS_xyz -> SB_xyz) This is a pure automated search-and-replace of the internal kernel superblock flags. The s_flags are now called SB_*, with the names and the values for the moment mirroring the MS_* flags that they're equivalent to. Note how the MS_xyz flags are the ones passed to the mount system call, while the SB_xyz flags are what we then use in sb->s_flags. The script to do this was: # places to look in; re security/*: it generally should *not* be # touched (that stuff parses mount(2) arguments directly), but # there are two places where we really deal with superblock flags. FILES="drivers/mtd drivers/staging/lustre fs ipc mm \ include/linux/fs.h include/uapi/linux/bfs_fs.h \ security/apparmor/apparmorfs.c security/apparmor/include/lib.h" # the list of MS_... constants SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \ DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \ POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \ I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \ ACTIVE NOUSER" SED_PROG= for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done # we want files that contain at least one of MS_..., # with fs/namespace.c and fs/pnode.c excluded. L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c') for f in $L; do sed -i $f $SED_PROG; done Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-27 21:05:09 +00:00
ASSERT(!(fs_info->sb->s_flags & SB_RDONLY));
BUG_ON(!mirror_num);
btrfs: zoned: relocate block group to repair IO failure in zoned filesystems When a bad checksum is found and if the filesystem has a mirror of the damaged data, we read the correct data from the mirror and writes it to damaged blocks. This however, violates the sequential write constraints of a zoned block device. We can consider three methods to repair an IO failure in zoned filesystems: (1) Reset and rewrite the damaged zone (2) Allocate new device extent and replace the damaged device extent to the new extent (3) Relocate the corresponding block group Method (1) is most similar to a behavior done with regular devices. However, it also wipes non-damaged data in the same device extent, and so it unnecessary degrades non-damaged data. Method (2) is much like device replacing but done in the same device. It is safe because it keeps the device extent until the replacing finish. However, extending device replacing is non-trivial. It assumes "src_dev->physical == dst_dev->physical". Also, the extent mapping replacing function should be extended to support replacing device extent position in one device. Method (3) invokes relocation of the damaged block group and is straightforward to implement. It relocates all the mirrored device extents, so it potentially is a more costly operation than method (1) or (2). But it relocates only used extents which reduce the total IO size. Let's apply method (3) for now. In the future, we can extend device-replace and apply method (2). For protecting a block group gets relocated multiple time with multiple IO errors, this commit introduces "relocating_repair" bit to show it's now relocating to repair IO failures. Also it uses a new kthread "btrfs-relocating-repair", not to block IO path with relocating process. This commit also supports repairing in the scrub process. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-04 10:22:16 +00:00
if (btrfs_is_zoned(fs_info))
return btrfs_repair_one_zone(fs_info, logical);
bio = btrfs_io_bio_alloc(1);
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 22:44:27 +00:00
bio->bi_iter.bi_size = 0;
map_length = length;
/*
* Avoid races with device replace and make sure our bbio has devices
* associated to its stripes that don't go away while we are doing the
* read repair operation.
*/
btrfs_bio_counter_inc_blocked(fs_info);
if (btrfs_is_parity_mirror(fs_info, logical, length)) {
/*
* Note that we don't use BTRFS_MAP_WRITE because it's supposed
* to update all raid stripes, but here we just want to correct
* bad stripe, thus BTRFS_MAP_READ is abused to only get the bad
* stripe's dev and sector.
*/
ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, logical,
&map_length, &bbio, 0);
if (ret) {
btrfs_bio_counter_dec(fs_info);
bio_put(bio);
return -EIO;
}
ASSERT(bbio->mirror_num == 1);
} else {
ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
&map_length, &bbio, mirror_num);
if (ret) {
btrfs_bio_counter_dec(fs_info);
bio_put(bio);
return -EIO;
}
BUG_ON(mirror_num != bbio->mirror_num);
}
sector = bbio->stripes[bbio->mirror_num - 1].physical >> 9;
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 22:44:27 +00:00
bio->bi_iter.bi_sector = sector;
dev = bbio->stripes[bbio->mirror_num - 1].dev;
btrfs_put_bbio(bbio);
if (!dev || !dev->bdev ||
!test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
btrfs_bio_counter_dec(fs_info);
bio_put(bio);
return -EIO;
}
bio_set_dev(bio, dev->bdev);
bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
bio_add_page(bio, page, length, pg_offset);
if (btrfsic_submit_bio_wait(bio)) {
/* try to remap that extent elsewhere? */
btrfs_bio_counter_dec(fs_info);
bio_put(bio);
btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
return -EIO;
}
btrfs_info_rl_in_rcu(fs_info,
"read error corrected: ino %llu off %llu (dev %s sector %llu)",
ino, start,
rcu_str_deref(dev->name), sector);
btrfs_bio_counter_dec(fs_info);
bio_put(bio);
return 0;
}
int btrfs_repair_eb_io_failure(const struct extent_buffer *eb, int mirror_num)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
u64 start = eb->start;
int i, num_pages = num_extent_pages(eb);
int ret = 0;
if (sb_rdonly(fs_info->sb))
return -EROFS;
for (i = 0; i < num_pages; i++) {
struct page *p = eb->pages[i];
ret = repair_io_failure(fs_info, 0, start, PAGE_SIZE, start, p,
start - page_offset(p), mirror_num);
if (ret)
break;
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
start += PAGE_SIZE;
}
return ret;
}
/*
* each time an IO finishes, we do a fast check in the IO failure tree
* to see if we need to process or clean up an io_failure_record
*/
int clean_io_failure(struct btrfs_fs_info *fs_info,
struct extent_io_tree *failure_tree,
struct extent_io_tree *io_tree, u64 start,
struct page *page, u64 ino, unsigned int pg_offset)
{
u64 private;
struct io_failure_record *failrec;
struct extent_state *state;
int num_copies;
int ret;
private = 0;
ret = count_range_bits(failure_tree, &private, (u64)-1, 1,
EXTENT_DIRTY, 0);
if (!ret)
return 0;
failrec = get_state_failrec(failure_tree, start);
if (IS_ERR(failrec))
return 0;
BUG_ON(!failrec->this_mirror);
if (failrec->in_validation) {
/* there was no real error, just free the record */
btrfs_debug(fs_info,
"clean_io_failure: freeing dummy error at %llu",
failrec->start);
goto out;
}
if (sb_rdonly(fs_info->sb))
goto out;
spin_lock(&io_tree->lock);
state = find_first_extent_bit_state(io_tree,
failrec->start,
EXTENT_LOCKED);
spin_unlock(&io_tree->lock);
if (state && state->start <= failrec->start &&
state->end >= failrec->start + failrec->len - 1) {
num_copies = btrfs_num_copies(fs_info, failrec->logical,
failrec->len);
if (num_copies > 1) {
repair_io_failure(fs_info, ino, start, failrec->len,
failrec->logical, page, pg_offset,
failrec->failed_mirror);
}
}
out:
free_io_failure(failure_tree, io_tree, failrec);
return 0;
}
/*
* Can be called when
* - hold extent lock
* - under ordered extent
* - the inode is freeing
*/
void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start, u64 end)
{
struct extent_io_tree *failure_tree = &inode->io_failure_tree;
struct io_failure_record *failrec;
struct extent_state *state, *next;
if (RB_EMPTY_ROOT(&failure_tree->state))
return;
spin_lock(&failure_tree->lock);
state = find_first_extent_bit_state(failure_tree, start, EXTENT_DIRTY);
while (state) {
if (state->start > end)
break;
ASSERT(state->end <= end);
next = next_state(state);
failrec = state->failrec;
free_extent_state(state);
kfree(failrec);
state = next;
}
spin_unlock(&failure_tree->lock);
}
static struct io_failure_record *btrfs_get_io_failure_record(struct inode *inode,
u64 start, u64 end)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct io_failure_record *failrec;
struct extent_map *em;
struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
int ret;
u64 logical;
failrec = get_state_failrec(failure_tree, start);
if (!IS_ERR(failrec)) {
btrfs_debug(fs_info,
"Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu, validation=%d",
failrec->logical, failrec->start, failrec->len,
failrec->in_validation);
/*
* when data can be on disk more than twice, add to failrec here
* (e.g. with a list for failed_mirror) to make
* clean_io_failure() clean all those errors at once.
*/
return failrec;
}
failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
if (!failrec)
return ERR_PTR(-ENOMEM);
failrec->start = start;
failrec->len = end - start + 1;
failrec->this_mirror = 0;
failrec->bio_flags = 0;
failrec->in_validation = 0;
read_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, start, failrec->len);
if (!em) {
read_unlock(&em_tree->lock);
kfree(failrec);
return ERR_PTR(-EIO);
}
if (em->start > start || em->start + em->len <= start) {
free_extent_map(em);
em = NULL;
}
read_unlock(&em_tree->lock);
if (!em) {
kfree(failrec);
return ERR_PTR(-EIO);
}
logical = start - em->start;
logical = em->block_start + logical;
if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
logical = em->block_start;
failrec->bio_flags = EXTENT_BIO_COMPRESSED;
extent_set_compress_type(&failrec->bio_flags, em->compress_type);
}
btrfs_debug(fs_info,
"Get IO Failure Record: (new) logical=%llu, start=%llu, len=%llu",
logical, start, failrec->len);
failrec->logical = logical;
free_extent_map(em);
/* Set the bits in the private failure tree */
ret = set_extent_bits(failure_tree, start, end,
EXTENT_LOCKED | EXTENT_DIRTY);
if (ret >= 0) {
ret = set_state_failrec(failure_tree, start, failrec);
/* Set the bits in the inode's tree */
ret = set_extent_bits(tree, start, end, EXTENT_DAMAGED);
} else if (ret < 0) {
kfree(failrec);
return ERR_PTR(ret);
}
return failrec;
}
static bool btrfs_check_repairable(struct inode *inode, bool needs_validation,
struct io_failure_record *failrec,
int failed_mirror)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
int num_copies;
num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
if (num_copies == 1) {
/*
* we only have a single copy of the data, so don't bother with
* all the retry and error correction code that follows. no
* matter what the error is, it is very likely to persist.
*/
btrfs_debug(fs_info,
"Check Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
num_copies, failrec->this_mirror, failed_mirror);
return false;
}
/*
* there are two premises:
* a) deliver good data to the caller
* b) correct the bad sectors on disk
*/
if (needs_validation) {
/*
* to fulfill b), we need to know the exact failing sectors, as
* we don't want to rewrite any more than the failed ones. thus,
* we need separate read requests for the failed bio
*
* if the following BUG_ON triggers, our validation request got
* merged. we need separate requests for our algorithm to work.
*/
BUG_ON(failrec->in_validation);
failrec->in_validation = 1;
failrec->this_mirror = failed_mirror;
} else {
/*
* we're ready to fulfill a) and b) alongside. get a good copy
* of the failed sector and if we succeed, we have setup
* everything for repair_io_failure to do the rest for us.
*/
if (failrec->in_validation) {
BUG_ON(failrec->this_mirror != failed_mirror);
failrec->in_validation = 0;
failrec->this_mirror = 0;
}
failrec->failed_mirror = failed_mirror;
failrec->this_mirror++;
if (failrec->this_mirror == failed_mirror)
failrec->this_mirror++;
}
if (failrec->this_mirror > num_copies) {
btrfs_debug(fs_info,
"Check Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
num_copies, failrec->this_mirror, failed_mirror);
return false;
}
return true;
}
static bool btrfs_io_needs_validation(struct inode *inode, struct bio *bio)
{
u64 len = 0;
const u32 blocksize = inode->i_sb->s_blocksize;
/*
* If bi_status is BLK_STS_OK, then this was a checksum error, not an
* I/O error. In this case, we already know exactly which sector was
* bad, so we don't need to validate.
*/
if (bio->bi_status == BLK_STS_OK)
return false;
/*
* We need to validate each sector individually if the failed I/O was
* for multiple sectors.
*
* There are a few possible bios that can end up here:
* 1. A buffered read bio, which is not cloned.
* 2. A direct I/O read bio, which is cloned.
* 3. A (buffered or direct) repair bio, which is not cloned.
*
* For cloned bios (case 2), we can get the size from
* btrfs_io_bio->iter; for non-cloned bios (cases 1 and 3), we can get
* it from the bvecs.
*/
if (bio_flagged(bio, BIO_CLONED)) {
if (btrfs_io_bio(bio)->iter.bi_size > blocksize)
return true;
} else {
struct bio_vec *bvec;
int i;
bio_for_each_bvec_all(bvec, bio, i) {
len += bvec->bv_len;
if (len > blocksize)
return true;
}
}
return false;
}
blk_status_t btrfs_submit_read_repair(struct inode *inode,
struct bio *failed_bio, u32 bio_offset,
struct page *page, unsigned int pgoff,
u64 start, u64 end, int failed_mirror,
submit_bio_hook_t *submit_bio_hook)
{
struct io_failure_record *failrec;
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
struct btrfs_io_bio *failed_io_bio = btrfs_io_bio(failed_bio);
const int icsum = bio_offset >> fs_info->sectorsize_bits;
bool need_validation;
struct bio *repair_bio;
struct btrfs_io_bio *repair_io_bio;
blk_status_t status;
btrfs_debug(fs_info,
"repair read error: read error at %llu", start);
BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
failrec = btrfs_get_io_failure_record(inode, start, end);
if (IS_ERR(failrec))
return errno_to_blk_status(PTR_ERR(failrec));
need_validation = btrfs_io_needs_validation(inode, failed_bio);
if (!btrfs_check_repairable(inode, need_validation, failrec,
failed_mirror)) {
free_io_failure(failure_tree, tree, failrec);
return BLK_STS_IOERR;
}
repair_bio = btrfs_io_bio_alloc(1);
repair_io_bio = btrfs_io_bio(repair_bio);
repair_bio->bi_opf = REQ_OP_READ;
if (need_validation)
repair_bio->bi_opf |= REQ_FAILFAST_DEV;
repair_bio->bi_end_io = failed_bio->bi_end_io;
repair_bio->bi_iter.bi_sector = failrec->logical >> 9;
repair_bio->bi_private = failed_bio->bi_private;
if (failed_io_bio->csum) {
const u32 csum_size = fs_info->csum_size;
repair_io_bio->csum = repair_io_bio->csum_inline;
memcpy(repair_io_bio->csum,
failed_io_bio->csum + csum_size * icsum, csum_size);
}
bio_add_page(repair_bio, page, failrec->len, pgoff);
repair_io_bio->logical = failrec->start;
repair_io_bio->iter = repair_bio->bi_iter;
btrfs_debug(btrfs_sb(inode->i_sb),
"repair read error: submitting new read to mirror %d, in_validation=%d",
failrec->this_mirror, failrec->in_validation);
status = submit_bio_hook(inode, repair_bio, failrec->this_mirror,
failrec->bio_flags);
if (status) {
free_io_failure(failure_tree, tree, failrec);
bio_put(repair_bio);
}
return status;
}
/* lots and lots of room for performance fixes in the end_bio funcs */
void end_extent_writepage(struct page *page, int err, u64 start, u64 end)
{
int uptodate = (err == 0);
int ret = 0;
btrfs_writepage_endio_finish_ordered(page, start, end, uptodate);
if (!uptodate) {
ClearPageUptodate(page);
SetPageError(page);
ret = err < 0 ? err : -EIO;
mapping_set_error(page->mapping, ret);
}
}
/*
* after a writepage IO is done, we need to:
* clear the uptodate bits on error
* clear the writeback bits in the extent tree for this IO
* end_page_writeback if the page has no more pending IO
*
* Scheduling is not allowed, so the extent state tree is expected
* to have one and only one object corresponding to this IO.
*/
static void end_bio_extent_writepage(struct bio *bio)
{
int error = blk_status_to_errno(bio->bi_status);
struct bio_vec *bvec;
u64 start;
u64 end;
struct bvec_iter_all iter_all;
bool first_bvec = true;
ASSERT(!bio_flagged(bio, BIO_CLONED));
bio_for_each_segment_all(bvec, bio, iter_all) {
struct page *page = bvec->bv_page;
struct inode *inode = page->mapping->host;
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
/* We always issue full-page reads, but if some block
* in a page fails to read, blk_update_request() will
* advance bv_offset and adjust bv_len to compensate.
* Print a warning for nonzero offsets, and an error
* if they don't add up to a full page. */
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
if (bvec->bv_offset || bvec->bv_len != PAGE_SIZE) {
if (bvec->bv_offset + bvec->bv_len != PAGE_SIZE)
btrfs_err(fs_info,
"partial page write in btrfs with offset %u and length %u",
bvec->bv_offset, bvec->bv_len);
else
btrfs_info(fs_info,
"incomplete page write in btrfs with offset %u and length %u",
bvec->bv_offset, bvec->bv_len);
}
start = page_offset(page);
end = start + bvec->bv_offset + bvec->bv_len - 1;
if (first_bvec) {
btrfs_record_physical_zoned(inode, start, bio);
first_bvec = false;
}
end_extent_writepage(page, error, start, end);
end_page_writeback(page);
}
bio_put(bio);
}
btrfs: add structure to keep track of extent range in end_bio_extent_readpage In end_bio_extent_readpage() we had a strange dance around extent_start/extent_len. Hidden behind the strange dance is, it's just calling endio_readpage_release_extent() on each bvec range. Here is an example to explain the original work flow: Bio is for inode 257, containing 2 pages, for range [1M, 1M+8K) end_bio_extent_extent_readpage() entered |- extent_start = 0; |- extent_end = 0; |- bio_for_each_segment_all() { | |- /* Got the 1st bvec */ | |- start = SZ_1M; | |- end = SZ_1M + SZ_4K - 1; | |- update = 1; | |- if (extent_len == 0) { | | |- extent_start = start; /* SZ_1M */ | | |- extent_len = end + 1 - start; /* SZ_1M */ | | } | | | |- /* Got the 2nd bvec */ | |- start = SZ_1M + 4K; | |- end = SZ_1M + 4K - 1; | |- update = 1; | |- if (extent_start + extent_len == start) { | | |- extent_len += end + 1 - start; /* SZ_8K */ | | } | } /* All bio vec iterated */ | |- if (extent_len) { |- endio_readpage_release_extent(tree, extent_start, extent_len, update); /* extent_start == SZ_1M, extent_len == SZ_8K, uptodate = 1 */ As the above flow shows, the existing code in end_bio_extent_readpage() is accumulates extent_start/extent_len, and when the contiguous range stops, calls endio_readpage_release_extent() for the range. However current behavior has something not really considered: - The inode can change For bio, its pages don't need to have contiguous page_offset. This means, even pages from different inodes can be packed into one bio. - bvec cross page boundary There is a feature called multi-page bvec, where bvec->bv_len can go beyond bvec->bv_page boundary. - Poor readability This patch will address the problem: - Introduce a proper structure, processed_extent, to record processed extent range - Integrate inode/start/end/uptodate check into endio_readpage_release_extent() - Add more comment on each step. This should greatly improve the readability, now in end_bio_extent_readpage() there are only two endio_readpage_release_extent() calls. - Add inode check for contiguity Now we also ensure the inode is the same one before checking if the range is contiguous. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-13 12:51:28 +00:00
/*
* Record previously processed extent range
*
* For endio_readpage_release_extent() to handle a full extent range, reducing
* the extent io operations.
*/
struct processed_extent {
struct btrfs_inode *inode;
/* Start of the range in @inode */
u64 start;
/* End of the range in @inode */
btrfs: add structure to keep track of extent range in end_bio_extent_readpage In end_bio_extent_readpage() we had a strange dance around extent_start/extent_len. Hidden behind the strange dance is, it's just calling endio_readpage_release_extent() on each bvec range. Here is an example to explain the original work flow: Bio is for inode 257, containing 2 pages, for range [1M, 1M+8K) end_bio_extent_extent_readpage() entered |- extent_start = 0; |- extent_end = 0; |- bio_for_each_segment_all() { | |- /* Got the 1st bvec */ | |- start = SZ_1M; | |- end = SZ_1M + SZ_4K - 1; | |- update = 1; | |- if (extent_len == 0) { | | |- extent_start = start; /* SZ_1M */ | | |- extent_len = end + 1 - start; /* SZ_1M */ | | } | | | |- /* Got the 2nd bvec */ | |- start = SZ_1M + 4K; | |- end = SZ_1M + 4K - 1; | |- update = 1; | |- if (extent_start + extent_len == start) { | | |- extent_len += end + 1 - start; /* SZ_8K */ | | } | } /* All bio vec iterated */ | |- if (extent_len) { |- endio_readpage_release_extent(tree, extent_start, extent_len, update); /* extent_start == SZ_1M, extent_len == SZ_8K, uptodate = 1 */ As the above flow shows, the existing code in end_bio_extent_readpage() is accumulates extent_start/extent_len, and when the contiguous range stops, calls endio_readpage_release_extent() for the range. However current behavior has something not really considered: - The inode can change For bio, its pages don't need to have contiguous page_offset. This means, even pages from different inodes can be packed into one bio. - bvec cross page boundary There is a feature called multi-page bvec, where bvec->bv_len can go beyond bvec->bv_page boundary. - Poor readability This patch will address the problem: - Introduce a proper structure, processed_extent, to record processed extent range - Integrate inode/start/end/uptodate check into endio_readpage_release_extent() - Add more comment on each step. This should greatly improve the readability, now in end_bio_extent_readpage() there are only two endio_readpage_release_extent() calls. - Add inode check for contiguity Now we also ensure the inode is the same one before checking if the range is contiguous. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-13 12:51:28 +00:00
u64 end;
bool uptodate;
};
/*
* Try to release processed extent range
*
* May not release the extent range right now if the current range is
* contiguous to processed extent.
*
* Will release processed extent when any of @inode, @uptodate, the range is
* no longer contiguous to the processed range.
*
* Passing @inode == NULL will force processed extent to be released.
*/
static void endio_readpage_release_extent(struct processed_extent *processed,
struct btrfs_inode *inode, u64 start, u64 end,
bool uptodate)
{
struct extent_state *cached = NULL;
btrfs: add structure to keep track of extent range in end_bio_extent_readpage In end_bio_extent_readpage() we had a strange dance around extent_start/extent_len. Hidden behind the strange dance is, it's just calling endio_readpage_release_extent() on each bvec range. Here is an example to explain the original work flow: Bio is for inode 257, containing 2 pages, for range [1M, 1M+8K) end_bio_extent_extent_readpage() entered |- extent_start = 0; |- extent_end = 0; |- bio_for_each_segment_all() { | |- /* Got the 1st bvec */ | |- start = SZ_1M; | |- end = SZ_1M + SZ_4K - 1; | |- update = 1; | |- if (extent_len == 0) { | | |- extent_start = start; /* SZ_1M */ | | |- extent_len = end + 1 - start; /* SZ_1M */ | | } | | | |- /* Got the 2nd bvec */ | |- start = SZ_1M + 4K; | |- end = SZ_1M + 4K - 1; | |- update = 1; | |- if (extent_start + extent_len == start) { | | |- extent_len += end + 1 - start; /* SZ_8K */ | | } | } /* All bio vec iterated */ | |- if (extent_len) { |- endio_readpage_release_extent(tree, extent_start, extent_len, update); /* extent_start == SZ_1M, extent_len == SZ_8K, uptodate = 1 */ As the above flow shows, the existing code in end_bio_extent_readpage() is accumulates extent_start/extent_len, and when the contiguous range stops, calls endio_readpage_release_extent() for the range. However current behavior has something not really considered: - The inode can change For bio, its pages don't need to have contiguous page_offset. This means, even pages from different inodes can be packed into one bio. - bvec cross page boundary There is a feature called multi-page bvec, where bvec->bv_len can go beyond bvec->bv_page boundary. - Poor readability This patch will address the problem: - Introduce a proper structure, processed_extent, to record processed extent range - Integrate inode/start/end/uptodate check into endio_readpage_release_extent() - Add more comment on each step. This should greatly improve the readability, now in end_bio_extent_readpage() there are only two endio_readpage_release_extent() calls. - Add inode check for contiguity Now we also ensure the inode is the same one before checking if the range is contiguous. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-13 12:51:28 +00:00
struct extent_io_tree *tree;
/* The first extent, initialize @processed */
if (!processed->inode)
goto update;
btrfs: add structure to keep track of extent range in end_bio_extent_readpage In end_bio_extent_readpage() we had a strange dance around extent_start/extent_len. Hidden behind the strange dance is, it's just calling endio_readpage_release_extent() on each bvec range. Here is an example to explain the original work flow: Bio is for inode 257, containing 2 pages, for range [1M, 1M+8K) end_bio_extent_extent_readpage() entered |- extent_start = 0; |- extent_end = 0; |- bio_for_each_segment_all() { | |- /* Got the 1st bvec */ | |- start = SZ_1M; | |- end = SZ_1M + SZ_4K - 1; | |- update = 1; | |- if (extent_len == 0) { | | |- extent_start = start; /* SZ_1M */ | | |- extent_len = end + 1 - start; /* SZ_1M */ | | } | | | |- /* Got the 2nd bvec */ | |- start = SZ_1M + 4K; | |- end = SZ_1M + 4K - 1; | |- update = 1; | |- if (extent_start + extent_len == start) { | | |- extent_len += end + 1 - start; /* SZ_8K */ | | } | } /* All bio vec iterated */ | |- if (extent_len) { |- endio_readpage_release_extent(tree, extent_start, extent_len, update); /* extent_start == SZ_1M, extent_len == SZ_8K, uptodate = 1 */ As the above flow shows, the existing code in end_bio_extent_readpage() is accumulates extent_start/extent_len, and when the contiguous range stops, calls endio_readpage_release_extent() for the range. However current behavior has something not really considered: - The inode can change For bio, its pages don't need to have contiguous page_offset. This means, even pages from different inodes can be packed into one bio. - bvec cross page boundary There is a feature called multi-page bvec, where bvec->bv_len can go beyond bvec->bv_page boundary. - Poor readability This patch will address the problem: - Introduce a proper structure, processed_extent, to record processed extent range - Integrate inode/start/end/uptodate check into endio_readpage_release_extent() - Add more comment on each step. This should greatly improve the readability, now in end_bio_extent_readpage() there are only two endio_readpage_release_extent() calls. - Add inode check for contiguity Now we also ensure the inode is the same one before checking if the range is contiguous. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-13 12:51:28 +00:00
/*
* Contiguous to processed extent, just uptodate the end.
*
* Several things to notice:
*
* - bio can be merged as long as on-disk bytenr is contiguous
* This means we can have page belonging to other inodes, thus need to
* check if the inode still matches.
* - bvec can contain range beyond current page for multi-page bvec
* Thus we need to do processed->end + 1 >= start check
*/
if (processed->inode == inode && processed->uptodate == uptodate &&
processed->end + 1 >= start && end >= processed->end) {
processed->end = end;
return;
}
tree = &processed->inode->io_tree;
/*
* Now we don't have range contiguous to the processed range, release
* the processed range now.
*/
if (processed->uptodate && tree->track_uptodate)
set_extent_uptodate(tree, processed->start, processed->end,
&cached, GFP_ATOMIC);
unlock_extent_cached_atomic(tree, processed->start, processed->end,
&cached);
update:
/* Update processed to current range */
processed->inode = inode;
processed->start = start;
processed->end = end;
processed->uptodate = uptodate;
}
btrfs: integrate page status update for data read path into begin/end_page_read In btrfs data page read path, the page status update are handled in two different locations: btrfs_do_read_page() { while (cur <= end) { /* No need to read from disk */ if (HOLE/PREALLOC/INLINE){ memset(); set_extent_uptodate(); continue; } /* Read from disk */ ret = submit_extent_page(end_bio_extent_readpage); } end_bio_extent_readpage() { endio_readpage_uptodate_page_status(); } This is fine for sectorsize == PAGE_SIZE case, as for above loop we should only hit one branch and then exit. But for subpage, there is more work to be done in page status update: - Page Unlock condition Unlike regular page size == sectorsize case, we can no longer just unlock a page. Only the last reader of the page can unlock the page. This means, we can unlock the page either in the while() loop, or in the endio function. - Page uptodate condition Since we have multiple sectors to read for a page, we can only mark the full page uptodate if all sectors are uptodate. To handle both subpage and regular cases, introduce a pair of functions to help handling page status update: - begin_page_read() For regular case, it does nothing. For subpage case, it updates the reader counters so that later end_page_read() can know who is the last one to unlock the page. - end_page_read() This is just endio_readpage_uptodate_page_status() renamed. The original name is a little too long and too specific for endio. The new thing added is the condition for page unlock. Now for subpage data, we unlock the page if we're the last reader. This does not only provide the basis for subpage data read, but also hide the special handling of page read from the main read loop. Also, since we're changing how the page lock is handled, there are two existing error paths where we need to manually unlock the page before calling begin_page_read(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-02 02:28:36 +00:00
static void begin_page_read(struct btrfs_fs_info *fs_info, struct page *page)
{
ASSERT(PageLocked(page));
if (fs_info->sectorsize == PAGE_SIZE)
return;
ASSERT(PagePrivate(page));
btrfs_subpage_start_reader(fs_info, page, page_offset(page), PAGE_SIZE);
}
static void end_page_read(struct page *page, bool uptodate, u64 start, u32 len)
{
struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
ASSERT(page_offset(page) <= start &&
start + len <= page_offset(page) + PAGE_SIZE);
if (uptodate) {
btrfs_page_set_uptodate(fs_info, page, start, len);
} else {
btrfs_page_clear_uptodate(fs_info, page, start, len);
btrfs_page_set_error(fs_info, page, start, len);
}
if (fs_info->sectorsize == PAGE_SIZE)
unlock_page(page);
btrfs: integrate page status update for data read path into begin/end_page_read In btrfs data page read path, the page status update are handled in two different locations: btrfs_do_read_page() { while (cur <= end) { /* No need to read from disk */ if (HOLE/PREALLOC/INLINE){ memset(); set_extent_uptodate(); continue; } /* Read from disk */ ret = submit_extent_page(end_bio_extent_readpage); } end_bio_extent_readpage() { endio_readpage_uptodate_page_status(); } This is fine for sectorsize == PAGE_SIZE case, as for above loop we should only hit one branch and then exit. But for subpage, there is more work to be done in page status update: - Page Unlock condition Unlike regular page size == sectorsize case, we can no longer just unlock a page. Only the last reader of the page can unlock the page. This means, we can unlock the page either in the while() loop, or in the endio function. - Page uptodate condition Since we have multiple sectors to read for a page, we can only mark the full page uptodate if all sectors are uptodate. To handle both subpage and regular cases, introduce a pair of functions to help handling page status update: - begin_page_read() For regular case, it does nothing. For subpage case, it updates the reader counters so that later end_page_read() can know who is the last one to unlock the page. - end_page_read() This is just endio_readpage_uptodate_page_status() renamed. The original name is a little too long and too specific for endio. The new thing added is the condition for page unlock. Now for subpage data, we unlock the page if we're the last reader. This does not only provide the basis for subpage data read, but also hide the special handling of page read from the main read loop. Also, since we're changing how the page lock is handled, there are two existing error paths where we need to manually unlock the page before calling begin_page_read(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-02 02:28:36 +00:00
else if (is_data_inode(page->mapping->host))
/*
* For subpage data, unlock the page if we're the last reader.
* For subpage metadata, page lock is not utilized for read.
*/
btrfs_subpage_end_reader(fs_info, page, start, len);
}
btrfs: subpage: fix wild pointer access during metadata read failure [BUG] When running fstests for btrfs subpage read-write test, it has a very high chance to crash at generic/475 with the following stack: BTRFS warning (device dm-8): direct IO failed ino 510 rw 1,34817 sector 0xcdf0 len 94208 err no 10 Unable to handle kernel paging request at virtual address ffff80001157e7c0 CPU: 2 PID: 687125 Comm: kworker/u12:4 Tainted: G WC 5.12.0-rc2-custom+ #5 Hardware name: Khadas VIM3 (DT) Workqueue: btrfs-endio-meta btrfs_work_helper [btrfs] pc : queued_spin_lock_slowpath+0x1a0/0x390 lr : do_raw_spin_lock+0xc4/0x11c Call trace: queued_spin_lock_slowpath+0x1a0/0x390 _raw_spin_lock+0x68/0x84 btree_readahead_hook+0x38/0xc0 [btrfs] end_bio_extent_readpage+0x504/0x5f4 [btrfs] bio_endio+0x170/0x1a4 end_workqueue_fn+0x3c/0x60 [btrfs] btrfs_work_helper+0x1b0/0x1b4 [btrfs] process_one_work+0x22c/0x430 worker_thread+0x70/0x3a0 kthread+0x13c/0x140 ret_from_fork+0x10/0x30 Code: 910020e0 8b0200c2 f861d884 aa0203e1 (f8246827) [CAUSE] In end_bio_extent_readpage(), if we hit an error during read, we will handle the error differently for data and metadata. For data we queue a repair, while for metadata, we record the error and let the caller choose what to do. But the code is still using page->private to grab extent buffer, which no longer points to extent buffer for subpage metadata pages. Thus this wild pointer access leads to above crash. [FIX] Introduce a helper, find_extent_buffer_readpage(), to grab extent buffer. The difference against find_extent_buffer_nospinlock() is: - Also handles regular sectorsize == PAGE_SIZE case - No extent buffer refs increase/decrease As extent buffer under IO must have non-zero refs, so this is safe Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-03-15 05:39:14 +00:00
/*
* Find extent buffer for a givne bytenr.
*
* This is for end_bio_extent_readpage(), thus we can't do any unsafe locking
* in endio context.
*/
static struct extent_buffer *find_extent_buffer_readpage(
struct btrfs_fs_info *fs_info, struct page *page, u64 bytenr)
{
struct extent_buffer *eb;
/*
* For regular sectorsize, we can use page->private to grab extent
* buffer
*/
if (fs_info->sectorsize == PAGE_SIZE) {
ASSERT(PagePrivate(page) && page->private);
return (struct extent_buffer *)page->private;
}
/* For subpage case, we need to lookup buffer radix tree */
rcu_read_lock();
eb = radix_tree_lookup(&fs_info->buffer_radix,
bytenr >> fs_info->sectorsize_bits);
rcu_read_unlock();
ASSERT(eb);
return eb;
}
/*
* after a readpage IO is done, we need to:
* clear the uptodate bits on error
* set the uptodate bits if things worked
* set the page up to date if all extents in the tree are uptodate
* clear the lock bit in the extent tree
* unlock the page if there are no other extents locked for it
*
* Scheduling is not allowed, so the extent state tree is expected
* to have one and only one object corresponding to this IO.
*/
static void end_bio_extent_readpage(struct bio *bio)
{
struct bio_vec *bvec;
int uptodate = !bio->bi_status;
struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
struct extent_io_tree *tree, *failure_tree;
btrfs: add structure to keep track of extent range in end_bio_extent_readpage In end_bio_extent_readpage() we had a strange dance around extent_start/extent_len. Hidden behind the strange dance is, it's just calling endio_readpage_release_extent() on each bvec range. Here is an example to explain the original work flow: Bio is for inode 257, containing 2 pages, for range [1M, 1M+8K) end_bio_extent_extent_readpage() entered |- extent_start = 0; |- extent_end = 0; |- bio_for_each_segment_all() { | |- /* Got the 1st bvec */ | |- start = SZ_1M; | |- end = SZ_1M + SZ_4K - 1; | |- update = 1; | |- if (extent_len == 0) { | | |- extent_start = start; /* SZ_1M */ | | |- extent_len = end + 1 - start; /* SZ_1M */ | | } | | | |- /* Got the 2nd bvec */ | |- start = SZ_1M + 4K; | |- end = SZ_1M + 4K - 1; | |- update = 1; | |- if (extent_start + extent_len == start) { | | |- extent_len += end + 1 - start; /* SZ_8K */ | | } | } /* All bio vec iterated */ | |- if (extent_len) { |- endio_readpage_release_extent(tree, extent_start, extent_len, update); /* extent_start == SZ_1M, extent_len == SZ_8K, uptodate = 1 */ As the above flow shows, the existing code in end_bio_extent_readpage() is accumulates extent_start/extent_len, and when the contiguous range stops, calls endio_readpage_release_extent() for the range. However current behavior has something not really considered: - The inode can change For bio, its pages don't need to have contiguous page_offset. This means, even pages from different inodes can be packed into one bio. - bvec cross page boundary There is a feature called multi-page bvec, where bvec->bv_len can go beyond bvec->bv_page boundary. - Poor readability This patch will address the problem: - Introduce a proper structure, processed_extent, to record processed extent range - Integrate inode/start/end/uptodate check into endio_readpage_release_extent() - Add more comment on each step. This should greatly improve the readability, now in end_bio_extent_readpage() there are only two endio_readpage_release_extent() calls. - Add inode check for contiguity Now we also ensure the inode is the same one before checking if the range is contiguous. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-13 12:51:28 +00:00
struct processed_extent processed = { 0 };
/*
* The offset to the beginning of a bio, since one bio can never be
* larger than UINT_MAX, u32 here is enough.
*/
u32 bio_offset = 0;
int mirror;
int ret;
struct bvec_iter_all iter_all;
ASSERT(!bio_flagged(bio, BIO_CLONED));
bio_for_each_segment_all(bvec, bio, iter_all) {
struct page *page = bvec->bv_page;
struct inode *inode = page->mapping->host;
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
const u32 sectorsize = fs_info->sectorsize;
u64 start;
u64 end;
u32 len;
btrfs_debug(fs_info,
"end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
bio->bi_iter.bi_sector, bio->bi_status,
io_bio->mirror_num);
tree = &BTRFS_I(inode)->io_tree;
failure_tree = &BTRFS_I(inode)->io_failure_tree;
/*
* We always issue full-sector reads, but if some block in a
* page fails to read, blk_update_request() will advance
* bv_offset and adjust bv_len to compensate. Print a warning
* for unaligned offsets, and an error if they don't add up to
* a full sector.
*/
if (!IS_ALIGNED(bvec->bv_offset, sectorsize))
btrfs_err(fs_info,
"partial page read in btrfs with offset %u and length %u",
bvec->bv_offset, bvec->bv_len);
else if (!IS_ALIGNED(bvec->bv_offset + bvec->bv_len,
sectorsize))
btrfs_info(fs_info,
"incomplete page read with offset %u and length %u",
bvec->bv_offset, bvec->bv_len);
start = page_offset(page) + bvec->bv_offset;
end = start + bvec->bv_len - 1;
len = bvec->bv_len;
mirror = io_bio->mirror_num;
if (likely(uptodate)) {
if (is_data_inode(inode))
ret = btrfs_verify_data_csum(io_bio,
bio_offset, page, start, end);
else
ret = btrfs_validate_metadata_buffer(io_bio,
page, start, end, mirror);
if (ret)
uptodate = 0;
else
clean_io_failure(BTRFS_I(inode)->root->fs_info,
failure_tree, tree, start,
page,
btrfs_ino(BTRFS_I(inode)), 0);
}
if (likely(uptodate))
goto readpage_ok;
if (is_data_inode(inode)) {
/*
* The generic bio_readpage_error handles errors the
* following way: If possible, new read requests are
* created and submitted and will end up in
* end_bio_extent_readpage as well (if we're lucky,
* not in the !uptodate case). In that case it returns
* 0 and we just go on with the next page in our bio.
* If it can't handle the error it will return -EIO and
* we remain responsible for that page.
*/
if (!btrfs_submit_read_repair(inode, bio, bio_offset,
page,
start - page_offset(page),
start, end, mirror,
btrfs_submit_data_bio)) {
uptodate = !bio->bi_status;
ASSERT(bio_offset + len > bio_offset);
bio_offset += len;
continue;
}
} else {
struct extent_buffer *eb;
btrfs: subpage: fix wild pointer access during metadata read failure [BUG] When running fstests for btrfs subpage read-write test, it has a very high chance to crash at generic/475 with the following stack: BTRFS warning (device dm-8): direct IO failed ino 510 rw 1,34817 sector 0xcdf0 len 94208 err no 10 Unable to handle kernel paging request at virtual address ffff80001157e7c0 CPU: 2 PID: 687125 Comm: kworker/u12:4 Tainted: G WC 5.12.0-rc2-custom+ #5 Hardware name: Khadas VIM3 (DT) Workqueue: btrfs-endio-meta btrfs_work_helper [btrfs] pc : queued_spin_lock_slowpath+0x1a0/0x390 lr : do_raw_spin_lock+0xc4/0x11c Call trace: queued_spin_lock_slowpath+0x1a0/0x390 _raw_spin_lock+0x68/0x84 btree_readahead_hook+0x38/0xc0 [btrfs] end_bio_extent_readpage+0x504/0x5f4 [btrfs] bio_endio+0x170/0x1a4 end_workqueue_fn+0x3c/0x60 [btrfs] btrfs_work_helper+0x1b0/0x1b4 [btrfs] process_one_work+0x22c/0x430 worker_thread+0x70/0x3a0 kthread+0x13c/0x140 ret_from_fork+0x10/0x30 Code: 910020e0 8b0200c2 f861d884 aa0203e1 (f8246827) [CAUSE] In end_bio_extent_readpage(), if we hit an error during read, we will handle the error differently for data and metadata. For data we queue a repair, while for metadata, we record the error and let the caller choose what to do. But the code is still using page->private to grab extent buffer, which no longer points to extent buffer for subpage metadata pages. Thus this wild pointer access leads to above crash. [FIX] Introduce a helper, find_extent_buffer_readpage(), to grab extent buffer. The difference against find_extent_buffer_nospinlock() is: - Also handles regular sectorsize == PAGE_SIZE case - No extent buffer refs increase/decrease As extent buffer under IO must have non-zero refs, so this is safe Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-03-15 05:39:14 +00:00
eb = find_extent_buffer_readpage(fs_info, page, start);
set_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
eb->read_mirror = mirror;
atomic_dec(&eb->io_pages);
if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD,
&eb->bflags))
btree_readahead_hook(eb, -EIO);
}
readpage_ok:
if (likely(uptodate)) {
loff_t i_size = i_size_read(inode);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
pgoff_t end_index = i_size >> PAGE_SHIFT;
btrfs: subpage: fix the false data csum mismatch error [BUG] When running fstresss, we can hit strange data csum mismatch where the on-disk data is in fact correct (passes scrub). With some extra debug info added, we have the following traces: 0482us: btrfs_do_readpage: root=5 ino=284 offset=393216, submit force=0 pgoff=0 iosize=8192 0494us: btrfs_do_readpage: root=5 ino=284 offset=401408, submit force=0 pgoff=8192 iosize=4096 0498us: btrfs_submit_data_bio: root=5 ino=284 bio first bvec=393216 len=8192 0591us: btrfs_do_readpage: root=5 ino=284 offset=405504, submit force=0 pgoff=12288 iosize=36864 0594us: btrfs_submit_data_bio: root=5 ino=284 bio first bvec=401408 len=4096 0863us: btrfs_submit_data_bio: root=5 ino=284 bio first bvec=405504 len=36864 0933us: btrfs_verify_data_csum: root=5 ino=284 offset=393216 len=8192 0967us: btrfs_do_readpage: root=5 ino=284 offset=442368, skip beyond isize pgoff=49152 iosize=16384 1047us: btrfs_verify_data_csum: root=5 ino=284 offset=401408 len=4096 1163us: btrfs_verify_data_csum: root=5 ino=284 offset=405504 len=36864 1290us: check_data_csum: !!! root=5 ino=284 offset=438272 pg_off=45056 !!! 7387us: end_bio_extent_readpage: root=5 ino=284 before pending_read_bios=0 [CAUSE] Normally we expect all submitted bio reads to only touch the range we specified, and under subpage context, it means we should only touch the range specified in each bvec. But in data read path, inside end_bio_extent_readpage(), we have page zeroing which only takes regular page size into consideration. This means for subpage if we have an inode whose content looks like below: 0 16K 32K 48K 64K |///////| |///////| | |//| = data needs to be read from disk | | = hole And i_size is 64K initially. Then the following race can happen: T1 | T2 --------------------------------+-------------------------------- btrfs_do_readpage() | |- isize = 64K; | | At this time, the isize is | | 64K | | | |- submit_extent_page() | | submit previous assembled bio| | assemble bio for [0, 16K) | | | |- submit_extent_page() | submit read bio for [0, 16K) | assemble read bio for | [32K, 48K) | | | btrfs_setsize() | |- i_size_write(, 16K); | Now i_size is only 16K end_io() for [0K, 16K) | |- end_bio_extent_readpage() | |- btrfs_verify_data_csum() | | No csum error | |- i_size = 16K; | |- zero_user_segment(16K, | PAGE_SIZE); | !!! We zeroed range | !!! [32K, 48K) | | end_io for [32K, 48K) | |- end_bio_extent_readpage() | |- btrfs_verify_data_csum() | ! CSUM MISMATCH ! | ! As the range is zeroed now ! [FIX] To fix the problem, make end_bio_extent_readpage() to only zero the range of bvec. The bug only affects subpage read-write support, as for full read-only mount we can't change i_size thus won't hit the race condition. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-03-01 08:44:22 +00:00
/*
* Zero out the remaining part if this range straddles
* i_size.
*
* Here we should only zero the range inside the bvec,
* not touch anything else.
*
* NOTE: i_size is exclusive while end is inclusive.
*/
if (page->index == end_index && i_size <= end) {
u32 zero_start = max(offset_in_page(i_size),
btrfs: fix wrong offset to zero out range beyond i_size [BUG] The test generic/091 fails , with the following output: fsx -N 10000 -o 128000 -l 500000 -r PSIZE -t BSIZE -w BSIZE -Z -W mapped writes DISABLED Seed set to 1 main: filesystem does not support fallocate mode FALLOC_FL_COLLAPSE_RANGE, disabling! main: filesystem does not support fallocate mode FALLOC_FL_INSERT_RANGE, disabling! skipping zero size read truncating to largest ever: 0xe400 copying to largest ever: 0x1f400 cloning to largest ever: 0x70000 cloning to largest ever: 0x77000 fallocating to largest ever: 0x7a120 Mapped Read: non-zero data past EOF (0x3a7ff) page offset 0x800 is 0xf2e1 <<< ... [CAUSE] In commit c28ea613fafa ("btrfs: subpage: fix the false data csum mismatch error") end_bio_extent_readpage() changes to only zero the range inside the bvec for incoming subpage support. But that commit is using incorrect offset to calculate the start. For subpage, we can have a case that the whole bvec is beyond isize, thus we need to calculate the correct offset. But the offending commit is using @end (bvec end), other than @start (bvec start) to calculate the start offset. This means, we only zero the last byte of the bvec, not from the isize. This stupid bug makes the range beyond isize is not properly zeroed, and failed above test. [FIX] Use correct @start to calculate the range start. Reported-by: kernel test robot <oliver.sang@intel.com> Fixes: c28ea613fafa ("btrfs: subpage: fix the false data csum mismatch error") Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-03-08 09:20:17 +00:00
offset_in_page(start));
btrfs: subpage: fix the false data csum mismatch error [BUG] When running fstresss, we can hit strange data csum mismatch where the on-disk data is in fact correct (passes scrub). With some extra debug info added, we have the following traces: 0482us: btrfs_do_readpage: root=5 ino=284 offset=393216, submit force=0 pgoff=0 iosize=8192 0494us: btrfs_do_readpage: root=5 ino=284 offset=401408, submit force=0 pgoff=8192 iosize=4096 0498us: btrfs_submit_data_bio: root=5 ino=284 bio first bvec=393216 len=8192 0591us: btrfs_do_readpage: root=5 ino=284 offset=405504, submit force=0 pgoff=12288 iosize=36864 0594us: btrfs_submit_data_bio: root=5 ino=284 bio first bvec=401408 len=4096 0863us: btrfs_submit_data_bio: root=5 ino=284 bio first bvec=405504 len=36864 0933us: btrfs_verify_data_csum: root=5 ino=284 offset=393216 len=8192 0967us: btrfs_do_readpage: root=5 ino=284 offset=442368, skip beyond isize pgoff=49152 iosize=16384 1047us: btrfs_verify_data_csum: root=5 ino=284 offset=401408 len=4096 1163us: btrfs_verify_data_csum: root=5 ino=284 offset=405504 len=36864 1290us: check_data_csum: !!! root=5 ino=284 offset=438272 pg_off=45056 !!! 7387us: end_bio_extent_readpage: root=5 ino=284 before pending_read_bios=0 [CAUSE] Normally we expect all submitted bio reads to only touch the range we specified, and under subpage context, it means we should only touch the range specified in each bvec. But in data read path, inside end_bio_extent_readpage(), we have page zeroing which only takes regular page size into consideration. This means for subpage if we have an inode whose content looks like below: 0 16K 32K 48K 64K |///////| |///////| | |//| = data needs to be read from disk | | = hole And i_size is 64K initially. Then the following race can happen: T1 | T2 --------------------------------+-------------------------------- btrfs_do_readpage() | |- isize = 64K; | | At this time, the isize is | | 64K | | | |- submit_extent_page() | | submit previous assembled bio| | assemble bio for [0, 16K) | | | |- submit_extent_page() | submit read bio for [0, 16K) | assemble read bio for | [32K, 48K) | | | btrfs_setsize() | |- i_size_write(, 16K); | Now i_size is only 16K end_io() for [0K, 16K) | |- end_bio_extent_readpage() | |- btrfs_verify_data_csum() | | No csum error | |- i_size = 16K; | |- zero_user_segment(16K, | PAGE_SIZE); | !!! We zeroed range | !!! [32K, 48K) | | end_io for [32K, 48K) | |- end_bio_extent_readpage() | |- btrfs_verify_data_csum() | ! CSUM MISMATCH ! | ! As the range is zeroed now ! [FIX] To fix the problem, make end_bio_extent_readpage() to only zero the range of bvec. The bug only affects subpage read-write support, as for full read-only mount we can't change i_size thus won't hit the race condition. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-03-01 08:44:22 +00:00
zero_user_segment(page, zero_start,
offset_in_page(end) + 1);
}
}
ASSERT(bio_offset + len > bio_offset);
bio_offset += len;
/* Update page status and unlock */
btrfs: integrate page status update for data read path into begin/end_page_read In btrfs data page read path, the page status update are handled in two different locations: btrfs_do_read_page() { while (cur <= end) { /* No need to read from disk */ if (HOLE/PREALLOC/INLINE){ memset(); set_extent_uptodate(); continue; } /* Read from disk */ ret = submit_extent_page(end_bio_extent_readpage); } end_bio_extent_readpage() { endio_readpage_uptodate_page_status(); } This is fine for sectorsize == PAGE_SIZE case, as for above loop we should only hit one branch and then exit. But for subpage, there is more work to be done in page status update: - Page Unlock condition Unlike regular page size == sectorsize case, we can no longer just unlock a page. Only the last reader of the page can unlock the page. This means, we can unlock the page either in the while() loop, or in the endio function. - Page uptodate condition Since we have multiple sectors to read for a page, we can only mark the full page uptodate if all sectors are uptodate. To handle both subpage and regular cases, introduce a pair of functions to help handling page status update: - begin_page_read() For regular case, it does nothing. For subpage case, it updates the reader counters so that later end_page_read() can know who is the last one to unlock the page. - end_page_read() This is just endio_readpage_uptodate_page_status() renamed. The original name is a little too long and too specific for endio. The new thing added is the condition for page unlock. Now for subpage data, we unlock the page if we're the last reader. This does not only provide the basis for subpage data read, but also hide the special handling of page read from the main read loop. Also, since we're changing how the page lock is handled, there are two existing error paths where we need to manually unlock the page before calling begin_page_read(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-02 02:28:36 +00:00
end_page_read(page, uptodate, start, len);
btrfs: add structure to keep track of extent range in end_bio_extent_readpage In end_bio_extent_readpage() we had a strange dance around extent_start/extent_len. Hidden behind the strange dance is, it's just calling endio_readpage_release_extent() on each bvec range. Here is an example to explain the original work flow: Bio is for inode 257, containing 2 pages, for range [1M, 1M+8K) end_bio_extent_extent_readpage() entered |- extent_start = 0; |- extent_end = 0; |- bio_for_each_segment_all() { | |- /* Got the 1st bvec */ | |- start = SZ_1M; | |- end = SZ_1M + SZ_4K - 1; | |- update = 1; | |- if (extent_len == 0) { | | |- extent_start = start; /* SZ_1M */ | | |- extent_len = end + 1 - start; /* SZ_1M */ | | } | | | |- /* Got the 2nd bvec */ | |- start = SZ_1M + 4K; | |- end = SZ_1M + 4K - 1; | |- update = 1; | |- if (extent_start + extent_len == start) { | | |- extent_len += end + 1 - start; /* SZ_8K */ | | } | } /* All bio vec iterated */ | |- if (extent_len) { |- endio_readpage_release_extent(tree, extent_start, extent_len, update); /* extent_start == SZ_1M, extent_len == SZ_8K, uptodate = 1 */ As the above flow shows, the existing code in end_bio_extent_readpage() is accumulates extent_start/extent_len, and when the contiguous range stops, calls endio_readpage_release_extent() for the range. However current behavior has something not really considered: - The inode can change For bio, its pages don't need to have contiguous page_offset. This means, even pages from different inodes can be packed into one bio. - bvec cross page boundary There is a feature called multi-page bvec, where bvec->bv_len can go beyond bvec->bv_page boundary. - Poor readability This patch will address the problem: - Introduce a proper structure, processed_extent, to record processed extent range - Integrate inode/start/end/uptodate check into endio_readpage_release_extent() - Add more comment on each step. This should greatly improve the readability, now in end_bio_extent_readpage() there are only two endio_readpage_release_extent() calls. - Add inode check for contiguity Now we also ensure the inode is the same one before checking if the range is contiguous. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-13 12:51:28 +00:00
endio_readpage_release_extent(&processed, BTRFS_I(inode),
start, end, uptodate);
}
btrfs: add structure to keep track of extent range in end_bio_extent_readpage In end_bio_extent_readpage() we had a strange dance around extent_start/extent_len. Hidden behind the strange dance is, it's just calling endio_readpage_release_extent() on each bvec range. Here is an example to explain the original work flow: Bio is for inode 257, containing 2 pages, for range [1M, 1M+8K) end_bio_extent_extent_readpage() entered |- extent_start = 0; |- extent_end = 0; |- bio_for_each_segment_all() { | |- /* Got the 1st bvec */ | |- start = SZ_1M; | |- end = SZ_1M + SZ_4K - 1; | |- update = 1; | |- if (extent_len == 0) { | | |- extent_start = start; /* SZ_1M */ | | |- extent_len = end + 1 - start; /* SZ_1M */ | | } | | | |- /* Got the 2nd bvec */ | |- start = SZ_1M + 4K; | |- end = SZ_1M + 4K - 1; | |- update = 1; | |- if (extent_start + extent_len == start) { | | |- extent_len += end + 1 - start; /* SZ_8K */ | | } | } /* All bio vec iterated */ | |- if (extent_len) { |- endio_readpage_release_extent(tree, extent_start, extent_len, update); /* extent_start == SZ_1M, extent_len == SZ_8K, uptodate = 1 */ As the above flow shows, the existing code in end_bio_extent_readpage() is accumulates extent_start/extent_len, and when the contiguous range stops, calls endio_readpage_release_extent() for the range. However current behavior has something not really considered: - The inode can change For bio, its pages don't need to have contiguous page_offset. This means, even pages from different inodes can be packed into one bio. - bvec cross page boundary There is a feature called multi-page bvec, where bvec->bv_len can go beyond bvec->bv_page boundary. - Poor readability This patch will address the problem: - Introduce a proper structure, processed_extent, to record processed extent range - Integrate inode/start/end/uptodate check into endio_readpage_release_extent() - Add more comment on each step. This should greatly improve the readability, now in end_bio_extent_readpage() there are only two endio_readpage_release_extent() calls. - Add inode check for contiguity Now we also ensure the inode is the same one before checking if the range is contiguous. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-13 12:51:28 +00:00
/* Release the last extent */
endio_readpage_release_extent(&processed, NULL, 0, 0, false);
btrfs_io_bio_free_csum(io_bio);
bio_put(bio);
}
/*
* Initialize the members up to but not including 'bio'. Use after allocating a
* new bio by bio_alloc_bioset as it does not initialize the bytes outside of
* 'bio' because use of __GFP_ZERO is not supported.
*/
static inline void btrfs_io_bio_init(struct btrfs_io_bio *btrfs_bio)
{
memset(btrfs_bio, 0, offsetof(struct btrfs_io_bio, bio));
}
/*
* The following helpers allocate a bio. As it's backed by a bioset, it'll
* never fail. We're returning a bio right now but you can call btrfs_io_bio
* for the appropriate container_of magic
*/
struct bio *btrfs_bio_alloc(u64 first_byte)
{
struct bio *bio;
bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_VECS, &btrfs_bioset);
bio->bi_iter.bi_sector = first_byte >> 9;
btrfs_io_bio_init(btrfs_io_bio(bio));
return bio;
}
struct bio *btrfs_bio_clone(struct bio *bio)
{
struct btrfs_io_bio *btrfs_bio;
struct bio *new;
/* Bio allocation backed by a bioset does not fail */
new = bio_clone_fast(bio, GFP_NOFS, &btrfs_bioset);
btrfs_bio = btrfs_io_bio(new);
btrfs_io_bio_init(btrfs_bio);
btrfs_bio->iter = bio->bi_iter;
return new;
}
struct bio *btrfs_io_bio_alloc(unsigned int nr_iovecs)
{
struct bio *bio;
/* Bio allocation backed by a bioset does not fail */
bio = bio_alloc_bioset(GFP_NOFS, nr_iovecs, &btrfs_bioset);
btrfs_io_bio_init(btrfs_io_bio(bio));
return bio;
}
struct bio *btrfs_bio_clone_partial(struct bio *orig, int offset, int size)
{
struct bio *bio;
struct btrfs_io_bio *btrfs_bio;
/* this will never fail when it's backed by a bioset */
bio = bio_clone_fast(orig, GFP_NOFS, &btrfs_bioset);
ASSERT(bio);
btrfs_bio = btrfs_io_bio(bio);
btrfs_io_bio_init(btrfs_bio);
bio_trim(bio, offset >> 9, size >> 9);
btrfs_bio->iter = bio->bi_iter;
return bio;
}
/**
* Attempt to add a page to bio
*
* @bio: destination bio
* @page: page to add to the bio
* @disk_bytenr: offset of the new bio or to check whether we are adding
* a contiguous page to the previous one
* @pg_offset: starting offset in the page
* @size: portion of page that we want to write
* @prev_bio_flags: flags of previous bio to see if we can merge the current one
* @bio_flags: flags of the current bio to see if we can merge them
* @return: true if page was added, false otherwise
*
* Attempt to add a page to bio considering stripe alignment etc.
*
* Return true if successfully page added. Otherwise, return false.
*/
static bool btrfs_bio_add_page(struct bio *bio, struct page *page,
u64 disk_bytenr, unsigned int size,
unsigned int pg_offset,
unsigned long prev_bio_flags,
unsigned long bio_flags)
{
const sector_t sector = disk_bytenr >> SECTOR_SHIFT;
bool contig;
int ret;
if (prev_bio_flags != bio_flags)
return false;
if (prev_bio_flags & EXTENT_BIO_COMPRESSED)
contig = bio->bi_iter.bi_sector == sector;
else
contig = bio_end_sector(bio) == sector;
if (!contig)
return false;
if (btrfs_bio_fits_in_stripe(page, size, bio, bio_flags))
return false;
if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
struct page *first_page = bio_first_bvec_all(bio)->bv_page;
if (!btrfs_bio_fits_in_ordered_extent(first_page, bio, size))
return false;
ret = bio_add_zone_append_page(bio, page, size, pg_offset);
} else {
ret = bio_add_page(bio, page, size, pg_offset);
}
return ret == size;
}
/*
* @opf: bio REQ_OP_* and REQ_* flags as one value
* @wbc: optional writeback control for io accounting
* @page: page to add to the bio
* @disk_bytenr: logical bytenr where the write will be
* @size: portion of page that we want to write to
* @pg_offset: offset of the new bio or to check whether we are adding
* a contiguous page to the previous one
* @bio_ret: must be valid pointer, newly allocated bio will be stored there
* @end_io_func: end_io callback for new bio
* @mirror_num: desired mirror to read/write
* @prev_bio_flags: flags of previous bio to see if we can merge the current one
* @bio_flags: flags of the current bio to see if we can merge them
*/
static int submit_extent_page(unsigned int opf,
struct writeback_control *wbc,
struct page *page, u64 disk_bytenr,
size_t size, unsigned long pg_offset,
struct bio **bio_ret,
bio_end_io_t end_io_func,
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
int mirror_num,
unsigned long prev_bio_flags,
Btrfs: fix read corruption of compressed and shared extents If a file has a range pointing to a compressed extent, followed by another range that points to the same compressed extent and a read operation attempts to read both ranges (either completely or part of them), the pages that correspond to the second range are incorrectly filled with zeroes. Consider the following example: File layout [0 - 8K] [8K - 24K] | | | | points to extent X, points to extent X, offset 4K, length of 8K offset 0, length 16K [extent X, compressed length = 4K uncompressed length = 16K] If a readpages() call spans the 2 ranges, a single bio to read the extent is submitted - extent_io.c:submit_extent_page() would only create a new bio to cover the second range pointing to the extent if the extent it points to had a different logical address than the extent associated with the first range. This has a consequence of the compressed read end io handler (compression.c:end_compressed_bio_read()) finish once the extent is decompressed into the pages covering the first range, leaving the remaining pages (belonging to the second range) filled with zeroes (done by compression.c:btrfs_clear_biovec_end()). So fix this by submitting the current bio whenever we find a range pointing to a compressed extent that was preceded by a range with a different extent map. This is the simplest solution for this corner case. Making the end io callback populate both ranges (or more, if we have multiple pointing to the same extent) is a much more complex solution since each bio is tightly coupled with a single extent map and the extent maps associated to the ranges pointing to the shared extent can have different offsets and lengths. The following test case for fstests triggers the issue: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" tmp=/tmp/$$ status=1 # failure is the default! trap "_cleanup; exit \$status" 0 1 2 3 15 _cleanup() { rm -f $tmp.* } # get standard environment, filters and checks . ./common/rc . ./common/filter # real QA test starts here _need_to_be_root _supported_fs btrfs _supported_os Linux _require_scratch _require_cloner rm -f $seqres.full test_clone_and_read_compressed_extent() { local mount_opts=$1 _scratch_mkfs >>$seqres.full 2>&1 _scratch_mount $mount_opts # Create a test file with a single extent that is compressed (the # data we write into it is highly compressible no matter which # compression algorithm is used, zlib or lzo). $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 4K" \ -c "pwrite -S 0xbb 4K 8K" \ -c "pwrite -S 0xcc 12K 4K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Now clone our extent into an adjacent offset. $CLONER_PROG -s $((4 * 1024)) -d $((16 * 1024)) -l $((8 * 1024)) \ $SCRATCH_MNT/foo $SCRATCH_MNT/foo # Same as before but for this file we clone the extent into a lower # file offset. $XFS_IO_PROG -f -c "pwrite -S 0xaa 8K 4K" \ -c "pwrite -S 0xbb 12K 8K" \ -c "pwrite -S 0xcc 20K 4K" \ $SCRATCH_MNT/bar | _filter_xfs_io $CLONER_PROG -s $((12 * 1024)) -d 0 -l $((8 * 1024)) \ $SCRATCH_MNT/bar $SCRATCH_MNT/bar echo "File digests before unmounting filesystem:" md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch # Evicting the inode or clearing the page cache before reading # again the file would also trigger the bug - reads were returning # all bytes in the range corresponding to the second reference to # the extent with a value of 0, but the correct data was persisted # (it was a bug exclusively in the read path). The issue happened # only if the same readpages() call targeted pages belonging to the # first and second ranges that point to the same compressed extent. _scratch_remount echo "File digests after mounting filesystem again:" # Must match the same digests we got before. md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch } echo -e "\nTesting with zlib compression..." test_clone_and_read_compressed_extent "-o compress=zlib" _scratch_unmount echo -e "\nTesting with lzo compression..." test_clone_and_read_compressed_extent "-o compress=lzo" status=0 exit Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Qu Wenruo<quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
2015-09-14 08:09:31 +00:00
unsigned long bio_flags,
bool force_bio_submit)
{
int ret = 0;
struct bio *bio;
size_t io_size = min_t(size_t, size, PAGE_SIZE);
struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
struct extent_io_tree *tree = &inode->io_tree;
struct btrfs_fs_info *fs_info = inode->root->fs_info;
ASSERT(bio_ret);
if (*bio_ret) {
bio = *bio_ret;
if (force_bio_submit ||
!btrfs_bio_add_page(bio, page, disk_bytenr, io_size,
pg_offset, prev_bio_flags, bio_flags)) {
ret = submit_one_bio(bio, mirror_num, prev_bio_flags);
if (ret < 0) {
*bio_ret = NULL;
return ret;
}
bio = NULL;
} else {
if (wbc)
wbc_account_cgroup_owner(wbc, page, io_size);
return 0;
}
}
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
bio = btrfs_bio_alloc(disk_bytenr);
bio_add_page(bio, page, io_size, pg_offset);
bio->bi_end_io = end_io_func;
bio->bi_private = tree;
bio->bi_write_hint = page->mapping->host->i_write_hint;
bio->bi_opf = opf;
if (wbc) {
struct block_device *bdev;
bdev = fs_info->fs_devices->latest_bdev;
bio_set_dev(bio, bdev);
wbc_init_bio(wbc, bio);
wbc_account_cgroup_owner(wbc, page, io_size);
}
if (btrfs_is_zoned(fs_info) && bio_op(bio) == REQ_OP_ZONE_APPEND) {
struct extent_map *em;
struct map_lookup *map;
em = btrfs_get_chunk_map(fs_info, disk_bytenr, io_size);
if (IS_ERR(em))
return PTR_ERR(em);
map = em->map_lookup;
/* We only support single profile for now */
ASSERT(map->num_stripes == 1);
btrfs_io_bio(bio)->device = map->stripes[0].dev;
free_extent_map(em);
}
*bio_ret = bio;
return ret;
}
static int attach_extent_buffer_page(struct extent_buffer *eb,
struct page *page,
struct btrfs_subpage *prealloc)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
int ret = 0;
/*
* If the page is mapped to btree inode, we should hold the private
* lock to prevent race.
* For cloned or dummy extent buffers, their pages are not mapped and
* will not race with any other ebs.
*/
if (page->mapping)
lockdep_assert_held(&page->mapping->private_lock);
if (fs_info->sectorsize == PAGE_SIZE) {
if (!PagePrivate(page))
attach_page_private(page, eb);
else
WARN_ON(page->private != (unsigned long)eb);
return 0;
}
/* Already mapped, just free prealloc */
if (PagePrivate(page)) {
btrfs_free_subpage(prealloc);
return 0;
}
if (prealloc)
/* Has preallocated memory for subpage */
attach_page_private(page, prealloc);
else
/* Do new allocation to attach subpage */
ret = btrfs_attach_subpage(fs_info, page,
BTRFS_SUBPAGE_METADATA);
return ret;
}
int set_page_extent_mapped(struct page *page)
{
struct btrfs_fs_info *fs_info;
ASSERT(page->mapping);
if (PagePrivate(page))
return 0;
fs_info = btrfs_sb(page->mapping->host->i_sb);
if (fs_info->sectorsize < PAGE_SIZE)
return btrfs_attach_subpage(fs_info, page, BTRFS_SUBPAGE_DATA);
attach_page_private(page, (void *)EXTENT_PAGE_PRIVATE);
return 0;
}
void clear_page_extent_mapped(struct page *page)
{
struct btrfs_fs_info *fs_info;
ASSERT(page->mapping);
if (!PagePrivate(page))
return;
fs_info = btrfs_sb(page->mapping->host->i_sb);
if (fs_info->sectorsize < PAGE_SIZE)
return btrfs_detach_subpage(fs_info, page);
detach_page_private(page);
}
static struct extent_map *
__get_extent_map(struct inode *inode, struct page *page, size_t pg_offset,
u64 start, u64 len, struct extent_map **em_cached)
{
struct extent_map *em;
if (em_cached && *em_cached) {
em = *em_cached;
if (extent_map_in_tree(em) && start >= em->start &&
start < extent_map_end(em)) {
refcount_inc(&em->refs);
return em;
}
free_extent_map(em);
*em_cached = NULL;
}
em = btrfs_get_extent(BTRFS_I(inode), page, pg_offset, start, len);
if (em_cached && !IS_ERR_OR_NULL(em)) {
BUG_ON(*em_cached);
refcount_inc(&em->refs);
*em_cached = em;
}
return em;
}
/*
* basic readpage implementation. Locked extent state structs are inserted
* into the tree that are removed when the IO is done (by the end_io
* handlers)
* XXX JDM: This needs looking at to ensure proper page locking
* return 0 on success, otherwise return error
*/
int btrfs_do_readpage(struct page *page, struct extent_map **em_cached,
struct bio **bio, unsigned long *bio_flags,
unsigned int read_flags, u64 *prev_em_start)
{
struct inode *inode = page->mapping->host;
btrfs: integrate page status update for data read path into begin/end_page_read In btrfs data page read path, the page status update are handled in two different locations: btrfs_do_read_page() { while (cur <= end) { /* No need to read from disk */ if (HOLE/PREALLOC/INLINE){ memset(); set_extent_uptodate(); continue; } /* Read from disk */ ret = submit_extent_page(end_bio_extent_readpage); } end_bio_extent_readpage() { endio_readpage_uptodate_page_status(); } This is fine for sectorsize == PAGE_SIZE case, as for above loop we should only hit one branch and then exit. But for subpage, there is more work to be done in page status update: - Page Unlock condition Unlike regular page size == sectorsize case, we can no longer just unlock a page. Only the last reader of the page can unlock the page. This means, we can unlock the page either in the while() loop, or in the endio function. - Page uptodate condition Since we have multiple sectors to read for a page, we can only mark the full page uptodate if all sectors are uptodate. To handle both subpage and regular cases, introduce a pair of functions to help handling page status update: - begin_page_read() For regular case, it does nothing. For subpage case, it updates the reader counters so that later end_page_read() can know who is the last one to unlock the page. - end_page_read() This is just endio_readpage_uptodate_page_status() renamed. The original name is a little too long and too specific for endio. The new thing added is the condition for page unlock. Now for subpage data, we unlock the page if we're the last reader. This does not only provide the basis for subpage data read, but also hide the special handling of page read from the main read loop. Also, since we're changing how the page lock is handled, there are two existing error paths where we need to manually unlock the page before calling begin_page_read(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-02 02:28:36 +00:00
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
u64 start = page_offset(page);
const u64 end = start + PAGE_SIZE - 1;
u64 cur = start;
u64 extent_offset;
u64 last_byte = i_size_read(inode);
u64 block_start;
u64 cur_end;
struct extent_map *em;
int ret = 0;
int nr = 0;
size_t pg_offset = 0;
size_t iosize;
size_t blocksize = inode->i_sb->s_blocksize;
unsigned long this_bio_flag = 0;
struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
ret = set_page_extent_mapped(page);
if (ret < 0) {
unlock_extent(tree, start, end);
btrfs: integrate page status update for data read path into begin/end_page_read In btrfs data page read path, the page status update are handled in two different locations: btrfs_do_read_page() { while (cur <= end) { /* No need to read from disk */ if (HOLE/PREALLOC/INLINE){ memset(); set_extent_uptodate(); continue; } /* Read from disk */ ret = submit_extent_page(end_bio_extent_readpage); } end_bio_extent_readpage() { endio_readpage_uptodate_page_status(); } This is fine for sectorsize == PAGE_SIZE case, as for above loop we should only hit one branch and then exit. But for subpage, there is more work to be done in page status update: - Page Unlock condition Unlike regular page size == sectorsize case, we can no longer just unlock a page. Only the last reader of the page can unlock the page. This means, we can unlock the page either in the while() loop, or in the endio function. - Page uptodate condition Since we have multiple sectors to read for a page, we can only mark the full page uptodate if all sectors are uptodate. To handle both subpage and regular cases, introduce a pair of functions to help handling page status update: - begin_page_read() For regular case, it does nothing. For subpage case, it updates the reader counters so that later end_page_read() can know who is the last one to unlock the page. - end_page_read() This is just endio_readpage_uptodate_page_status() renamed. The original name is a little too long and too specific for endio. The new thing added is the condition for page unlock. Now for subpage data, we unlock the page if we're the last reader. This does not only provide the basis for subpage data read, but also hide the special handling of page read from the main read loop. Also, since we're changing how the page lock is handled, there are two existing error paths where we need to manually unlock the page before calling begin_page_read(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-02 02:28:36 +00:00
btrfs_page_set_error(fs_info, page, start, PAGE_SIZE);
unlock_page(page);
goto out;
}
if (!PageUptodate(page)) {
if (cleancache_get_page(page) == 0) {
BUG_ON(blocksize != PAGE_SIZE);
unlock_extent(tree, start, end);
btrfs: integrate page status update for data read path into begin/end_page_read In btrfs data page read path, the page status update are handled in two different locations: btrfs_do_read_page() { while (cur <= end) { /* No need to read from disk */ if (HOLE/PREALLOC/INLINE){ memset(); set_extent_uptodate(); continue; } /* Read from disk */ ret = submit_extent_page(end_bio_extent_readpage); } end_bio_extent_readpage() { endio_readpage_uptodate_page_status(); } This is fine for sectorsize == PAGE_SIZE case, as for above loop we should only hit one branch and then exit. But for subpage, there is more work to be done in page status update: - Page Unlock condition Unlike regular page size == sectorsize case, we can no longer just unlock a page. Only the last reader of the page can unlock the page. This means, we can unlock the page either in the while() loop, or in the endio function. - Page uptodate condition Since we have multiple sectors to read for a page, we can only mark the full page uptodate if all sectors are uptodate. To handle both subpage and regular cases, introduce a pair of functions to help handling page status update: - begin_page_read() For regular case, it does nothing. For subpage case, it updates the reader counters so that later end_page_read() can know who is the last one to unlock the page. - end_page_read() This is just endio_readpage_uptodate_page_status() renamed. The original name is a little too long and too specific for endio. The new thing added is the condition for page unlock. Now for subpage data, we unlock the page if we're the last reader. This does not only provide the basis for subpage data read, but also hide the special handling of page read from the main read loop. Also, since we're changing how the page lock is handled, there are two existing error paths where we need to manually unlock the page before calling begin_page_read(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-02 02:28:36 +00:00
unlock_page(page);
goto out;
}
}
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
if (page->index == last_byte >> PAGE_SHIFT) {
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
char *userpage;
size_t zero_offset = offset_in_page(last_byte);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
if (zero_offset) {
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
iosize = PAGE_SIZE - zero_offset;
userpage = kmap_atomic(page);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
memset(userpage + zero_offset, 0, iosize);
flush_dcache_page(page);
kunmap_atomic(userpage);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
}
}
btrfs: integrate page status update for data read path into begin/end_page_read In btrfs data page read path, the page status update are handled in two different locations: btrfs_do_read_page() { while (cur <= end) { /* No need to read from disk */ if (HOLE/PREALLOC/INLINE){ memset(); set_extent_uptodate(); continue; } /* Read from disk */ ret = submit_extent_page(end_bio_extent_readpage); } end_bio_extent_readpage() { endio_readpage_uptodate_page_status(); } This is fine for sectorsize == PAGE_SIZE case, as for above loop we should only hit one branch and then exit. But for subpage, there is more work to be done in page status update: - Page Unlock condition Unlike regular page size == sectorsize case, we can no longer just unlock a page. Only the last reader of the page can unlock the page. This means, we can unlock the page either in the while() loop, or in the endio function. - Page uptodate condition Since we have multiple sectors to read for a page, we can only mark the full page uptodate if all sectors are uptodate. To handle both subpage and regular cases, introduce a pair of functions to help handling page status update: - begin_page_read() For regular case, it does nothing. For subpage case, it updates the reader counters so that later end_page_read() can know who is the last one to unlock the page. - end_page_read() This is just endio_readpage_uptodate_page_status() renamed. The original name is a little too long and too specific for endio. The new thing added is the condition for page unlock. Now for subpage data, we unlock the page if we're the last reader. This does not only provide the basis for subpage data read, but also hide the special handling of page read from the main read loop. Also, since we're changing how the page lock is handled, there are two existing error paths where we need to manually unlock the page before calling begin_page_read(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-02 02:28:36 +00:00
begin_page_read(fs_info, page);
while (cur <= end) {
Btrfs: fix read corruption of compressed and shared extents If a file has a range pointing to a compressed extent, followed by another range that points to the same compressed extent and a read operation attempts to read both ranges (either completely or part of them), the pages that correspond to the second range are incorrectly filled with zeroes. Consider the following example: File layout [0 - 8K] [8K - 24K] | | | | points to extent X, points to extent X, offset 4K, length of 8K offset 0, length 16K [extent X, compressed length = 4K uncompressed length = 16K] If a readpages() call spans the 2 ranges, a single bio to read the extent is submitted - extent_io.c:submit_extent_page() would only create a new bio to cover the second range pointing to the extent if the extent it points to had a different logical address than the extent associated with the first range. This has a consequence of the compressed read end io handler (compression.c:end_compressed_bio_read()) finish once the extent is decompressed into the pages covering the first range, leaving the remaining pages (belonging to the second range) filled with zeroes (done by compression.c:btrfs_clear_biovec_end()). So fix this by submitting the current bio whenever we find a range pointing to a compressed extent that was preceded by a range with a different extent map. This is the simplest solution for this corner case. Making the end io callback populate both ranges (or more, if we have multiple pointing to the same extent) is a much more complex solution since each bio is tightly coupled with a single extent map and the extent maps associated to the ranges pointing to the shared extent can have different offsets and lengths. The following test case for fstests triggers the issue: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" tmp=/tmp/$$ status=1 # failure is the default! trap "_cleanup; exit \$status" 0 1 2 3 15 _cleanup() { rm -f $tmp.* } # get standard environment, filters and checks . ./common/rc . ./common/filter # real QA test starts here _need_to_be_root _supported_fs btrfs _supported_os Linux _require_scratch _require_cloner rm -f $seqres.full test_clone_and_read_compressed_extent() { local mount_opts=$1 _scratch_mkfs >>$seqres.full 2>&1 _scratch_mount $mount_opts # Create a test file with a single extent that is compressed (the # data we write into it is highly compressible no matter which # compression algorithm is used, zlib or lzo). $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 4K" \ -c "pwrite -S 0xbb 4K 8K" \ -c "pwrite -S 0xcc 12K 4K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Now clone our extent into an adjacent offset. $CLONER_PROG -s $((4 * 1024)) -d $((16 * 1024)) -l $((8 * 1024)) \ $SCRATCH_MNT/foo $SCRATCH_MNT/foo # Same as before but for this file we clone the extent into a lower # file offset. $XFS_IO_PROG -f -c "pwrite -S 0xaa 8K 4K" \ -c "pwrite -S 0xbb 12K 8K" \ -c "pwrite -S 0xcc 20K 4K" \ $SCRATCH_MNT/bar | _filter_xfs_io $CLONER_PROG -s $((12 * 1024)) -d 0 -l $((8 * 1024)) \ $SCRATCH_MNT/bar $SCRATCH_MNT/bar echo "File digests before unmounting filesystem:" md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch # Evicting the inode or clearing the page cache before reading # again the file would also trigger the bug - reads were returning # all bytes in the range corresponding to the second reference to # the extent with a value of 0, but the correct data was persisted # (it was a bug exclusively in the read path). The issue happened # only if the same readpages() call targeted pages belonging to the # first and second ranges that point to the same compressed extent. _scratch_remount echo "File digests after mounting filesystem again:" # Must match the same digests we got before. md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch } echo -e "\nTesting with zlib compression..." test_clone_and_read_compressed_extent "-o compress=zlib" _scratch_unmount echo -e "\nTesting with lzo compression..." test_clone_and_read_compressed_extent "-o compress=lzo" status=0 exit Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Qu Wenruo<quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
2015-09-14 08:09:31 +00:00
bool force_bio_submit = false;
u64 disk_bytenr;
if (cur >= last_byte) {
char *userpage;
struct extent_state *cached = NULL;
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
iosize = PAGE_SIZE - pg_offset;
userpage = kmap_atomic(page);
memset(userpage + pg_offset, 0, iosize);
flush_dcache_page(page);
kunmap_atomic(userpage);
set_extent_uptodate(tree, cur, cur + iosize - 1,
&cached, GFP_NOFS);
unlock_extent_cached(tree, cur,
cur + iosize - 1, &cached);
btrfs: integrate page status update for data read path into begin/end_page_read In btrfs data page read path, the page status update are handled in two different locations: btrfs_do_read_page() { while (cur <= end) { /* No need to read from disk */ if (HOLE/PREALLOC/INLINE){ memset(); set_extent_uptodate(); continue; } /* Read from disk */ ret = submit_extent_page(end_bio_extent_readpage); } end_bio_extent_readpage() { endio_readpage_uptodate_page_status(); } This is fine for sectorsize == PAGE_SIZE case, as for above loop we should only hit one branch and then exit. But for subpage, there is more work to be done in page status update: - Page Unlock condition Unlike regular page size == sectorsize case, we can no longer just unlock a page. Only the last reader of the page can unlock the page. This means, we can unlock the page either in the while() loop, or in the endio function. - Page uptodate condition Since we have multiple sectors to read for a page, we can only mark the full page uptodate if all sectors are uptodate. To handle both subpage and regular cases, introduce a pair of functions to help handling page status update: - begin_page_read() For regular case, it does nothing. For subpage case, it updates the reader counters so that later end_page_read() can know who is the last one to unlock the page. - end_page_read() This is just endio_readpage_uptodate_page_status() renamed. The original name is a little too long and too specific for endio. The new thing added is the condition for page unlock. Now for subpage data, we unlock the page if we're the last reader. This does not only provide the basis for subpage data read, but also hide the special handling of page read from the main read loop. Also, since we're changing how the page lock is handled, there are two existing error paths where we need to manually unlock the page before calling begin_page_read(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-02 02:28:36 +00:00
end_page_read(page, true, cur, iosize);
break;
}
em = __get_extent_map(inode, page, pg_offset, cur,
end - cur + 1, em_cached);
if (IS_ERR_OR_NULL(em)) {
unlock_extent(tree, cur, end);
btrfs: integrate page status update for data read path into begin/end_page_read In btrfs data page read path, the page status update are handled in two different locations: btrfs_do_read_page() { while (cur <= end) { /* No need to read from disk */ if (HOLE/PREALLOC/INLINE){ memset(); set_extent_uptodate(); continue; } /* Read from disk */ ret = submit_extent_page(end_bio_extent_readpage); } end_bio_extent_readpage() { endio_readpage_uptodate_page_status(); } This is fine for sectorsize == PAGE_SIZE case, as for above loop we should only hit one branch and then exit. But for subpage, there is more work to be done in page status update: - Page Unlock condition Unlike regular page size == sectorsize case, we can no longer just unlock a page. Only the last reader of the page can unlock the page. This means, we can unlock the page either in the while() loop, or in the endio function. - Page uptodate condition Since we have multiple sectors to read for a page, we can only mark the full page uptodate if all sectors are uptodate. To handle both subpage and regular cases, introduce a pair of functions to help handling page status update: - begin_page_read() For regular case, it does nothing. For subpage case, it updates the reader counters so that later end_page_read() can know who is the last one to unlock the page. - end_page_read() This is just endio_readpage_uptodate_page_status() renamed. The original name is a little too long and too specific for endio. The new thing added is the condition for page unlock. Now for subpage data, we unlock the page if we're the last reader. This does not only provide the basis for subpage data read, but also hide the special handling of page read from the main read loop. Also, since we're changing how the page lock is handled, there are two existing error paths where we need to manually unlock the page before calling begin_page_read(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-02 02:28:36 +00:00
end_page_read(page, false, cur, end + 1 - cur);
break;
}
extent_offset = cur - em->start;
BUG_ON(extent_map_end(em) <= cur);
BUG_ON(end < cur);
if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
this_bio_flag |= EXTENT_BIO_COMPRESSED;
extent_set_compress_type(&this_bio_flag,
em->compress_type);
}
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
iosize = min(extent_map_end(em) - cur, end - cur + 1);
cur_end = min(extent_map_end(em) - 1, end);
iosize = ALIGN(iosize, blocksize);
if (this_bio_flag & EXTENT_BIO_COMPRESSED)
disk_bytenr = em->block_start;
else
disk_bytenr = em->block_start + extent_offset;
block_start = em->block_start;
if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
block_start = EXTENT_MAP_HOLE;
Btrfs: fix read corruption of compressed and shared extents If a file has a range pointing to a compressed extent, followed by another range that points to the same compressed extent and a read operation attempts to read both ranges (either completely or part of them), the pages that correspond to the second range are incorrectly filled with zeroes. Consider the following example: File layout [0 - 8K] [8K - 24K] | | | | points to extent X, points to extent X, offset 4K, length of 8K offset 0, length 16K [extent X, compressed length = 4K uncompressed length = 16K] If a readpages() call spans the 2 ranges, a single bio to read the extent is submitted - extent_io.c:submit_extent_page() would only create a new bio to cover the second range pointing to the extent if the extent it points to had a different logical address than the extent associated with the first range. This has a consequence of the compressed read end io handler (compression.c:end_compressed_bio_read()) finish once the extent is decompressed into the pages covering the first range, leaving the remaining pages (belonging to the second range) filled with zeroes (done by compression.c:btrfs_clear_biovec_end()). So fix this by submitting the current bio whenever we find a range pointing to a compressed extent that was preceded by a range with a different extent map. This is the simplest solution for this corner case. Making the end io callback populate both ranges (or more, if we have multiple pointing to the same extent) is a much more complex solution since each bio is tightly coupled with a single extent map and the extent maps associated to the ranges pointing to the shared extent can have different offsets and lengths. The following test case for fstests triggers the issue: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" tmp=/tmp/$$ status=1 # failure is the default! trap "_cleanup; exit \$status" 0 1 2 3 15 _cleanup() { rm -f $tmp.* } # get standard environment, filters and checks . ./common/rc . ./common/filter # real QA test starts here _need_to_be_root _supported_fs btrfs _supported_os Linux _require_scratch _require_cloner rm -f $seqres.full test_clone_and_read_compressed_extent() { local mount_opts=$1 _scratch_mkfs >>$seqres.full 2>&1 _scratch_mount $mount_opts # Create a test file with a single extent that is compressed (the # data we write into it is highly compressible no matter which # compression algorithm is used, zlib or lzo). $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 4K" \ -c "pwrite -S 0xbb 4K 8K" \ -c "pwrite -S 0xcc 12K 4K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Now clone our extent into an adjacent offset. $CLONER_PROG -s $((4 * 1024)) -d $((16 * 1024)) -l $((8 * 1024)) \ $SCRATCH_MNT/foo $SCRATCH_MNT/foo # Same as before but for this file we clone the extent into a lower # file offset. $XFS_IO_PROG -f -c "pwrite -S 0xaa 8K 4K" \ -c "pwrite -S 0xbb 12K 8K" \ -c "pwrite -S 0xcc 20K 4K" \ $SCRATCH_MNT/bar | _filter_xfs_io $CLONER_PROG -s $((12 * 1024)) -d 0 -l $((8 * 1024)) \ $SCRATCH_MNT/bar $SCRATCH_MNT/bar echo "File digests before unmounting filesystem:" md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch # Evicting the inode or clearing the page cache before reading # again the file would also trigger the bug - reads were returning # all bytes in the range corresponding to the second reference to # the extent with a value of 0, but the correct data was persisted # (it was a bug exclusively in the read path). The issue happened # only if the same readpages() call targeted pages belonging to the # first and second ranges that point to the same compressed extent. _scratch_remount echo "File digests after mounting filesystem again:" # Must match the same digests we got before. md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch } echo -e "\nTesting with zlib compression..." test_clone_and_read_compressed_extent "-o compress=zlib" _scratch_unmount echo -e "\nTesting with lzo compression..." test_clone_and_read_compressed_extent "-o compress=lzo" status=0 exit Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Qu Wenruo<quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
2015-09-14 08:09:31 +00:00
/*
* If we have a file range that points to a compressed extent
* and it's followed by a consecutive file range that points
Btrfs: fix read corruption of compressed and shared extents If a file has a range pointing to a compressed extent, followed by another range that points to the same compressed extent and a read operation attempts to read both ranges (either completely or part of them), the pages that correspond to the second range are incorrectly filled with zeroes. Consider the following example: File layout [0 - 8K] [8K - 24K] | | | | points to extent X, points to extent X, offset 4K, length of 8K offset 0, length 16K [extent X, compressed length = 4K uncompressed length = 16K] If a readpages() call spans the 2 ranges, a single bio to read the extent is submitted - extent_io.c:submit_extent_page() would only create a new bio to cover the second range pointing to the extent if the extent it points to had a different logical address than the extent associated with the first range. This has a consequence of the compressed read end io handler (compression.c:end_compressed_bio_read()) finish once the extent is decompressed into the pages covering the first range, leaving the remaining pages (belonging to the second range) filled with zeroes (done by compression.c:btrfs_clear_biovec_end()). So fix this by submitting the current bio whenever we find a range pointing to a compressed extent that was preceded by a range with a different extent map. This is the simplest solution for this corner case. Making the end io callback populate both ranges (or more, if we have multiple pointing to the same extent) is a much more complex solution since each bio is tightly coupled with a single extent map and the extent maps associated to the ranges pointing to the shared extent can have different offsets and lengths. The following test case for fstests triggers the issue: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" tmp=/tmp/$$ status=1 # failure is the default! trap "_cleanup; exit \$status" 0 1 2 3 15 _cleanup() { rm -f $tmp.* } # get standard environment, filters and checks . ./common/rc . ./common/filter # real QA test starts here _need_to_be_root _supported_fs btrfs _supported_os Linux _require_scratch _require_cloner rm -f $seqres.full test_clone_and_read_compressed_extent() { local mount_opts=$1 _scratch_mkfs >>$seqres.full 2>&1 _scratch_mount $mount_opts # Create a test file with a single extent that is compressed (the # data we write into it is highly compressible no matter which # compression algorithm is used, zlib or lzo). $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 4K" \ -c "pwrite -S 0xbb 4K 8K" \ -c "pwrite -S 0xcc 12K 4K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Now clone our extent into an adjacent offset. $CLONER_PROG -s $((4 * 1024)) -d $((16 * 1024)) -l $((8 * 1024)) \ $SCRATCH_MNT/foo $SCRATCH_MNT/foo # Same as before but for this file we clone the extent into a lower # file offset. $XFS_IO_PROG -f -c "pwrite -S 0xaa 8K 4K" \ -c "pwrite -S 0xbb 12K 8K" \ -c "pwrite -S 0xcc 20K 4K" \ $SCRATCH_MNT/bar | _filter_xfs_io $CLONER_PROG -s $((12 * 1024)) -d 0 -l $((8 * 1024)) \ $SCRATCH_MNT/bar $SCRATCH_MNT/bar echo "File digests before unmounting filesystem:" md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch # Evicting the inode or clearing the page cache before reading # again the file would also trigger the bug - reads were returning # all bytes in the range corresponding to the second reference to # the extent with a value of 0, but the correct data was persisted # (it was a bug exclusively in the read path). The issue happened # only if the same readpages() call targeted pages belonging to the # first and second ranges that point to the same compressed extent. _scratch_remount echo "File digests after mounting filesystem again:" # Must match the same digests we got before. md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch } echo -e "\nTesting with zlib compression..." test_clone_and_read_compressed_extent "-o compress=zlib" _scratch_unmount echo -e "\nTesting with lzo compression..." test_clone_and_read_compressed_extent "-o compress=lzo" status=0 exit Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Qu Wenruo<quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
2015-09-14 08:09:31 +00:00
* to the same compressed extent (possibly with a different
* offset and/or length, so it either points to the whole extent
* or only part of it), we must make sure we do not submit a
* single bio to populate the pages for the 2 ranges because
* this makes the compressed extent read zero out the pages
* belonging to the 2nd range. Imagine the following scenario:
*
* File layout
* [0 - 8K] [8K - 24K]
* | |
* | |
* points to extent X, points to extent X,
* offset 4K, length of 8K offset 0, length 16K
*
* [extent X, compressed length = 4K uncompressed length = 16K]
*
* If the bio to read the compressed extent covers both ranges,
* it will decompress extent X into the pages belonging to the
* first range and then it will stop, zeroing out the remaining
* pages that belong to the other range that points to extent X.
* So here we make sure we submit 2 bios, one for the first
* range and another one for the third range. Both will target
* the same physical extent from disk, but we can't currently
* make the compressed bio endio callback populate the pages
* for both ranges because each compressed bio is tightly
* coupled with a single extent map, and each range can have
* an extent map with a different offset value relative to the
* uncompressed data of our extent and different lengths. This
* is a corner case so we prioritize correctness over
* non-optimal behavior (submitting 2 bios for the same extent).
*/
if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) &&
prev_em_start && *prev_em_start != (u64)-1 &&
Btrfs: fix corruption reading shared and compressed extents after hole punching In the past we had data corruption when reading compressed extents that are shared within the same file and they are consecutive, this got fixed by commit 005efedf2c7d0 ("Btrfs: fix read corruption of compressed and shared extents") and by commit 808f80b46790f ("Btrfs: update fix for read corruption of compressed and shared extents"). However there was a case that was missing in those fixes, which is when the shared and compressed extents are referenced with a non-zero offset. The following shell script creates a reproducer for this issue: #!/bin/bash mkfs.btrfs -f /dev/sdc &> /dev/null mount -o compress /dev/sdc /mnt/sdc # Create a file with 3 consecutive compressed extents, each has an # uncompressed size of 128Kb and a compressed size of 4Kb. for ((i = 1; i <= 3; i++)); do head -c 4096 /dev/zero for ((j = 1; j <= 31; j++)); do head -c 4096 /dev/zero | tr '\0' "\377" done done > /mnt/sdc/foobar sync echo "Digest after file creation: $(md5sum /mnt/sdc/foobar)" # Clone the first extent into offsets 128K and 256K. xfs_io -c "reflink /mnt/sdc/foobar 0 128K 128K" /mnt/sdc/foobar xfs_io -c "reflink /mnt/sdc/foobar 0 256K 128K" /mnt/sdc/foobar sync echo "Digest after cloning: $(md5sum /mnt/sdc/foobar)" # Punch holes into the regions that are already full of zeroes. xfs_io -c "fpunch 0 4K" /mnt/sdc/foobar xfs_io -c "fpunch 128K 4K" /mnt/sdc/foobar xfs_io -c "fpunch 256K 4K" /mnt/sdc/foobar sync echo "Digest after hole punching: $(md5sum /mnt/sdc/foobar)" echo "Dropping page cache..." sysctl -q vm.drop_caches=1 echo "Digest after hole punching: $(md5sum /mnt/sdc/foobar)" umount /dev/sdc When running the script we get the following output: Digest after file creation: 5a0888d80d7ab1fd31c229f83a3bbcc8 /mnt/sdc/foobar linked 131072/131072 bytes at offset 131072 128 KiB, 1 ops; 0.0033 sec (36.960 MiB/sec and 295.6830 ops/sec) linked 131072/131072 bytes at offset 262144 128 KiB, 1 ops; 0.0015 sec (78.567 MiB/sec and 628.5355 ops/sec) Digest after cloning: 5a0888d80d7ab1fd31c229f83a3bbcc8 /mnt/sdc/foobar Digest after hole punching: 5a0888d80d7ab1fd31c229f83a3bbcc8 /mnt/sdc/foobar Dropping page cache... Digest after hole punching: fba694ae8664ed0c2e9ff8937e7f1484 /mnt/sdc/foobar This happens because after reading all the pages of the extent in the range from 128K to 256K for example, we read the hole at offset 256K and then when reading the page at offset 260K we don't submit the existing bio, which is responsible for filling all the page in the range 128K to 256K only, therefore adding the pages from range 260K to 384K to the existing bio and submitting it after iterating over the entire range. Once the bio completes, the uncompressed data fills only the pages in the range 128K to 256K because there's no more data read from disk, leaving the pages in the range 260K to 384K unfilled. It is just a slightly different variant of what was solved by commit 005efedf2c7d0 ("Btrfs: fix read corruption of compressed and shared extents"). Fix this by forcing a bio submit, during readpages(), whenever we find a compressed extent map for a page that is different from the extent map for the previous page or has a different starting offset (in case it's the same compressed extent), instead of the extent map's original start offset. A test case for fstests follows soon. Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> Fixes: 808f80b46790f ("Btrfs: update fix for read corruption of compressed and shared extents") Fixes: 005efedf2c7d0 ("Btrfs: fix read corruption of compressed and shared extents") Cc: stable@vger.kernel.org # 4.3+ Tested-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-02-14 15:17:20 +00:00
*prev_em_start != em->start)
Btrfs: fix read corruption of compressed and shared extents If a file has a range pointing to a compressed extent, followed by another range that points to the same compressed extent and a read operation attempts to read both ranges (either completely or part of them), the pages that correspond to the second range are incorrectly filled with zeroes. Consider the following example: File layout [0 - 8K] [8K - 24K] | | | | points to extent X, points to extent X, offset 4K, length of 8K offset 0, length 16K [extent X, compressed length = 4K uncompressed length = 16K] If a readpages() call spans the 2 ranges, a single bio to read the extent is submitted - extent_io.c:submit_extent_page() would only create a new bio to cover the second range pointing to the extent if the extent it points to had a different logical address than the extent associated with the first range. This has a consequence of the compressed read end io handler (compression.c:end_compressed_bio_read()) finish once the extent is decompressed into the pages covering the first range, leaving the remaining pages (belonging to the second range) filled with zeroes (done by compression.c:btrfs_clear_biovec_end()). So fix this by submitting the current bio whenever we find a range pointing to a compressed extent that was preceded by a range with a different extent map. This is the simplest solution for this corner case. Making the end io callback populate both ranges (or more, if we have multiple pointing to the same extent) is a much more complex solution since each bio is tightly coupled with a single extent map and the extent maps associated to the ranges pointing to the shared extent can have different offsets and lengths. The following test case for fstests triggers the issue: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" tmp=/tmp/$$ status=1 # failure is the default! trap "_cleanup; exit \$status" 0 1 2 3 15 _cleanup() { rm -f $tmp.* } # get standard environment, filters and checks . ./common/rc . ./common/filter # real QA test starts here _need_to_be_root _supported_fs btrfs _supported_os Linux _require_scratch _require_cloner rm -f $seqres.full test_clone_and_read_compressed_extent() { local mount_opts=$1 _scratch_mkfs >>$seqres.full 2>&1 _scratch_mount $mount_opts # Create a test file with a single extent that is compressed (the # data we write into it is highly compressible no matter which # compression algorithm is used, zlib or lzo). $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 4K" \ -c "pwrite -S 0xbb 4K 8K" \ -c "pwrite -S 0xcc 12K 4K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Now clone our extent into an adjacent offset. $CLONER_PROG -s $((4 * 1024)) -d $((16 * 1024)) -l $((8 * 1024)) \ $SCRATCH_MNT/foo $SCRATCH_MNT/foo # Same as before but for this file we clone the extent into a lower # file offset. $XFS_IO_PROG -f -c "pwrite -S 0xaa 8K 4K" \ -c "pwrite -S 0xbb 12K 8K" \ -c "pwrite -S 0xcc 20K 4K" \ $SCRATCH_MNT/bar | _filter_xfs_io $CLONER_PROG -s $((12 * 1024)) -d 0 -l $((8 * 1024)) \ $SCRATCH_MNT/bar $SCRATCH_MNT/bar echo "File digests before unmounting filesystem:" md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch # Evicting the inode or clearing the page cache before reading # again the file would also trigger the bug - reads were returning # all bytes in the range corresponding to the second reference to # the extent with a value of 0, but the correct data was persisted # (it was a bug exclusively in the read path). The issue happened # only if the same readpages() call targeted pages belonging to the # first and second ranges that point to the same compressed extent. _scratch_remount echo "File digests after mounting filesystem again:" # Must match the same digests we got before. md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch } echo -e "\nTesting with zlib compression..." test_clone_and_read_compressed_extent "-o compress=zlib" _scratch_unmount echo -e "\nTesting with lzo compression..." test_clone_and_read_compressed_extent "-o compress=lzo" status=0 exit Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Qu Wenruo<quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
2015-09-14 08:09:31 +00:00
force_bio_submit = true;
if (prev_em_start)
Btrfs: fix corruption reading shared and compressed extents after hole punching In the past we had data corruption when reading compressed extents that are shared within the same file and they are consecutive, this got fixed by commit 005efedf2c7d0 ("Btrfs: fix read corruption of compressed and shared extents") and by commit 808f80b46790f ("Btrfs: update fix for read corruption of compressed and shared extents"). However there was a case that was missing in those fixes, which is when the shared and compressed extents are referenced with a non-zero offset. The following shell script creates a reproducer for this issue: #!/bin/bash mkfs.btrfs -f /dev/sdc &> /dev/null mount -o compress /dev/sdc /mnt/sdc # Create a file with 3 consecutive compressed extents, each has an # uncompressed size of 128Kb and a compressed size of 4Kb. for ((i = 1; i <= 3; i++)); do head -c 4096 /dev/zero for ((j = 1; j <= 31; j++)); do head -c 4096 /dev/zero | tr '\0' "\377" done done > /mnt/sdc/foobar sync echo "Digest after file creation: $(md5sum /mnt/sdc/foobar)" # Clone the first extent into offsets 128K and 256K. xfs_io -c "reflink /mnt/sdc/foobar 0 128K 128K" /mnt/sdc/foobar xfs_io -c "reflink /mnt/sdc/foobar 0 256K 128K" /mnt/sdc/foobar sync echo "Digest after cloning: $(md5sum /mnt/sdc/foobar)" # Punch holes into the regions that are already full of zeroes. xfs_io -c "fpunch 0 4K" /mnt/sdc/foobar xfs_io -c "fpunch 128K 4K" /mnt/sdc/foobar xfs_io -c "fpunch 256K 4K" /mnt/sdc/foobar sync echo "Digest after hole punching: $(md5sum /mnt/sdc/foobar)" echo "Dropping page cache..." sysctl -q vm.drop_caches=1 echo "Digest after hole punching: $(md5sum /mnt/sdc/foobar)" umount /dev/sdc When running the script we get the following output: Digest after file creation: 5a0888d80d7ab1fd31c229f83a3bbcc8 /mnt/sdc/foobar linked 131072/131072 bytes at offset 131072 128 KiB, 1 ops; 0.0033 sec (36.960 MiB/sec and 295.6830 ops/sec) linked 131072/131072 bytes at offset 262144 128 KiB, 1 ops; 0.0015 sec (78.567 MiB/sec and 628.5355 ops/sec) Digest after cloning: 5a0888d80d7ab1fd31c229f83a3bbcc8 /mnt/sdc/foobar Digest after hole punching: 5a0888d80d7ab1fd31c229f83a3bbcc8 /mnt/sdc/foobar Dropping page cache... Digest after hole punching: fba694ae8664ed0c2e9ff8937e7f1484 /mnt/sdc/foobar This happens because after reading all the pages of the extent in the range from 128K to 256K for example, we read the hole at offset 256K and then when reading the page at offset 260K we don't submit the existing bio, which is responsible for filling all the page in the range 128K to 256K only, therefore adding the pages from range 260K to 384K to the existing bio and submitting it after iterating over the entire range. Once the bio completes, the uncompressed data fills only the pages in the range 128K to 256K because there's no more data read from disk, leaving the pages in the range 260K to 384K unfilled. It is just a slightly different variant of what was solved by commit 005efedf2c7d0 ("Btrfs: fix read corruption of compressed and shared extents"). Fix this by forcing a bio submit, during readpages(), whenever we find a compressed extent map for a page that is different from the extent map for the previous page or has a different starting offset (in case it's the same compressed extent), instead of the extent map's original start offset. A test case for fstests follows soon. Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> Fixes: 808f80b46790f ("Btrfs: update fix for read corruption of compressed and shared extents") Fixes: 005efedf2c7d0 ("Btrfs: fix read corruption of compressed and shared extents") Cc: stable@vger.kernel.org # 4.3+ Tested-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-02-14 15:17:20 +00:00
*prev_em_start = em->start;
Btrfs: fix read corruption of compressed and shared extents If a file has a range pointing to a compressed extent, followed by another range that points to the same compressed extent and a read operation attempts to read both ranges (either completely or part of them), the pages that correspond to the second range are incorrectly filled with zeroes. Consider the following example: File layout [0 - 8K] [8K - 24K] | | | | points to extent X, points to extent X, offset 4K, length of 8K offset 0, length 16K [extent X, compressed length = 4K uncompressed length = 16K] If a readpages() call spans the 2 ranges, a single bio to read the extent is submitted - extent_io.c:submit_extent_page() would only create a new bio to cover the second range pointing to the extent if the extent it points to had a different logical address than the extent associated with the first range. This has a consequence of the compressed read end io handler (compression.c:end_compressed_bio_read()) finish once the extent is decompressed into the pages covering the first range, leaving the remaining pages (belonging to the second range) filled with zeroes (done by compression.c:btrfs_clear_biovec_end()). So fix this by submitting the current bio whenever we find a range pointing to a compressed extent that was preceded by a range with a different extent map. This is the simplest solution for this corner case. Making the end io callback populate both ranges (or more, if we have multiple pointing to the same extent) is a much more complex solution since each bio is tightly coupled with a single extent map and the extent maps associated to the ranges pointing to the shared extent can have different offsets and lengths. The following test case for fstests triggers the issue: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" tmp=/tmp/$$ status=1 # failure is the default! trap "_cleanup; exit \$status" 0 1 2 3 15 _cleanup() { rm -f $tmp.* } # get standard environment, filters and checks . ./common/rc . ./common/filter # real QA test starts here _need_to_be_root _supported_fs btrfs _supported_os Linux _require_scratch _require_cloner rm -f $seqres.full test_clone_and_read_compressed_extent() { local mount_opts=$1 _scratch_mkfs >>$seqres.full 2>&1 _scratch_mount $mount_opts # Create a test file with a single extent that is compressed (the # data we write into it is highly compressible no matter which # compression algorithm is used, zlib or lzo). $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 4K" \ -c "pwrite -S 0xbb 4K 8K" \ -c "pwrite -S 0xcc 12K 4K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Now clone our extent into an adjacent offset. $CLONER_PROG -s $((4 * 1024)) -d $((16 * 1024)) -l $((8 * 1024)) \ $SCRATCH_MNT/foo $SCRATCH_MNT/foo # Same as before but for this file we clone the extent into a lower # file offset. $XFS_IO_PROG -f -c "pwrite -S 0xaa 8K 4K" \ -c "pwrite -S 0xbb 12K 8K" \ -c "pwrite -S 0xcc 20K 4K" \ $SCRATCH_MNT/bar | _filter_xfs_io $CLONER_PROG -s $((12 * 1024)) -d 0 -l $((8 * 1024)) \ $SCRATCH_MNT/bar $SCRATCH_MNT/bar echo "File digests before unmounting filesystem:" md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch # Evicting the inode or clearing the page cache before reading # again the file would also trigger the bug - reads were returning # all bytes in the range corresponding to the second reference to # the extent with a value of 0, but the correct data was persisted # (it was a bug exclusively in the read path). The issue happened # only if the same readpages() call targeted pages belonging to the # first and second ranges that point to the same compressed extent. _scratch_remount echo "File digests after mounting filesystem again:" # Must match the same digests we got before. md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch } echo -e "\nTesting with zlib compression..." test_clone_and_read_compressed_extent "-o compress=zlib" _scratch_unmount echo -e "\nTesting with lzo compression..." test_clone_and_read_compressed_extent "-o compress=lzo" status=0 exit Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Qu Wenruo<quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
2015-09-14 08:09:31 +00:00
free_extent_map(em);
em = NULL;
/* we've found a hole, just zero and go on */
if (block_start == EXTENT_MAP_HOLE) {
char *userpage;
struct extent_state *cached = NULL;
userpage = kmap_atomic(page);
memset(userpage + pg_offset, 0, iosize);
flush_dcache_page(page);
kunmap_atomic(userpage);
set_extent_uptodate(tree, cur, cur + iosize - 1,
&cached, GFP_NOFS);
unlock_extent_cached(tree, cur,
cur + iosize - 1, &cached);
btrfs: integrate page status update for data read path into begin/end_page_read In btrfs data page read path, the page status update are handled in two different locations: btrfs_do_read_page() { while (cur <= end) { /* No need to read from disk */ if (HOLE/PREALLOC/INLINE){ memset(); set_extent_uptodate(); continue; } /* Read from disk */ ret = submit_extent_page(end_bio_extent_readpage); } end_bio_extent_readpage() { endio_readpage_uptodate_page_status(); } This is fine for sectorsize == PAGE_SIZE case, as for above loop we should only hit one branch and then exit. But for subpage, there is more work to be done in page status update: - Page Unlock condition Unlike regular page size == sectorsize case, we can no longer just unlock a page. Only the last reader of the page can unlock the page. This means, we can unlock the page either in the while() loop, or in the endio function. - Page uptodate condition Since we have multiple sectors to read for a page, we can only mark the full page uptodate if all sectors are uptodate. To handle both subpage and regular cases, introduce a pair of functions to help handling page status update: - begin_page_read() For regular case, it does nothing. For subpage case, it updates the reader counters so that later end_page_read() can know who is the last one to unlock the page. - end_page_read() This is just endio_readpage_uptodate_page_status() renamed. The original name is a little too long and too specific for endio. The new thing added is the condition for page unlock. Now for subpage data, we unlock the page if we're the last reader. This does not only provide the basis for subpage data read, but also hide the special handling of page read from the main read loop. Also, since we're changing how the page lock is handled, there are two existing error paths where we need to manually unlock the page before calling begin_page_read(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-02 02:28:36 +00:00
end_page_read(page, true, cur, iosize);
cur = cur + iosize;
pg_offset += iosize;
continue;
}
/* the get_extent function already copied into the page */
if (test_range_bit(tree, cur, cur_end,
EXTENT_UPTODATE, 1, NULL)) {
check_page_uptodate(tree, page);
unlock_extent(tree, cur, cur + iosize - 1);
btrfs: integrate page status update for data read path into begin/end_page_read In btrfs data page read path, the page status update are handled in two different locations: btrfs_do_read_page() { while (cur <= end) { /* No need to read from disk */ if (HOLE/PREALLOC/INLINE){ memset(); set_extent_uptodate(); continue; } /* Read from disk */ ret = submit_extent_page(end_bio_extent_readpage); } end_bio_extent_readpage() { endio_readpage_uptodate_page_status(); } This is fine for sectorsize == PAGE_SIZE case, as for above loop we should only hit one branch and then exit. But for subpage, there is more work to be done in page status update: - Page Unlock condition Unlike regular page size == sectorsize case, we can no longer just unlock a page. Only the last reader of the page can unlock the page. This means, we can unlock the page either in the while() loop, or in the endio function. - Page uptodate condition Since we have multiple sectors to read for a page, we can only mark the full page uptodate if all sectors are uptodate. To handle both subpage and regular cases, introduce a pair of functions to help handling page status update: - begin_page_read() For regular case, it does nothing. For subpage case, it updates the reader counters so that later end_page_read() can know who is the last one to unlock the page. - end_page_read() This is just endio_readpage_uptodate_page_status() renamed. The original name is a little too long and too specific for endio. The new thing added is the condition for page unlock. Now for subpage data, we unlock the page if we're the last reader. This does not only provide the basis for subpage data read, but also hide the special handling of page read from the main read loop. Also, since we're changing how the page lock is handled, there are two existing error paths where we need to manually unlock the page before calling begin_page_read(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-02 02:28:36 +00:00
end_page_read(page, true, cur, iosize);
cur = cur + iosize;
pg_offset += iosize;
continue;
}
/* we have an inline extent but it didn't get marked up
* to date. Error out
*/
if (block_start == EXTENT_MAP_INLINE) {
unlock_extent(tree, cur, cur + iosize - 1);
btrfs: integrate page status update for data read path into begin/end_page_read In btrfs data page read path, the page status update are handled in two different locations: btrfs_do_read_page() { while (cur <= end) { /* No need to read from disk */ if (HOLE/PREALLOC/INLINE){ memset(); set_extent_uptodate(); continue; } /* Read from disk */ ret = submit_extent_page(end_bio_extent_readpage); } end_bio_extent_readpage() { endio_readpage_uptodate_page_status(); } This is fine for sectorsize == PAGE_SIZE case, as for above loop we should only hit one branch and then exit. But for subpage, there is more work to be done in page status update: - Page Unlock condition Unlike regular page size == sectorsize case, we can no longer just unlock a page. Only the last reader of the page can unlock the page. This means, we can unlock the page either in the while() loop, or in the endio function. - Page uptodate condition Since we have multiple sectors to read for a page, we can only mark the full page uptodate if all sectors are uptodate. To handle both subpage and regular cases, introduce a pair of functions to help handling page status update: - begin_page_read() For regular case, it does nothing. For subpage case, it updates the reader counters so that later end_page_read() can know who is the last one to unlock the page. - end_page_read() This is just endio_readpage_uptodate_page_status() renamed. The original name is a little too long and too specific for endio. The new thing added is the condition for page unlock. Now for subpage data, we unlock the page if we're the last reader. This does not only provide the basis for subpage data read, but also hide the special handling of page read from the main read loop. Also, since we're changing how the page lock is handled, there are two existing error paths where we need to manually unlock the page before calling begin_page_read(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-02 02:28:36 +00:00
end_page_read(page, false, cur, iosize);
cur = cur + iosize;
pg_offset += iosize;
continue;
}
ret = submit_extent_page(REQ_OP_READ | read_flags, NULL,
page, disk_bytenr, iosize,
pg_offset, bio,
end_bio_extent_readpage, 0,
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
*bio_flags,
Btrfs: fix read corruption of compressed and shared extents If a file has a range pointing to a compressed extent, followed by another range that points to the same compressed extent and a read operation attempts to read both ranges (either completely or part of them), the pages that correspond to the second range are incorrectly filled with zeroes. Consider the following example: File layout [0 - 8K] [8K - 24K] | | | | points to extent X, points to extent X, offset 4K, length of 8K offset 0, length 16K [extent X, compressed length = 4K uncompressed length = 16K] If a readpages() call spans the 2 ranges, a single bio to read the extent is submitted - extent_io.c:submit_extent_page() would only create a new bio to cover the second range pointing to the extent if the extent it points to had a different logical address than the extent associated with the first range. This has a consequence of the compressed read end io handler (compression.c:end_compressed_bio_read()) finish once the extent is decompressed into the pages covering the first range, leaving the remaining pages (belonging to the second range) filled with zeroes (done by compression.c:btrfs_clear_biovec_end()). So fix this by submitting the current bio whenever we find a range pointing to a compressed extent that was preceded by a range with a different extent map. This is the simplest solution for this corner case. Making the end io callback populate both ranges (or more, if we have multiple pointing to the same extent) is a much more complex solution since each bio is tightly coupled with a single extent map and the extent maps associated to the ranges pointing to the shared extent can have different offsets and lengths. The following test case for fstests triggers the issue: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" tmp=/tmp/$$ status=1 # failure is the default! trap "_cleanup; exit \$status" 0 1 2 3 15 _cleanup() { rm -f $tmp.* } # get standard environment, filters and checks . ./common/rc . ./common/filter # real QA test starts here _need_to_be_root _supported_fs btrfs _supported_os Linux _require_scratch _require_cloner rm -f $seqres.full test_clone_and_read_compressed_extent() { local mount_opts=$1 _scratch_mkfs >>$seqres.full 2>&1 _scratch_mount $mount_opts # Create a test file with a single extent that is compressed (the # data we write into it is highly compressible no matter which # compression algorithm is used, zlib or lzo). $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 4K" \ -c "pwrite -S 0xbb 4K 8K" \ -c "pwrite -S 0xcc 12K 4K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Now clone our extent into an adjacent offset. $CLONER_PROG -s $((4 * 1024)) -d $((16 * 1024)) -l $((8 * 1024)) \ $SCRATCH_MNT/foo $SCRATCH_MNT/foo # Same as before but for this file we clone the extent into a lower # file offset. $XFS_IO_PROG -f -c "pwrite -S 0xaa 8K 4K" \ -c "pwrite -S 0xbb 12K 8K" \ -c "pwrite -S 0xcc 20K 4K" \ $SCRATCH_MNT/bar | _filter_xfs_io $CLONER_PROG -s $((12 * 1024)) -d 0 -l $((8 * 1024)) \ $SCRATCH_MNT/bar $SCRATCH_MNT/bar echo "File digests before unmounting filesystem:" md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch # Evicting the inode or clearing the page cache before reading # again the file would also trigger the bug - reads were returning # all bytes in the range corresponding to the second reference to # the extent with a value of 0, but the correct data was persisted # (it was a bug exclusively in the read path). The issue happened # only if the same readpages() call targeted pages belonging to the # first and second ranges that point to the same compressed extent. _scratch_remount echo "File digests after mounting filesystem again:" # Must match the same digests we got before. md5sum $SCRATCH_MNT/foo | _filter_scratch md5sum $SCRATCH_MNT/bar | _filter_scratch } echo -e "\nTesting with zlib compression..." test_clone_and_read_compressed_extent "-o compress=zlib" _scratch_unmount echo -e "\nTesting with lzo compression..." test_clone_and_read_compressed_extent "-o compress=lzo" status=0 exit Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Qu Wenruo<quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
2015-09-14 08:09:31 +00:00
this_bio_flag,
force_bio_submit);
if (!ret) {
nr++;
*bio_flags = this_bio_flag;
} else {
unlock_extent(tree, cur, cur + iosize - 1);
btrfs: integrate page status update for data read path into begin/end_page_read In btrfs data page read path, the page status update are handled in two different locations: btrfs_do_read_page() { while (cur <= end) { /* No need to read from disk */ if (HOLE/PREALLOC/INLINE){ memset(); set_extent_uptodate(); continue; } /* Read from disk */ ret = submit_extent_page(end_bio_extent_readpage); } end_bio_extent_readpage() { endio_readpage_uptodate_page_status(); } This is fine for sectorsize == PAGE_SIZE case, as for above loop we should only hit one branch and then exit. But for subpage, there is more work to be done in page status update: - Page Unlock condition Unlike regular page size == sectorsize case, we can no longer just unlock a page. Only the last reader of the page can unlock the page. This means, we can unlock the page either in the while() loop, or in the endio function. - Page uptodate condition Since we have multiple sectors to read for a page, we can only mark the full page uptodate if all sectors are uptodate. To handle both subpage and regular cases, introduce a pair of functions to help handling page status update: - begin_page_read() For regular case, it does nothing. For subpage case, it updates the reader counters so that later end_page_read() can know who is the last one to unlock the page. - end_page_read() This is just endio_readpage_uptodate_page_status() renamed. The original name is a little too long and too specific for endio. The new thing added is the condition for page unlock. Now for subpage data, we unlock the page if we're the last reader. This does not only provide the basis for subpage data read, but also hide the special handling of page read from the main read loop. Also, since we're changing how the page lock is handled, there are two existing error paths where we need to manually unlock the page before calling begin_page_read(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-02 02:28:36 +00:00
end_page_read(page, false, cur, iosize);
goto out;
}
cur = cur + iosize;
pg_offset += iosize;
}
out:
return ret;
}
static inline void contiguous_readpages(struct page *pages[], int nr_pages,
u64 start, u64 end,
struct extent_map **em_cached,
struct bio **bio,
unsigned long *bio_flags,
Btrfs: update fix for read corruption of compressed and shared extents My previous fix in commit 005efedf2c7d ("Btrfs: fix read corruption of compressed and shared extents") was effective only if the compressed extents cover a file range with a length that is not a multiple of 16 pages. That's because the detection of when we reached a different range of the file that shares the same compressed extent as the previously processed range was done at extent_io.c:__do_contiguous_readpages(), which covers subranges with a length up to 16 pages, because extent_readpages() groups the pages in clusters no larger than 16 pages. So fix this by tracking the start of the previously processed file range's extent map at extent_readpages(). The following test case for fstests reproduces the issue: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" tmp=/tmp/$$ status=1 # failure is the default! trap "_cleanup; exit \$status" 0 1 2 3 15 _cleanup() { rm -f $tmp.* } # get standard environment, filters and checks . ./common/rc . ./common/filter # real QA test starts here _need_to_be_root _supported_fs btrfs _supported_os Linux _require_scratch _require_cloner rm -f $seqres.full test_clone_and_read_compressed_extent() { local mount_opts=$1 _scratch_mkfs >>$seqres.full 2>&1 _scratch_mount $mount_opts # Create our test file with a single extent of 64Kb that is going to # be compressed no matter which compression algo is used (zlib/lzo). $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 64K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Now clone the compressed extent into an adjacent file offset. $CLONER_PROG -s 0 -d $((64 * 1024)) -l $((64 * 1024)) \ $SCRATCH_MNT/foo $SCRATCH_MNT/foo echo "File digest before unmount:" md5sum $SCRATCH_MNT/foo | _filter_scratch # Remount the fs or clear the page cache to trigger the bug in # btrfs. Because the extent has an uncompressed length that is a # multiple of 16 pages, all the pages belonging to the second range # of the file (64K to 128K), which points to the same extent as the # first range (0K to 64K), had their contents full of zeroes instead # of the byte 0xaa. This was a bug exclusively in the read path of # compressed extents, the correct data was stored on disk, btrfs # just failed to fill in the pages correctly. _scratch_remount echo "File digest after remount:" # Must match the digest we got before. md5sum $SCRATCH_MNT/foo | _filter_scratch } echo -e "\nTesting with zlib compression..." test_clone_and_read_compressed_extent "-o compress=zlib" _scratch_unmount echo -e "\nTesting with lzo compression..." test_clone_and_read_compressed_extent "-o compress=lzo" status=0 exit Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: Timofey Titovets <nefelim4ag@gmail.com>
2015-09-28 08:56:26 +00:00
u64 *prev_em_start)
{
struct btrfs_inode *inode = BTRFS_I(pages[0]->mapping->host);
int index;
btrfs_lock_and_flush_ordered_range(inode, start, end, NULL);
for (index = 0; index < nr_pages; index++) {
btrfs_do_readpage(pages[index], em_cached, bio, bio_flags,
REQ_RAHEAD, prev_em_start);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
put_page(pages[index]);
}
}
static void update_nr_written(struct writeback_control *wbc,
unsigned long nr_written)
{
wbc->nr_to_write -= nr_written;
}
/*
* helper for __extent_writepage, doing all of the delayed allocation setup.
*
* This returns 1 if btrfs_run_delalloc_range function did all the work required
* to write the page (copy into inline extent). In this case the IO has
* been started and the page is already unlocked.
*
* This returns 0 if all went well (page still locked)
* This returns < 0 if there were errors (page still locked)
*/
static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
struct page *page, struct writeback_control *wbc,
u64 delalloc_start, unsigned long *nr_written)
{
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
u64 page_end = delalloc_start + PAGE_SIZE - 1;
bool found;
u64 delalloc_to_write = 0;
u64 delalloc_end = 0;
int ret;
int page_started = 0;
while (delalloc_end < page_end) {
found = find_lock_delalloc_range(&inode->vfs_inode, page,
&delalloc_start,
&delalloc_end);
if (!found) {
delalloc_start = delalloc_end + 1;
continue;
}
ret = btrfs_run_delalloc_range(inode, page, delalloc_start,
delalloc_end, &page_started, nr_written, wbc);
if (ret) {
SetPageError(page);
/*
* btrfs_run_delalloc_range should return < 0 for error
* but just in case, we use > 0 here meaning the IO is
* started, so we don't want to return > 0 unless
* things are going well.
*/
return ret < 0 ? ret : -EIO;
}
/*
* delalloc_end is already one less than the total length, so
* we don't subtract one from PAGE_SIZE
*/
delalloc_to_write += (delalloc_end - delalloc_start +
PAGE_SIZE) >> PAGE_SHIFT;
delalloc_start = delalloc_end + 1;
}
if (wbc->nr_to_write < delalloc_to_write) {
int thresh = 8192;
if (delalloc_to_write < thresh * 2)
thresh = delalloc_to_write;
wbc->nr_to_write = min_t(u64, delalloc_to_write,
thresh);
}
/* did the fill delalloc function already unlock and start
* the IO?
*/
if (page_started) {
/*
* we've unlocked the page, so we can't update
* the mapping's writeback index, just update
* nr_to_write.
*/
wbc->nr_to_write -= *nr_written;
return 1;
}
return 0;
}
/*
* helper for __extent_writepage. This calls the writepage start hooks,
* and does the loop to map the page into extents and bios.
*
* We return 1 if the IO is started and the page is unlocked,
* 0 if all went well (page still locked)
* < 0 if there were errors (page still locked)
*/
static noinline_for_stack int __extent_writepage_io(struct btrfs_inode *inode,
struct page *page,
struct writeback_control *wbc,
struct extent_page_data *epd,
loff_t i_size,
unsigned long nr_written,
int *nr_ret)
{
struct btrfs_fs_info *fs_info = inode->root->fs_info;
struct extent_io_tree *tree = &inode->io_tree;
u64 start = page_offset(page);
u64 end = start + PAGE_SIZE - 1;
u64 cur = start;
u64 extent_offset;
u64 block_start;
struct extent_map *em;
int ret = 0;
int nr = 0;
u32 opf = REQ_OP_WRITE;
const unsigned int write_flags = wbc_to_write_flags(wbc);
bool compressed;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
ret = btrfs_writepage_cow_fixup(page, start, end);
if (ret) {
/* Fixup worker will requeue */
redirty_page_for_writepage(wbc, page);
update_nr_written(wbc, nr_written);
unlock_page(page);
return 1;
}
/*
* we don't want to touch the inode after unlocking the page,
* so we update the mapping writeback index now
*/
update_nr_written(wbc, nr_written + 1);
while (cur <= end) {
u64 disk_bytenr;
u64 em_end;
u32 iosize;
if (cur >= i_size) {
btrfs_writepage_endio_finish_ordered(page, cur, end, 1);
break;
}
em = btrfs_get_extent(inode, NULL, 0, cur, end - cur + 1);
if (IS_ERR_OR_NULL(em)) {
SetPageError(page);
Btrfs: fix hang on error (such as ENOSPC) when writing extent pages When running low on available disk space and having several processes doing buffered file IO, I got the following trace in dmesg: [ 4202.720152] INFO: task kworker/u8:1:5450 blocked for more than 120 seconds. [ 4202.720401] Not tainted 3.13.0-fdm-btrfs-next-26+ #1 [ 4202.720596] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 4202.720874] kworker/u8:1 D 0000000000000001 0 5450 2 0x00000000 [ 4202.720904] Workqueue: btrfs-flush_delalloc normal_work_helper [btrfs] [ 4202.720908] ffff8801f62ddc38 0000000000000082 ffff880203ac2490 00000000001d3f40 [ 4202.720913] ffff8801f62ddfd8 00000000001d3f40 ffff8800c4f0c920 ffff880203ac2490 [ 4202.720918] 00000000001d4a40 ffff88020fe85a40 ffff88020fe85ab8 0000000000000001 [ 4202.720922] Call Trace: [ 4202.720931] [<ffffffff816a3cb9>] schedule+0x29/0x70 [ 4202.720950] [<ffffffffa01ec48d>] btrfs_start_ordered_extent+0x6d/0x110 [btrfs] [ 4202.720956] [<ffffffff8108e620>] ? bit_waitqueue+0xc0/0xc0 [ 4202.720972] [<ffffffffa01ec559>] btrfs_run_ordered_extent_work+0x29/0x40 [btrfs] [ 4202.720988] [<ffffffffa0201987>] normal_work_helper+0x137/0x2c0 [btrfs] [ 4202.720994] [<ffffffff810680e5>] process_one_work+0x1f5/0x530 (...) [ 4202.721027] 2 locks held by kworker/u8:1/5450: [ 4202.721028] #0: (%s-%s){++++..}, at: [<ffffffff81068083>] process_one_work+0x193/0x530 [ 4202.721037] #1: ((&work->normal_work)){+.+...}, at: [<ffffffff81068083>] process_one_work+0x193/0x530 [ 4202.721054] INFO: task btrfs:7891 blocked for more than 120 seconds. [ 4202.721258] Not tainted 3.13.0-fdm-btrfs-next-26+ #1 [ 4202.721444] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 4202.721699] btrfs D 0000000000000001 0 7891 7890 0x00000001 [ 4202.721704] ffff88018c2119e8 0000000000000086 ffff8800a33d2490 00000000001d3f40 [ 4202.721710] ffff88018c211fd8 00000000001d3f40 ffff8802144b0000 ffff8800a33d2490 [ 4202.721714] ffff8800d8576640 ffff88020fe85bc0 ffff88020fe85bc8 7fffffffffffffff [ 4202.721718] Call Trace: [ 4202.721723] [<ffffffff816a3cb9>] schedule+0x29/0x70 [ 4202.721727] [<ffffffff816a2ebc>] schedule_timeout+0x1dc/0x270 [ 4202.721732] [<ffffffff8109bd79>] ? mark_held_locks+0xb9/0x140 [ 4202.721736] [<ffffffff816a90c0>] ? _raw_spin_unlock_irq+0x30/0x40 [ 4202.721740] [<ffffffff8109bf0d>] ? trace_hardirqs_on_caller+0x10d/0x1d0 [ 4202.721744] [<ffffffff816a488f>] wait_for_completion+0xdf/0x120 [ 4202.721749] [<ffffffff8107fa90>] ? try_to_wake_up+0x310/0x310 [ 4202.721765] [<ffffffffa01ebee4>] btrfs_wait_ordered_extents+0x1f4/0x280 [btrfs] [ 4202.721781] [<ffffffffa020526e>] btrfs_mksubvol.isra.62+0x30e/0x5a0 [btrfs] [ 4202.721786] [<ffffffff8108e620>] ? bit_waitqueue+0xc0/0xc0 [ 4202.721799] [<ffffffffa02056a9>] btrfs_ioctl_snap_create_transid+0x1a9/0x1b0 [btrfs] [ 4202.721813] [<ffffffffa020583a>] btrfs_ioctl_snap_create_v2+0x10a/0x170 [btrfs] (...) It turns out that extent_io.c:__extent_writepage(), which ends up being called through filemap_fdatawrite_range() in btrfs_start_ordered_extent(), was getting -ENOSPC when calling the fill_delalloc callback. In this situation, it returned without the writepage_end_io_hook callback (inode.c:btrfs_writepage_end_io_hook) ever being called for the respective page, which prevents the ordered extent's bytes_left count from ever reaching 0, and therefore a finish_ordered_fn work is never queued into the endio_write_workers queue. This makes the task that called btrfs_start_ordered_extent() hang forever on the wait queue of the ordered extent. This is fairly easy to reproduce using a small filesystem and fsstress on a quad core vm: mkfs.btrfs -f -b `expr 2100 \* 1024 \* 1024` /dev/sdd mount /dev/sdd /mnt fsstress -p 6 -d /mnt -n 100000 -x \ "btrfs subvolume snapshot -r /mnt /mnt/mysnap" \ -f allocsp=0 \ -f bulkstat=0 \ -f bulkstat1=0 \ -f chown=0 \ -f creat=1 \ -f dread=0 \ -f dwrite=0 \ -f fallocate=1 \ -f fdatasync=0 \ -f fiemap=0 \ -f freesp=0 \ -f fsync=0 \ -f getattr=0 \ -f getdents=0 \ -f link=0 \ -f mkdir=0 \ -f mknod=0 \ -f punch=1 \ -f read=0 \ -f readlink=0 \ -f rename=0 \ -f resvsp=0 \ -f rmdir=0 \ -f setxattr=0 \ -f stat=0 \ -f symlink=0 \ -f sync=0 \ -f truncate=1 \ -f unlink=0 \ -f unresvsp=0 \ -f write=4 So just ensure that if an error happens while writing the extent page we call the writepage_end_io_hook callback. Also make it return the error code and ensure the caller (extent_write_cache_pages) processes all pages in the page vector even if an error happens only for some of them, so that ordered extents end up released. Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-05-09 16:17:40 +00:00
ret = PTR_ERR_OR_ZERO(em);
break;
}
extent_offset = cur - em->start;
em_end = extent_map_end(em);
ASSERT(cur <= em_end);
ASSERT(cur < end);
ASSERT(IS_ALIGNED(em->start, fs_info->sectorsize));
ASSERT(IS_ALIGNED(em->len, fs_info->sectorsize));
block_start = em->block_start;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
disk_bytenr = em->block_start + extent_offset;
/* Note that em_end from extent_map_end() is exclusive */
iosize = min(em_end, end + 1) - cur;
if (btrfs_use_zone_append(inode, em))
opf = REQ_OP_ZONE_APPEND;
free_extent_map(em);
em = NULL;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
/*
* compressed and inline extents are written through other
* paths in the FS
*/
if (compressed || block_start == EXTENT_MAP_HOLE ||
block_start == EXTENT_MAP_INLINE) {
if (compressed)
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
nr++;
else
btrfs_writepage_endio_finish_ordered(page, cur,
cur + iosize - 1, 1);
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
cur += iosize;
continue;
}
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
btrfs_set_range_writeback(tree, cur, cur + iosize - 1);
if (!PageWriteback(page)) {
btrfs_err(inode->root->fs_info,
"page %lu not writeback, cur %llu end %llu",
page->index, cur, end);
}
ret = submit_extent_page(opf | write_flags, wbc, page,
disk_bytenr, iosize,
cur - page_offset(page), &epd->bio,
end_bio_extent_writepage,
0, 0, 0, false);
if (ret) {
SetPageError(page);
if (PageWriteback(page))
end_page_writeback(page);
}
cur += iosize;
nr++;
}
*nr_ret = nr;
return ret;
}
/*
* the writepage semantics are similar to regular writepage. extent
* records are inserted to lock ranges in the tree, and as dirty areas
* are found, they are marked writeback. Then the lock bits are removed
* and the end_io handler clears the writeback ranges
*
* Return 0 if everything goes well.
* Return <0 for error.
*/
static int __extent_writepage(struct page *page, struct writeback_control *wbc,
struct extent_page_data *epd)
{
struct inode *inode = page->mapping->host;
u64 start = page_offset(page);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
u64 page_end = start + PAGE_SIZE - 1;
int ret;
int nr = 0;
size_t pg_offset;
loff_t i_size = i_size_read(inode);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
unsigned long end_index = i_size >> PAGE_SHIFT;
unsigned long nr_written = 0;
trace___extent_writepage(page, inode, wbc);
WARN_ON(!PageLocked(page));
ClearPageError(page);
pg_offset = offset_in_page(i_size);
if (page->index > end_index ||
(page->index == end_index && !pg_offset)) {
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
unlock_page(page);
return 0;
}
if (page->index == end_index) {
char *userpage;
userpage = kmap_atomic(page);
memset(userpage + pg_offset, 0,
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
PAGE_SIZE - pg_offset);
kunmap_atomic(userpage);
flush_dcache_page(page);
}
ret = set_page_extent_mapped(page);
if (ret < 0) {
SetPageError(page);
goto done;
}
if (!epd->extent_locked) {
ret = writepage_delalloc(BTRFS_I(inode), page, wbc, start,
&nr_written);
if (ret == 1)
return 0;
if (ret)
goto done;
}
ret = __extent_writepage_io(BTRFS_I(inode), page, wbc, epd, i_size,
nr_written, &nr);
if (ret == 1)
return 0;
done:
if (nr == 0) {
/* make sure the mapping tag for page dirty gets cleared */
set_page_writeback(page);
end_page_writeback(page);
}
Btrfs: fix hang on error (such as ENOSPC) when writing extent pages When running low on available disk space and having several processes doing buffered file IO, I got the following trace in dmesg: [ 4202.720152] INFO: task kworker/u8:1:5450 blocked for more than 120 seconds. [ 4202.720401] Not tainted 3.13.0-fdm-btrfs-next-26+ #1 [ 4202.720596] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 4202.720874] kworker/u8:1 D 0000000000000001 0 5450 2 0x00000000 [ 4202.720904] Workqueue: btrfs-flush_delalloc normal_work_helper [btrfs] [ 4202.720908] ffff8801f62ddc38 0000000000000082 ffff880203ac2490 00000000001d3f40 [ 4202.720913] ffff8801f62ddfd8 00000000001d3f40 ffff8800c4f0c920 ffff880203ac2490 [ 4202.720918] 00000000001d4a40 ffff88020fe85a40 ffff88020fe85ab8 0000000000000001 [ 4202.720922] Call Trace: [ 4202.720931] [<ffffffff816a3cb9>] schedule+0x29/0x70 [ 4202.720950] [<ffffffffa01ec48d>] btrfs_start_ordered_extent+0x6d/0x110 [btrfs] [ 4202.720956] [<ffffffff8108e620>] ? bit_waitqueue+0xc0/0xc0 [ 4202.720972] [<ffffffffa01ec559>] btrfs_run_ordered_extent_work+0x29/0x40 [btrfs] [ 4202.720988] [<ffffffffa0201987>] normal_work_helper+0x137/0x2c0 [btrfs] [ 4202.720994] [<ffffffff810680e5>] process_one_work+0x1f5/0x530 (...) [ 4202.721027] 2 locks held by kworker/u8:1/5450: [ 4202.721028] #0: (%s-%s){++++..}, at: [<ffffffff81068083>] process_one_work+0x193/0x530 [ 4202.721037] #1: ((&work->normal_work)){+.+...}, at: [<ffffffff81068083>] process_one_work+0x193/0x530 [ 4202.721054] INFO: task btrfs:7891 blocked for more than 120 seconds. [ 4202.721258] Not tainted 3.13.0-fdm-btrfs-next-26+ #1 [ 4202.721444] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 4202.721699] btrfs D 0000000000000001 0 7891 7890 0x00000001 [ 4202.721704] ffff88018c2119e8 0000000000000086 ffff8800a33d2490 00000000001d3f40 [ 4202.721710] ffff88018c211fd8 00000000001d3f40 ffff8802144b0000 ffff8800a33d2490 [ 4202.721714] ffff8800d8576640 ffff88020fe85bc0 ffff88020fe85bc8 7fffffffffffffff [ 4202.721718] Call Trace: [ 4202.721723] [<ffffffff816a3cb9>] schedule+0x29/0x70 [ 4202.721727] [<ffffffff816a2ebc>] schedule_timeout+0x1dc/0x270 [ 4202.721732] [<ffffffff8109bd79>] ? mark_held_locks+0xb9/0x140 [ 4202.721736] [<ffffffff816a90c0>] ? _raw_spin_unlock_irq+0x30/0x40 [ 4202.721740] [<ffffffff8109bf0d>] ? trace_hardirqs_on_caller+0x10d/0x1d0 [ 4202.721744] [<ffffffff816a488f>] wait_for_completion+0xdf/0x120 [ 4202.721749] [<ffffffff8107fa90>] ? try_to_wake_up+0x310/0x310 [ 4202.721765] [<ffffffffa01ebee4>] btrfs_wait_ordered_extents+0x1f4/0x280 [btrfs] [ 4202.721781] [<ffffffffa020526e>] btrfs_mksubvol.isra.62+0x30e/0x5a0 [btrfs] [ 4202.721786] [<ffffffff8108e620>] ? bit_waitqueue+0xc0/0xc0 [ 4202.721799] [<ffffffffa02056a9>] btrfs_ioctl_snap_create_transid+0x1a9/0x1b0 [btrfs] [ 4202.721813] [<ffffffffa020583a>] btrfs_ioctl_snap_create_v2+0x10a/0x170 [btrfs] (...) It turns out that extent_io.c:__extent_writepage(), which ends up being called through filemap_fdatawrite_range() in btrfs_start_ordered_extent(), was getting -ENOSPC when calling the fill_delalloc callback. In this situation, it returned without the writepage_end_io_hook callback (inode.c:btrfs_writepage_end_io_hook) ever being called for the respective page, which prevents the ordered extent's bytes_left count from ever reaching 0, and therefore a finish_ordered_fn work is never queued into the endio_write_workers queue. This makes the task that called btrfs_start_ordered_extent() hang forever on the wait queue of the ordered extent. This is fairly easy to reproduce using a small filesystem and fsstress on a quad core vm: mkfs.btrfs -f -b `expr 2100 \* 1024 \* 1024` /dev/sdd mount /dev/sdd /mnt fsstress -p 6 -d /mnt -n 100000 -x \ "btrfs subvolume snapshot -r /mnt /mnt/mysnap" \ -f allocsp=0 \ -f bulkstat=0 \ -f bulkstat1=0 \ -f chown=0 \ -f creat=1 \ -f dread=0 \ -f dwrite=0 \ -f fallocate=1 \ -f fdatasync=0 \ -f fiemap=0 \ -f freesp=0 \ -f fsync=0 \ -f getattr=0 \ -f getdents=0 \ -f link=0 \ -f mkdir=0 \ -f mknod=0 \ -f punch=1 \ -f read=0 \ -f readlink=0 \ -f rename=0 \ -f resvsp=0 \ -f rmdir=0 \ -f setxattr=0 \ -f stat=0 \ -f symlink=0 \ -f sync=0 \ -f truncate=1 \ -f unlink=0 \ -f unresvsp=0 \ -f write=4 So just ensure that if an error happens while writing the extent page we call the writepage_end_io_hook callback. Also make it return the error code and ensure the caller (extent_write_cache_pages) processes all pages in the page vector even if an error happens only for some of them, so that ordered extents end up released. Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-05-09 16:17:40 +00:00
if (PageError(page)) {
ret = ret < 0 ? ret : -EIO;
end_extent_writepage(page, ret, start, page_end);
}
unlock_page(page);
ASSERT(ret <= 0);
return ret;
}
void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
{
sched: Remove proliferation of wait_on_bit() action functions The current "wait_on_bit" interface requires an 'action' function to be provided which does the actual waiting. There are over 20 such functions, many of them identical. Most cases can be satisfied by one of just two functions, one which uses io_schedule() and one which just uses schedule(). So: Rename wait_on_bit and wait_on_bit_lock to wait_on_bit_action and wait_on_bit_lock_action to make it explicit that they need an action function. Introduce new wait_on_bit{,_lock} and wait_on_bit{,_lock}_io which are *not* given an action function but implicitly use a standard one. The decision to error-out if a signal is pending is now made based on the 'mode' argument rather than being encoded in the action function. All instances of the old wait_on_bit and wait_on_bit_lock which can use the new version have been changed accordingly and their action functions have been discarded. wait_on_bit{_lock} does not return any specific error code in the event of a signal so the caller must check for non-zero and interpolate their own error code as appropriate. The wait_on_bit() call in __fscache_wait_on_invalidate() was ambiguous as it specified TASK_UNINTERRUPTIBLE but used fscache_wait_bit_interruptible as an action function. David Howells confirms this should be uniformly "uninterruptible" The main remaining user of wait_on_bit{,_lock}_action is NFS which needs to use a freezer-aware schedule() call. A comment in fs/gfs2/glock.c notes that having multiple 'action' functions is useful as they display differently in the 'wchan' field of 'ps'. (and /proc/$PID/wchan). As the new bit_wait{,_io} functions are tagged "__sched", they will not show up at all, but something higher in the stack. So the distinction will still be visible, only with different function names (gds2_glock_wait versus gfs2_glock_dq_wait in the gfs2/glock.c case). Since first version of this patch (against 3.15) two new action functions appeared, on in NFS and one in CIFS. CIFS also now uses an action function that makes the same freezer aware schedule call as NFS. Signed-off-by: NeilBrown <neilb@suse.de> Acked-by: David Howells <dhowells@redhat.com> (fscache, keys) Acked-by: Steven Whitehouse <swhiteho@redhat.com> (gfs2) Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steve French <sfrench@samba.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140707051603.28027.72349.stgit@notabene.brown Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-07-07 05:16:04 +00:00
wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,
TASK_UNINTERRUPTIBLE);
}
Btrfs: fix unwritten extent buffers and hangs on future writeback attempts The lock_extent_buffer_io() returns 1 to the caller to tell it everything went fine and the callers needs to start writeback for the extent buffer (submit a bio, etc), 0 to tell the caller everything went fine but it does not need to start writeback for the extent buffer, and a negative value if some error happened. When it's about to return 1 it tries to lock all pages, and if a try lock on a page fails, and we didn't flush any existing bio in our "epd", it calls flush_write_bio(epd) and overwrites the return value of 1 to 0 or an error. The page might have been locked elsewhere, not with the goal of starting writeback of the extent buffer, and even by some code other than btrfs, like page migration for example, so it does not mean the writeback of the extent buffer was already started by some other task, so returning a 0 tells the caller (btree_write_cache_pages()) to not start writeback for the extent buffer. Note that epd might currently have either no bio, so flush_write_bio() returns 0 (success) or it might have a bio for another extent buffer with a lower index (logical address). Since we return 0 with the EXTENT_BUFFER_WRITEBACK bit set on the extent buffer and writeback is never started for the extent buffer, future attempts to writeback the extent buffer will hang forever waiting on that bit to be cleared, since it can only be cleared after writeback completes. Such hang is reported with a trace like the following: [49887.347053] INFO: task btrfs-transacti:1752 blocked for more than 122 seconds. [49887.347059] Not tainted 5.2.13-gentoo #2 [49887.347060] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [49887.347062] btrfs-transacti D 0 1752 2 0x80004000 [49887.347064] Call Trace: [49887.347069] ? __schedule+0x265/0x830 [49887.347071] ? bit_wait+0x50/0x50 [49887.347072] ? bit_wait+0x50/0x50 [49887.347074] schedule+0x24/0x90 [49887.347075] io_schedule+0x3c/0x60 [49887.347077] bit_wait_io+0x8/0x50 [49887.347079] __wait_on_bit+0x6c/0x80 [49887.347081] ? __lock_release.isra.29+0x155/0x2d0 [49887.347083] out_of_line_wait_on_bit+0x7b/0x80 [49887.347084] ? var_wake_function+0x20/0x20 [49887.347087] lock_extent_buffer_for_io+0x28c/0x390 [49887.347089] btree_write_cache_pages+0x18e/0x340 [49887.347091] do_writepages+0x29/0xb0 [49887.347093] ? kmem_cache_free+0x132/0x160 [49887.347095] ? convert_extent_bit+0x544/0x680 [49887.347097] filemap_fdatawrite_range+0x70/0x90 [49887.347099] btrfs_write_marked_extents+0x53/0x120 [49887.347100] btrfs_write_and_wait_transaction.isra.4+0x38/0xa0 [49887.347102] btrfs_commit_transaction+0x6bb/0x990 [49887.347103] ? start_transaction+0x33e/0x500 [49887.347105] transaction_kthread+0x139/0x15c So fix this by not overwriting the return value (ret) with the result from flush_write_bio(). We also need to clear the EXTENT_BUFFER_WRITEBACK bit in case flush_write_bio() returns an error, otherwise it will hang any future attempts to writeback the extent buffer, and undo all work done before (set back EXTENT_BUFFER_DIRTY, etc). This is a regression introduced in the 5.2 kernel. Fixes: 2e3c25136adfb ("btrfs: extent_io: add proper error handling to lock_extent_buffer_for_io()") Fixes: f4340622e0226 ("btrfs: extent_io: Move the BUG_ON() in flush_write_bio() one level up") Reported-by: Zdenek Sojka <zsojka@seznam.cz> Link: https://lore.kernel.org/linux-btrfs/GpO.2yos.3WGDOLpx6t%7D.1TUDYM@seznam.cz/T/#u Reported-by: Stefan Priebe - Profihost AG <s.priebe@profihost.ag> Link: https://lore.kernel.org/linux-btrfs/5c4688ac-10a7-fb07-70e8-c5d31a3fbb38@profihost.ag/T/#t Reported-by: Drazen Kacar <drazen.kacar@oradian.com> Link: https://lore.kernel.org/linux-btrfs/DB8PR03MB562876ECE2319B3E579590F799C80@DB8PR03MB5628.eurprd03.prod.outlook.com/ Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204377 Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-11 16:42:00 +00:00
static void end_extent_buffer_writeback(struct extent_buffer *eb)
{
clear_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
smp_mb__after_atomic();
wake_up_bit(&eb->bflags, EXTENT_BUFFER_WRITEBACK);
}
/*
* Lock extent buffer status and pages for writeback.
*
* May try to flush write bio if we can't get the lock.
*
* Return 0 if the extent buffer doesn't need to be submitted.
* (E.g. the extent buffer is not dirty)
* Return >0 is the extent buffer is submitted to bio.
* Return <0 if something went wrong, no page is locked.
*/
static noinline_for_stack int lock_extent_buffer_for_io(struct extent_buffer *eb,
struct extent_page_data *epd)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
int i, num_pages, failed_page_nr;
int flush = 0;
int ret = 0;
if (!btrfs_try_tree_write_lock(eb)) {
ret = flush_write_bio(epd);
if (ret < 0)
return ret;
flush = 1;
btrfs_tree_lock(eb);
}
if (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags)) {
btrfs_tree_unlock(eb);
if (!epd->sync_io)
return 0;
if (!flush) {
ret = flush_write_bio(epd);
if (ret < 0)
return ret;
flush = 1;
}
while (1) {
wait_on_extent_buffer_writeback(eb);
btrfs_tree_lock(eb);
if (!test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags))
break;
btrfs_tree_unlock(eb);
}
}
/*
* We need to do this to prevent races in people who check if the eb is
* under IO since we can end up having no IO bits set for a short period
* of time.
*/
spin_lock(&eb->refs_lock);
if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
spin_unlock(&eb->refs_lock);
btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
-eb->len,
fs_info->dirty_metadata_batch);
ret = 1;
} else {
spin_unlock(&eb->refs_lock);
}
btrfs_tree_unlock(eb);
if (!ret)
return ret;
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
struct page *p = eb->pages[i];
if (!trylock_page(p)) {
if (!flush) {
Btrfs: fix unwritten extent buffers and hangs on future writeback attempts The lock_extent_buffer_io() returns 1 to the caller to tell it everything went fine and the callers needs to start writeback for the extent buffer (submit a bio, etc), 0 to tell the caller everything went fine but it does not need to start writeback for the extent buffer, and a negative value if some error happened. When it's about to return 1 it tries to lock all pages, and if a try lock on a page fails, and we didn't flush any existing bio in our "epd", it calls flush_write_bio(epd) and overwrites the return value of 1 to 0 or an error. The page might have been locked elsewhere, not with the goal of starting writeback of the extent buffer, and even by some code other than btrfs, like page migration for example, so it does not mean the writeback of the extent buffer was already started by some other task, so returning a 0 tells the caller (btree_write_cache_pages()) to not start writeback for the extent buffer. Note that epd might currently have either no bio, so flush_write_bio() returns 0 (success) or it might have a bio for another extent buffer with a lower index (logical address). Since we return 0 with the EXTENT_BUFFER_WRITEBACK bit set on the extent buffer and writeback is never started for the extent buffer, future attempts to writeback the extent buffer will hang forever waiting on that bit to be cleared, since it can only be cleared after writeback completes. Such hang is reported with a trace like the following: [49887.347053] INFO: task btrfs-transacti:1752 blocked for more than 122 seconds. [49887.347059] Not tainted 5.2.13-gentoo #2 [49887.347060] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [49887.347062] btrfs-transacti D 0 1752 2 0x80004000 [49887.347064] Call Trace: [49887.347069] ? __schedule+0x265/0x830 [49887.347071] ? bit_wait+0x50/0x50 [49887.347072] ? bit_wait+0x50/0x50 [49887.347074] schedule+0x24/0x90 [49887.347075] io_schedule+0x3c/0x60 [49887.347077] bit_wait_io+0x8/0x50 [49887.347079] __wait_on_bit+0x6c/0x80 [49887.347081] ? __lock_release.isra.29+0x155/0x2d0 [49887.347083] out_of_line_wait_on_bit+0x7b/0x80 [49887.347084] ? var_wake_function+0x20/0x20 [49887.347087] lock_extent_buffer_for_io+0x28c/0x390 [49887.347089] btree_write_cache_pages+0x18e/0x340 [49887.347091] do_writepages+0x29/0xb0 [49887.347093] ? kmem_cache_free+0x132/0x160 [49887.347095] ? convert_extent_bit+0x544/0x680 [49887.347097] filemap_fdatawrite_range+0x70/0x90 [49887.347099] btrfs_write_marked_extents+0x53/0x120 [49887.347100] btrfs_write_and_wait_transaction.isra.4+0x38/0xa0 [49887.347102] btrfs_commit_transaction+0x6bb/0x990 [49887.347103] ? start_transaction+0x33e/0x500 [49887.347105] transaction_kthread+0x139/0x15c So fix this by not overwriting the return value (ret) with the result from flush_write_bio(). We also need to clear the EXTENT_BUFFER_WRITEBACK bit in case flush_write_bio() returns an error, otherwise it will hang any future attempts to writeback the extent buffer, and undo all work done before (set back EXTENT_BUFFER_DIRTY, etc). This is a regression introduced in the 5.2 kernel. Fixes: 2e3c25136adfb ("btrfs: extent_io: add proper error handling to lock_extent_buffer_for_io()") Fixes: f4340622e0226 ("btrfs: extent_io: Move the BUG_ON() in flush_write_bio() one level up") Reported-by: Zdenek Sojka <zsojka@seznam.cz> Link: https://lore.kernel.org/linux-btrfs/GpO.2yos.3WGDOLpx6t%7D.1TUDYM@seznam.cz/T/#u Reported-by: Stefan Priebe - Profihost AG <s.priebe@profihost.ag> Link: https://lore.kernel.org/linux-btrfs/5c4688ac-10a7-fb07-70e8-c5d31a3fbb38@profihost.ag/T/#t Reported-by: Drazen Kacar <drazen.kacar@oradian.com> Link: https://lore.kernel.org/linux-btrfs/DB8PR03MB562876ECE2319B3E579590F799C80@DB8PR03MB5628.eurprd03.prod.outlook.com/ Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204377 Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-11 16:42:00 +00:00
int err;
err = flush_write_bio(epd);
if (err < 0) {
ret = err;
failed_page_nr = i;
goto err_unlock;
}
flush = 1;
}
lock_page(p);
}
}
return ret;
err_unlock:
/* Unlock already locked pages */
for (i = 0; i < failed_page_nr; i++)
unlock_page(eb->pages[i]);
Btrfs: fix unwritten extent buffers and hangs on future writeback attempts The lock_extent_buffer_io() returns 1 to the caller to tell it everything went fine and the callers needs to start writeback for the extent buffer (submit a bio, etc), 0 to tell the caller everything went fine but it does not need to start writeback for the extent buffer, and a negative value if some error happened. When it's about to return 1 it tries to lock all pages, and if a try lock on a page fails, and we didn't flush any existing bio in our "epd", it calls flush_write_bio(epd) and overwrites the return value of 1 to 0 or an error. The page might have been locked elsewhere, not with the goal of starting writeback of the extent buffer, and even by some code other than btrfs, like page migration for example, so it does not mean the writeback of the extent buffer was already started by some other task, so returning a 0 tells the caller (btree_write_cache_pages()) to not start writeback for the extent buffer. Note that epd might currently have either no bio, so flush_write_bio() returns 0 (success) or it might have a bio for another extent buffer with a lower index (logical address). Since we return 0 with the EXTENT_BUFFER_WRITEBACK bit set on the extent buffer and writeback is never started for the extent buffer, future attempts to writeback the extent buffer will hang forever waiting on that bit to be cleared, since it can only be cleared after writeback completes. Such hang is reported with a trace like the following: [49887.347053] INFO: task btrfs-transacti:1752 blocked for more than 122 seconds. [49887.347059] Not tainted 5.2.13-gentoo #2 [49887.347060] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [49887.347062] btrfs-transacti D 0 1752 2 0x80004000 [49887.347064] Call Trace: [49887.347069] ? __schedule+0x265/0x830 [49887.347071] ? bit_wait+0x50/0x50 [49887.347072] ? bit_wait+0x50/0x50 [49887.347074] schedule+0x24/0x90 [49887.347075] io_schedule+0x3c/0x60 [49887.347077] bit_wait_io+0x8/0x50 [49887.347079] __wait_on_bit+0x6c/0x80 [49887.347081] ? __lock_release.isra.29+0x155/0x2d0 [49887.347083] out_of_line_wait_on_bit+0x7b/0x80 [49887.347084] ? var_wake_function+0x20/0x20 [49887.347087] lock_extent_buffer_for_io+0x28c/0x390 [49887.347089] btree_write_cache_pages+0x18e/0x340 [49887.347091] do_writepages+0x29/0xb0 [49887.347093] ? kmem_cache_free+0x132/0x160 [49887.347095] ? convert_extent_bit+0x544/0x680 [49887.347097] filemap_fdatawrite_range+0x70/0x90 [49887.347099] btrfs_write_marked_extents+0x53/0x120 [49887.347100] btrfs_write_and_wait_transaction.isra.4+0x38/0xa0 [49887.347102] btrfs_commit_transaction+0x6bb/0x990 [49887.347103] ? start_transaction+0x33e/0x500 [49887.347105] transaction_kthread+0x139/0x15c So fix this by not overwriting the return value (ret) with the result from flush_write_bio(). We also need to clear the EXTENT_BUFFER_WRITEBACK bit in case flush_write_bio() returns an error, otherwise it will hang any future attempts to writeback the extent buffer, and undo all work done before (set back EXTENT_BUFFER_DIRTY, etc). This is a regression introduced in the 5.2 kernel. Fixes: 2e3c25136adfb ("btrfs: extent_io: add proper error handling to lock_extent_buffer_for_io()") Fixes: f4340622e0226 ("btrfs: extent_io: Move the BUG_ON() in flush_write_bio() one level up") Reported-by: Zdenek Sojka <zsojka@seznam.cz> Link: https://lore.kernel.org/linux-btrfs/GpO.2yos.3WGDOLpx6t%7D.1TUDYM@seznam.cz/T/#u Reported-by: Stefan Priebe - Profihost AG <s.priebe@profihost.ag> Link: https://lore.kernel.org/linux-btrfs/5c4688ac-10a7-fb07-70e8-c5d31a3fbb38@profihost.ag/T/#t Reported-by: Drazen Kacar <drazen.kacar@oradian.com> Link: https://lore.kernel.org/linux-btrfs/DB8PR03MB562876ECE2319B3E579590F799C80@DB8PR03MB5628.eurprd03.prod.outlook.com/ Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204377 Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-09-11 16:42:00 +00:00
/*
* Clear EXTENT_BUFFER_WRITEBACK and wake up anyone waiting on it.
* Also set back EXTENT_BUFFER_DIRTY so future attempts to this eb can
* be made and undo everything done before.
*/
btrfs_tree_lock(eb);
spin_lock(&eb->refs_lock);
set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
end_extent_buffer_writeback(eb);
spin_unlock(&eb->refs_lock);
percpu_counter_add_batch(&fs_info->dirty_metadata_bytes, eb->len,
fs_info->dirty_metadata_batch);
btrfs_clear_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
btrfs_tree_unlock(eb);
return ret;
}
static void set_btree_ioerr(struct page *page, struct extent_buffer *eb)
Btrfs: be aware of btree inode write errors to avoid fs corruption While we have a transaction ongoing, the VM might decide at any time to call btree_inode->i_mapping->a_ops->writepages(), which will start writeback of dirty pages belonging to btree nodes/leafs. This call might return an error or the writeback might finish with an error before we attempt to commit the running transaction. If this happens, we might have no way of knowing that such error happened when we are committing the transaction - because the pages might no longer be marked dirty nor tagged for writeback (if a subsequent modification to the extent buffer didn't happen before the transaction commit) which makes filemap_fdata[write|wait]_range unable to find such pages (even if they're marked with SetPageError). So if this happens we must abort the transaction, otherwise we commit a super block with btree roots that point to btree nodes/leafs whose content on disk is invalid - either garbage or the content of some node/leaf from a past generation that got cowed or deleted and is no longer valid (for this later case we end up getting error messages like "parent transid verify failed on 10826481664 wanted 25748 found 29562" when reading btree nodes/leafs from disk). Note that setting and checking AS_EIO/AS_ENOSPC in the btree inode's i_mapping would not be enough because we need to distinguish between log tree extents (not fatal) vs non-log tree extents (fatal) and because the next call to filemap_fdatawait_range() will catch and clear such errors in the mapping - and that call might be from a log sync and not from a transaction commit, which means we would not know about the error at transaction commit time. Also, checking for the eb flag EXTENT_BUFFER_IOERR at transaction commit time isn't done and would not be completely reliable, as the eb might be removed from memory and read back when trying to get it, which clears that flag right before reading the eb's pages from disk, making us not know about the previous write error. Using the new 3 flags for the btree inode also makes us achieve the goal of AS_EIO/AS_ENOSPC when writepages() returns success, started writeback for all dirty pages and before filemap_fdatawait_range() is called, the writeback for all dirty pages had already finished with errors - because we were not using AS_EIO/AS_ENOSPC, filemap_fdatawait_range() would return success, as it could not know that writeback errors happened (the pages were no longer tagged for writeback). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-26 11:25:56 +00:00
{
struct btrfs_fs_info *fs_info = eb->fs_info;
Btrfs: be aware of btree inode write errors to avoid fs corruption While we have a transaction ongoing, the VM might decide at any time to call btree_inode->i_mapping->a_ops->writepages(), which will start writeback of dirty pages belonging to btree nodes/leafs. This call might return an error or the writeback might finish with an error before we attempt to commit the running transaction. If this happens, we might have no way of knowing that such error happened when we are committing the transaction - because the pages might no longer be marked dirty nor tagged for writeback (if a subsequent modification to the extent buffer didn't happen before the transaction commit) which makes filemap_fdata[write|wait]_range unable to find such pages (even if they're marked with SetPageError). So if this happens we must abort the transaction, otherwise we commit a super block with btree roots that point to btree nodes/leafs whose content on disk is invalid - either garbage or the content of some node/leaf from a past generation that got cowed or deleted and is no longer valid (for this later case we end up getting error messages like "parent transid verify failed on 10826481664 wanted 25748 found 29562" when reading btree nodes/leafs from disk). Note that setting and checking AS_EIO/AS_ENOSPC in the btree inode's i_mapping would not be enough because we need to distinguish between log tree extents (not fatal) vs non-log tree extents (fatal) and because the next call to filemap_fdatawait_range() will catch and clear such errors in the mapping - and that call might be from a log sync and not from a transaction commit, which means we would not know about the error at transaction commit time. Also, checking for the eb flag EXTENT_BUFFER_IOERR at transaction commit time isn't done and would not be completely reliable, as the eb might be removed from memory and read back when trying to get it, which clears that flag right before reading the eb's pages from disk, making us not know about the previous write error. Using the new 3 flags for the btree inode also makes us achieve the goal of AS_EIO/AS_ENOSPC when writepages() returns success, started writeback for all dirty pages and before filemap_fdatawait_range() is called, the writeback for all dirty pages had already finished with errors - because we were not using AS_EIO/AS_ENOSPC, filemap_fdatawait_range() would return success, as it could not know that writeback errors happened (the pages were no longer tagged for writeback). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-26 11:25:56 +00:00
btrfs_page_set_error(fs_info, page, eb->start, eb->len);
Btrfs: be aware of btree inode write errors to avoid fs corruption While we have a transaction ongoing, the VM might decide at any time to call btree_inode->i_mapping->a_ops->writepages(), which will start writeback of dirty pages belonging to btree nodes/leafs. This call might return an error or the writeback might finish with an error before we attempt to commit the running transaction. If this happens, we might have no way of knowing that such error happened when we are committing the transaction - because the pages might no longer be marked dirty nor tagged for writeback (if a subsequent modification to the extent buffer didn't happen before the transaction commit) which makes filemap_fdata[write|wait]_range unable to find such pages (even if they're marked with SetPageError). So if this happens we must abort the transaction, otherwise we commit a super block with btree roots that point to btree nodes/leafs whose content on disk is invalid - either garbage or the content of some node/leaf from a past generation that got cowed or deleted and is no longer valid (for this later case we end up getting error messages like "parent transid verify failed on 10826481664 wanted 25748 found 29562" when reading btree nodes/leafs from disk). Note that setting and checking AS_EIO/AS_ENOSPC in the btree inode's i_mapping would not be enough because we need to distinguish between log tree extents (not fatal) vs non-log tree extents (fatal) and because the next call to filemap_fdatawait_range() will catch and clear such errors in the mapping - and that call might be from a log sync and not from a transaction commit, which means we would not know about the error at transaction commit time. Also, checking for the eb flag EXTENT_BUFFER_IOERR at transaction commit time isn't done and would not be completely reliable, as the eb might be removed from memory and read back when trying to get it, which clears that flag right before reading the eb's pages from disk, making us not know about the previous write error. Using the new 3 flags for the btree inode also makes us achieve the goal of AS_EIO/AS_ENOSPC when writepages() returns success, started writeback for all dirty pages and before filemap_fdatawait_range() is called, the writeback for all dirty pages had already finished with errors - because we were not using AS_EIO/AS_ENOSPC, filemap_fdatawait_range() would return success, as it could not know that writeback errors happened (the pages were no longer tagged for writeback). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-26 11:25:56 +00:00
if (test_and_set_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags))
return;
/*
* If we error out, we should add back the dirty_metadata_bytes
* to make it consistent.
*/
percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
eb->len, fs_info->dirty_metadata_batch);
Btrfs: be aware of btree inode write errors to avoid fs corruption While we have a transaction ongoing, the VM might decide at any time to call btree_inode->i_mapping->a_ops->writepages(), which will start writeback of dirty pages belonging to btree nodes/leafs. This call might return an error or the writeback might finish with an error before we attempt to commit the running transaction. If this happens, we might have no way of knowing that such error happened when we are committing the transaction - because the pages might no longer be marked dirty nor tagged for writeback (if a subsequent modification to the extent buffer didn't happen before the transaction commit) which makes filemap_fdata[write|wait]_range unable to find such pages (even if they're marked with SetPageError). So if this happens we must abort the transaction, otherwise we commit a super block with btree roots that point to btree nodes/leafs whose content on disk is invalid - either garbage or the content of some node/leaf from a past generation that got cowed or deleted and is no longer valid (for this later case we end up getting error messages like "parent transid verify failed on 10826481664 wanted 25748 found 29562" when reading btree nodes/leafs from disk). Note that setting and checking AS_EIO/AS_ENOSPC in the btree inode's i_mapping would not be enough because we need to distinguish between log tree extents (not fatal) vs non-log tree extents (fatal) and because the next call to filemap_fdatawait_range() will catch and clear such errors in the mapping - and that call might be from a log sync and not from a transaction commit, which means we would not know about the error at transaction commit time. Also, checking for the eb flag EXTENT_BUFFER_IOERR at transaction commit time isn't done and would not be completely reliable, as the eb might be removed from memory and read back when trying to get it, which clears that flag right before reading the eb's pages from disk, making us not know about the previous write error. Using the new 3 flags for the btree inode also makes us achieve the goal of AS_EIO/AS_ENOSPC when writepages() returns success, started writeback for all dirty pages and before filemap_fdatawait_range() is called, the writeback for all dirty pages had already finished with errors - because we were not using AS_EIO/AS_ENOSPC, filemap_fdatawait_range() would return success, as it could not know that writeback errors happened (the pages were no longer tagged for writeback). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-26 11:25:56 +00:00
/*
* If writeback for a btree extent that doesn't belong to a log tree
* failed, increment the counter transaction->eb_write_errors.
* We do this because while the transaction is running and before it's
* committing (when we call filemap_fdata[write|wait]_range against
* the btree inode), we might have
* btree_inode->i_mapping->a_ops->writepages() called by the VM - if it
* returns an error or an error happens during writeback, when we're
* committing the transaction we wouldn't know about it, since the pages
* can be no longer dirty nor marked anymore for writeback (if a
* subsequent modification to the extent buffer didn't happen before the
* transaction commit), which makes filemap_fdata[write|wait]_range not
* able to find the pages tagged with SetPageError at transaction
* commit time. So if this happens we must abort the transaction,
* otherwise we commit a super block with btree roots that point to
* btree nodes/leafs whose content on disk is invalid - either garbage
* or the content of some node/leaf from a past generation that got
* cowed or deleted and is no longer valid.
*
* Note: setting AS_EIO/AS_ENOSPC in the btree inode's i_mapping would
* not be enough - we need to distinguish between log tree extents vs
* non-log tree extents, and the next filemap_fdatawait_range() call
* will catch and clear such errors in the mapping - and that call might
* be from a log sync and not from a transaction commit. Also, checking
* for the eb flag EXTENT_BUFFER_WRITE_ERR at transaction commit time is
* not done and would not be reliable - the eb might have been released
* from memory and reading it back again means that flag would not be
* set (since it's a runtime flag, not persisted on disk).
*
* Using the flags below in the btree inode also makes us achieve the
* goal of AS_EIO/AS_ENOSPC when writepages() returns success, started
* writeback for all dirty pages and before filemap_fdatawait_range()
* is called, the writeback for all dirty pages had already finished
* with errors - because we were not using AS_EIO/AS_ENOSPC,
* filemap_fdatawait_range() would return success, as it could not know
* that writeback errors happened (the pages were no longer tagged for
* writeback).
*/
switch (eb->log_index) {
case -1:
set_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags);
Btrfs: be aware of btree inode write errors to avoid fs corruption While we have a transaction ongoing, the VM might decide at any time to call btree_inode->i_mapping->a_ops->writepages(), which will start writeback of dirty pages belonging to btree nodes/leafs. This call might return an error or the writeback might finish with an error before we attempt to commit the running transaction. If this happens, we might have no way of knowing that such error happened when we are committing the transaction - because the pages might no longer be marked dirty nor tagged for writeback (if a subsequent modification to the extent buffer didn't happen before the transaction commit) which makes filemap_fdata[write|wait]_range unable to find such pages (even if they're marked with SetPageError). So if this happens we must abort the transaction, otherwise we commit a super block with btree roots that point to btree nodes/leafs whose content on disk is invalid - either garbage or the content of some node/leaf from a past generation that got cowed or deleted and is no longer valid (for this later case we end up getting error messages like "parent transid verify failed on 10826481664 wanted 25748 found 29562" when reading btree nodes/leafs from disk). Note that setting and checking AS_EIO/AS_ENOSPC in the btree inode's i_mapping would not be enough because we need to distinguish between log tree extents (not fatal) vs non-log tree extents (fatal) and because the next call to filemap_fdatawait_range() will catch and clear such errors in the mapping - and that call might be from a log sync and not from a transaction commit, which means we would not know about the error at transaction commit time. Also, checking for the eb flag EXTENT_BUFFER_IOERR at transaction commit time isn't done and would not be completely reliable, as the eb might be removed from memory and read back when trying to get it, which clears that flag right before reading the eb's pages from disk, making us not know about the previous write error. Using the new 3 flags for the btree inode also makes us achieve the goal of AS_EIO/AS_ENOSPC when writepages() returns success, started writeback for all dirty pages and before filemap_fdatawait_range() is called, the writeback for all dirty pages had already finished with errors - because we were not using AS_EIO/AS_ENOSPC, filemap_fdatawait_range() would return success, as it could not know that writeback errors happened (the pages were no longer tagged for writeback). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-26 11:25:56 +00:00
break;
case 0:
set_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
Btrfs: be aware of btree inode write errors to avoid fs corruption While we have a transaction ongoing, the VM might decide at any time to call btree_inode->i_mapping->a_ops->writepages(), which will start writeback of dirty pages belonging to btree nodes/leafs. This call might return an error or the writeback might finish with an error before we attempt to commit the running transaction. If this happens, we might have no way of knowing that such error happened when we are committing the transaction - because the pages might no longer be marked dirty nor tagged for writeback (if a subsequent modification to the extent buffer didn't happen before the transaction commit) which makes filemap_fdata[write|wait]_range unable to find such pages (even if they're marked with SetPageError). So if this happens we must abort the transaction, otherwise we commit a super block with btree roots that point to btree nodes/leafs whose content on disk is invalid - either garbage or the content of some node/leaf from a past generation that got cowed or deleted and is no longer valid (for this later case we end up getting error messages like "parent transid verify failed on 10826481664 wanted 25748 found 29562" when reading btree nodes/leafs from disk). Note that setting and checking AS_EIO/AS_ENOSPC in the btree inode's i_mapping would not be enough because we need to distinguish between log tree extents (not fatal) vs non-log tree extents (fatal) and because the next call to filemap_fdatawait_range() will catch and clear such errors in the mapping - and that call might be from a log sync and not from a transaction commit, which means we would not know about the error at transaction commit time. Also, checking for the eb flag EXTENT_BUFFER_IOERR at transaction commit time isn't done and would not be completely reliable, as the eb might be removed from memory and read back when trying to get it, which clears that flag right before reading the eb's pages from disk, making us not know about the previous write error. Using the new 3 flags for the btree inode also makes us achieve the goal of AS_EIO/AS_ENOSPC when writepages() returns success, started writeback for all dirty pages and before filemap_fdatawait_range() is called, the writeback for all dirty pages had already finished with errors - because we were not using AS_EIO/AS_ENOSPC, filemap_fdatawait_range() would return success, as it could not know that writeback errors happened (the pages were no longer tagged for writeback). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-26 11:25:56 +00:00
break;
case 1:
set_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
Btrfs: be aware of btree inode write errors to avoid fs corruption While we have a transaction ongoing, the VM might decide at any time to call btree_inode->i_mapping->a_ops->writepages(), which will start writeback of dirty pages belonging to btree nodes/leafs. This call might return an error or the writeback might finish with an error before we attempt to commit the running transaction. If this happens, we might have no way of knowing that such error happened when we are committing the transaction - because the pages might no longer be marked dirty nor tagged for writeback (if a subsequent modification to the extent buffer didn't happen before the transaction commit) which makes filemap_fdata[write|wait]_range unable to find such pages (even if they're marked with SetPageError). So if this happens we must abort the transaction, otherwise we commit a super block with btree roots that point to btree nodes/leafs whose content on disk is invalid - either garbage or the content of some node/leaf from a past generation that got cowed or deleted and is no longer valid (for this later case we end up getting error messages like "parent transid verify failed on 10826481664 wanted 25748 found 29562" when reading btree nodes/leafs from disk). Note that setting and checking AS_EIO/AS_ENOSPC in the btree inode's i_mapping would not be enough because we need to distinguish between log tree extents (not fatal) vs non-log tree extents (fatal) and because the next call to filemap_fdatawait_range() will catch and clear such errors in the mapping - and that call might be from a log sync and not from a transaction commit, which means we would not know about the error at transaction commit time. Also, checking for the eb flag EXTENT_BUFFER_IOERR at transaction commit time isn't done and would not be completely reliable, as the eb might be removed from memory and read back when trying to get it, which clears that flag right before reading the eb's pages from disk, making us not know about the previous write error. Using the new 3 flags for the btree inode also makes us achieve the goal of AS_EIO/AS_ENOSPC when writepages() returns success, started writeback for all dirty pages and before filemap_fdatawait_range() is called, the writeback for all dirty pages had already finished with errors - because we were not using AS_EIO/AS_ENOSPC, filemap_fdatawait_range() would return success, as it could not know that writeback errors happened (the pages were no longer tagged for writeback). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-26 11:25:56 +00:00
break;
default:
BUG(); /* unexpected, logic error */
}
}
static void end_bio_extent_buffer_writepage(struct bio *bio)
{
struct bio_vec *bvec;
struct extent_buffer *eb;
int done;
struct bvec_iter_all iter_all;
ASSERT(!bio_flagged(bio, BIO_CLONED));
bio_for_each_segment_all(bvec, bio, iter_all) {
struct page *page = bvec->bv_page;
eb = (struct extent_buffer *)page->private;
BUG_ON(!eb);
done = atomic_dec_and_test(&eb->io_pages);
if (bio->bi_status ||
test_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags)) {
ClearPageUptodate(page);
set_btree_ioerr(page, eb);
}
end_page_writeback(page);
if (!done)
continue;
end_extent_buffer_writeback(eb);
}
bio_put(bio);
}
static noinline_for_stack int write_one_eb(struct extent_buffer *eb,
struct writeback_control *wbc,
struct extent_page_data *epd)
{
u64 disk_bytenr = eb->start;
u32 nritems;
int i, num_pages;
unsigned long start, end;
unsigned int write_flags = wbc_to_write_flags(wbc) | REQ_META;
int ret = 0;
Btrfs: be aware of btree inode write errors to avoid fs corruption While we have a transaction ongoing, the VM might decide at any time to call btree_inode->i_mapping->a_ops->writepages(), which will start writeback of dirty pages belonging to btree nodes/leafs. This call might return an error or the writeback might finish with an error before we attempt to commit the running transaction. If this happens, we might have no way of knowing that such error happened when we are committing the transaction - because the pages might no longer be marked dirty nor tagged for writeback (if a subsequent modification to the extent buffer didn't happen before the transaction commit) which makes filemap_fdata[write|wait]_range unable to find such pages (even if they're marked with SetPageError). So if this happens we must abort the transaction, otherwise we commit a super block with btree roots that point to btree nodes/leafs whose content on disk is invalid - either garbage or the content of some node/leaf from a past generation that got cowed or deleted and is no longer valid (for this later case we end up getting error messages like "parent transid verify failed on 10826481664 wanted 25748 found 29562" when reading btree nodes/leafs from disk). Note that setting and checking AS_EIO/AS_ENOSPC in the btree inode's i_mapping would not be enough because we need to distinguish between log tree extents (not fatal) vs non-log tree extents (fatal) and because the next call to filemap_fdatawait_range() will catch and clear such errors in the mapping - and that call might be from a log sync and not from a transaction commit, which means we would not know about the error at transaction commit time. Also, checking for the eb flag EXTENT_BUFFER_IOERR at transaction commit time isn't done and would not be completely reliable, as the eb might be removed from memory and read back when trying to get it, which clears that flag right before reading the eb's pages from disk, making us not know about the previous write error. Using the new 3 flags for the btree inode also makes us achieve the goal of AS_EIO/AS_ENOSPC when writepages() returns success, started writeback for all dirty pages and before filemap_fdatawait_range() is called, the writeback for all dirty pages had already finished with errors - because we were not using AS_EIO/AS_ENOSPC, filemap_fdatawait_range() would return success, as it could not know that writeback errors happened (the pages were no longer tagged for writeback). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-26 11:25:56 +00:00
clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
num_pages = num_extent_pages(eb);
atomic_set(&eb->io_pages, num_pages);
/* set btree blocks beyond nritems with 0 to avoid stale content. */
nritems = btrfs_header_nritems(eb);
if (btrfs_header_level(eb) > 0) {
end = btrfs_node_key_ptr_offset(nritems);
memzero_extent_buffer(eb, end, eb->len - end);
} else {
/*
* leaf:
* header 0 1 2 .. N ... data_N .. data_2 data_1 data_0
*/
start = btrfs_item_nr_offset(nritems);
end = BTRFS_LEAF_DATA_OFFSET + leaf_data_end(eb);
memzero_extent_buffer(eb, start, end - start);
}
for (i = 0; i < num_pages; i++) {
struct page *p = eb->pages[i];
clear_page_dirty_for_io(p);
set_page_writeback(p);
ret = submit_extent_page(REQ_OP_WRITE | write_flags, wbc,
p, disk_bytenr, PAGE_SIZE, 0,
&epd->bio,
end_bio_extent_buffer_writepage,
0, 0, 0, false);
if (ret) {
set_btree_ioerr(p, eb);
if (PageWriteback(p))
end_page_writeback(p);
if (atomic_sub_and_test(num_pages - i, &eb->io_pages))
end_extent_buffer_writeback(eb);
ret = -EIO;
break;
}
disk_bytenr += PAGE_SIZE;
update_nr_written(wbc, 1);
unlock_page(p);
}
if (unlikely(ret)) {
for (; i < num_pages; i++) {
struct page *p = eb->pages[i];
clear_page_dirty_for_io(p);
unlock_page(p);
}
}
return ret;
}
/*
* Submit all page(s) of one extent buffer.
*
* @page: the page of one extent buffer
* @eb_context: to determine if we need to submit this page, if current page
* belongs to this eb, we don't need to submit
*
* The caller should pass each page in their bytenr order, and here we use
* @eb_context to determine if we have submitted pages of one extent buffer.
*
* If we have, we just skip until we hit a new page that doesn't belong to
* current @eb_context.
*
* If not, we submit all the page(s) of the extent buffer.
*
* Return >0 if we have submitted the extent buffer successfully.
* Return 0 if we don't need to submit the page, as it's already submitted by
* previous call.
* Return <0 for fatal error.
*/
static int submit_eb_page(struct page *page, struct writeback_control *wbc,
struct extent_page_data *epd,
struct extent_buffer **eb_context)
{
struct address_space *mapping = page->mapping;
struct btrfs_block_group *cache = NULL;
struct extent_buffer *eb;
int ret;
if (!PagePrivate(page))
return 0;
spin_lock(&mapping->private_lock);
if (!PagePrivate(page)) {
spin_unlock(&mapping->private_lock);
return 0;
}
eb = (struct extent_buffer *)page->private;
/*
* Shouldn't happen and normally this would be a BUG_ON but no point
* crashing the machine for something we can survive anyway.
*/
if (WARN_ON(!eb)) {
spin_unlock(&mapping->private_lock);
return 0;
}
if (eb == *eb_context) {
spin_unlock(&mapping->private_lock);
return 0;
}
ret = atomic_inc_not_zero(&eb->refs);
spin_unlock(&mapping->private_lock);
if (!ret)
return 0;
if (!btrfs_check_meta_write_pointer(eb->fs_info, eb, &cache)) {
/*
* If for_sync, this hole will be filled with
* trasnsaction commit.
*/
if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync)
ret = -EAGAIN;
else
ret = 0;
free_extent_buffer(eb);
return ret;
}
*eb_context = eb;
ret = lock_extent_buffer_for_io(eb, epd);
if (ret <= 0) {
btrfs_revert_meta_write_pointer(cache, eb);
if (cache)
btrfs_put_block_group(cache);
free_extent_buffer(eb);
return ret;
}
if (cache)
btrfs_put_block_group(cache);
ret = write_one_eb(eb, wbc, epd);
free_extent_buffer(eb);
if (ret < 0)
return ret;
return 1;
}
int btree_write_cache_pages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct extent_buffer *eb_context = NULL;
struct extent_page_data epd = {
.bio = NULL,
.extent_locked = 0,
.sync_io = wbc->sync_mode == WB_SYNC_ALL,
};
btrfs: Don't submit any btree write bio if the fs has errors [BUG] There is a fuzzed image which could cause KASAN report at unmount time. BUG: KASAN: use-after-free in btrfs_queue_work+0x2c1/0x390 Read of size 8 at addr ffff888067cf6848 by task umount/1922 CPU: 0 PID: 1922 Comm: umount Tainted: G W 5.0.21 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 Call Trace: dump_stack+0x5b/0x8b print_address_description+0x70/0x280 kasan_report+0x13a/0x19b btrfs_queue_work+0x2c1/0x390 btrfs_wq_submit_bio+0x1cd/0x240 btree_submit_bio_hook+0x18c/0x2a0 submit_one_bio+0x1be/0x320 flush_write_bio.isra.41+0x2c/0x70 btree_write_cache_pages+0x3bb/0x7f0 do_writepages+0x5c/0x130 __writeback_single_inode+0xa3/0x9a0 writeback_single_inode+0x23d/0x390 write_inode_now+0x1b5/0x280 iput+0x2ef/0x600 close_ctree+0x341/0x750 generic_shutdown_super+0x126/0x370 kill_anon_super+0x31/0x50 btrfs_kill_super+0x36/0x2b0 deactivate_locked_super+0x80/0xc0 deactivate_super+0x13c/0x150 cleanup_mnt+0x9a/0x130 task_work_run+0x11a/0x1b0 exit_to_usermode_loop+0x107/0x130 do_syscall_64+0x1e5/0x280 entry_SYSCALL_64_after_hwframe+0x44/0xa9 [CAUSE] The fuzzed image has a completely screwd up extent tree: leaf 29421568 gen 8 total ptrs 6 free space 3587 owner EXTENT_TREE refs 2 lock (w:0 r:0 bw:0 br:0 sw:0 sr:0) lock_owner 0 current 5938 item 0 key (12587008 168 4096) itemoff 3942 itemsize 53 extent refs 1 gen 9 flags 1 ref#0: extent data backref root 5 objectid 259 offset 0 count 1 item 1 key (12591104 168 8192) itemoff 3889 itemsize 53 extent refs 1 gen 9 flags 1 ref#0: extent data backref root 5 objectid 271 offset 0 count 1 item 2 key (12599296 168 4096) itemoff 3836 itemsize 53 extent refs 1 gen 9 flags 1 ref#0: extent data backref root 5 objectid 259 offset 4096 count 1 item 3 key (29360128 169 0) itemoff 3803 itemsize 33 extent refs 1 gen 9 flags 2 ref#0: tree block backref root 5 item 4 key (29368320 169 1) itemoff 3770 itemsize 33 extent refs 1 gen 9 flags 2 ref#0: tree block backref root 5 item 5 key (29372416 169 0) itemoff 3737 itemsize 33 extent refs 1 gen 9 flags 2 ref#0: tree block backref root 5 Note that leaf 29421568 doesn't have its backref in the extent tree. Thus extent allocator can re-allocate leaf 29421568 for other trees. In short, the bug is caused by: - Existing tree block gets allocated to log tree This got its generation bumped. - Log tree balance cleaned dirty bit of offending tree block It will not be written back to disk, thus no WRITTEN flag. - Original owner of the tree block gets COWed Since the tree block has higher transid, no WRITTEN flag, it's reused, and not traced by transaction::dirty_pages. - Transaction aborted Tree blocks get cleaned according to transaction::dirty_pages. But the offending tree block is not recorded at all. - Filesystem unmount All pages are assumed to be are clean, destroying all workqueue, then call iput(btree_inode). But offending tree block is still dirty, which triggers writeback, and causes use-after-free bug. The detailed sequence looks like this: - Initial status eb: 29421568, header=WRITTEN bflags_dirty=0, page_dirty=0, gen=8, not traced by any dirty extent_iot_tree. - New tree block is allocated Since there is no backref for 29421568, it's re-allocated as new tree block. Keep in mind that tree block 29421568 is still referred by extent tree. - Tree block 29421568 is filled for log tree eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9 << (gen bumped) traced by btrfs_root::dirty_log_pages - Some log tree operations Since the fs is using node size 4096, the log tree can easily go a level higher. - Log tree needs balance Tree block 29421568 gets all its content pushed to right, thus now it is empty, and we don't need it. btrfs_clean_tree_block() from __push_leaf_right() get called. eb: 29421568, header=0 bflags_dirty=0, page_dirty=0, gen=9 traced by btrfs_root::dirty_log_pages - Log tree write back btree_write_cache_pages() goes through dirty pages ranges, but since page of tree block 29421568 gets cleaned already, it's not written back to disk. Thus it doesn't have WRITTEN bit set. But ranges in dirty_log_pages are cleared. eb: 29421568, header=0 bflags_dirty=0, page_dirty=0, gen=9 not traced by any dirty extent_iot_tree. - Extent tree update when committing transaction Since tree block 29421568 has transid equal to running trans, and has no WRITTEN bit, should_cow_block() will use it directly without adding it to btrfs_transaction::dirty_pages. eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9 not traced by any dirty extent_iot_tree. At this stage, we're doomed. We have a dirty eb not tracked by any extent io tree. - Transaction gets aborted due to corrupted extent tree Btrfs cleans up dirty pages according to transaction::dirty_pages and btrfs_root::dirty_log_pages. But since tree block 29421568 is not tracked by neither of them, it's still dirty. eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9 not traced by any dirty extent_iot_tree. - Filesystem unmount Since all cleanup is assumed to be done, all workqueus are destroyed. Then iput(btree_inode) is called, expecting no dirty pages. But tree 29421568 is still dirty, thus triggering writeback. Since all workqueues are already freed, we cause use-after-free. This shows us that, log tree blocks + bad extent tree can cause wild dirty pages. [FIX] To fix the problem, don't submit any btree write bio if the filesytem has any error. This is the last safe net, just in case other cleanup haven't caught catch it. Link: https://github.com/bobfuzzer/CVE/tree/master/CVE-2019-19377 CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-02-12 06:12:44 +00:00
struct btrfs_fs_info *fs_info = BTRFS_I(mapping->host)->root->fs_info;
int ret = 0;
int done = 0;
int nr_to_write_done = 0;
struct pagevec pvec;
int nr_pages;
pgoff_t index;
pgoff_t end; /* Inclusive */
int scanned = 0;
xa_mark_t tag;
pagevec_init(&pvec);
if (wbc->range_cyclic) {
index = mapping->writeback_index; /* Start from prev offset */
end = -1;
btrfs: fix improper setting of scanned for range cyclic write cache pages We noticed that we were having regular CG OOM kills in cases where there was still enough dirty pages to avoid OOM'ing. It turned out there's this corner case in btrfs's handling of range_cyclic where files that were being redirtied were not getting fully written out because of how we do range_cyclic writeback. We unconditionally were setting scanned = 1; the first time we found any pages in the inode. This isn't actually what we want, we want it to be set if we've scanned the entire file. For range_cyclic we could be starting in the middle or towards the end of the file, so we could write one page and then not write any of the other dirty pages in the file because we set scanned = 1. Fix this by not setting scanned = 1 if we find pages. The rules for setting scanned should be 1) !range_cyclic. In this case we have a specified range to write out. 2) range_cyclic && index == 0. In this case we've started at the beginning and there is no need to loop around a second time. 3) range_cyclic && we started at index > 0 and we've reached the end of the file without satisfying our nr_to_write. This patch fixes both of our writepages implementations to make sure these rules hold true. This fixed our over zealous CG OOMs in production. Fixes: d1310b2e0cd9 ("Btrfs: Split the extent_map code into two parts") Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add comment ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-03 15:38:44 +00:00
/*
* Start from the beginning does not need to cycle over the
* range, mark it as scanned.
*/
scanned = (index == 0);
} else {
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
index = wbc->range_start >> PAGE_SHIFT;
end = wbc->range_end >> PAGE_SHIFT;
scanned = 1;
}
if (wbc->sync_mode == WB_SYNC_ALL)
tag = PAGECACHE_TAG_TOWRITE;
else
tag = PAGECACHE_TAG_DIRTY;
btrfs_zoned_meta_io_lock(fs_info);
retry:
if (wbc->sync_mode == WB_SYNC_ALL)
tag_pages_for_writeback(mapping, index, end);
while (!done && !nr_to_write_done && (index <= end) &&
(nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
tag))) {
unsigned i;
for (i = 0; i < nr_pages; i++) {
struct page *page = pvec.pages[i];
ret = submit_eb_page(page, wbc, &epd, &eb_context);
if (ret == 0)
continue;
if (ret < 0) {
done = 1;
break;
}
/*
* the filesystem may choose to bump up nr_to_write.
* We have to make sure to honor the new nr_to_write
* at any time
*/
nr_to_write_done = wbc->nr_to_write <= 0;
}
pagevec_release(&pvec);
cond_resched();
}
if (!scanned && !done) {
/*
* We hit the last page and there is more work to be done: wrap
* back to the start of the file
*/
scanned = 1;
index = 0;
goto retry;
}
if (ret < 0) {
end_write_bio(&epd, ret);
goto out;
}
btrfs: Don't submit any btree write bio if the fs has errors [BUG] There is a fuzzed image which could cause KASAN report at unmount time. BUG: KASAN: use-after-free in btrfs_queue_work+0x2c1/0x390 Read of size 8 at addr ffff888067cf6848 by task umount/1922 CPU: 0 PID: 1922 Comm: umount Tainted: G W 5.0.21 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 Call Trace: dump_stack+0x5b/0x8b print_address_description+0x70/0x280 kasan_report+0x13a/0x19b btrfs_queue_work+0x2c1/0x390 btrfs_wq_submit_bio+0x1cd/0x240 btree_submit_bio_hook+0x18c/0x2a0 submit_one_bio+0x1be/0x320 flush_write_bio.isra.41+0x2c/0x70 btree_write_cache_pages+0x3bb/0x7f0 do_writepages+0x5c/0x130 __writeback_single_inode+0xa3/0x9a0 writeback_single_inode+0x23d/0x390 write_inode_now+0x1b5/0x280 iput+0x2ef/0x600 close_ctree+0x341/0x750 generic_shutdown_super+0x126/0x370 kill_anon_super+0x31/0x50 btrfs_kill_super+0x36/0x2b0 deactivate_locked_super+0x80/0xc0 deactivate_super+0x13c/0x150 cleanup_mnt+0x9a/0x130 task_work_run+0x11a/0x1b0 exit_to_usermode_loop+0x107/0x130 do_syscall_64+0x1e5/0x280 entry_SYSCALL_64_after_hwframe+0x44/0xa9 [CAUSE] The fuzzed image has a completely screwd up extent tree: leaf 29421568 gen 8 total ptrs 6 free space 3587 owner EXTENT_TREE refs 2 lock (w:0 r:0 bw:0 br:0 sw:0 sr:0) lock_owner 0 current 5938 item 0 key (12587008 168 4096) itemoff 3942 itemsize 53 extent refs 1 gen 9 flags 1 ref#0: extent data backref root 5 objectid 259 offset 0 count 1 item 1 key (12591104 168 8192) itemoff 3889 itemsize 53 extent refs 1 gen 9 flags 1 ref#0: extent data backref root 5 objectid 271 offset 0 count 1 item 2 key (12599296 168 4096) itemoff 3836 itemsize 53 extent refs 1 gen 9 flags 1 ref#0: extent data backref root 5 objectid 259 offset 4096 count 1 item 3 key (29360128 169 0) itemoff 3803 itemsize 33 extent refs 1 gen 9 flags 2 ref#0: tree block backref root 5 item 4 key (29368320 169 1) itemoff 3770 itemsize 33 extent refs 1 gen 9 flags 2 ref#0: tree block backref root 5 item 5 key (29372416 169 0) itemoff 3737 itemsize 33 extent refs 1 gen 9 flags 2 ref#0: tree block backref root 5 Note that leaf 29421568 doesn't have its backref in the extent tree. Thus extent allocator can re-allocate leaf 29421568 for other trees. In short, the bug is caused by: - Existing tree block gets allocated to log tree This got its generation bumped. - Log tree balance cleaned dirty bit of offending tree block It will not be written back to disk, thus no WRITTEN flag. - Original owner of the tree block gets COWed Since the tree block has higher transid, no WRITTEN flag, it's reused, and not traced by transaction::dirty_pages. - Transaction aborted Tree blocks get cleaned according to transaction::dirty_pages. But the offending tree block is not recorded at all. - Filesystem unmount All pages are assumed to be are clean, destroying all workqueue, then call iput(btree_inode). But offending tree block is still dirty, which triggers writeback, and causes use-after-free bug. The detailed sequence looks like this: - Initial status eb: 29421568, header=WRITTEN bflags_dirty=0, page_dirty=0, gen=8, not traced by any dirty extent_iot_tree. - New tree block is allocated Since there is no backref for 29421568, it's re-allocated as new tree block. Keep in mind that tree block 29421568 is still referred by extent tree. - Tree block 29421568 is filled for log tree eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9 << (gen bumped) traced by btrfs_root::dirty_log_pages - Some log tree operations Since the fs is using node size 4096, the log tree can easily go a level higher. - Log tree needs balance Tree block 29421568 gets all its content pushed to right, thus now it is empty, and we don't need it. btrfs_clean_tree_block() from __push_leaf_right() get called. eb: 29421568, header=0 bflags_dirty=0, page_dirty=0, gen=9 traced by btrfs_root::dirty_log_pages - Log tree write back btree_write_cache_pages() goes through dirty pages ranges, but since page of tree block 29421568 gets cleaned already, it's not written back to disk. Thus it doesn't have WRITTEN bit set. But ranges in dirty_log_pages are cleared. eb: 29421568, header=0 bflags_dirty=0, page_dirty=0, gen=9 not traced by any dirty extent_iot_tree. - Extent tree update when committing transaction Since tree block 29421568 has transid equal to running trans, and has no WRITTEN bit, should_cow_block() will use it directly without adding it to btrfs_transaction::dirty_pages. eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9 not traced by any dirty extent_iot_tree. At this stage, we're doomed. We have a dirty eb not tracked by any extent io tree. - Transaction gets aborted due to corrupted extent tree Btrfs cleans up dirty pages according to transaction::dirty_pages and btrfs_root::dirty_log_pages. But since tree block 29421568 is not tracked by neither of them, it's still dirty. eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9 not traced by any dirty extent_iot_tree. - Filesystem unmount Since all cleanup is assumed to be done, all workqueus are destroyed. Then iput(btree_inode) is called, expecting no dirty pages. But tree 29421568 is still dirty, thus triggering writeback. Since all workqueues are already freed, we cause use-after-free. This shows us that, log tree blocks + bad extent tree can cause wild dirty pages. [FIX] To fix the problem, don't submit any btree write bio if the filesytem has any error. This is the last safe net, just in case other cleanup haven't caught catch it. Link: https://github.com/bobfuzzer/CVE/tree/master/CVE-2019-19377 CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-02-12 06:12:44 +00:00
/*
* If something went wrong, don't allow any metadata write bio to be
* submitted.
*
* This would prevent use-after-free if we had dirty pages not
* cleaned up, which can still happen by fuzzed images.
*
* - Bad extent tree
* Allowing existing tree block to be allocated for other trees.
*
* - Log tree operations
* Exiting tree blocks get allocated to log tree, bumps its
* generation, then get cleaned in tree re-balance.
* Such tree block will not be written back, since it's clean,
* thus no WRITTEN flag set.
* And after log writes back, this tree block is not traced by
* any dirty extent_io_tree.
*
* - Offending tree block gets re-dirtied from its original owner
* Since it has bumped generation, no WRITTEN flag, it can be
* reused without COWing. This tree block will not be traced
* by btrfs_transaction::dirty_pages.
*
* Now such dirty tree block will not be cleaned by any dirty
* extent io tree. Thus we don't want to submit such wild eb
* if the fs already has error.
*/
if (!test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
ret = flush_write_bio(&epd);
} else {
btrfs: return EROFS for BTRFS_FS_STATE_ERROR cases Eric reported seeing this message while running generic/475 BTRFS: error (device dm-3) in btrfs_sync_log:3084: errno=-117 Filesystem corrupted Full stack trace: BTRFS: error (device dm-0) in btrfs_commit_transaction:2323: errno=-5 IO failure (Error while writing out transaction) BTRFS info (device dm-0): forced readonly BTRFS warning (device dm-0): Skipping commit of aborted transaction. ------------[ cut here ]------------ BTRFS: error (device dm-0) in cleanup_transaction:1894: errno=-5 IO failure BTRFS: Transaction aborted (error -117) BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6480 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6488 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6490 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6498 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64a0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64a8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64b0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64b8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64c0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3572 rw 0,0 sector 0x1b85e8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3572 rw 0,0 sector 0x1b85f0 len 4096 err no 10 WARNING: CPU: 3 PID: 23985 at fs/btrfs/tree-log.c:3084 btrfs_sync_log+0xbc8/0xd60 [btrfs] BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d4288 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d4290 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d4298 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42a0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42a8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42b0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42b8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42c0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42c8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42d0 len 4096 err no 10 CPU: 3 PID: 23985 Comm: fsstress Tainted: G W L 5.8.0-rc4-default+ #1181 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014 RIP: 0010:btrfs_sync_log+0xbc8/0xd60 [btrfs] RSP: 0018:ffff909a44d17bd0 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000001 RDX: ffff8f3be41cb940 RSI: ffffffffb0108d2b RDI: ffffffffb0108ff7 RBP: ffff909a44d17e70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000037988 R12: ffff8f3bd20e4000 R13: ffff8f3bd20e4428 R14: 00000000ffffff8b R15: ffff909a44d17c70 FS: 00007f6a6ed3fb80(0000) GS:ffff8f3c3dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6a6ed3e000 CR3: 00000000525c0003 CR4: 0000000000160ee0 Call Trace: ? finish_wait+0x90/0x90 ? __mutex_unlock_slowpath+0x45/0x2a0 ? lock_acquire+0xa3/0x440 ? lockref_put_or_lock+0x9/0x30 ? dput+0x20/0x4a0 ? dput+0x20/0x4a0 ? do_raw_spin_unlock+0x4b/0xc0 ? _raw_spin_unlock+0x1f/0x30 btrfs_sync_file+0x335/0x490 [btrfs] do_fsync+0x38/0x70 __x64_sys_fsync+0x10/0x20 do_syscall_64+0x50/0xe0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f6a6ef1b6e3 Code: Bad RIP value. RSP: 002b:00007ffd01e20038 EFLAGS: 00000246 ORIG_RAX: 000000000000004a RAX: ffffffffffffffda RBX: 000000000007a120 RCX: 00007f6a6ef1b6e3 RDX: 00007ffd01e1ffa0 RSI: 00007ffd01e1ffa0 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000001 R09: 00007ffd01e2004c R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000009f R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 irq event stamp: 0 hardirqs last enabled at (0): [<0000000000000000>] 0x0 hardirqs last disabled at (0): [<ffffffffb007fe0b>] copy_process+0x67b/0x1b00 softirqs last enabled at (0): [<ffffffffb007fe0b>] copy_process+0x67b/0x1b00 softirqs last disabled at (0): [<0000000000000000>] 0x0 ---[ end trace af146e0e38433456 ]--- BTRFS: error (device dm-0) in btrfs_sync_log:3084: errno=-117 Filesystem corrupted This ret came from btrfs_write_marked_extents(). If we get an aborted transaction via EIO before, we'll see it in btree_write_cache_pages() and return EUCLEAN, which gets printed as "Filesystem corrupted". Except we shouldn't be returning EUCLEAN here, we need to be returning EROFS because EUCLEAN is reserved for actual corruption, not IO errors. We are inconsistent about our handling of BTRFS_FS_STATE_ERROR elsewhere, but we want to use EROFS for this particular case. The original transaction abort has the real error code for why we ended up with an aborted transaction, all subsequent actions just need to return EROFS because they may not have a trans handle and have no idea about the original cause of the abort. After patch "btrfs: don't WARN if we abort a transaction with EROFS" the stacktrace will not be dumped either. Reported-by: Eric Sandeen <esandeen@redhat.com> CC: stable@vger.kernel.org # 5.4+ Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add full test stacktrace ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-21 14:38:37 +00:00
ret = -EROFS;
btrfs: Don't submit any btree write bio if the fs has errors [BUG] There is a fuzzed image which could cause KASAN report at unmount time. BUG: KASAN: use-after-free in btrfs_queue_work+0x2c1/0x390 Read of size 8 at addr ffff888067cf6848 by task umount/1922 CPU: 0 PID: 1922 Comm: umount Tainted: G W 5.0.21 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 Call Trace: dump_stack+0x5b/0x8b print_address_description+0x70/0x280 kasan_report+0x13a/0x19b btrfs_queue_work+0x2c1/0x390 btrfs_wq_submit_bio+0x1cd/0x240 btree_submit_bio_hook+0x18c/0x2a0 submit_one_bio+0x1be/0x320 flush_write_bio.isra.41+0x2c/0x70 btree_write_cache_pages+0x3bb/0x7f0 do_writepages+0x5c/0x130 __writeback_single_inode+0xa3/0x9a0 writeback_single_inode+0x23d/0x390 write_inode_now+0x1b5/0x280 iput+0x2ef/0x600 close_ctree+0x341/0x750 generic_shutdown_super+0x126/0x370 kill_anon_super+0x31/0x50 btrfs_kill_super+0x36/0x2b0 deactivate_locked_super+0x80/0xc0 deactivate_super+0x13c/0x150 cleanup_mnt+0x9a/0x130 task_work_run+0x11a/0x1b0 exit_to_usermode_loop+0x107/0x130 do_syscall_64+0x1e5/0x280 entry_SYSCALL_64_after_hwframe+0x44/0xa9 [CAUSE] The fuzzed image has a completely screwd up extent tree: leaf 29421568 gen 8 total ptrs 6 free space 3587 owner EXTENT_TREE refs 2 lock (w:0 r:0 bw:0 br:0 sw:0 sr:0) lock_owner 0 current 5938 item 0 key (12587008 168 4096) itemoff 3942 itemsize 53 extent refs 1 gen 9 flags 1 ref#0: extent data backref root 5 objectid 259 offset 0 count 1 item 1 key (12591104 168 8192) itemoff 3889 itemsize 53 extent refs 1 gen 9 flags 1 ref#0: extent data backref root 5 objectid 271 offset 0 count 1 item 2 key (12599296 168 4096) itemoff 3836 itemsize 53 extent refs 1 gen 9 flags 1 ref#0: extent data backref root 5 objectid 259 offset 4096 count 1 item 3 key (29360128 169 0) itemoff 3803 itemsize 33 extent refs 1 gen 9 flags 2 ref#0: tree block backref root 5 item 4 key (29368320 169 1) itemoff 3770 itemsize 33 extent refs 1 gen 9 flags 2 ref#0: tree block backref root 5 item 5 key (29372416 169 0) itemoff 3737 itemsize 33 extent refs 1 gen 9 flags 2 ref#0: tree block backref root 5 Note that leaf 29421568 doesn't have its backref in the extent tree. Thus extent allocator can re-allocate leaf 29421568 for other trees. In short, the bug is caused by: - Existing tree block gets allocated to log tree This got its generation bumped. - Log tree balance cleaned dirty bit of offending tree block It will not be written back to disk, thus no WRITTEN flag. - Original owner of the tree block gets COWed Since the tree block has higher transid, no WRITTEN flag, it's reused, and not traced by transaction::dirty_pages. - Transaction aborted Tree blocks get cleaned according to transaction::dirty_pages. But the offending tree block is not recorded at all. - Filesystem unmount All pages are assumed to be are clean, destroying all workqueue, then call iput(btree_inode). But offending tree block is still dirty, which triggers writeback, and causes use-after-free bug. The detailed sequence looks like this: - Initial status eb: 29421568, header=WRITTEN bflags_dirty=0, page_dirty=0, gen=8, not traced by any dirty extent_iot_tree. - New tree block is allocated Since there is no backref for 29421568, it's re-allocated as new tree block. Keep in mind that tree block 29421568 is still referred by extent tree. - Tree block 29421568 is filled for log tree eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9 << (gen bumped) traced by btrfs_root::dirty_log_pages - Some log tree operations Since the fs is using node size 4096, the log tree can easily go a level higher. - Log tree needs balance Tree block 29421568 gets all its content pushed to right, thus now it is empty, and we don't need it. btrfs_clean_tree_block() from __push_leaf_right() get called. eb: 29421568, header=0 bflags_dirty=0, page_dirty=0, gen=9 traced by btrfs_root::dirty_log_pages - Log tree write back btree_write_cache_pages() goes through dirty pages ranges, but since page of tree block 29421568 gets cleaned already, it's not written back to disk. Thus it doesn't have WRITTEN bit set. But ranges in dirty_log_pages are cleared. eb: 29421568, header=0 bflags_dirty=0, page_dirty=0, gen=9 not traced by any dirty extent_iot_tree. - Extent tree update when committing transaction Since tree block 29421568 has transid equal to running trans, and has no WRITTEN bit, should_cow_block() will use it directly without adding it to btrfs_transaction::dirty_pages. eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9 not traced by any dirty extent_iot_tree. At this stage, we're doomed. We have a dirty eb not tracked by any extent io tree. - Transaction gets aborted due to corrupted extent tree Btrfs cleans up dirty pages according to transaction::dirty_pages and btrfs_root::dirty_log_pages. But since tree block 29421568 is not tracked by neither of them, it's still dirty. eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9 not traced by any dirty extent_iot_tree. - Filesystem unmount Since all cleanup is assumed to be done, all workqueus are destroyed. Then iput(btree_inode) is called, expecting no dirty pages. But tree 29421568 is still dirty, thus triggering writeback. Since all workqueues are already freed, we cause use-after-free. This shows us that, log tree blocks + bad extent tree can cause wild dirty pages. [FIX] To fix the problem, don't submit any btree write bio if the filesytem has any error. This is the last safe net, just in case other cleanup haven't caught catch it. Link: https://github.com/bobfuzzer/CVE/tree/master/CVE-2019-19377 CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-02-12 06:12:44 +00:00
end_write_bio(&epd, ret);
}
out:
btrfs_zoned_meta_io_unlock(fs_info);
return ret;
}
/**
btrfs: fix parameter description for functions in extent_io.c This makes the file W=1 clean and fixes the following warnings: fs/btrfs/extent_io.c:414: warning: Function parameter or member 'tree' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'offset' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'next_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'prev_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'p_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'parent_ret' not described in '__etree_search' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'tree' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start_ret' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'end_ret' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'bits' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'tree' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start_ret' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'end_ret' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'bits' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:4187: warning: Function parameter or member 'epd' not described in 'extent_write_cache_pages' fs/btrfs/extent_io.c:4187: warning: Excess function parameter 'data' description in 'extent_write_cache_pages' Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-22 09:58:03 +00:00
* Walk the list of dirty pages of the given address space and write all of them.
*
* @mapping: address space structure to write
btrfs: fix parameter description for functions in extent_io.c This makes the file W=1 clean and fixes the following warnings: fs/btrfs/extent_io.c:414: warning: Function parameter or member 'tree' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'offset' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'next_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'prev_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'p_ret' not described in '__etree_search' fs/btrfs/extent_io.c:414: warning: Function parameter or member 'parent_ret' not described in '__etree_search' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'tree' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'start_ret' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'end_ret' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1607: warning: Function parameter or member 'bits' not described in 'find_contiguous_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'tree' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'start_ret' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'end_ret' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:1644: warning: Function parameter or member 'bits' not described in 'find_first_clear_extent_bit' fs/btrfs/extent_io.c:4187: warning: Function parameter or member 'epd' not described in 'extent_write_cache_pages' fs/btrfs/extent_io.c:4187: warning: Excess function parameter 'data' description in 'extent_write_cache_pages' Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-22 09:58:03 +00:00
* @wbc: subtract the number of written pages from *@wbc->nr_to_write
* @epd: holds context for the write, namely the bio
*
* If a page is already under I/O, write_cache_pages() skips it, even
* if it's dirty. This is desirable behaviour for memory-cleaning writeback,
* but it is INCORRECT for data-integrity system calls such as fsync(). fsync()
* and msync() need to guarantee that all the data which was dirty at the time
* the call was made get new I/O started against them. If wbc->sync_mode is
* WB_SYNC_ALL then we were called for data integrity and we must wait for
* existing IO to complete.
*/
static int extent_write_cache_pages(struct address_space *mapping,
struct writeback_control *wbc,
struct extent_page_data *epd)
{
struct inode *inode = mapping->host;
int ret = 0;
int done = 0;
int nr_to_write_done = 0;
struct pagevec pvec;
int nr_pages;
pgoff_t index;
pgoff_t end; /* Inclusive */
pgoff_t done_index;
int range_whole = 0;
int scanned = 0;
xa_mark_t tag;
/*
* We have to hold onto the inode so that ordered extents can do their
* work when the IO finishes. The alternative to this is failing to add
* an ordered extent if the igrab() fails there and that is a huge pain
* to deal with, so instead just hold onto the inode throughout the
* writepages operation. If it fails here we are freeing up the inode
* anyway and we'd rather not waste our time writing out stuff that is
* going to be truncated anyway.
*/
if (!igrab(inode))
return 0;
pagevec_init(&pvec);
if (wbc->range_cyclic) {
index = mapping->writeback_index; /* Start from prev offset */
end = -1;
btrfs: fix improper setting of scanned for range cyclic write cache pages We noticed that we were having regular CG OOM kills in cases where there was still enough dirty pages to avoid OOM'ing. It turned out there's this corner case in btrfs's handling of range_cyclic where files that were being redirtied were not getting fully written out because of how we do range_cyclic writeback. We unconditionally were setting scanned = 1; the first time we found any pages in the inode. This isn't actually what we want, we want it to be set if we've scanned the entire file. For range_cyclic we could be starting in the middle or towards the end of the file, so we could write one page and then not write any of the other dirty pages in the file because we set scanned = 1. Fix this by not setting scanned = 1 if we find pages. The rules for setting scanned should be 1) !range_cyclic. In this case we have a specified range to write out. 2) range_cyclic && index == 0. In this case we've started at the beginning and there is no need to loop around a second time. 3) range_cyclic && we started at index > 0 and we've reached the end of the file without satisfying our nr_to_write. This patch fixes both of our writepages implementations to make sure these rules hold true. This fixed our over zealous CG OOMs in production. Fixes: d1310b2e0cd9 ("Btrfs: Split the extent_map code into two parts") Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add comment ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-03 15:38:44 +00:00
/*
* Start from the beginning does not need to cycle over the
* range, mark it as scanned.
*/
scanned = (index == 0);
} else {
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
index = wbc->range_start >> PAGE_SHIFT;
end = wbc->range_end >> PAGE_SHIFT;
if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
range_whole = 1;
scanned = 1;
}
btrfs: use tagged writepage to mitigate livelock of snapshot Snapshot is expected to be fast. But if there are writers steadily creating dirty pages in our subvolume, the snapshot may take a very long time to complete. To fix the problem, we use tagged writepage for snapshot flusher as we do in the generic write_cache_pages(), so we can omit pages dirtied after the snapshot command. This does not change the semantics regarding which data get to the snapshot, if there are pages being dirtied during the snapshotting operation. There's a sync called before snapshot is taken in old/new case, any IO in flight just after that may be in the snapshot but this depends on other system effects that might still sync the IO. We do a simple snapshot speed test on a Intel D-1531 box: fio --ioengine=libaio --iodepth=32 --bs=4k --rw=write --size=64G --direct=0 --thread=1 --numjobs=1 --time_based --runtime=120 --filename=/mnt/sub/testfile --name=job1 --group_reporting & sleep 5; time btrfs sub snap -r /mnt/sub /mnt/snap; killall fio original: 1m58sec patched: 6.54sec This is the best case for this patch since for a sequential write case, we omit nearly all pages dirtied after the snapshot command. For a multi writers, random write test: fio --ioengine=libaio --iodepth=32 --bs=4k --rw=randwrite --size=64G --direct=0 --thread=1 --numjobs=4 --time_based --runtime=120 --filename=/mnt/sub/testfile --name=job1 --group_reporting & sleep 5; time btrfs sub snap -r /mnt/sub /mnt/snap; killall fio original: 15.83sec patched: 10.35sec The improvement is smaller compared to the sequential write case, since we omit only half of the pages dirtied after snapshot command. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Ethan Lien <ethanlien@synology.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-11-01 06:49:03 +00:00
/*
* We do the tagged writepage as long as the snapshot flush bit is set
* and we are the first one who do the filemap_flush() on this inode.
*
* The nr_to_write == LONG_MAX is needed to make sure other flushers do
* not race in and drop the bit.
*/
if (range_whole && wbc->nr_to_write == LONG_MAX &&
test_and_clear_bit(BTRFS_INODE_SNAPSHOT_FLUSH,
&BTRFS_I(inode)->runtime_flags))
wbc->tagged_writepages = 1;
if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
tag = PAGECACHE_TAG_TOWRITE;
else
tag = PAGECACHE_TAG_DIRTY;
retry:
btrfs: use tagged writepage to mitigate livelock of snapshot Snapshot is expected to be fast. But if there are writers steadily creating dirty pages in our subvolume, the snapshot may take a very long time to complete. To fix the problem, we use tagged writepage for snapshot flusher as we do in the generic write_cache_pages(), so we can omit pages dirtied after the snapshot command. This does not change the semantics regarding which data get to the snapshot, if there are pages being dirtied during the snapshotting operation. There's a sync called before snapshot is taken in old/new case, any IO in flight just after that may be in the snapshot but this depends on other system effects that might still sync the IO. We do a simple snapshot speed test on a Intel D-1531 box: fio --ioengine=libaio --iodepth=32 --bs=4k --rw=write --size=64G --direct=0 --thread=1 --numjobs=1 --time_based --runtime=120 --filename=/mnt/sub/testfile --name=job1 --group_reporting & sleep 5; time btrfs sub snap -r /mnt/sub /mnt/snap; killall fio original: 1m58sec patched: 6.54sec This is the best case for this patch since for a sequential write case, we omit nearly all pages dirtied after the snapshot command. For a multi writers, random write test: fio --ioengine=libaio --iodepth=32 --bs=4k --rw=randwrite --size=64G --direct=0 --thread=1 --numjobs=4 --time_based --runtime=120 --filename=/mnt/sub/testfile --name=job1 --group_reporting & sleep 5; time btrfs sub snap -r /mnt/sub /mnt/snap; killall fio original: 15.83sec patched: 10.35sec The improvement is smaller compared to the sequential write case, since we omit only half of the pages dirtied after snapshot command. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Ethan Lien <ethanlien@synology.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-11-01 06:49:03 +00:00
if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
tag_pages_for_writeback(mapping, index, end);
done_index = index;
while (!done && !nr_to_write_done && (index <= end) &&
(nr_pages = pagevec_lookup_range_tag(&pvec, mapping,
&index, end, tag))) {
unsigned i;
for (i = 0; i < nr_pages; i++) {
struct page *page = pvec.pages[i];
btrfs: Avoid getting stuck during cyclic writebacks During a cyclic writeback, extent_write_cache_pages() uses done_index to update the writeback_index after the current run is over. However, instead of current index + 1, it gets to to the current index itself. Unfortunately, this, combined with returning on EOF instead of looping back, can lead to the following pathlogical behavior. 1. There is a single file which has accumulated enough dirty pages to trigger balance_dirty_pages() and the writer appending to the file with a series of short writes. 2. balance_dirty_pages kicks in, wakes up background writeback and sleeps. 3. Writeback kicks in and the cursor is on the last page of the dirty file. Writeback is started or skipped if already in progress. As it's EOF, extent_write_cache_pages() returns and the cursor is set to done_index which is pointing to the last page. 4. Writeback is done. Nothing happens till balance_dirty_pages finishes, at which point we go back to #1. This can almost completely stall out writing back of the file and keep the system over dirty threshold for a long time which can mess up the whole system. We encountered this issue in production with a package handling application which can reliably reproduce the issue when running under tight memory limits. Reading the comment in the error handling section, this seems to be to avoid accidentally skipping a page in case the write attempt on the page doesn't succeed. However, this concern seems bogus. On each page, the code either: * Skips and moves onto the next page. * Fails issue and sets done_index to index + 1. * Successfully issues and continue to the next page if budget allows and not EOF. IOW, as long as it's not EOF and there's budget, the code never retries writing back the same page. Only when a page happens to be the last page of a particular run, we end up retrying the page, which can't possibly guarantee anything data integrity related. Besides, cyclic writes are only used for non-syncing writebacks meaning that there's no data integrity implication to begin with. Fix it by always setting done_index past the current page being processed. Note that this problem exists in other writepages too. CC: stable@vger.kernel.org # 4.19+ Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-03 14:27:13 +00:00
done_index = page->index + 1;
/*
* At this point we hold neither the i_pages lock nor
* the page lock: the page may be truncated or
* invalidated (changing page->mapping to NULL),
* or even swizzled back from swapper_space to
* tmpfs file mapping
*/
if (!trylock_page(page)) {
ret = flush_write_bio(epd);
BUG_ON(ret < 0);
lock_page(page);
}
if (unlikely(page->mapping != mapping)) {
unlock_page(page);
continue;
}
if (wbc->sync_mode != WB_SYNC_NONE) {
if (PageWriteback(page)) {
ret = flush_write_bio(epd);
BUG_ON(ret < 0);
}
wait_on_page_writeback(page);
}
if (PageWriteback(page) ||
!clear_page_dirty_for_io(page)) {
unlock_page(page);
continue;
}
ret = __extent_writepage(page, wbc, epd);
if (ret < 0) {
done = 1;
break;
}
/*
* the filesystem may choose to bump up nr_to_write.
* We have to make sure to honor the new nr_to_write
* at any time
*/
nr_to_write_done = wbc->nr_to_write <= 0;
}
pagevec_release(&pvec);
cond_resched();
}
if (!scanned && !done) {
/*
* We hit the last page and there is more work to be done: wrap
* back to the start of the file
*/
scanned = 1;
index = 0;
btrfs: flush write bio if we loop in extent_write_cache_pages There exists a deadlock with range_cyclic that has existed forever. If we loop around with a bio already built we could deadlock with a writer who has the page locked that we're attempting to write but is waiting on a page in our bio to be written out. The task traces are as follows PID: 1329874 TASK: ffff889ebcdf3800 CPU: 33 COMMAND: "kworker/u113:5" #0 [ffffc900297bb658] __schedule at ffffffff81a4c33f #1 [ffffc900297bb6e0] schedule at ffffffff81a4c6e3 #2 [ffffc900297bb6f8] io_schedule at ffffffff81a4ca42 #3 [ffffc900297bb708] __lock_page at ffffffff811f145b #4 [ffffc900297bb798] __process_pages_contig at ffffffff814bc502 #5 [ffffc900297bb8c8] lock_delalloc_pages at ffffffff814bc684 #6 [ffffc900297bb900] find_lock_delalloc_range at ffffffff814be9ff #7 [ffffc900297bb9a0] writepage_delalloc at ffffffff814bebd0 #8 [ffffc900297bba18] __extent_writepage at ffffffff814bfbf2 #9 [ffffc900297bba98] extent_write_cache_pages at ffffffff814bffbd PID: 2167901 TASK: ffff889dc6a59c00 CPU: 14 COMMAND: "aio-dio-invalid" #0 [ffffc9003b50bb18] __schedule at ffffffff81a4c33f #1 [ffffc9003b50bba0] schedule at ffffffff81a4c6e3 #2 [ffffc9003b50bbb8] io_schedule at ffffffff81a4ca42 #3 [ffffc9003b50bbc8] wait_on_page_bit at ffffffff811f24d6 #4 [ffffc9003b50bc60] prepare_pages at ffffffff814b05a7 #5 [ffffc9003b50bcd8] btrfs_buffered_write at ffffffff814b1359 #6 [ffffc9003b50bdb0] btrfs_file_write_iter at ffffffff814b5933 #7 [ffffc9003b50be38] new_sync_write at ffffffff8128f6a8 #8 [ffffc9003b50bec8] vfs_write at ffffffff81292b9d #9 [ffffc9003b50bf00] ksys_pwrite64 at ffffffff81293032 I used drgn to find the respective pages we were stuck on page_entry.page 0xffffea00fbfc7500 index 8148 bit 15 pid 2167901 page_entry.page 0xffffea00f9bb7400 index 7680 bit 0 pid 1329874 As you can see the kworker is waiting for bit 0 (PG_locked) on index 7680, and aio-dio-invalid is waiting for bit 15 (PG_writeback) on index 8148. aio-dio-invalid has 7680, and the kworker epd looks like the following crash> struct extent_page_data ffffc900297bbbb0 struct extent_page_data { bio = 0xffff889f747ed830, tree = 0xffff889eed6ba448, extent_locked = 0, sync_io = 0 } Probably worth mentioning as well that it waits for writeback of the page to complete while holding a lock on it (at prepare_pages()). Using drgn I walked the bio pages looking for page 0xffffea00fbfc7500 which is the one we're waiting for writeback on bio = Object(prog, 'struct bio', address=0xffff889f747ed830) for i in range(0, bio.bi_vcnt.value_()): bv = bio.bi_io_vec[i] if bv.bv_page.value_() == 0xffffea00fbfc7500: print("FOUND IT") which validated what I suspected. The fix for this is simple, flush the epd before we loop back around to the beginning of the file during writeout. Fixes: b293f02e1423 ("Btrfs: Add writepages support") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-23 20:33:02 +00:00
/*
* If we're looping we could run into a page that is locked by a
* writer and that writer could be waiting on writeback for a
* page in our current bio, and thus deadlock, so flush the
* write bio here.
*/
ret = flush_write_bio(epd);
if (!ret)
goto retry;
}
if (wbc->range_cyclic || (wbc->nr_to_write > 0 && range_whole))
mapping->writeback_index = done_index;
btrfs_add_delayed_iput(inode);
return ret;
}
int extent_write_full_page(struct page *page, struct writeback_control *wbc)
{
int ret;
struct extent_page_data epd = {
.bio = NULL,
.extent_locked = 0,
.sync_io = wbc->sync_mode == WB_SYNC_ALL,
};
ret = __extent_writepage(page, wbc, &epd);
ASSERT(ret <= 0);
if (ret < 0) {
end_write_bio(&epd, ret);
return ret;
}
ret = flush_write_bio(&epd);
ASSERT(ret <= 0);
return ret;
}
int extent_write_locked_range(struct inode *inode, u64 start, u64 end,
int mode)
{
int ret = 0;
struct address_space *mapping = inode->i_mapping;
struct page *page;
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
unsigned long nr_pages = (end - start + PAGE_SIZE) >>
PAGE_SHIFT;
struct extent_page_data epd = {
.bio = NULL,
.extent_locked = 1,
.sync_io = mode == WB_SYNC_ALL,
};
struct writeback_control wbc_writepages = {
.sync_mode = mode,
.nr_to_write = nr_pages * 2,
.range_start = start,
.range_end = end + 1,
/* We're called from an async helper function */
.punt_to_cgroup = 1,
.no_cgroup_owner = 1,
};
wbc_attach_fdatawrite_inode(&wbc_writepages, inode);
while (start <= end) {
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
page = find_get_page(mapping, start >> PAGE_SHIFT);
if (clear_page_dirty_for_io(page))
ret = __extent_writepage(page, &wbc_writepages, &epd);
else {
btrfs_writepage_endio_finish_ordered(page, start,
start + PAGE_SIZE - 1, 1);
unlock_page(page);
}
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
put_page(page);
start += PAGE_SIZE;
}
ASSERT(ret <= 0);
if (ret == 0)
ret = flush_write_bio(&epd);
else
end_write_bio(&epd, ret);
wbc_detach_inode(&wbc_writepages);
return ret;
}
int extent_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
int ret = 0;
struct extent_page_data epd = {
.bio = NULL,
.extent_locked = 0,
.sync_io = wbc->sync_mode == WB_SYNC_ALL,
};
ret = extent_write_cache_pages(mapping, wbc, &epd);
ASSERT(ret <= 0);
if (ret < 0) {
end_write_bio(&epd, ret);
return ret;
}
ret = flush_write_bio(&epd);
return ret;
}
void extent_readahead(struct readahead_control *rac)
{
struct bio *bio = NULL;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
unsigned long bio_flags = 0;
struct page *pagepool[16];
struct extent_map *em_cached = NULL;
Btrfs: update fix for read corruption of compressed and shared extents My previous fix in commit 005efedf2c7d ("Btrfs: fix read corruption of compressed and shared extents") was effective only if the compressed extents cover a file range with a length that is not a multiple of 16 pages. That's because the detection of when we reached a different range of the file that shares the same compressed extent as the previously processed range was done at extent_io.c:__do_contiguous_readpages(), which covers subranges with a length up to 16 pages, because extent_readpages() groups the pages in clusters no larger than 16 pages. So fix this by tracking the start of the previously processed file range's extent map at extent_readpages(). The following test case for fstests reproduces the issue: seq=`basename $0` seqres=$RESULT_DIR/$seq echo "QA output created by $seq" tmp=/tmp/$$ status=1 # failure is the default! trap "_cleanup; exit \$status" 0 1 2 3 15 _cleanup() { rm -f $tmp.* } # get standard environment, filters and checks . ./common/rc . ./common/filter # real QA test starts here _need_to_be_root _supported_fs btrfs _supported_os Linux _require_scratch _require_cloner rm -f $seqres.full test_clone_and_read_compressed_extent() { local mount_opts=$1 _scratch_mkfs >>$seqres.full 2>&1 _scratch_mount $mount_opts # Create our test file with a single extent of 64Kb that is going to # be compressed no matter which compression algo is used (zlib/lzo). $XFS_IO_PROG -f -c "pwrite -S 0xaa 0K 64K" \ $SCRATCH_MNT/foo | _filter_xfs_io # Now clone the compressed extent into an adjacent file offset. $CLONER_PROG -s 0 -d $((64 * 1024)) -l $((64 * 1024)) \ $SCRATCH_MNT/foo $SCRATCH_MNT/foo echo "File digest before unmount:" md5sum $SCRATCH_MNT/foo | _filter_scratch # Remount the fs or clear the page cache to trigger the bug in # btrfs. Because the extent has an uncompressed length that is a # multiple of 16 pages, all the pages belonging to the second range # of the file (64K to 128K), which points to the same extent as the # first range (0K to 64K), had their contents full of zeroes instead # of the byte 0xaa. This was a bug exclusively in the read path of # compressed extents, the correct data was stored on disk, btrfs # just failed to fill in the pages correctly. _scratch_remount echo "File digest after remount:" # Must match the digest we got before. md5sum $SCRATCH_MNT/foo | _filter_scratch } echo -e "\nTesting with zlib compression..." test_clone_and_read_compressed_extent "-o compress=zlib" _scratch_unmount echo -e "\nTesting with lzo compression..." test_clone_and_read_compressed_extent "-o compress=lzo" status=0 exit Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Tested-by: Timofey Titovets <nefelim4ag@gmail.com>
2015-09-28 08:56:26 +00:00
u64 prev_em_start = (u64)-1;
int nr;
while ((nr = readahead_page_batch(rac, pagepool))) {
u64 contig_start = readahead_pos(rac);
u64 contig_end = contig_start + readahead_batch_length(rac) - 1;
contiguous_readpages(pagepool, nr, contig_start, contig_end,
&em_cached, &bio, &bio_flags, &prev_em_start);
}
if (em_cached)
free_extent_map(em_cached);
if (bio) {
if (submit_one_bio(bio, 0, bio_flags))
return;
}
}
/*
* basic invalidatepage code, this waits on any locked or writeback
* ranges corresponding to the page, and then deletes any extent state
* records from the tree
*/
int extent_invalidatepage(struct extent_io_tree *tree,
struct page *page, unsigned long offset)
{
struct extent_state *cached_state = NULL;
u64 start = page_offset(page);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
u64 end = start + PAGE_SIZE - 1;
size_t blocksize = page->mapping->host->i_sb->s_blocksize;
/* This function is only called for the btree inode */
ASSERT(tree->owner == IO_TREE_BTREE_INODE_IO);
start += ALIGN(offset, blocksize);
if (start > end)
return 0;
lock_extent_bits(tree, start, end, &cached_state);
wait_on_page_writeback(page);
/*
* Currently for btree io tree, only EXTENT_LOCKED is utilized,
* so here we only need to unlock the extent range to free any
* existing extent state.
*/
unlock_extent_cached(tree, start, end, &cached_state);
return 0;
}
/*
* a helper for releasepage, this tests for areas of the page that
* are locked or under IO and drops the related state bits if it is safe
* to drop the page.
*/
static int try_release_extent_state(struct extent_io_tree *tree,
struct page *page, gfp_t mask)
{
u64 start = page_offset(page);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
u64 end = start + PAGE_SIZE - 1;
int ret = 1;
if (test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL)) {
ret = 0;
} else {
/*
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 11:07:34 +00:00
* At this point we can safely clear everything except the
* locked bit, the nodatasum bit and the delalloc new bit.
* The delalloc new bit will be cleared by ordered extent
* completion.
*/
ret = __clear_extent_bit(tree, start, end,
btrfs: update the number of bytes used by an inode atomically There are several occasions where we do not update the inode's number of used bytes atomically, resulting in a concurrent stat(2) syscall to report a value of used blocks that does not correspond to a valid value, that is, a value that does not match neither what we had before the operation nor what we get after the operation completes. In extreme cases it can result in stat(2) reporting zero used blocks, which can cause problems for some userspace tools where they can consider a file with a non-zero size and zero used blocks as completely sparse and skip reading data, as reported/discussed a long time ago in some threads like the following: https://lists.gnu.org/archive/html/bug-tar/2016-07/msg00001.html The cases where this can happen are the following: -> Case 1 If we do a write (buffered or direct IO) against a file region for which there is already an allocated extent (or multiple extents), then we have a short time window where we can report a number of used blocks to stat(2) that does not take into account the file region being overwritten. This short time window happens when completing the ordered extent(s). This happens because when we drop the extents in the write range we decrement the inode's number of bytes and later on when we insert the new extent(s) we increment the number of bytes in the inode, resulting in a short time window where a stat(2) syscall can get an incorrect number of used blocks. If we do writes that overwrite an entire file, then we have a short time window where we report 0 used blocks to stat(2). Example reproducer: $ cat reproducer-1.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT xfs_io -f -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null expected=$(stat -c %b $MNT/foobar) # Create a process to keep calling stat(2) on the file and see if the # reported number of blocks used (disk space used) changes, it should # not because we are not increasing the file size nor punching holes. stat_loop $MNT/foobar $expected & loop_pid=$! for ((i = 0; i < 50000; i++)); do xfs_io -s -c "pwrite -b 64K 0 64K" $MNT/foobar >/dev/null done kill $loop_pid &> /dev/null wait umount $DEV $ ./reproducer-1.sh ERROR: unexpected used blocks (got: 0 expected: 128) ERROR: unexpected used blocks (got: 0 expected: 128) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 2 If we do a buffered write against a file region that does not have any allocated extents, like a hole or beyond EOF, then during ordered extent completion we have a short time window where a concurrent stat(2) syscall can report a number of used blocks that does not correspond to the value before or after the write operation, a value that is actually larger than the value after the write completes. This happens because once we start a buffered write into an unallocated file range we increment the inode's 'new_delalloc_bytes', to make sure any stat(2) call gets a correct used blocks value before delalloc is flushed and completes. However at ordered extent completion, after we inserted the new extent, we increment the inode's number of bytes used with the size of the new extent, and only later, when clearing the range in the inode's iotree, we decrement the inode's 'new_delalloc_bytes' counter with the size of the extent. So this results in a short time window where a concurrent stat(2) syscall can report a number of used blocks that accounts for the new extent twice. Example reproducer: $ cat reproducer-2.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi stat_loop() { trap "wait; exit" SIGTERM local filepath=$1 local expected=$2 local got while :; do got=$(stat -c %b $filepath) if [ $got -ne $expected ]; then echo -n "ERROR: unexpected used blocks" echo " (got: $got expected: $expected)" fi done } mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f $DEV > /dev/null # mkfs.ext4 -F $DEV > /dev/null # mkfs.f2fs -f $DEV > /dev/null # mkfs.reiserfs -f $DEV > /dev/null mount $DEV $MNT touch $MNT/foobar write_size=$((64 * 1024)) for ((i = 0; i < 16384; i++)); do offset=$(($i * $write_size)) xfs_io -c "pwrite -S 0xab $offset $write_size" $MNT/foobar >/dev/null blocks_used=$(stat -c %b $MNT/foobar) # Fsync the file to trigger writeback and keep calling stat(2) on it # to see if the number of blocks used changes. stat_loop $MNT/foobar $blocks_used & loop_pid=$! xfs_io -c "fsync" $MNT/foobar kill $loop_pid &> /dev/null wait $loop_pid done umount $DEV $ ./reproducer-2.sh ERROR: unexpected used blocks (got: 265472 expected: 265344) ERROR: unexpected used blocks (got: 284032 expected: 283904) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. -> Case 3 Another case where such problems happen is during other operations that replace extents in a file range with other extents. Those operations are extent cloning, deduplication and fallocate's zero range operation. The cause of the problem is similar to the first case. When we drop the extents from a range, we decrement the inode's number of bytes, and later on, after inserting the new extents we increment it. Since this is not done atomically, a concurrent stat(2) call can see and return a number of used blocks that is smaller than it should be, does not match the number of used blocks before or after the clone/deduplication/zero operation. Like for the first case, when doing a clone, deduplication or zero range operation against an entire file, we end up having a time window where we can report 0 used blocks to a stat(2) call. Example reproducer: $ cat reproducer-3.sh #!/bin/bash MNT=/mnt/sdi DEV=/dev/sdi mkfs.btrfs -f $DEV > /dev/null # mkfs.xfs -f -m reflink=1 $DEV > /dev/null mount $DEV $MNT extent_size=$((64 * 1024)) num_extents=16384 file_size=$(($extent_size * $num_extents)) # File foo has many small extents. xfs_io -f -s -c "pwrite -S 0xab -b $extent_size 0 $file_size" $MNT/foo \ > /dev/null # File bar has much less extents and has exactly the same data as foo. xfs_io -f -c "pwrite -S 0xab 0 $file_size" $MNT/bar > /dev/null expected=$(stat -c %b $MNT/foo) # Now deduplicate bar into foo. While the deduplication is in progres, # the number of used blocks/file size reported by stat should not change xfs_io -c "dedupe $MNT/bar 0 0 $file_size" $MNT/foo > /dev/null & dedupe_pid=$! while [ -n "$(ps -p $dedupe_pid -o pid=)" ]; do used=$(stat -c %b $MNT/foo) if [ $used -ne $expected ]; then echo "Unexpected blocks used: $used (expected: $expected)" fi done umount $DEV $ ./reproducer-3.sh Unexpected blocks used: 2076800 (expected: 2097152) Unexpected blocks used: 2097024 (expected: 2097152) Unexpected blocks used: 2079872 (expected: 2097152) (...) Note that since this is a short time window where the race can happen, the reproducer may not be able to always trigger the bug in one run, or it may trigger it multiple times. So fix this by: 1) Making btrfs_drop_extents() not decrement the VFS inode's number of bytes, and instead return the number of bytes; 2) Making any code that drops extents and adds new extents update the inode's number of bytes atomically, while holding the btrfs inode's spinlock, which is also used by the stat(2) callback to get the inode's number of bytes; 3) For ranges in the inode's iotree that are marked as 'delalloc new', corresponding to previously unallocated ranges, increment the inode's number of bytes when clearing the 'delalloc new' bit from the range, in the same critical section that decrements the inode's 'new_delalloc_bytes' counter, delimited by the btrfs inode's spinlock. An alternative would be to have btrfs_getattr() wait for any IO (ordered extents in progress) and locking the whole range (0 to (u64)-1) while it it computes the number of blocks used. But that would mean blocking stat(2), which is a very used syscall and expected to be fast, waiting for writes, clone/dedupe, fallocate, page reads, fiemap, etc. CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-04 11:07:34 +00:00
~(EXTENT_LOCKED | EXTENT_NODATASUM | EXTENT_DELALLOC_NEW),
0, 0, NULL, mask, NULL);
/* if clear_extent_bit failed for enomem reasons,
* we can't allow the release to continue.
*/
if (ret < 0)
ret = 0;
else
ret = 1;
}
return ret;
}
/*
* a helper for releasepage. As long as there are no locked extents
* in the range corresponding to the page, both state records and extent
* map records are removed
*/
int try_release_extent_mapping(struct page *page, gfp_t mask)
{
struct extent_map *em;
u64 start = page_offset(page);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
u64 end = start + PAGE_SIZE - 1;
Btrfs: fix file data corruption after cloning a range and fsync When we clone a range into a file we can end up dropping existing extent maps (or trimming them) and replacing them with new ones if the range to be cloned overlaps with a range in the destination inode. When that happens we add the new extent maps to the list of modified extents in the inode's extent map tree, so that a "fast" fsync (the flag BTRFS_INODE_NEEDS_FULL_SYNC not set in the inode) will see the extent maps and log corresponding extent items. However, at the end of range cloning operation we do truncate all the pages in the affected range (in order to ensure future reads will not get stale data). Sometimes this truncation will release the corresponding extent maps besides the pages from the page cache. If this happens, then a "fast" fsync operation will miss logging some extent items, because it relies exclusively on the extent maps being present in the inode's extent tree, leading to data loss/corruption if the fsync ends up using the same transaction used by the clone operation (that transaction was not committed in the meanwhile). An extent map is released through the callback btrfs_invalidatepage(), which gets called by truncate_inode_pages_range(), and it calls __btrfs_releasepage(). The later ends up calling try_release_extent_mapping() which will release the extent map if some conditions are met, like the file size being greater than 16Mb, gfp flags allow blocking and the range not being locked (which is the case during the clone operation) nor being the extent map flagged as pinned (also the case for cloning). The following example, turned into a test for fstests, reproduces the issue: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "pwrite -S 0x18 9000K 6908K" /mnt/foo $ xfs_io -f -c "pwrite -S 0x20 2572K 156K" /mnt/bar $ xfs_io -c "fsync" /mnt/bar # reflink destination offset corresponds to the size of file bar, # 2728Kb minus 4Kb. $ xfs_io -c ""reflink ${SCRATCH_MNT}/foo 0 2724K 15908K" /mnt/bar $ xfs_io -c "fsync" /mnt/bar $ md5sum /mnt/bar 95a95813a8c2abc9aa75a6c2914a077e /mnt/bar <power fail> $ mount /dev/sdb /mnt $ md5sum /mnt/bar 207fd8d0b161be8a84b945f0df8d5f8d /mnt/bar # digest should be 95a95813a8c2abc9aa75a6c2914a077e like before the # power failure In the above example, the destination offset of the clone operation corresponds to the size of the "bar" file minus 4Kb. So during the clone operation, the extent map covering the range from 2572Kb to 2728Kb gets trimmed so that it ends at offset 2724Kb, and a new extent map covering the range from 2724Kb to 11724Kb is created. So at the end of the clone operation when we ask to truncate the pages in the range from 2724Kb to 2724Kb + 15908Kb, the page invalidation callback ends up removing the new extent map (through try_release_extent_mapping()) when the page at offset 2724Kb is passed to that callback. Fix this by setting the bit BTRFS_INODE_NEEDS_FULL_SYNC whenever an extent map is removed at try_release_extent_mapping(), forcing the next fsync to search for modified extents in the fs/subvolume tree instead of relying on the presence of extent maps in memory. This way we can continue doing a "fast" fsync if the destination range of a clone operation does not overlap with an existing range or if any of the criteria necessary to remove an extent map at try_release_extent_mapping() is not met (file size not bigger then 16Mb or gfp flags do not allow blocking). CC: stable@vger.kernel.org # 3.16+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-07-12 00:36:43 +00:00
struct btrfs_inode *btrfs_inode = BTRFS_I(page->mapping->host);
struct extent_io_tree *tree = &btrfs_inode->io_tree;
struct extent_map_tree *map = &btrfs_inode->extent_tree;
mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd __GFP_WAIT has been used to identify atomic context in callers that hold spinlocks or are in interrupts. They are expected to be high priority and have access one of two watermarks lower than "min" which can be referred to as the "atomic reserve". __GFP_HIGH users get access to the first lower watermark and can be called the "high priority reserve". Over time, callers had a requirement to not block when fallback options were available. Some have abused __GFP_WAIT leading to a situation where an optimisitic allocation with a fallback option can access atomic reserves. This patch uses __GFP_ATOMIC to identify callers that are truely atomic, cannot sleep and have no alternative. High priority users continue to use __GFP_HIGH. __GFP_DIRECT_RECLAIM identifies callers that can sleep and are willing to enter direct reclaim. __GFP_KSWAPD_RECLAIM to identify callers that want to wake kswapd for background reclaim. __GFP_WAIT is redefined as a caller that is willing to enter direct reclaim and wake kswapd for background reclaim. This patch then converts a number of sites o __GFP_ATOMIC is used by callers that are high priority and have memory pools for those requests. GFP_ATOMIC uses this flag. o Callers that have a limited mempool to guarantee forward progress clear __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall into this category where kswapd will still be woken but atomic reserves are not used as there is a one-entry mempool to guarantee progress. o Callers that are checking if they are non-blocking should use the helper gfpflags_allow_blocking() where possible. This is because checking for __GFP_WAIT as was done historically now can trigger false positives. Some exceptions like dm-crypt.c exist where the code intent is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to flag manipulations. o Callers that built their own GFP flags instead of starting with GFP_KERNEL and friends now also need to specify __GFP_KSWAPD_RECLAIM. The first key hazard to watch out for is callers that removed __GFP_WAIT and was depending on access to atomic reserves for inconspicuous reasons. In some cases it may be appropriate for them to use __GFP_HIGH. The second key hazard is callers that assembled their own combination of GFP flags instead of starting with something like GFP_KERNEL. They may now wish to specify __GFP_KSWAPD_RECLAIM. It's almost certainly harmless if it's missed in most cases as other activity will wake kswapd. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-07 00:28:21 +00:00
if (gfpflags_allow_blocking(mask) &&
page->mapping->host->i_size > SZ_16M) {
u64 len;
while (start <= end) {
struct btrfs_fs_info *fs_info;
u64 cur_gen;
len = end - start + 1;
write_lock(&map->lock);
em = lookup_extent_mapping(map, start, len);
if (!em) {
write_unlock(&map->lock);
break;
}
if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
em->start != start) {
write_unlock(&map->lock);
free_extent_map(em);
break;
}
btrfs: fix race between page release and a fast fsync When releasing an extent map, done through the page release callback, we can race with an ongoing fast fsync and cause the fsync to miss a new extent and not log it. The steps for this to happen are the following: 1) A page is dirtied for some inode I; 2) Writeback for that page is triggered by a path other than fsync, for example by the system due to memory pressure; 3) When the ordered extent for the extent (a single 4K page) finishes, we unpin the corresponding extent map and set its generation to N, the current transaction's generation; 4) The btrfs_releasepage() callback is invoked by the system due to memory pressure for that no longer dirty page of inode I; 5) At the same time, some task calls fsync on inode I, joins transaction N, and at btrfs_log_inode() it sees that the inode does not have the full sync flag set, so we proceed with a fast fsync. But before we get into btrfs_log_changed_extents() and lock the inode's extent map tree: 6) Through btrfs_releasepage() we end up at try_release_extent_mapping() and we remove the extent map for the new 4Kb extent, because it is neither pinned anymore nor locked. By calling remove_extent_mapping(), we remove the extent map from the list of modified extents, since the extent map does not have the logging flag set. We unlock the inode's extent map tree; 7) The task doing the fast fsync now enters btrfs_log_changed_extents(), locks the inode's extent map tree and iterates its list of modified extents, which no longer has the 4Kb extent in it, so it does not log the extent; 8) The fsync finishes; 9) Before transaction N is committed, a power failure happens. After replaying the log, the 4K extent of inode I will be missing, since it was not logged due to the race with try_release_extent_mapping(). So fix this by teaching try_release_extent_mapping() to not remove an extent map if it's still in the list of modified extents. Fixes: ff44c6e36dc9dc ("Btrfs: do not hold the write_lock on the extent tree while logging") CC: stable@vger.kernel.org # 5.4+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-22 11:28:37 +00:00
if (test_range_bit(tree, em->start,
extent_map_end(em) - 1,
EXTENT_LOCKED, 0, NULL))
goto next;
/*
* If it's not in the list of modified extents, used
* by a fast fsync, we can remove it. If it's being
* logged we can safely remove it since fsync took an
* extra reference on the em.
*/
if (list_empty(&em->list) ||
test_bit(EXTENT_FLAG_LOGGING, &em->flags))
goto remove_em;
/*
* If it's in the list of modified extents, remove it
* only if its generation is older then the current one,
* in which case we don't need it for a fast fsync.
* Otherwise don't remove it, we could be racing with an
* ongoing fast fsync that could miss the new extent.
*/
fs_info = btrfs_inode->root->fs_info;
spin_lock(&fs_info->trans_lock);
cur_gen = fs_info->generation;
spin_unlock(&fs_info->trans_lock);
if (em->generation >= cur_gen)
goto next;
remove_em:
btrfs: do not set the full sync flag on the inode during page release When removing an extent map at try_release_extent_mapping(), called through the page release callback (btrfs_releasepage()), we always set the full sync flag on the inode, which forces the next fsync to use a slower code path. This hurts performance for workloads that dirty an amount of data that exceeds or is very close to the system's RAM memory and do frequent fsync operations (like database servers can for example). In particular if there are concurrent fsyncs against different files, by falling back to a full fsync we do a lot more checksum lookups in the checksums btree, as we do it for all the extents created in the current transaction, instead of only the new ones since the last fsync. These checksums lookups not only take some time but, more importantly, they also cause contention on the checksums btree locks due to the concurrency with checksum insertions in the btree by ordered extents from other inodes. We actually don't need to set the full sync flag on the inode, because we only remove extent maps that are in the list of modified extents if they were created in a past transaction, in which case an fsync skips them as it's pointless to log them. So stop setting the full fsync flag on the inode whenever we remove an extent map. This patch is part of a patchset that consists of 3 patches, which have the following subjects: 1/3 btrfs: fix race between page release and a fast fsync 2/3 btrfs: release old extent maps during page release 3/3 btrfs: do not set the full sync flag on the inode during page release Performance tests were ran against a branch (misc-next) containing the whole patchset. The test exercises a workload where there are multiple processes writing to files and fsyncing them (each writing and fsyncing its own file), and in total the amount of data dirtied ranges from 2x to 4x the system's RAM memory (16GiB), so that the page release callback is invoked frequently. The following script, using fio, was used to perform the tests: $ cat test-fsync.sh #!/bin/bash DEV=/dev/sdk MNT=/mnt/sdk MOUNT_OPTIONS="-o ssd" MKFS_OPTIONS="-d single -m single" if [ $# -ne 3 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 cat <<EOF > /tmp/fio-job.ini [writers] rw=write fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=64k ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS thread EOF echo "Using config:" echo cat /tmp/fio-job.ini echo mkfs.btrfs -f $MKFS_OPTIONS $DEV &> /dev/null mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The tests were performed for different numbers of jobs, file sizes and fsync frequency. A qemu VM using kvm was used, with 8 cores (the host has 12 cores, with cpu governance set to performance mode on all cores), 16GiB of ram (the host has 64GiB) and using a NVMe device directly (without an intermediary filesystem in the host). While running the tests, the host was not used for anything else, to avoid disturbing the tests. The obtained results were the following, and the last line printed by fio is pasted (includes aggregated throughput and test run time). ***************************************************** **** 1 job, 32GiB file, fsync frequency 1 **** ***************************************************** Before patchset: WRITE: bw=29.1MiB/s (30.5MB/s), 29.1MiB/s-29.1MiB/s (30.5MB/s-30.5MB/s), io=32.0GiB (34.4GB), run=1127557-1127557msec After patchset: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=32.0GiB (34.4GB), run=1119042-1119042msec (+0.7% throughput, -0.8% run time) ***************************************************** **** 2 jobs, 16GiB files, fsync frequency 1 **** ***************************************************** Before patchset: WRITE: bw=33.5MiB/s (35.1MB/s), 33.5MiB/s-33.5MiB/s (35.1MB/s-35.1MB/s), io=32.0GiB (34.4GB), run=979000-979000msec After patchset: WRITE: bw=39.9MiB/s (41.8MB/s), 39.9MiB/s-39.9MiB/s (41.8MB/s-41.8MB/s), io=32.0GiB (34.4GB), run=821283-821283msec (+19.1% throughput, -16.1% runtime) ***************************************************** **** 4 jobs, 8GiB files, fsync frequency 1 **** ***************************************************** Before patchset: WRITE: bw=52.1MiB/s (54.6MB/s), 52.1MiB/s-52.1MiB/s (54.6MB/s-54.6MB/s), io=32.0GiB (34.4GB), run=629130-629130msec After patchset: WRITE: bw=71.8MiB/s (75.3MB/s), 71.8MiB/s-71.8MiB/s (75.3MB/s-75.3MB/s), io=32.0GiB (34.4GB), run=456357-456357msec (+37.8% throughput, -27.5% runtime) ***************************************************** **** 8 jobs, 4GiB files, fsync frequency 1 **** ***************************************************** Before patchset: WRITE: bw=76.1MiB/s (79.8MB/s), 76.1MiB/s-76.1MiB/s (79.8MB/s-79.8MB/s), io=32.0GiB (34.4GB), run=430708-430708msec After patchset: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=245458-245458msec (+74.7% throughput, -43.0% run time) ***************************************************** **** 16 jobs, 2GiB files, fsync frequency 1 **** ***************************************************** Before patchset: WRITE: bw=74.7MiB/s (78.3MB/s), 74.7MiB/s-74.7MiB/s (78.3MB/s-78.3MB/s), io=32.0GiB (34.4GB), run=438625-438625msec After patchset: WRITE: bw=184MiB/s (193MB/s), 184MiB/s-184MiB/s (193MB/s-193MB/s), io=32.0GiB (34.4GB), run=177864-177864msec (+146.3% throughput, -59.5% run time) ***************************************************** **** 32 jobs, 2GiB files, fsync frequency 1 **** ***************************************************** Before patchset: WRITE: bw=72.6MiB/s (76.1MB/s), 72.6MiB/s-72.6MiB/s (76.1MB/s-76.1MB/s), io=64.0GiB (68.7GB), run=902615-902615msec After patchset: WRITE: bw=227MiB/s (238MB/s), 227MiB/s-227MiB/s (238MB/s-238MB/s), io=64.0GiB (68.7GB), run=288936-288936msec (+212.7% throughput, -68.0% run time) ***************************************************** **** 64 jobs, 1GiB files, fsync frequency 1 **** ***************************************************** Before patchset: WRITE: bw=98.8MiB/s (104MB/s), 98.8MiB/s-98.8MiB/s (104MB/s-104MB/s), io=64.0GiB (68.7GB), run=663126-663126msec After patchset: WRITE: bw=294MiB/s (308MB/s), 294MiB/s-294MiB/s (308MB/s-308MB/s), io=64.0GiB (68.7GB), run=222940-222940msec (+197.6% throughput, -66.4% run time) Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-22 11:29:01 +00:00
/*
* We only remove extent maps that are not in the list of
* modified extents or that are in the list but with a
* generation lower then the current generation, so there
* is no need to set the full fsync flag on the inode (it
* hurts the fsync performance for workloads with a data
* size that exceeds or is close to the system's memory).
*/
remove_extent_mapping(map, em);
/* once for the rb tree */
free_extent_map(em);
btrfs: fix race between page release and a fast fsync When releasing an extent map, done through the page release callback, we can race with an ongoing fast fsync and cause the fsync to miss a new extent and not log it. The steps for this to happen are the following: 1) A page is dirtied for some inode I; 2) Writeback for that page is triggered by a path other than fsync, for example by the system due to memory pressure; 3) When the ordered extent for the extent (a single 4K page) finishes, we unpin the corresponding extent map and set its generation to N, the current transaction's generation; 4) The btrfs_releasepage() callback is invoked by the system due to memory pressure for that no longer dirty page of inode I; 5) At the same time, some task calls fsync on inode I, joins transaction N, and at btrfs_log_inode() it sees that the inode does not have the full sync flag set, so we proceed with a fast fsync. But before we get into btrfs_log_changed_extents() and lock the inode's extent map tree: 6) Through btrfs_releasepage() we end up at try_release_extent_mapping() and we remove the extent map for the new 4Kb extent, because it is neither pinned anymore nor locked. By calling remove_extent_mapping(), we remove the extent map from the list of modified extents, since the extent map does not have the logging flag set. We unlock the inode's extent map tree; 7) The task doing the fast fsync now enters btrfs_log_changed_extents(), locks the inode's extent map tree and iterates its list of modified extents, which no longer has the 4Kb extent in it, so it does not log the extent; 8) The fsync finishes; 9) Before transaction N is committed, a power failure happens. After replaying the log, the 4K extent of inode I will be missing, since it was not logged due to the race with try_release_extent_mapping(). So fix this by teaching try_release_extent_mapping() to not remove an extent map if it's still in the list of modified extents. Fixes: ff44c6e36dc9dc ("Btrfs: do not hold the write_lock on the extent tree while logging") CC: stable@vger.kernel.org # 5.4+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-22 11:28:37 +00:00
next:
start = extent_map_end(em);
write_unlock(&map->lock);
/* once for us */
free_extent_map(em);
fs/btrfs: Add cond_resched() for try_release_extent_mapping() stalls Very large I/Os can cause the following RCU CPU stall warning: RIP: 0010:rb_prev+0x8/0x50 Code: 49 89 c0 49 89 d1 48 89 c2 48 89 f8 e9 e5 fd ff ff 4c 89 48 10 c3 4c = 89 06 c3 4c 89 40 10 c3 0f 1f 00 48 8b 0f 48 39 cf 74 38 <48> 8b 47 10 48 85 c0 74 22 48 8b 50 08 48 85 d2 74 0c 48 89 d0 48 RSP: 0018:ffffc9002212bab0 EFLAGS: 00000287 ORIG_RAX: ffffffffffffff13 RAX: ffff888821f93630 RBX: ffff888821f93630 RCX: ffff888821f937e0 RDX: 0000000000000000 RSI: 0000000000102000 RDI: ffff888821f93630 RBP: 0000000000103000 R08: 000000000006c000 R09: 0000000000000238 R10: 0000000000102fff R11: ffffc9002212bac8 R12: 0000000000000001 R13: ffffffffffffffff R14: 0000000000102000 R15: ffff888821f937e0 __lookup_extent_mapping+0xa0/0x110 try_release_extent_mapping+0xdc/0x220 btrfs_releasepage+0x45/0x70 shrink_page_list+0xa39/0xb30 shrink_inactive_list+0x18f/0x3b0 shrink_lruvec+0x38e/0x6b0 shrink_node+0x14d/0x690 do_try_to_free_pages+0xc6/0x3e0 try_to_free_mem_cgroup_pages+0xe6/0x1e0 reclaim_high.constprop.73+0x87/0xc0 mem_cgroup_handle_over_high+0x66/0x150 exit_to_usermode_loop+0x82/0xd0 do_syscall_64+0xd4/0x100 entry_SYSCALL_64_after_hwframe+0x44/0xa9 On a PREEMPT=n kernel, the try_release_extent_mapping() function's "while" loop might run for a very long time on a large I/O. This commit therefore adds a cond_resched() to this loop, providing RCU any needed quiescent states. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-05-08 21:15:37 +00:00
cond_resched(); /* Allow large-extent preemption. */
}
}
return try_release_extent_state(tree, page, mask);
}
/*
* helper function for fiemap, which doesn't want to see any holes.
* This maps until we find something past 'last'
*/
static struct extent_map *get_extent_skip_holes(struct btrfs_inode *inode,
u64 offset, u64 last)
{
u64 sectorsize = btrfs_inode_sectorsize(inode);
struct extent_map *em;
u64 len;
if (offset >= last)
return NULL;
while (1) {
len = last - offset;
if (len == 0)
break;
len = ALIGN(len, sectorsize);
em = btrfs_get_extent_fiemap(inode, offset, len);
if (IS_ERR_OR_NULL(em))
return em;
/* if this isn't a hole return it */
if (em->block_start != EXTENT_MAP_HOLE)
return em;
/* this is a hole, advance to the next extent */
offset = extent_map_end(em);
free_extent_map(em);
if (offset >= last)
break;
}
return NULL;
}
btrfs: fiemap: Cache and merge fiemap extent before submit it to user [BUG] Cycle mount btrfs can cause fiemap to return different result. Like: # mount /dev/vdb5 /mnt/btrfs # dd if=/dev/zero bs=16K count=4 oflag=dsync of=/mnt/btrfs/file # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 # umount /mnt/btrfs # mount /dev/vdb5 /mnt/btrfs # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..31]: 25088..25119 32 0x0 1: [32..63]: 25120..25151 32 0x0 2: [64..95]: 25152..25183 32 0x0 3: [96..127]: 25184..25215 32 0x1 But after above fiemap, we get correct merged result if we call fiemap again. # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 [REASON] Btrfs will try to merge extent map when inserting new extent map. btrfs_fiemap(start=0 len=(u64)-1) |- extent_fiemap(start=0 len=(u64)-1) |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=0 len=64k) | | Found on-disk (ino, EXTENT_DATA, 0) | |- add_extent_mapping() | |- Return (em->start=0, len=16k) | |- fiemap_fill_next_extent(logic=0 phys=X len=16k) | |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=16k len=48k) | | Found on-disk (ino, EXTENT_DATA, 16k) | |- add_extent_mapping() | | |- try_merge_map() | | Merge with previous em start=0 len=16k | | resulting em start=0 len=32k | |- Return (em->start=0, len=32K) << Merged result |- Stripe off the unrelated range (0~16K) of return em |- fiemap_fill_next_extent(logic=16K phys=X+16K len=16K) ^^^ Causing split fiemap extent. And since in add_extent_mapping(), em is already merged, in next fiemap() call, we will get merged result. [FIX] Here we introduce a new structure, fiemap_cache, which records previous fiemap extent. And will always try to merge current fiemap_cache result before calling fiemap_fill_next_extent(). Only when we failed to merge current fiemap extent with cached one, we will call fiemap_fill_next_extent() to submit cached one. So by this method, we can merge all fiemap extents. It can also be done in fs/ioctl.c, however the problem is if fieinfo->fi_extents_max == 0, we have no space to cache previous fiemap extent. So I choose to merge it in btrfs. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-04-07 02:43:15 +00:00
/*
* To cache previous fiemap extent
*
* Will be used for merging fiemap extent
*/
struct fiemap_cache {
u64 offset;
u64 phys;
u64 len;
u32 flags;
bool cached;
};
/*
* Helper to submit fiemap extent.
*
* Will try to merge current fiemap extent specified by @offset, @phys,
* @len and @flags with cached one.
* And only when we fails to merge, cached one will be submitted as
* fiemap extent.
*
* Return value is the same as fiemap_fill_next_extent().
*/
static int emit_fiemap_extent(struct fiemap_extent_info *fieinfo,
struct fiemap_cache *cache,
u64 offset, u64 phys, u64 len, u32 flags)
{
int ret = 0;
if (!cache->cached)
goto assign;
/*
* Sanity check, extent_fiemap() should have ensured that new
* fiemap extent won't overlap with cached one.
btrfs: fiemap: Cache and merge fiemap extent before submit it to user [BUG] Cycle mount btrfs can cause fiemap to return different result. Like: # mount /dev/vdb5 /mnt/btrfs # dd if=/dev/zero bs=16K count=4 oflag=dsync of=/mnt/btrfs/file # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 # umount /mnt/btrfs # mount /dev/vdb5 /mnt/btrfs # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..31]: 25088..25119 32 0x0 1: [32..63]: 25120..25151 32 0x0 2: [64..95]: 25152..25183 32 0x0 3: [96..127]: 25184..25215 32 0x1 But after above fiemap, we get correct merged result if we call fiemap again. # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 [REASON] Btrfs will try to merge extent map when inserting new extent map. btrfs_fiemap(start=0 len=(u64)-1) |- extent_fiemap(start=0 len=(u64)-1) |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=0 len=64k) | | Found on-disk (ino, EXTENT_DATA, 0) | |- add_extent_mapping() | |- Return (em->start=0, len=16k) | |- fiemap_fill_next_extent(logic=0 phys=X len=16k) | |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=16k len=48k) | | Found on-disk (ino, EXTENT_DATA, 16k) | |- add_extent_mapping() | | |- try_merge_map() | | Merge with previous em start=0 len=16k | | resulting em start=0 len=32k | |- Return (em->start=0, len=32K) << Merged result |- Stripe off the unrelated range (0~16K) of return em |- fiemap_fill_next_extent(logic=16K phys=X+16K len=16K) ^^^ Causing split fiemap extent. And since in add_extent_mapping(), em is already merged, in next fiemap() call, we will get merged result. [FIX] Here we introduce a new structure, fiemap_cache, which records previous fiemap extent. And will always try to merge current fiemap_cache result before calling fiemap_fill_next_extent(). Only when we failed to merge current fiemap extent with cached one, we will call fiemap_fill_next_extent() to submit cached one. So by this method, we can merge all fiemap extents. It can also be done in fs/ioctl.c, however the problem is if fieinfo->fi_extents_max == 0, we have no space to cache previous fiemap extent. So I choose to merge it in btrfs. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-04-07 02:43:15 +00:00
* Not recoverable.
*
* NOTE: Physical address can overlap, due to compression
*/
if (cache->offset + cache->len > offset) {
WARN_ON(1);
return -EINVAL;
}
/*
* Only merges fiemap extents if
* 1) Their logical addresses are continuous
*
* 2) Their physical addresses are continuous
* So truly compressed (physical size smaller than logical size)
* extents won't get merged with each other
*
* 3) Share same flags except FIEMAP_EXTENT_LAST
* So regular extent won't get merged with prealloc extent
*/
if (cache->offset + cache->len == offset &&
cache->phys + cache->len == phys &&
(cache->flags & ~FIEMAP_EXTENT_LAST) ==
(flags & ~FIEMAP_EXTENT_LAST)) {
cache->len += len;
cache->flags |= flags;
goto try_submit_last;
}
/* Not mergeable, need to submit cached one */
ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
cache->len, cache->flags);
cache->cached = false;
if (ret)
return ret;
assign:
cache->cached = true;
cache->offset = offset;
cache->phys = phys;
cache->len = len;
cache->flags = flags;
try_submit_last:
if (cache->flags & FIEMAP_EXTENT_LAST) {
ret = fiemap_fill_next_extent(fieinfo, cache->offset,
cache->phys, cache->len, cache->flags);
cache->cached = false;
}
return ret;
}
/*
* Emit last fiemap cache
btrfs: fiemap: Cache and merge fiemap extent before submit it to user [BUG] Cycle mount btrfs can cause fiemap to return different result. Like: # mount /dev/vdb5 /mnt/btrfs # dd if=/dev/zero bs=16K count=4 oflag=dsync of=/mnt/btrfs/file # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 # umount /mnt/btrfs # mount /dev/vdb5 /mnt/btrfs # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..31]: 25088..25119 32 0x0 1: [32..63]: 25120..25151 32 0x0 2: [64..95]: 25152..25183 32 0x0 3: [96..127]: 25184..25215 32 0x1 But after above fiemap, we get correct merged result if we call fiemap again. # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 [REASON] Btrfs will try to merge extent map when inserting new extent map. btrfs_fiemap(start=0 len=(u64)-1) |- extent_fiemap(start=0 len=(u64)-1) |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=0 len=64k) | | Found on-disk (ino, EXTENT_DATA, 0) | |- add_extent_mapping() | |- Return (em->start=0, len=16k) | |- fiemap_fill_next_extent(logic=0 phys=X len=16k) | |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=16k len=48k) | | Found on-disk (ino, EXTENT_DATA, 16k) | |- add_extent_mapping() | | |- try_merge_map() | | Merge with previous em start=0 len=16k | | resulting em start=0 len=32k | |- Return (em->start=0, len=32K) << Merged result |- Stripe off the unrelated range (0~16K) of return em |- fiemap_fill_next_extent(logic=16K phys=X+16K len=16K) ^^^ Causing split fiemap extent. And since in add_extent_mapping(), em is already merged, in next fiemap() call, we will get merged result. [FIX] Here we introduce a new structure, fiemap_cache, which records previous fiemap extent. And will always try to merge current fiemap_cache result before calling fiemap_fill_next_extent(). Only when we failed to merge current fiemap extent with cached one, we will call fiemap_fill_next_extent() to submit cached one. So by this method, we can merge all fiemap extents. It can also be done in fs/ioctl.c, however the problem is if fieinfo->fi_extents_max == 0, we have no space to cache previous fiemap extent. So I choose to merge it in btrfs. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-04-07 02:43:15 +00:00
*
* The last fiemap cache may still be cached in the following case:
* 0 4k 8k
* |<- Fiemap range ->|
* |<------------ First extent ----------->|
*
* In this case, the first extent range will be cached but not emitted.
* So we must emit it before ending extent_fiemap().
btrfs: fiemap: Cache and merge fiemap extent before submit it to user [BUG] Cycle mount btrfs can cause fiemap to return different result. Like: # mount /dev/vdb5 /mnt/btrfs # dd if=/dev/zero bs=16K count=4 oflag=dsync of=/mnt/btrfs/file # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 # umount /mnt/btrfs # mount /dev/vdb5 /mnt/btrfs # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..31]: 25088..25119 32 0x0 1: [32..63]: 25120..25151 32 0x0 2: [64..95]: 25152..25183 32 0x0 3: [96..127]: 25184..25215 32 0x1 But after above fiemap, we get correct merged result if we call fiemap again. # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 [REASON] Btrfs will try to merge extent map when inserting new extent map. btrfs_fiemap(start=0 len=(u64)-1) |- extent_fiemap(start=0 len=(u64)-1) |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=0 len=64k) | | Found on-disk (ino, EXTENT_DATA, 0) | |- add_extent_mapping() | |- Return (em->start=0, len=16k) | |- fiemap_fill_next_extent(logic=0 phys=X len=16k) | |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=16k len=48k) | | Found on-disk (ino, EXTENT_DATA, 16k) | |- add_extent_mapping() | | |- try_merge_map() | | Merge with previous em start=0 len=16k | | resulting em start=0 len=32k | |- Return (em->start=0, len=32K) << Merged result |- Stripe off the unrelated range (0~16K) of return em |- fiemap_fill_next_extent(logic=16K phys=X+16K len=16K) ^^^ Causing split fiemap extent. And since in add_extent_mapping(), em is already merged, in next fiemap() call, we will get merged result. [FIX] Here we introduce a new structure, fiemap_cache, which records previous fiemap extent. And will always try to merge current fiemap_cache result before calling fiemap_fill_next_extent(). Only when we failed to merge current fiemap extent with cached one, we will call fiemap_fill_next_extent() to submit cached one. So by this method, we can merge all fiemap extents. It can also be done in fs/ioctl.c, however the problem is if fieinfo->fi_extents_max == 0, we have no space to cache previous fiemap extent. So I choose to merge it in btrfs. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-04-07 02:43:15 +00:00
*/
static int emit_last_fiemap_cache(struct fiemap_extent_info *fieinfo,
struct fiemap_cache *cache)
btrfs: fiemap: Cache and merge fiemap extent before submit it to user [BUG] Cycle mount btrfs can cause fiemap to return different result. Like: # mount /dev/vdb5 /mnt/btrfs # dd if=/dev/zero bs=16K count=4 oflag=dsync of=/mnt/btrfs/file # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 # umount /mnt/btrfs # mount /dev/vdb5 /mnt/btrfs # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..31]: 25088..25119 32 0x0 1: [32..63]: 25120..25151 32 0x0 2: [64..95]: 25152..25183 32 0x0 3: [96..127]: 25184..25215 32 0x1 But after above fiemap, we get correct merged result if we call fiemap again. # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 [REASON] Btrfs will try to merge extent map when inserting new extent map. btrfs_fiemap(start=0 len=(u64)-1) |- extent_fiemap(start=0 len=(u64)-1) |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=0 len=64k) | | Found on-disk (ino, EXTENT_DATA, 0) | |- add_extent_mapping() | |- Return (em->start=0, len=16k) | |- fiemap_fill_next_extent(logic=0 phys=X len=16k) | |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=16k len=48k) | | Found on-disk (ino, EXTENT_DATA, 16k) | |- add_extent_mapping() | | |- try_merge_map() | | Merge with previous em start=0 len=16k | | resulting em start=0 len=32k | |- Return (em->start=0, len=32K) << Merged result |- Stripe off the unrelated range (0~16K) of return em |- fiemap_fill_next_extent(logic=16K phys=X+16K len=16K) ^^^ Causing split fiemap extent. And since in add_extent_mapping(), em is already merged, in next fiemap() call, we will get merged result. [FIX] Here we introduce a new structure, fiemap_cache, which records previous fiemap extent. And will always try to merge current fiemap_cache result before calling fiemap_fill_next_extent(). Only when we failed to merge current fiemap extent with cached one, we will call fiemap_fill_next_extent() to submit cached one. So by this method, we can merge all fiemap extents. It can also be done in fs/ioctl.c, however the problem is if fieinfo->fi_extents_max == 0, we have no space to cache previous fiemap extent. So I choose to merge it in btrfs. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-04-07 02:43:15 +00:00
{
int ret;
if (!cache->cached)
return 0;
ret = fiemap_fill_next_extent(fieinfo, cache->offset, cache->phys,
cache->len, cache->flags);
cache->cached = false;
if (ret > 0)
ret = 0;
return ret;
}
int extent_fiemap(struct btrfs_inode *inode, struct fiemap_extent_info *fieinfo,
u64 start, u64 len)
{
int ret = 0;
u64 off = start;
u64 max = start + len;
u32 flags = 0;
u32 found_type;
u64 last;
u64 last_for_get_extent = 0;
u64 disko = 0;
u64 isize = i_size_read(&inode->vfs_inode);
struct btrfs_key found_key;
struct extent_map *em = NULL;
struct extent_state *cached_state = NULL;
struct btrfs_path *path;
struct btrfs_root *root = inode->root;
btrfs: fiemap: Cache and merge fiemap extent before submit it to user [BUG] Cycle mount btrfs can cause fiemap to return different result. Like: # mount /dev/vdb5 /mnt/btrfs # dd if=/dev/zero bs=16K count=4 oflag=dsync of=/mnt/btrfs/file # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 # umount /mnt/btrfs # mount /dev/vdb5 /mnt/btrfs # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..31]: 25088..25119 32 0x0 1: [32..63]: 25120..25151 32 0x0 2: [64..95]: 25152..25183 32 0x0 3: [96..127]: 25184..25215 32 0x1 But after above fiemap, we get correct merged result if we call fiemap again. # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 [REASON] Btrfs will try to merge extent map when inserting new extent map. btrfs_fiemap(start=0 len=(u64)-1) |- extent_fiemap(start=0 len=(u64)-1) |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=0 len=64k) | | Found on-disk (ino, EXTENT_DATA, 0) | |- add_extent_mapping() | |- Return (em->start=0, len=16k) | |- fiemap_fill_next_extent(logic=0 phys=X len=16k) | |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=16k len=48k) | | Found on-disk (ino, EXTENT_DATA, 16k) | |- add_extent_mapping() | | |- try_merge_map() | | Merge with previous em start=0 len=16k | | resulting em start=0 len=32k | |- Return (em->start=0, len=32K) << Merged result |- Stripe off the unrelated range (0~16K) of return em |- fiemap_fill_next_extent(logic=16K phys=X+16K len=16K) ^^^ Causing split fiemap extent. And since in add_extent_mapping(), em is already merged, in next fiemap() call, we will get merged result. [FIX] Here we introduce a new structure, fiemap_cache, which records previous fiemap extent. And will always try to merge current fiemap_cache result before calling fiemap_fill_next_extent(). Only when we failed to merge current fiemap extent with cached one, we will call fiemap_fill_next_extent() to submit cached one. So by this method, we can merge all fiemap extents. It can also be done in fs/ioctl.c, however the problem is if fieinfo->fi_extents_max == 0, we have no space to cache previous fiemap extent. So I choose to merge it in btrfs. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-04-07 02:43:15 +00:00
struct fiemap_cache cache = { 0 };
struct ulist *roots;
struct ulist *tmp_ulist;
int end = 0;
u64 em_start = 0;
u64 em_len = 0;
u64 em_end = 0;
if (len == 0)
return -EINVAL;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
roots = ulist_alloc(GFP_KERNEL);
tmp_ulist = ulist_alloc(GFP_KERNEL);
if (!roots || !tmp_ulist) {
ret = -ENOMEM;
goto out_free_ulist;
}
start = round_down(start, btrfs_inode_sectorsize(inode));
len = round_up(max, btrfs_inode_sectorsize(inode)) - start;
/*
* lookup the last file extent. We're not using i_size here
* because there might be preallocation past i_size
*/
ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(inode), -1,
0);
if (ret < 0) {
goto out_free_ulist;
} else {
WARN_ON(!ret);
if (ret == 1)
ret = 0;
}
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
found_type = found_key.type;
/* No extents, but there might be delalloc bits */
if (found_key.objectid != btrfs_ino(inode) ||
found_type != BTRFS_EXTENT_DATA_KEY) {
/* have to trust i_size as the end */
last = (u64)-1;
last_for_get_extent = isize;
} else {
/*
* remember the start of the last extent. There are a
* bunch of different factors that go into the length of the
* extent, so its much less complex to remember where it started
*/
last = found_key.offset;
last_for_get_extent = last + 1;
}
btrfs_release_path(path);
/*
* we might have some extents allocated but more delalloc past those
* extents. so, we trust isize unless the start of the last extent is
* beyond isize
*/
if (last < isize) {
last = (u64)-1;
last_for_get_extent = isize;
}
lock_extent_bits(&inode->io_tree, start, start + len - 1,
&cached_state);
em = get_extent_skip_holes(inode, start, last_for_get_extent);
if (!em)
goto out;
if (IS_ERR(em)) {
ret = PTR_ERR(em);
goto out;
}
while (!end) {
u64 offset_in_extent = 0;
/* break if the extent we found is outside the range */
if (em->start >= max || extent_map_end(em) < off)
break;
/*
* get_extent may return an extent that starts before our
* requested range. We have to make sure the ranges
* we return to fiemap always move forward and don't
* overlap, so adjust the offsets here
*/
em_start = max(em->start, off);
/*
* record the offset from the start of the extent
* for adjusting the disk offset below. Only do this if the
* extent isn't compressed since our in ram offset may be past
* what we have actually allocated on disk.
*/
if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
offset_in_extent = em_start - em->start;
em_end = extent_map_end(em);
em_len = em_end - em_start;
flags = 0;
Btrfs: fix physical offset reported by fiemap for inline extents Commit 9d311e11fc1f ("Btrfs: fiemap: pass correct bytenr when fm_extent_count is zero") introduced a regression where we no longer report 0 as the physical offset for inline extents (and other extents with a special block_start value). This is because it always sets the variable used to report the physical offset ("disko") as em->block_start plus some offset, and em->block_start has the value 18446744073709551614 ((u64) -2) for inline extents. This made the btrfs test 004 (from fstests) often fail, for example, for a file with an inline extent we have the following items in the subvolume tree: item 101 key (418 INODE_ITEM 0) itemoff 11029 itemsize 160 generation 25 transid 38 size 1525 nbytes 1525 block group 0 mode 100666 links 1 uid 0 gid 0 rdev 0 sequence 0 flags 0x2(none) atime 1529342058.461891730 (2018-06-18 18:14:18) ctime 1529342058.461891730 (2018-06-18 18:14:18) mtime 1529342058.461891730 (2018-06-18 18:14:18) otime 1529342055.869892885 (2018-06-18 18:14:15) item 102 key (418 INODE_REF 264) itemoff 11016 itemsize 13 index 25 namelen 3 name: fc7 item 103 key (418 EXTENT_DATA 0) itemoff 9470 itemsize 1546 generation 38 type 0 (inline) inline extent data size 1525 ram_bytes 1525 compression 0 (none) Then when test 004 invoked fiemap against the file it got a non-zero physical offset: $ filefrag -v /mnt/p0/d4/d7/fc7 Filesystem type is: 9123683e File size of /mnt/p0/d4/d7/fc7 is 1525 (1 block of 4096 bytes) ext: logical_offset: physical_offset: length: expected: flags: 0: 0.. 4095: 18446744073709551614.. 4093: 4096: last,not_aligned,inline,eof /mnt/p0/d4/d7/fc7: 1 extent found This resulted in the test failing like this: btrfs/004 49s ... [failed, exit status 1]- output mismatch (see /home/fdmanana/git/hub/xfstests/results//btrfs/004.out.bad) --- tests/btrfs/004.out 2016-08-23 10:17:35.027012095 +0100 +++ /home/fdmanana/git/hub/xfstests/results//btrfs/004.out.bad 2018-06-18 18:15:02.385872155 +0100 @@ -1,3 +1,10 @@ QA output created by 004 *** test backref walking -*** done +./tests/btrfs/004: line 227: [: 7.55578637259143e+22: integer expression expected +ERROR: 7.55578637259143e+22 is not a valid numeric value. +unexpected output from + /home/fdmanana/git/hub/btrfs-progs/btrfs inspect-internal logical-resolve -s 65536 -P 7.55578637259143e+22 /home/fdmanana/btrfs-tests/scratch_1 ... (Run 'diff -u tests/btrfs/004.out /home/fdmanana/git/hub/xfstests/results//btrfs/004.out.bad' to see the entire diff) Ran: btrfs/004 The large number in scientific notation reported as an invalid numeric value is the result from the filter passed to perl which multiplies the physical offset by the block size reported by fiemap. So fix this by ensuring the physical offset is always set to 0 when we are processing an extent with a special block_start value. Fixes: 9d311e11fc1f ("Btrfs: fiemap: pass correct bytenr when fm_extent_count is zero") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-06-20 09:02:30 +00:00
if (em->block_start < EXTENT_MAP_LAST_BYTE)
disko = em->block_start + offset_in_extent;
else
disko = 0;
/*
* bump off for our next call to get_extent
*/
off = extent_map_end(em);
if (off >= max)
end = 1;
if (em->block_start == EXTENT_MAP_LAST_BYTE) {
end = 1;
flags |= FIEMAP_EXTENT_LAST;
} else if (em->block_start == EXTENT_MAP_INLINE) {
flags |= (FIEMAP_EXTENT_DATA_INLINE |
FIEMAP_EXTENT_NOT_ALIGNED);
} else if (em->block_start == EXTENT_MAP_DELALLOC) {
flags |= (FIEMAP_EXTENT_DELALLOC |
FIEMAP_EXTENT_UNKNOWN);
} else if (fieinfo->fi_extents_max) {
u64 bytenr = em->block_start -
(em->start - em->orig_start);
/*
* As btrfs supports shared space, this information
* can be exported to userspace tools via
* flag FIEMAP_EXTENT_SHARED. If fi_extents_max == 0
* then we're just getting a count and we can skip the
* lookup stuff.
*/
ret = btrfs_check_shared(root, btrfs_ino(inode),
bytenr, roots, tmp_ulist);
if (ret < 0)
goto out_free;
if (ret)
flags |= FIEMAP_EXTENT_SHARED;
ret = 0;
}
if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
flags |= FIEMAP_EXTENT_ENCODED;
if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
flags |= FIEMAP_EXTENT_UNWRITTEN;
free_extent_map(em);
em = NULL;
if ((em_start >= last) || em_len == (u64)-1 ||
(last == (u64)-1 && isize <= em_end)) {
flags |= FIEMAP_EXTENT_LAST;
end = 1;
}
/* now scan forward to see if this is really the last extent. */
em = get_extent_skip_holes(inode, off, last_for_get_extent);
if (IS_ERR(em)) {
ret = PTR_ERR(em);
goto out;
}
if (!em) {
flags |= FIEMAP_EXTENT_LAST;
end = 1;
}
btrfs: fiemap: Cache and merge fiemap extent before submit it to user [BUG] Cycle mount btrfs can cause fiemap to return different result. Like: # mount /dev/vdb5 /mnt/btrfs # dd if=/dev/zero bs=16K count=4 oflag=dsync of=/mnt/btrfs/file # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 # umount /mnt/btrfs # mount /dev/vdb5 /mnt/btrfs # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..31]: 25088..25119 32 0x0 1: [32..63]: 25120..25151 32 0x0 2: [64..95]: 25152..25183 32 0x0 3: [96..127]: 25184..25215 32 0x1 But after above fiemap, we get correct merged result if we call fiemap again. # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 [REASON] Btrfs will try to merge extent map when inserting new extent map. btrfs_fiemap(start=0 len=(u64)-1) |- extent_fiemap(start=0 len=(u64)-1) |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=0 len=64k) | | Found on-disk (ino, EXTENT_DATA, 0) | |- add_extent_mapping() | |- Return (em->start=0, len=16k) | |- fiemap_fill_next_extent(logic=0 phys=X len=16k) | |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=16k len=48k) | | Found on-disk (ino, EXTENT_DATA, 16k) | |- add_extent_mapping() | | |- try_merge_map() | | Merge with previous em start=0 len=16k | | resulting em start=0 len=32k | |- Return (em->start=0, len=32K) << Merged result |- Stripe off the unrelated range (0~16K) of return em |- fiemap_fill_next_extent(logic=16K phys=X+16K len=16K) ^^^ Causing split fiemap extent. And since in add_extent_mapping(), em is already merged, in next fiemap() call, we will get merged result. [FIX] Here we introduce a new structure, fiemap_cache, which records previous fiemap extent. And will always try to merge current fiemap_cache result before calling fiemap_fill_next_extent(). Only when we failed to merge current fiemap extent with cached one, we will call fiemap_fill_next_extent() to submit cached one. So by this method, we can merge all fiemap extents. It can also be done in fs/ioctl.c, however the problem is if fieinfo->fi_extents_max == 0, we have no space to cache previous fiemap extent. So I choose to merge it in btrfs. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-04-07 02:43:15 +00:00
ret = emit_fiemap_extent(fieinfo, &cache, em_start, disko,
em_len, flags);
if (ret) {
if (ret == 1)
ret = 0;
goto out_free;
}
}
out_free:
btrfs: fiemap: Cache and merge fiemap extent before submit it to user [BUG] Cycle mount btrfs can cause fiemap to return different result. Like: # mount /dev/vdb5 /mnt/btrfs # dd if=/dev/zero bs=16K count=4 oflag=dsync of=/mnt/btrfs/file # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 # umount /mnt/btrfs # mount /dev/vdb5 /mnt/btrfs # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..31]: 25088..25119 32 0x0 1: [32..63]: 25120..25151 32 0x0 2: [64..95]: 25152..25183 32 0x0 3: [96..127]: 25184..25215 32 0x1 But after above fiemap, we get correct merged result if we call fiemap again. # xfs_io -c "fiemap -v" /mnt/btrfs/file /mnt/test/file: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..127]: 25088..25215 128 0x1 [REASON] Btrfs will try to merge extent map when inserting new extent map. btrfs_fiemap(start=0 len=(u64)-1) |- extent_fiemap(start=0 len=(u64)-1) |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=0 len=64k) | | Found on-disk (ino, EXTENT_DATA, 0) | |- add_extent_mapping() | |- Return (em->start=0, len=16k) | |- fiemap_fill_next_extent(logic=0 phys=X len=16k) | |- get_extent_skip_holes(start=0 len=64k) | |- btrfs_get_extent_fiemap(start=0 len=64k) | |- btrfs_get_extent(start=16k len=48k) | | Found on-disk (ino, EXTENT_DATA, 16k) | |- add_extent_mapping() | | |- try_merge_map() | | Merge with previous em start=0 len=16k | | resulting em start=0 len=32k | |- Return (em->start=0, len=32K) << Merged result |- Stripe off the unrelated range (0~16K) of return em |- fiemap_fill_next_extent(logic=16K phys=X+16K len=16K) ^^^ Causing split fiemap extent. And since in add_extent_mapping(), em is already merged, in next fiemap() call, we will get merged result. [FIX] Here we introduce a new structure, fiemap_cache, which records previous fiemap extent. And will always try to merge current fiemap_cache result before calling fiemap_fill_next_extent(). Only when we failed to merge current fiemap extent with cached one, we will call fiemap_fill_next_extent() to submit cached one. So by this method, we can merge all fiemap extents. It can also be done in fs/ioctl.c, however the problem is if fieinfo->fi_extents_max == 0, we have no space to cache previous fiemap extent. So I choose to merge it in btrfs. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-04-07 02:43:15 +00:00
if (!ret)
ret = emit_last_fiemap_cache(fieinfo, &cache);
free_extent_map(em);
out:
unlock_extent_cached(&inode->io_tree, start, start + len - 1,
&cached_state);
out_free_ulist:
btrfs_free_path(path);
ulist_free(roots);
ulist_free(tmp_ulist);
return ret;
}
static void __free_extent_buffer(struct extent_buffer *eb)
{
kmem_cache_free(extent_buffer_cache, eb);
}
int extent_buffer_under_io(const struct extent_buffer *eb)
{
return (atomic_read(&eb->io_pages) ||
test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) ||
test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
}
btrfs: support subpage for extent buffer page release In btrfs_release_extent_buffer_pages(), we need to add extra handling for subpage. Introduce a helper, detach_extent_buffer_page(), to do different handling for regular and subpage cases. For subpage case, handle detaching page private. For unmapped (dummy or cloned) ebs, we can detach the page private immediately as the page can only be attached to one unmapped eb. For mapped ebs, we have to ensure there are no eb in the page range before we delete it, as page->private is shared between all ebs in the same page. But there is a subpage specific race, where we can race with extent buffer allocation, and clear the page private while new eb is still being utilized, like this: Extent buffer A is the new extent buffer which will be allocated, while extent buffer B is the last existing extent buffer of the page. T1 (eb A) | T2 (eb B) -------------------------------+------------------------------ alloc_extent_buffer() | btrfs_release_extent_buffer_pages() |- p = find_or_create_page() | | |- attach_extent_buffer_page() | | | | |- detach_extent_buffer_page() | | |- if (!page_range_has_eb()) | | | No new eb in the page range yet | | | As new eb A hasn't yet been | | | inserted into radix tree. | | |- btrfs_detach_subpage() | | |- detach_page_private(); |- radix_tree_insert() | Then we have a metadata eb whose page has no private bit. To avoid such race, we introduce a subpage metadata-specific member, btrfs_subpage::eb_refs. In alloc_extent_buffer() we increase eb_refs in the critical section of private_lock. Then page_range_has_eb() will return true for detach_extent_buffer_page(), and will not detach page private. The section is marked by: - btrfs_page_inc_eb_refs() - btrfs_page_dec_eb_refs() Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-26 08:33:50 +00:00
static bool page_range_has_eb(struct btrfs_fs_info *fs_info, struct page *page)
{
btrfs: support subpage for extent buffer page release In btrfs_release_extent_buffer_pages(), we need to add extra handling for subpage. Introduce a helper, detach_extent_buffer_page(), to do different handling for regular and subpage cases. For subpage case, handle detaching page private. For unmapped (dummy or cloned) ebs, we can detach the page private immediately as the page can only be attached to one unmapped eb. For mapped ebs, we have to ensure there are no eb in the page range before we delete it, as page->private is shared between all ebs in the same page. But there is a subpage specific race, where we can race with extent buffer allocation, and clear the page private while new eb is still being utilized, like this: Extent buffer A is the new extent buffer which will be allocated, while extent buffer B is the last existing extent buffer of the page. T1 (eb A) | T2 (eb B) -------------------------------+------------------------------ alloc_extent_buffer() | btrfs_release_extent_buffer_pages() |- p = find_or_create_page() | | |- attach_extent_buffer_page() | | | | |- detach_extent_buffer_page() | | |- if (!page_range_has_eb()) | | | No new eb in the page range yet | | | As new eb A hasn't yet been | | | inserted into radix tree. | | |- btrfs_detach_subpage() | | |- detach_page_private(); |- radix_tree_insert() | Then we have a metadata eb whose page has no private bit. To avoid such race, we introduce a subpage metadata-specific member, btrfs_subpage::eb_refs. In alloc_extent_buffer() we increase eb_refs in the critical section of private_lock. Then page_range_has_eb() will return true for detach_extent_buffer_page(), and will not detach page private. The section is marked by: - btrfs_page_inc_eb_refs() - btrfs_page_dec_eb_refs() Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-26 08:33:50 +00:00
struct btrfs_subpage *subpage;
btrfs: support subpage for extent buffer page release In btrfs_release_extent_buffer_pages(), we need to add extra handling for subpage. Introduce a helper, detach_extent_buffer_page(), to do different handling for regular and subpage cases. For subpage case, handle detaching page private. For unmapped (dummy or cloned) ebs, we can detach the page private immediately as the page can only be attached to one unmapped eb. For mapped ebs, we have to ensure there are no eb in the page range before we delete it, as page->private is shared between all ebs in the same page. But there is a subpage specific race, where we can race with extent buffer allocation, and clear the page private while new eb is still being utilized, like this: Extent buffer A is the new extent buffer which will be allocated, while extent buffer B is the last existing extent buffer of the page. T1 (eb A) | T2 (eb B) -------------------------------+------------------------------ alloc_extent_buffer() | btrfs_release_extent_buffer_pages() |- p = find_or_create_page() | | |- attach_extent_buffer_page() | | | | |- detach_extent_buffer_page() | | |- if (!page_range_has_eb()) | | | No new eb in the page range yet | | | As new eb A hasn't yet been | | | inserted into radix tree. | | |- btrfs_detach_subpage() | | |- detach_page_private(); |- radix_tree_insert() | Then we have a metadata eb whose page has no private bit. To avoid such race, we introduce a subpage metadata-specific member, btrfs_subpage::eb_refs. In alloc_extent_buffer() we increase eb_refs in the critical section of private_lock. Then page_range_has_eb() will return true for detach_extent_buffer_page(), and will not detach page private. The section is marked by: - btrfs_page_inc_eb_refs() - btrfs_page_dec_eb_refs() Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-26 08:33:50 +00:00
lockdep_assert_held(&page->mapping->private_lock);
btrfs: support subpage for extent buffer page release In btrfs_release_extent_buffer_pages(), we need to add extra handling for subpage. Introduce a helper, detach_extent_buffer_page(), to do different handling for regular and subpage cases. For subpage case, handle detaching page private. For unmapped (dummy or cloned) ebs, we can detach the page private immediately as the page can only be attached to one unmapped eb. For mapped ebs, we have to ensure there are no eb in the page range before we delete it, as page->private is shared between all ebs in the same page. But there is a subpage specific race, where we can race with extent buffer allocation, and clear the page private while new eb is still being utilized, like this: Extent buffer A is the new extent buffer which will be allocated, while extent buffer B is the last existing extent buffer of the page. T1 (eb A) | T2 (eb B) -------------------------------+------------------------------ alloc_extent_buffer() | btrfs_release_extent_buffer_pages() |- p = find_or_create_page() | | |- attach_extent_buffer_page() | | | | |- detach_extent_buffer_page() | | |- if (!page_range_has_eb()) | | | No new eb in the page range yet | | | As new eb A hasn't yet been | | | inserted into radix tree. | | |- btrfs_detach_subpage() | | |- detach_page_private(); |- radix_tree_insert() | Then we have a metadata eb whose page has no private bit. To avoid such race, we introduce a subpage metadata-specific member, btrfs_subpage::eb_refs. In alloc_extent_buffer() we increase eb_refs in the critical section of private_lock. Then page_range_has_eb() will return true for detach_extent_buffer_page(), and will not detach page private. The section is marked by: - btrfs_page_inc_eb_refs() - btrfs_page_dec_eb_refs() Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-26 08:33:50 +00:00
if (PagePrivate(page)) {
subpage = (struct btrfs_subpage *)page->private;
if (atomic_read(&subpage->eb_refs))
return true;
}
return false;
}
btrfs: support subpage for extent buffer page release In btrfs_release_extent_buffer_pages(), we need to add extra handling for subpage. Introduce a helper, detach_extent_buffer_page(), to do different handling for regular and subpage cases. For subpage case, handle detaching page private. For unmapped (dummy or cloned) ebs, we can detach the page private immediately as the page can only be attached to one unmapped eb. For mapped ebs, we have to ensure there are no eb in the page range before we delete it, as page->private is shared between all ebs in the same page. But there is a subpage specific race, where we can race with extent buffer allocation, and clear the page private while new eb is still being utilized, like this: Extent buffer A is the new extent buffer which will be allocated, while extent buffer B is the last existing extent buffer of the page. T1 (eb A) | T2 (eb B) -------------------------------+------------------------------ alloc_extent_buffer() | btrfs_release_extent_buffer_pages() |- p = find_or_create_page() | | |- attach_extent_buffer_page() | | | | |- detach_extent_buffer_page() | | |- if (!page_range_has_eb()) | | | No new eb in the page range yet | | | As new eb A hasn't yet been | | | inserted into radix tree. | | |- btrfs_detach_subpage() | | |- detach_page_private(); |- radix_tree_insert() | Then we have a metadata eb whose page has no private bit. To avoid such race, we introduce a subpage metadata-specific member, btrfs_subpage::eb_refs. In alloc_extent_buffer() we increase eb_refs in the critical section of private_lock. Then page_range_has_eb() will return true for detach_extent_buffer_page(), and will not detach page private. The section is marked by: - btrfs_page_inc_eb_refs() - btrfs_page_dec_eb_refs() Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-26 08:33:50 +00:00
static void detach_extent_buffer_page(struct extent_buffer *eb, struct page *page)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
const bool mapped = !test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
/*
* For mapped eb, we're going to change the page private, which should
* be done under the private_lock.
*/
if (mapped)
spin_lock(&page->mapping->private_lock);
if (!PagePrivate(page)) {
if (mapped)
btrfs: support subpage for extent buffer page release In btrfs_release_extent_buffer_pages(), we need to add extra handling for subpage. Introduce a helper, detach_extent_buffer_page(), to do different handling for regular and subpage cases. For subpage case, handle detaching page private. For unmapped (dummy or cloned) ebs, we can detach the page private immediately as the page can only be attached to one unmapped eb. For mapped ebs, we have to ensure there are no eb in the page range before we delete it, as page->private is shared between all ebs in the same page. But there is a subpage specific race, where we can race with extent buffer allocation, and clear the page private while new eb is still being utilized, like this: Extent buffer A is the new extent buffer which will be allocated, while extent buffer B is the last existing extent buffer of the page. T1 (eb A) | T2 (eb B) -------------------------------+------------------------------ alloc_extent_buffer() | btrfs_release_extent_buffer_pages() |- p = find_or_create_page() | | |- attach_extent_buffer_page() | | | | |- detach_extent_buffer_page() | | |- if (!page_range_has_eb()) | | | No new eb in the page range yet | | | As new eb A hasn't yet been | | | inserted into radix tree. | | |- btrfs_detach_subpage() | | |- detach_page_private(); |- radix_tree_insert() | Then we have a metadata eb whose page has no private bit. To avoid such race, we introduce a subpage metadata-specific member, btrfs_subpage::eb_refs. In alloc_extent_buffer() we increase eb_refs in the critical section of private_lock. Then page_range_has_eb() will return true for detach_extent_buffer_page(), and will not detach page private. The section is marked by: - btrfs_page_inc_eb_refs() - btrfs_page_dec_eb_refs() Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-26 08:33:50 +00:00
spin_unlock(&page->mapping->private_lock);
return;
}
if (fs_info->sectorsize == PAGE_SIZE) {
/*
* We do this since we'll remove the pages after we've
* removed the eb from the radix tree, so we could race
* and have this page now attached to the new eb. So
* only clear page_private if it's still connected to
* this eb.
*/
if (PagePrivate(page) &&
page->private == (unsigned long)eb) {
BUG_ON(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
BUG_ON(PageDirty(page));
BUG_ON(PageWriteback(page));
/*
* We need to make sure we haven't be attached
* to a new eb.
*/
detach_page_private(page);
}
if (mapped)
spin_unlock(&page->mapping->private_lock);
btrfs: support subpage for extent buffer page release In btrfs_release_extent_buffer_pages(), we need to add extra handling for subpage. Introduce a helper, detach_extent_buffer_page(), to do different handling for regular and subpage cases. For subpage case, handle detaching page private. For unmapped (dummy or cloned) ebs, we can detach the page private immediately as the page can only be attached to one unmapped eb. For mapped ebs, we have to ensure there are no eb in the page range before we delete it, as page->private is shared between all ebs in the same page. But there is a subpage specific race, where we can race with extent buffer allocation, and clear the page private while new eb is still being utilized, like this: Extent buffer A is the new extent buffer which will be allocated, while extent buffer B is the last existing extent buffer of the page. T1 (eb A) | T2 (eb B) -------------------------------+------------------------------ alloc_extent_buffer() | btrfs_release_extent_buffer_pages() |- p = find_or_create_page() | | |- attach_extent_buffer_page() | | | | |- detach_extent_buffer_page() | | |- if (!page_range_has_eb()) | | | No new eb in the page range yet | | | As new eb A hasn't yet been | | | inserted into radix tree. | | |- btrfs_detach_subpage() | | |- detach_page_private(); |- radix_tree_insert() | Then we have a metadata eb whose page has no private bit. To avoid such race, we introduce a subpage metadata-specific member, btrfs_subpage::eb_refs. In alloc_extent_buffer() we increase eb_refs in the critical section of private_lock. Then page_range_has_eb() will return true for detach_extent_buffer_page(), and will not detach page private. The section is marked by: - btrfs_page_inc_eb_refs() - btrfs_page_dec_eb_refs() Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-26 08:33:50 +00:00
return;
}
/*
* For subpage, we can have dummy eb with page private. In this case,
* we can directly detach the private as such page is only attached to
* one dummy eb, no sharing.
*/
if (!mapped) {
btrfs_detach_subpage(fs_info, page);
return;
}
btrfs_page_dec_eb_refs(fs_info, page);
/*
* We can only detach the page private if there are no other ebs in the
* page range.
*/
if (!page_range_has_eb(fs_info, page))
btrfs_detach_subpage(fs_info, page);
spin_unlock(&page->mapping->private_lock);
}
/* Release all pages attached to the extent buffer */
static void btrfs_release_extent_buffer_pages(struct extent_buffer *eb)
{
int i;
int num_pages;
ASSERT(!extent_buffer_under_io(eb));
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
struct page *page = eb->pages[i];
if (!page)
continue;
detach_extent_buffer_page(eb, page);
/* One for when we allocated the page */
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
put_page(page);
}
}
/*
* Helper for releasing the extent buffer.
*/
static inline void btrfs_release_extent_buffer(struct extent_buffer *eb)
{
btrfs_release_extent_buffer_pages(eb);
btrfs_leak_debug_del(&eb->fs_info->eb_leak_lock, &eb->leak_list);
__free_extent_buffer(eb);
}
static struct extent_buffer *
__alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
unsigned long len)
{
struct extent_buffer *eb = NULL;
btrfs: Prevent from early transaction abort Btrfs relies on GFP_NOFS allocation when committing the transaction but this allocation context is rather weak wrt. reclaim capabilities. The page allocator currently tries hard to not fail these allocations if they are small (<=PAGE_ALLOC_COSTLY_ORDER) so this is not a problem currently but there is an attempt to move away from the default no-fail behavior and allow these allocation to fail more eagerly. And this would lead to a pre-mature transaction abort as follows: [ 55.328093] Call Trace: [ 55.328890] [<ffffffff8154e6f0>] dump_stack+0x4f/0x7b [ 55.330518] [<ffffffff8108fa28>] ? console_unlock+0x334/0x363 [ 55.332738] [<ffffffff8110873e>] __alloc_pages_nodemask+0x81d/0x8d4 [ 55.334910] [<ffffffff81100752>] pagecache_get_page+0x10e/0x20c [ 55.336844] [<ffffffffa007d916>] alloc_extent_buffer+0xd0/0x350 [btrfs] [ 55.338973] [<ffffffffa0059d8c>] btrfs_find_create_tree_block+0x15/0x17 [btrfs] [ 55.341329] [<ffffffffa004f728>] btrfs_alloc_tree_block+0x18c/0x405 [btrfs] [ 55.343566] [<ffffffffa003fa34>] split_leaf+0x1e4/0x6a6 [btrfs] [ 55.345577] [<ffffffffa0040567>] btrfs_search_slot+0x671/0x831 [btrfs] [ 55.347679] [<ffffffff810682d7>] ? get_parent_ip+0xe/0x3e [ 55.349434] [<ffffffffa0041cb2>] btrfs_insert_empty_items+0x5d/0xa8 [btrfs] [ 55.351681] [<ffffffffa004ecfb>] __btrfs_run_delayed_refs+0x7a6/0xf35 [btrfs] [ 55.353979] [<ffffffffa00512ea>] btrfs_run_delayed_refs+0x6e/0x226 [btrfs] [ 55.356212] [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs] [ 55.358378] [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs] [ 55.360626] [<ffffffffa0060221>] btrfs_commit_transaction+0x4c/0xaba [btrfs] [ 55.362894] [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs] [ 55.365221] [<ffffffffa0073428>] btrfs_sync_file+0x29c/0x310 [btrfs] [ 55.367273] [<ffffffff81186808>] vfs_fsync_range+0x8f/0x9e [ 55.369047] [<ffffffff81186833>] vfs_fsync+0x1c/0x1e [ 55.370654] [<ffffffff81186869>] do_fsync+0x34/0x4e [ 55.372246] [<ffffffff81186ab3>] SyS_fsync+0x10/0x14 [ 55.373851] [<ffffffff81554f97>] system_call_fastpath+0x12/0x6f [ 55.381070] BTRFS: error (device hdb1) in btrfs_run_delayed_refs:2821: errno=-12 Out of memory [ 55.382431] BTRFS warning (device hdb1): Skipping commit of aborted transaction. [ 55.382433] BTRFS warning (device hdb1): cleanup_transaction:1692: Aborting unused transaction(IO failure). [ 55.384280] ------------[ cut here ]------------ [ 55.384312] WARNING: CPU: 0 PID: 3010 at fs/btrfs/delayed-ref.c:438 btrfs_select_ref_head+0xd9/0xfe [btrfs]() [...] [ 55.384337] Call Trace: [ 55.384353] [<ffffffff8154e6f0>] dump_stack+0x4f/0x7b [ 55.384357] [<ffffffff8107f717>] ? down_trylock+0x2d/0x37 [ 55.384359] [<ffffffff81046977>] warn_slowpath_common+0xa1/0xbb [ 55.384398] [<ffffffffa00a1d6b>] ? btrfs_select_ref_head+0xd9/0xfe [btrfs] [ 55.384400] [<ffffffff81046a34>] warn_slowpath_null+0x1a/0x1c [ 55.384423] [<ffffffffa00a1d6b>] btrfs_select_ref_head+0xd9/0xfe [btrfs] [ 55.384446] [<ffffffffa004e5f7>] ? __btrfs_run_delayed_refs+0xa2/0xf35 [btrfs] [ 55.384455] [<ffffffffa004e600>] __btrfs_run_delayed_refs+0xab/0xf35 [btrfs] [ 55.384476] [<ffffffffa00512ea>] btrfs_run_delayed_refs+0x6e/0x226 [btrfs] [ 55.384499] [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs] [ 55.384521] [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs] [ 55.384543] [<ffffffffa0060221>] btrfs_commit_transaction+0x4c/0xaba [btrfs] [ 55.384565] [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs] [ 55.384588] [<ffffffffa0073428>] btrfs_sync_file+0x29c/0x310 [btrfs] [ 55.384591] [<ffffffff81186808>] vfs_fsync_range+0x8f/0x9e [ 55.384592] [<ffffffff81186833>] vfs_fsync+0x1c/0x1e [ 55.384593] [<ffffffff81186869>] do_fsync+0x34/0x4e [ 55.384594] [<ffffffff81186ab3>] SyS_fsync+0x10/0x14 [ 55.384595] [<ffffffff81554f97>] system_call_fastpath+0x12/0x6f [...] [ 55.384608] ---[ end trace c29799da1d4dd621 ]--- [ 55.437323] BTRFS info (device hdb1): forced readonly [ 55.438815] BTRFS info (device hdb1): delayed_refs has NO entry Fix this by being explicit about the no-fail behavior of this allocation path and use __GFP_NOFAIL. Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-08-19 12:17:40 +00:00
eb = kmem_cache_zalloc(extent_buffer_cache, GFP_NOFS|__GFP_NOFAIL);
eb->start = start;
eb->len = len;
eb->fs_info = fs_info;
eb->bflags = 0;
btrfs: switch extent buffer tree lock to rw_semaphore Historically we've implemented our own locking because we wanted to be able to selectively spin or sleep based on what we were doing in the tree. For instance, if all of our nodes were in cache then there's rarely a reason to need to sleep waiting for node locks, as they'll likely become available soon. At the time this code was written the rw_semaphore didn't do adaptive spinning, and thus was orders of magnitude slower than our home grown locking. However now the opposite is the case. There are a few problems with how we implement blocking locks, namely that we use a normal waitqueue and simply wake everybody up in reverse sleep order. This leads to some suboptimal performance behavior, and a lot of context switches in highly contended cases. The rw_semaphores actually do this properly, and also have adaptive spinning that works relatively well. The locking code is also a bit of a bear to understand, and we lose the benefit of lockdep for the most part because the blocking states of the lock are simply ad-hoc and not mapped into lockdep. So rework the locking code to drop all of this custom locking stuff, and simply use a rw_semaphore for everything. This makes the locking much simpler for everything, as we can now drop a lot of cruft and blocking transitions. The performance numbers vary depending on the workload, because generally speaking there doesn't tend to be a lot of contention on the btree. However, on my test system which is an 80 core single socket system with 256GiB of RAM and a 2TiB NVMe drive I get the following results (with all debug options off): dbench 200 baseline Throughput 216.056 MB/sec 200 clients 200 procs max_latency=1471.197 ms dbench 200 with patch Throughput 737.188 MB/sec 200 clients 200 procs max_latency=714.346 ms Previously we also used fs_mark to test this sort of contention, and those results are far less impressive, mostly because there's not enough tasks to really stress the locking fs_mark -d /d[0-15] -S 0 -L 20 -n 100000 -s 0 -t 16 baseline Average Files/sec: 160166.7 p50 Files/sec: 165832 p90 Files/sec: 123886 p99 Files/sec: 123495 real 3m26.527s user 2m19.223s sys 48m21.856s patched Average Files/sec: 164135.7 p50 Files/sec: 171095 p90 Files/sec: 122889 p99 Files/sec: 113819 real 3m29.660s user 2m19.990s sys 44m12.259s Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-20 15:46:09 +00:00
init_rwsem(&eb->lock);
Btrfs: Change btree locking to use explicit blocking points Most of the btrfs metadata operations can be protected by a spinlock, but some operations still need to schedule. So far, btrfs has been using a mutex along with a trylock loop, most of the time it is able to avoid going for the full mutex, so the trylock loop is a big performance gain. This commit is step one for getting rid of the blocking locks entirely. btrfs_tree_lock takes a spinlock, and the code explicitly switches to a blocking lock when it starts an operation that can schedule. We'll be able get rid of the blocking locks in smaller pieces over time. Tracing allows us to find the most common cause of blocking, so we can start with the hot spots first. The basic idea is: btrfs_tree_lock() returns with the spin lock held btrfs_set_lock_blocking() sets the EXTENT_BUFFER_BLOCKING bit in the extent buffer flags, and then drops the spin lock. The buffer is still considered locked by all of the btrfs code. If btrfs_tree_lock gets the spinlock but finds the blocking bit set, it drops the spin lock and waits on a wait queue for the blocking bit to go away. Much of the code that needs to set the blocking bit finishes without actually blocking a good percentage of the time. So, an adaptive spin is still used against the blocking bit to avoid very high context switch rates. btrfs_clear_lock_blocking() clears the blocking bit and returns with the spinlock held again. btrfs_tree_unlock() can be called on either blocking or spinning locks, it does the right thing based on the blocking bit. ctree.c has a helper function to set/clear all the locked buffers in a path as blocking. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 14:25:08 +00:00
btrfs_leak_debug_add(&fs_info->eb_leak_lock, &eb->leak_list,
&fs_info->allocated_ebs);
INIT_LIST_HEAD(&eb->release_list);
spin_lock_init(&eb->refs_lock);
atomic_set(&eb->refs, 1);
atomic_set(&eb->io_pages, 0);
ASSERT(len <= BTRFS_MAX_METADATA_BLOCKSIZE);
return eb;
}
struct extent_buffer *btrfs_clone_extent_buffer(const struct extent_buffer *src)
{
int i;
struct page *p;
struct extent_buffer *new;
int num_pages = num_extent_pages(src);
new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
if (new == NULL)
return NULL;
/*
* Set UNMAPPED before calling btrfs_release_extent_buffer(), as
* btrfs_release_extent_buffer() have different behavior for
* UNMAPPED subpage extent buffer.
*/
set_bit(EXTENT_BUFFER_UNMAPPED, &new->bflags);
for (i = 0; i < num_pages; i++) {
int ret;
p = alloc_page(GFP_NOFS);
if (!p) {
btrfs_release_extent_buffer(new);
return NULL;
}
ret = attach_extent_buffer_page(new, p, NULL);
if (ret < 0) {
put_page(p);
btrfs_release_extent_buffer(new);
return NULL;
}
WARN_ON(PageDirty(p));
new->pages[i] = p;
copy_page(page_address(p), page_address(src->pages[i]));
}
set_extent_buffer_uptodate(new);
return new;
}
struct extent_buffer *__alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
u64 start, unsigned long len)
{
struct extent_buffer *eb;
int num_pages;
int i;
eb = __alloc_extent_buffer(fs_info, start, len);
if (!eb)
return NULL;
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
int ret;
eb->pages[i] = alloc_page(GFP_NOFS);
if (!eb->pages[i])
goto err;
ret = attach_extent_buffer_page(eb, eb->pages[i], NULL);
if (ret < 0)
goto err;
}
set_extent_buffer_uptodate(eb);
btrfs_set_header_nritems(eb, 0);
set_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags);
return eb;
err:
for (; i > 0; i--) {
detach_extent_buffer_page(eb, eb->pages[i - 1]);
__free_page(eb->pages[i - 1]);
}
__free_extent_buffer(eb);
return NULL;
}
struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
u64 start)
{
return __alloc_dummy_extent_buffer(fs_info, start, fs_info->nodesize);
}
static void check_buffer_tree_ref(struct extent_buffer *eb)
{
int refs;
btrfs: fix fatal extent_buffer readahead vs releasepage race Under somewhat convoluted conditions, it is possible to attempt to release an extent_buffer that is under io, which triggers a BUG_ON in btrfs_release_extent_buffer_pages. This relies on a few different factors. First, extent_buffer reads done as readahead for searching use WAIT_NONE, so they free the local extent buffer reference while the io is outstanding. However, they should still be protected by TREE_REF. However, if the system is doing signficant reclaim, and simultaneously heavily accessing the extent_buffers, it is possible for releasepage to race with two concurrent readahead attempts in a way that leaves TREE_REF unset when the readahead extent buffer is released. Essentially, if two tasks race to allocate a new extent_buffer, but the winner who attempts the first io is rebuffed by a page being locked (likely by the reclaim itself) then the loser will still go ahead with issuing the readahead. The loser's call to find_extent_buffer must also race with the reclaim task reading the extent_buffer's refcount as 1 in a way that allows the reclaim to re-clear the TREE_REF checked by find_extent_buffer. The following represents an example execution demonstrating the race: CPU0 CPU1 CPU2 reada_for_search reada_for_search readahead_tree_block readahead_tree_block find_create_tree_block find_create_tree_block alloc_extent_buffer alloc_extent_buffer find_extent_buffer // not found allocates eb lock pages associate pages to eb insert eb into radix tree set TREE_REF, refs == 2 unlock pages read_extent_buffer_pages // WAIT_NONE not uptodate (brand new eb) lock_page if !trylock_page goto unlock_exit // not an error free_extent_buffer release_extent_buffer atomic_dec_and_test refs to 1 find_extent_buffer // found try_release_extent_buffer take refs_lock reads refs == 1; no io atomic_inc_not_zero refs to 2 mark_buffer_accessed check_buffer_tree_ref // not STALE, won't take refs_lock refs == 2; TREE_REF set // no action read_extent_buffer_pages // WAIT_NONE clear TREE_REF release_extent_buffer atomic_dec_and_test refs to 1 unlock_page still not uptodate (CPU1 read failed on trylock_page) locks pages set io_pages > 0 submit io return free_extent_buffer release_extent_buffer dec refs to 0 delete from radix tree btrfs_release_extent_buffer_pages BUG_ON(io_pages > 0)!!! We observe this at a very low rate in production and were also able to reproduce it in a test environment by introducing some spurious delays and by introducing probabilistic trylock_page failures. To fix it, we apply check_tree_ref at a point where it could not possibly be unset by a competing task: after io_pages has been incremented. All the codepaths that clear TREE_REF check for io, so they would not be able to clear it after this point until the io is done. Stack trace, for reference: [1417839.424739] ------------[ cut here ]------------ [1417839.435328] kernel BUG at fs/btrfs/extent_io.c:4841! [1417839.447024] invalid opcode: 0000 [#1] SMP [1417839.502972] RIP: 0010:btrfs_release_extent_buffer_pages+0x20/0x1f0 [1417839.517008] Code: ed e9 ... [1417839.558895] RSP: 0018:ffffc90020bcf798 EFLAGS: 00010202 [1417839.570816] RAX: 0000000000000002 RBX: ffff888102d6def0 RCX: 0000000000000028 [1417839.586962] RDX: 0000000000000002 RSI: ffff8887f0296482 RDI: ffff888102d6def0 [1417839.603108] RBP: ffff88885664a000 R08: 0000000000000046 R09: 0000000000000238 [1417839.619255] R10: 0000000000000028 R11: ffff88885664af68 R12: 0000000000000000 [1417839.635402] R13: 0000000000000000 R14: ffff88875f573ad0 R15: ffff888797aafd90 [1417839.651549] FS: 00007f5a844fa700(0000) GS:ffff88885f680000(0000) knlGS:0000000000000000 [1417839.669810] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1417839.682887] CR2: 00007f7884541fe0 CR3: 000000049f609002 CR4: 00000000003606e0 [1417839.699037] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [1417839.715187] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [1417839.731320] Call Trace: [1417839.737103] release_extent_buffer+0x39/0x90 [1417839.746913] read_block_for_search.isra.38+0x2a3/0x370 [1417839.758645] btrfs_search_slot+0x260/0x9b0 [1417839.768054] btrfs_lookup_file_extent+0x4a/0x70 [1417839.778427] btrfs_get_extent+0x15f/0x830 [1417839.787665] ? submit_extent_page+0xc4/0x1c0 [1417839.797474] ? __do_readpage+0x299/0x7a0 [1417839.806515] __do_readpage+0x33b/0x7a0 [1417839.815171] ? btrfs_releasepage+0x70/0x70 [1417839.824597] extent_readpages+0x28f/0x400 [1417839.833836] read_pages+0x6a/0x1c0 [1417839.841729] ? startup_64+0x2/0x30 [1417839.849624] __do_page_cache_readahead+0x13c/0x1a0 [1417839.860590] filemap_fault+0x6c7/0x990 [1417839.869252] ? xas_load+0x8/0x80 [1417839.876756] ? xas_find+0x150/0x190 [1417839.884839] ? filemap_map_pages+0x295/0x3b0 [1417839.894652] __do_fault+0x32/0x110 [1417839.902540] __handle_mm_fault+0xacd/0x1000 [1417839.912156] handle_mm_fault+0xaa/0x1c0 [1417839.921004] __do_page_fault+0x242/0x4b0 [1417839.930044] ? page_fault+0x8/0x30 [1417839.937933] page_fault+0x1e/0x30 [1417839.945631] RIP: 0033:0x33c4bae [1417839.952927] Code: Bad RIP value. [1417839.960411] RSP: 002b:00007f5a844f7350 EFLAGS: 00010206 [1417839.972331] RAX: 000000000000006e RBX: 1614b3ff6a50398a RCX: 0000000000000000 [1417839.988477] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002 [1417840.004626] RBP: 00007f5a844f7420 R08: 000000000000006e R09: 00007f5a94aeccb8 [1417840.020784] R10: 00007f5a844f7350 R11: 0000000000000000 R12: 00007f5a94aecc79 [1417840.036932] R13: 00007f5a94aecc78 R14: 00007f5a94aecc90 R15: 00007f5a94aecc40 CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2020-06-17 18:35:19 +00:00
/*
* The TREE_REF bit is first set when the extent_buffer is added
* to the radix tree. It is also reset, if unset, when a new reference
* is created by find_extent_buffer.
*
btrfs: fix fatal extent_buffer readahead vs releasepage race Under somewhat convoluted conditions, it is possible to attempt to release an extent_buffer that is under io, which triggers a BUG_ON in btrfs_release_extent_buffer_pages. This relies on a few different factors. First, extent_buffer reads done as readahead for searching use WAIT_NONE, so they free the local extent buffer reference while the io is outstanding. However, they should still be protected by TREE_REF. However, if the system is doing signficant reclaim, and simultaneously heavily accessing the extent_buffers, it is possible for releasepage to race with two concurrent readahead attempts in a way that leaves TREE_REF unset when the readahead extent buffer is released. Essentially, if two tasks race to allocate a new extent_buffer, but the winner who attempts the first io is rebuffed by a page being locked (likely by the reclaim itself) then the loser will still go ahead with issuing the readahead. The loser's call to find_extent_buffer must also race with the reclaim task reading the extent_buffer's refcount as 1 in a way that allows the reclaim to re-clear the TREE_REF checked by find_extent_buffer. The following represents an example execution demonstrating the race: CPU0 CPU1 CPU2 reada_for_search reada_for_search readahead_tree_block readahead_tree_block find_create_tree_block find_create_tree_block alloc_extent_buffer alloc_extent_buffer find_extent_buffer // not found allocates eb lock pages associate pages to eb insert eb into radix tree set TREE_REF, refs == 2 unlock pages read_extent_buffer_pages // WAIT_NONE not uptodate (brand new eb) lock_page if !trylock_page goto unlock_exit // not an error free_extent_buffer release_extent_buffer atomic_dec_and_test refs to 1 find_extent_buffer // found try_release_extent_buffer take refs_lock reads refs == 1; no io atomic_inc_not_zero refs to 2 mark_buffer_accessed check_buffer_tree_ref // not STALE, won't take refs_lock refs == 2; TREE_REF set // no action read_extent_buffer_pages // WAIT_NONE clear TREE_REF release_extent_buffer atomic_dec_and_test refs to 1 unlock_page still not uptodate (CPU1 read failed on trylock_page) locks pages set io_pages > 0 submit io return free_extent_buffer release_extent_buffer dec refs to 0 delete from radix tree btrfs_release_extent_buffer_pages BUG_ON(io_pages > 0)!!! We observe this at a very low rate in production and were also able to reproduce it in a test environment by introducing some spurious delays and by introducing probabilistic trylock_page failures. To fix it, we apply check_tree_ref at a point where it could not possibly be unset by a competing task: after io_pages has been incremented. All the codepaths that clear TREE_REF check for io, so they would not be able to clear it after this point until the io is done. Stack trace, for reference: [1417839.424739] ------------[ cut here ]------------ [1417839.435328] kernel BUG at fs/btrfs/extent_io.c:4841! [1417839.447024] invalid opcode: 0000 [#1] SMP [1417839.502972] RIP: 0010:btrfs_release_extent_buffer_pages+0x20/0x1f0 [1417839.517008] Code: ed e9 ... [1417839.558895] RSP: 0018:ffffc90020bcf798 EFLAGS: 00010202 [1417839.570816] RAX: 0000000000000002 RBX: ffff888102d6def0 RCX: 0000000000000028 [1417839.586962] RDX: 0000000000000002 RSI: ffff8887f0296482 RDI: ffff888102d6def0 [1417839.603108] RBP: ffff88885664a000 R08: 0000000000000046 R09: 0000000000000238 [1417839.619255] R10: 0000000000000028 R11: ffff88885664af68 R12: 0000000000000000 [1417839.635402] R13: 0000000000000000 R14: ffff88875f573ad0 R15: ffff888797aafd90 [1417839.651549] FS: 00007f5a844fa700(0000) GS:ffff88885f680000(0000) knlGS:0000000000000000 [1417839.669810] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1417839.682887] CR2: 00007f7884541fe0 CR3: 000000049f609002 CR4: 00000000003606e0 [1417839.699037] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [1417839.715187] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [1417839.731320] Call Trace: [1417839.737103] release_extent_buffer+0x39/0x90 [1417839.746913] read_block_for_search.isra.38+0x2a3/0x370 [1417839.758645] btrfs_search_slot+0x260/0x9b0 [1417839.768054] btrfs_lookup_file_extent+0x4a/0x70 [1417839.778427] btrfs_get_extent+0x15f/0x830 [1417839.787665] ? submit_extent_page+0xc4/0x1c0 [1417839.797474] ? __do_readpage+0x299/0x7a0 [1417839.806515] __do_readpage+0x33b/0x7a0 [1417839.815171] ? btrfs_releasepage+0x70/0x70 [1417839.824597] extent_readpages+0x28f/0x400 [1417839.833836] read_pages+0x6a/0x1c0 [1417839.841729] ? startup_64+0x2/0x30 [1417839.849624] __do_page_cache_readahead+0x13c/0x1a0 [1417839.860590] filemap_fault+0x6c7/0x990 [1417839.869252] ? xas_load+0x8/0x80 [1417839.876756] ? xas_find+0x150/0x190 [1417839.884839] ? filemap_map_pages+0x295/0x3b0 [1417839.894652] __do_fault+0x32/0x110 [1417839.902540] __handle_mm_fault+0xacd/0x1000 [1417839.912156] handle_mm_fault+0xaa/0x1c0 [1417839.921004] __do_page_fault+0x242/0x4b0 [1417839.930044] ? page_fault+0x8/0x30 [1417839.937933] page_fault+0x1e/0x30 [1417839.945631] RIP: 0033:0x33c4bae [1417839.952927] Code: Bad RIP value. [1417839.960411] RSP: 002b:00007f5a844f7350 EFLAGS: 00010206 [1417839.972331] RAX: 000000000000006e RBX: 1614b3ff6a50398a RCX: 0000000000000000 [1417839.988477] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002 [1417840.004626] RBP: 00007f5a844f7420 R08: 000000000000006e R09: 00007f5a94aeccb8 [1417840.020784] R10: 00007f5a844f7350 R11: 0000000000000000 R12: 00007f5a94aecc79 [1417840.036932] R13: 00007f5a94aecc78 R14: 00007f5a94aecc90 R15: 00007f5a94aecc40 CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2020-06-17 18:35:19 +00:00
* It is only cleared in two cases: freeing the last non-tree
* reference to the extent_buffer when its STALE bit is set or
* calling releasepage when the tree reference is the only reference.
*
btrfs: fix fatal extent_buffer readahead vs releasepage race Under somewhat convoluted conditions, it is possible to attempt to release an extent_buffer that is under io, which triggers a BUG_ON in btrfs_release_extent_buffer_pages. This relies on a few different factors. First, extent_buffer reads done as readahead for searching use WAIT_NONE, so they free the local extent buffer reference while the io is outstanding. However, they should still be protected by TREE_REF. However, if the system is doing signficant reclaim, and simultaneously heavily accessing the extent_buffers, it is possible for releasepage to race with two concurrent readahead attempts in a way that leaves TREE_REF unset when the readahead extent buffer is released. Essentially, if two tasks race to allocate a new extent_buffer, but the winner who attempts the first io is rebuffed by a page being locked (likely by the reclaim itself) then the loser will still go ahead with issuing the readahead. The loser's call to find_extent_buffer must also race with the reclaim task reading the extent_buffer's refcount as 1 in a way that allows the reclaim to re-clear the TREE_REF checked by find_extent_buffer. The following represents an example execution demonstrating the race: CPU0 CPU1 CPU2 reada_for_search reada_for_search readahead_tree_block readahead_tree_block find_create_tree_block find_create_tree_block alloc_extent_buffer alloc_extent_buffer find_extent_buffer // not found allocates eb lock pages associate pages to eb insert eb into radix tree set TREE_REF, refs == 2 unlock pages read_extent_buffer_pages // WAIT_NONE not uptodate (brand new eb) lock_page if !trylock_page goto unlock_exit // not an error free_extent_buffer release_extent_buffer atomic_dec_and_test refs to 1 find_extent_buffer // found try_release_extent_buffer take refs_lock reads refs == 1; no io atomic_inc_not_zero refs to 2 mark_buffer_accessed check_buffer_tree_ref // not STALE, won't take refs_lock refs == 2; TREE_REF set // no action read_extent_buffer_pages // WAIT_NONE clear TREE_REF release_extent_buffer atomic_dec_and_test refs to 1 unlock_page still not uptodate (CPU1 read failed on trylock_page) locks pages set io_pages > 0 submit io return free_extent_buffer release_extent_buffer dec refs to 0 delete from radix tree btrfs_release_extent_buffer_pages BUG_ON(io_pages > 0)!!! We observe this at a very low rate in production and were also able to reproduce it in a test environment by introducing some spurious delays and by introducing probabilistic trylock_page failures. To fix it, we apply check_tree_ref at a point where it could not possibly be unset by a competing task: after io_pages has been incremented. All the codepaths that clear TREE_REF check for io, so they would not be able to clear it after this point until the io is done. Stack trace, for reference: [1417839.424739] ------------[ cut here ]------------ [1417839.435328] kernel BUG at fs/btrfs/extent_io.c:4841! [1417839.447024] invalid opcode: 0000 [#1] SMP [1417839.502972] RIP: 0010:btrfs_release_extent_buffer_pages+0x20/0x1f0 [1417839.517008] Code: ed e9 ... [1417839.558895] RSP: 0018:ffffc90020bcf798 EFLAGS: 00010202 [1417839.570816] RAX: 0000000000000002 RBX: ffff888102d6def0 RCX: 0000000000000028 [1417839.586962] RDX: 0000000000000002 RSI: ffff8887f0296482 RDI: ffff888102d6def0 [1417839.603108] RBP: ffff88885664a000 R08: 0000000000000046 R09: 0000000000000238 [1417839.619255] R10: 0000000000000028 R11: ffff88885664af68 R12: 0000000000000000 [1417839.635402] R13: 0000000000000000 R14: ffff88875f573ad0 R15: ffff888797aafd90 [1417839.651549] FS: 00007f5a844fa700(0000) GS:ffff88885f680000(0000) knlGS:0000000000000000 [1417839.669810] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1417839.682887] CR2: 00007f7884541fe0 CR3: 000000049f609002 CR4: 00000000003606e0 [1417839.699037] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [1417839.715187] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [1417839.731320] Call Trace: [1417839.737103] release_extent_buffer+0x39/0x90 [1417839.746913] read_block_for_search.isra.38+0x2a3/0x370 [1417839.758645] btrfs_search_slot+0x260/0x9b0 [1417839.768054] btrfs_lookup_file_extent+0x4a/0x70 [1417839.778427] btrfs_get_extent+0x15f/0x830 [1417839.787665] ? submit_extent_page+0xc4/0x1c0 [1417839.797474] ? __do_readpage+0x299/0x7a0 [1417839.806515] __do_readpage+0x33b/0x7a0 [1417839.815171] ? btrfs_releasepage+0x70/0x70 [1417839.824597] extent_readpages+0x28f/0x400 [1417839.833836] read_pages+0x6a/0x1c0 [1417839.841729] ? startup_64+0x2/0x30 [1417839.849624] __do_page_cache_readahead+0x13c/0x1a0 [1417839.860590] filemap_fault+0x6c7/0x990 [1417839.869252] ? xas_load+0x8/0x80 [1417839.876756] ? xas_find+0x150/0x190 [1417839.884839] ? filemap_map_pages+0x295/0x3b0 [1417839.894652] __do_fault+0x32/0x110 [1417839.902540] __handle_mm_fault+0xacd/0x1000 [1417839.912156] handle_mm_fault+0xaa/0x1c0 [1417839.921004] __do_page_fault+0x242/0x4b0 [1417839.930044] ? page_fault+0x8/0x30 [1417839.937933] page_fault+0x1e/0x30 [1417839.945631] RIP: 0033:0x33c4bae [1417839.952927] Code: Bad RIP value. [1417839.960411] RSP: 002b:00007f5a844f7350 EFLAGS: 00010206 [1417839.972331] RAX: 000000000000006e RBX: 1614b3ff6a50398a RCX: 0000000000000000 [1417839.988477] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002 [1417840.004626] RBP: 00007f5a844f7420 R08: 000000000000006e R09: 00007f5a94aeccb8 [1417840.020784] R10: 00007f5a844f7350 R11: 0000000000000000 R12: 00007f5a94aecc79 [1417840.036932] R13: 00007f5a94aecc78 R14: 00007f5a94aecc90 R15: 00007f5a94aecc40 CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2020-06-17 18:35:19 +00:00
* In both cases, care is taken to ensure that the extent_buffer's
* pages are not under io. However, releasepage can be concurrently
* called with creating new references, which is prone to race
* conditions between the calls to check_buffer_tree_ref in those
* codepaths and clearing TREE_REF in try_release_extent_buffer.
*
btrfs: fix fatal extent_buffer readahead vs releasepage race Under somewhat convoluted conditions, it is possible to attempt to release an extent_buffer that is under io, which triggers a BUG_ON in btrfs_release_extent_buffer_pages. This relies on a few different factors. First, extent_buffer reads done as readahead for searching use WAIT_NONE, so they free the local extent buffer reference while the io is outstanding. However, they should still be protected by TREE_REF. However, if the system is doing signficant reclaim, and simultaneously heavily accessing the extent_buffers, it is possible for releasepage to race with two concurrent readahead attempts in a way that leaves TREE_REF unset when the readahead extent buffer is released. Essentially, if two tasks race to allocate a new extent_buffer, but the winner who attempts the first io is rebuffed by a page being locked (likely by the reclaim itself) then the loser will still go ahead with issuing the readahead. The loser's call to find_extent_buffer must also race with the reclaim task reading the extent_buffer's refcount as 1 in a way that allows the reclaim to re-clear the TREE_REF checked by find_extent_buffer. The following represents an example execution demonstrating the race: CPU0 CPU1 CPU2 reada_for_search reada_for_search readahead_tree_block readahead_tree_block find_create_tree_block find_create_tree_block alloc_extent_buffer alloc_extent_buffer find_extent_buffer // not found allocates eb lock pages associate pages to eb insert eb into radix tree set TREE_REF, refs == 2 unlock pages read_extent_buffer_pages // WAIT_NONE not uptodate (brand new eb) lock_page if !trylock_page goto unlock_exit // not an error free_extent_buffer release_extent_buffer atomic_dec_and_test refs to 1 find_extent_buffer // found try_release_extent_buffer take refs_lock reads refs == 1; no io atomic_inc_not_zero refs to 2 mark_buffer_accessed check_buffer_tree_ref // not STALE, won't take refs_lock refs == 2; TREE_REF set // no action read_extent_buffer_pages // WAIT_NONE clear TREE_REF release_extent_buffer atomic_dec_and_test refs to 1 unlock_page still not uptodate (CPU1 read failed on trylock_page) locks pages set io_pages > 0 submit io return free_extent_buffer release_extent_buffer dec refs to 0 delete from radix tree btrfs_release_extent_buffer_pages BUG_ON(io_pages > 0)!!! We observe this at a very low rate in production and were also able to reproduce it in a test environment by introducing some spurious delays and by introducing probabilistic trylock_page failures. To fix it, we apply check_tree_ref at a point where it could not possibly be unset by a competing task: after io_pages has been incremented. All the codepaths that clear TREE_REF check for io, so they would not be able to clear it after this point until the io is done. Stack trace, for reference: [1417839.424739] ------------[ cut here ]------------ [1417839.435328] kernel BUG at fs/btrfs/extent_io.c:4841! [1417839.447024] invalid opcode: 0000 [#1] SMP [1417839.502972] RIP: 0010:btrfs_release_extent_buffer_pages+0x20/0x1f0 [1417839.517008] Code: ed e9 ... [1417839.558895] RSP: 0018:ffffc90020bcf798 EFLAGS: 00010202 [1417839.570816] RAX: 0000000000000002 RBX: ffff888102d6def0 RCX: 0000000000000028 [1417839.586962] RDX: 0000000000000002 RSI: ffff8887f0296482 RDI: ffff888102d6def0 [1417839.603108] RBP: ffff88885664a000 R08: 0000000000000046 R09: 0000000000000238 [1417839.619255] R10: 0000000000000028 R11: ffff88885664af68 R12: 0000000000000000 [1417839.635402] R13: 0000000000000000 R14: ffff88875f573ad0 R15: ffff888797aafd90 [1417839.651549] FS: 00007f5a844fa700(0000) GS:ffff88885f680000(0000) knlGS:0000000000000000 [1417839.669810] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1417839.682887] CR2: 00007f7884541fe0 CR3: 000000049f609002 CR4: 00000000003606e0 [1417839.699037] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [1417839.715187] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [1417839.731320] Call Trace: [1417839.737103] release_extent_buffer+0x39/0x90 [1417839.746913] read_block_for_search.isra.38+0x2a3/0x370 [1417839.758645] btrfs_search_slot+0x260/0x9b0 [1417839.768054] btrfs_lookup_file_extent+0x4a/0x70 [1417839.778427] btrfs_get_extent+0x15f/0x830 [1417839.787665] ? submit_extent_page+0xc4/0x1c0 [1417839.797474] ? __do_readpage+0x299/0x7a0 [1417839.806515] __do_readpage+0x33b/0x7a0 [1417839.815171] ? btrfs_releasepage+0x70/0x70 [1417839.824597] extent_readpages+0x28f/0x400 [1417839.833836] read_pages+0x6a/0x1c0 [1417839.841729] ? startup_64+0x2/0x30 [1417839.849624] __do_page_cache_readahead+0x13c/0x1a0 [1417839.860590] filemap_fault+0x6c7/0x990 [1417839.869252] ? xas_load+0x8/0x80 [1417839.876756] ? xas_find+0x150/0x190 [1417839.884839] ? filemap_map_pages+0x295/0x3b0 [1417839.894652] __do_fault+0x32/0x110 [1417839.902540] __handle_mm_fault+0xacd/0x1000 [1417839.912156] handle_mm_fault+0xaa/0x1c0 [1417839.921004] __do_page_fault+0x242/0x4b0 [1417839.930044] ? page_fault+0x8/0x30 [1417839.937933] page_fault+0x1e/0x30 [1417839.945631] RIP: 0033:0x33c4bae [1417839.952927] Code: Bad RIP value. [1417839.960411] RSP: 002b:00007f5a844f7350 EFLAGS: 00010206 [1417839.972331] RAX: 000000000000006e RBX: 1614b3ff6a50398a RCX: 0000000000000000 [1417839.988477] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002 [1417840.004626] RBP: 00007f5a844f7420 R08: 000000000000006e R09: 00007f5a94aeccb8 [1417840.020784] R10: 00007f5a844f7350 R11: 0000000000000000 R12: 00007f5a94aecc79 [1417840.036932] R13: 00007f5a94aecc78 R14: 00007f5a94aecc90 R15: 00007f5a94aecc40 CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2020-06-17 18:35:19 +00:00
* The actual lifetime of the extent_buffer in the radix tree is
* adequately protected by the refcount, but the TREE_REF bit and
* its corresponding reference are not. To protect against this
* class of races, we call check_buffer_tree_ref from the codepaths
* which trigger io after they set eb->io_pages. Note that once io is
* initiated, TREE_REF can no longer be cleared, so that is the
* moment at which any such race is best fixed.
*/
refs = atomic_read(&eb->refs);
if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
return;
spin_lock(&eb->refs_lock);
if (!test_and_set_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
atomic_inc(&eb->refs);
spin_unlock(&eb->refs_lock);
}
mm: non-atomically mark page accessed during page cache allocation where possible aops->write_begin may allocate a new page and make it visible only to have mark_page_accessed called almost immediately after. Once the page is visible the atomic operations are necessary which is noticable overhead when writing to an in-memory filesystem like tmpfs but should also be noticable with fast storage. The objective of the patch is to initialse the accessed information with non-atomic operations before the page is visible. The bulk of filesystems directly or indirectly use grab_cache_page_write_begin or find_or_create_page for the initial allocation of a page cache page. This patch adds an init_page_accessed() helper which behaves like the first call to mark_page_accessed() but may called before the page is visible and can be done non-atomically. The primary APIs of concern in this care are the following and are used by most filesystems. find_get_page find_lock_page find_or_create_page grab_cache_page_nowait grab_cache_page_write_begin All of them are very similar in detail to the patch creates a core helper pagecache_get_page() which takes a flags parameter that affects its behavior such as whether the page should be marked accessed or not. Then old API is preserved but is basically a thin wrapper around this core function. Each of the filesystems are then updated to avoid calling mark_page_accessed when it is known that the VM interfaces have already done the job. There is a slight snag in that the timing of the mark_page_accessed() has now changed so in rare cases it's possible a page gets to the end of the LRU as PageReferenced where as previously it might have been repromoted. This is expected to be rare but it's worth the filesystem people thinking about it in case they see a problem with the timing change. It is also the case that some filesystems may be marking pages accessed that previously did not but it makes sense that filesystems have consistent behaviour in this regard. The test case used to evaulate this is a simple dd of a large file done multiple times with the file deleted on each iterations. The size of the file is 1/10th physical memory to avoid dirty page balancing. In the async case it will be possible that the workload completes without even hitting the disk and will have variable results but highlight the impact of mark_page_accessed for async IO. The sync results are expected to be more stable. The exception is tmpfs where the normal case is for the "IO" to not hit the disk. The test machine was single socket and UMA to avoid any scheduling or NUMA artifacts. Throughput and wall times are presented for sync IO, only wall times are shown for async as the granularity reported by dd and the variability is unsuitable for comparison. As async results were variable do to writback timings, I'm only reporting the maximum figures. The sync results were stable enough to make the mean and stddev uninteresting. The performance results are reported based on a run with no profiling. Profile data is based on a separate run with oprofile running. async dd 3.15.0-rc3 3.15.0-rc3 vanilla accessed-v2 ext3 Max elapsed 13.9900 ( 0.00%) 11.5900 ( 17.16%) tmpfs Max elapsed 0.5100 ( 0.00%) 0.4900 ( 3.92%) btrfs Max elapsed 12.8100 ( 0.00%) 12.7800 ( 0.23%) ext4 Max elapsed 18.6000 ( 0.00%) 13.3400 ( 28.28%) xfs Max elapsed 12.5600 ( 0.00%) 2.0900 ( 83.36%) The XFS figure is a bit strange as it managed to avoid a worst case by sheer luck but the average figures looked reasonable. samples percentage ext3 86107 0.9783 vmlinux-3.15.0-rc4-vanilla mark_page_accessed ext3 23833 0.2710 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed ext3 5036 0.0573 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed ext4 64566 0.8961 vmlinux-3.15.0-rc4-vanilla mark_page_accessed ext4 5322 0.0713 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed ext4 2869 0.0384 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed xfs 62126 1.7675 vmlinux-3.15.0-rc4-vanilla mark_page_accessed xfs 1904 0.0554 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed xfs 103 0.0030 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed btrfs 10655 0.1338 vmlinux-3.15.0-rc4-vanilla mark_page_accessed btrfs 2020 0.0273 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed btrfs 587 0.0079 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed tmpfs 59562 3.2628 vmlinux-3.15.0-rc4-vanilla mark_page_accessed tmpfs 1210 0.0696 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed tmpfs 94 0.0054 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed [akpm@linux-foundation.org: don't run init_page_accessed() against an uninitialised pointer] Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Tested-by: Prabhakar Lad <prabhakar.csengg@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 23:10:31 +00:00
static void mark_extent_buffer_accessed(struct extent_buffer *eb,
struct page *accessed)
{
int num_pages, i;
check_buffer_tree_ref(eb);
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
struct page *p = eb->pages[i];
mm: non-atomically mark page accessed during page cache allocation where possible aops->write_begin may allocate a new page and make it visible only to have mark_page_accessed called almost immediately after. Once the page is visible the atomic operations are necessary which is noticable overhead when writing to an in-memory filesystem like tmpfs but should also be noticable with fast storage. The objective of the patch is to initialse the accessed information with non-atomic operations before the page is visible. The bulk of filesystems directly or indirectly use grab_cache_page_write_begin or find_or_create_page for the initial allocation of a page cache page. This patch adds an init_page_accessed() helper which behaves like the first call to mark_page_accessed() but may called before the page is visible and can be done non-atomically. The primary APIs of concern in this care are the following and are used by most filesystems. find_get_page find_lock_page find_or_create_page grab_cache_page_nowait grab_cache_page_write_begin All of them are very similar in detail to the patch creates a core helper pagecache_get_page() which takes a flags parameter that affects its behavior such as whether the page should be marked accessed or not. Then old API is preserved but is basically a thin wrapper around this core function. Each of the filesystems are then updated to avoid calling mark_page_accessed when it is known that the VM interfaces have already done the job. There is a slight snag in that the timing of the mark_page_accessed() has now changed so in rare cases it's possible a page gets to the end of the LRU as PageReferenced where as previously it might have been repromoted. This is expected to be rare but it's worth the filesystem people thinking about it in case they see a problem with the timing change. It is also the case that some filesystems may be marking pages accessed that previously did not but it makes sense that filesystems have consistent behaviour in this regard. The test case used to evaulate this is a simple dd of a large file done multiple times with the file deleted on each iterations. The size of the file is 1/10th physical memory to avoid dirty page balancing. In the async case it will be possible that the workload completes without even hitting the disk and will have variable results but highlight the impact of mark_page_accessed for async IO. The sync results are expected to be more stable. The exception is tmpfs where the normal case is for the "IO" to not hit the disk. The test machine was single socket and UMA to avoid any scheduling or NUMA artifacts. Throughput and wall times are presented for sync IO, only wall times are shown for async as the granularity reported by dd and the variability is unsuitable for comparison. As async results were variable do to writback timings, I'm only reporting the maximum figures. The sync results were stable enough to make the mean and stddev uninteresting. The performance results are reported based on a run with no profiling. Profile data is based on a separate run with oprofile running. async dd 3.15.0-rc3 3.15.0-rc3 vanilla accessed-v2 ext3 Max elapsed 13.9900 ( 0.00%) 11.5900 ( 17.16%) tmpfs Max elapsed 0.5100 ( 0.00%) 0.4900 ( 3.92%) btrfs Max elapsed 12.8100 ( 0.00%) 12.7800 ( 0.23%) ext4 Max elapsed 18.6000 ( 0.00%) 13.3400 ( 28.28%) xfs Max elapsed 12.5600 ( 0.00%) 2.0900 ( 83.36%) The XFS figure is a bit strange as it managed to avoid a worst case by sheer luck but the average figures looked reasonable. samples percentage ext3 86107 0.9783 vmlinux-3.15.0-rc4-vanilla mark_page_accessed ext3 23833 0.2710 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed ext3 5036 0.0573 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed ext4 64566 0.8961 vmlinux-3.15.0-rc4-vanilla mark_page_accessed ext4 5322 0.0713 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed ext4 2869 0.0384 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed xfs 62126 1.7675 vmlinux-3.15.0-rc4-vanilla mark_page_accessed xfs 1904 0.0554 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed xfs 103 0.0030 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed btrfs 10655 0.1338 vmlinux-3.15.0-rc4-vanilla mark_page_accessed btrfs 2020 0.0273 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed btrfs 587 0.0079 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed tmpfs 59562 3.2628 vmlinux-3.15.0-rc4-vanilla mark_page_accessed tmpfs 1210 0.0696 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed tmpfs 94 0.0054 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed [akpm@linux-foundation.org: don't run init_page_accessed() against an uninitialised pointer] Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Tested-by: Prabhakar Lad <prabhakar.csengg@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 23:10:31 +00:00
if (p != accessed)
mark_page_accessed(p);
}
}
struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
u64 start)
{
struct extent_buffer *eb;
rcu_read_lock();
eb = radix_tree_lookup(&fs_info->buffer_radix,
start >> fs_info->sectorsize_bits);
if (eb && atomic_inc_not_zero(&eb->refs)) {
rcu_read_unlock();
Btrfs: fix race when reusing stale extent buffers that leads to BUG_ON There's a race between releasing extent buffers that are flagged as stale and recycling them that makes us it the following BUG_ON at btrfs_release_extent_buffer_page: BUG_ON(extent_buffer_under_io(eb)) The BUG_ON is triggered because the extent buffer has the flag EXTENT_BUFFER_DIRTY set as a consequence of having been reused and made dirty by another concurrent task. Here follows a sequence of steps that leads to the BUG_ON. CPU 0 CPU 1 CPU 2 path->nodes[0] == eb X X->refs == 2 (1 for the tree, 1 for the path) btrfs_header_generation(X) == current trans id flag EXTENT_BUFFER_DIRTY set on X btrfs_release_path(path) unlocks X reads eb X X->refs incremented to 3 locks eb X btrfs_del_items(X) X becomes empty clean_tree_block(X) clear EXTENT_BUFFER_DIRTY from X btrfs_del_leaf(X) unlocks X extent_buffer_get(X) X->refs incremented to 4 btrfs_free_tree_block(X) X's range is not pinned X's range added to free space cache free_extent_buffer_stale(X) lock X->refs_lock set EXTENT_BUFFER_STALE on X release_extent_buffer(X) X->refs decremented to 3 unlocks X->refs_lock btrfs_release_path() unlocks X free_extent_buffer(X) X->refs becomes 2 __btrfs_cow_block(Y) btrfs_alloc_tree_block() btrfs_reserve_extent() find_free_extent() gets offset == X->start btrfs_init_new_buffer(X->start) btrfs_find_create_tree_block(X->start) alloc_extent_buffer(X->start) find_extent_buffer(X->start) finds eb X in radix tree free_extent_buffer(X) lock X->refs_lock test X->refs == 2 test bit EXTENT_BUFFER_STALE is set test !extent_buffer_under_io(eb) increments X->refs to 3 mark_extent_buffer_accessed(X) check_buffer_tree_ref(X) --> does nothing, X->refs >= 2 and EXTENT_BUFFER_TREE_REF is set in X clear EXTENT_BUFFER_STALE from X locks X btrfs_mark_buffer_dirty() set_extent_buffer_dirty(X) check_buffer_tree_ref(X) --> does nothing, X->refs >= 2 and EXTENT_BUFFER_TREE_REF is set sets EXTENT_BUFFER_DIRTY on X test and clear EXTENT_BUFFER_TREE_REF decrements X->refs to 2 release_extent_buffer(X) decrements X->refs to 1 unlock X->refs_lock unlock X free_extent_buffer(X) lock X->refs_lock release_extent_buffer(X) decrements X->refs to 0 btrfs_release_extent_buffer_page(X) BUG_ON(extent_buffer_under_io(X)) --> EXTENT_BUFFER_DIRTY set on X Fix this by making find_extent buffer wait for any ongoing task currently executing free_extent_buffer()/free_extent_buffer_stale() if the extent buffer has the stale flag set. A more clean alternative would be to always increment the extent buffer's reference count while holding its refs_lock spinlock but find_extent_buffer is a performance critical area and that would cause lock contention whenever multiple tasks search for the same extent buffer concurrently. A build server running a SLES 12 kernel (3.12 kernel + over 450 upstream btrfs patches backported from newer kernels) was hitting this often: [1212302.461948] kernel BUG at ../fs/btrfs/extent_io.c:4507! (...) [1212302.470219] CPU: 1 PID: 19259 Comm: bs_sched Not tainted 3.12.36-38-default #1 [1212302.540792] Hardware name: Supermicro PDSM4/PDSM4, BIOS 6.00 04/17/2006 [1212302.540792] task: ffff8800e07e0100 ti: ffff8800d6412000 task.ti: ffff8800d6412000 [1212302.540792] RIP: 0010:[<ffffffffa0507081>] [<ffffffffa0507081>] btrfs_release_extent_buffer_page.constprop.51+0x101/0x110 [btrfs] (...) [1212302.630008] Call Trace: [1212302.630008] [<ffffffffa05070cd>] release_extent_buffer+0x3d/0xa0 [btrfs] [1212302.630008] [<ffffffffa04c2d9d>] btrfs_release_path+0x1d/0xa0 [btrfs] [1212302.630008] [<ffffffffa04c5c7e>] read_block_for_search.isra.33+0x13e/0x3a0 [btrfs] [1212302.630008] [<ffffffffa04c8094>] btrfs_search_slot+0x3f4/0xa80 [btrfs] [1212302.630008] [<ffffffffa04cf5d8>] lookup_inline_extent_backref+0xf8/0x630 [btrfs] [1212302.630008] [<ffffffffa04d13dd>] __btrfs_free_extent+0x11d/0xc40 [btrfs] [1212302.630008] [<ffffffffa04d64a4>] __btrfs_run_delayed_refs+0x394/0x11d0 [btrfs] [1212302.630008] [<ffffffffa04db379>] btrfs_run_delayed_refs.part.66+0x69/0x280 [btrfs] [1212302.630008] [<ffffffffa04ed2ad>] __btrfs_end_transaction+0x2ad/0x3d0 [btrfs] [1212302.630008] [<ffffffffa04f7505>] btrfs_evict_inode+0x4a5/0x500 [btrfs] [1212302.630008] [<ffffffff811b9e28>] evict+0xa8/0x190 [1212302.630008] [<ffffffff811b0330>] do_unlinkat+0x1a0/0x2b0 I was also able to reproduce this on a 3.19 kernel, corresponding to Chris' integration branch from about a month ago, running the following stress test on a qemu/kvm guest (with 4 virtual cpus and 16Gb of ram): while true; do mkfs.btrfs -l 4096 -f -b `expr 20 \* 1024 \* 1024 \* 1024` /dev/sdd mount /dev/sdd /mnt snapshot_cmd="btrfs subvolume snapshot -r /mnt" snapshot_cmd="$snapshot_cmd /mnt/snap_\`date +'%H_%M_%S_%N'\`" fsstress -d /mnt -n 25000 -p 8 -x "$snapshot_cmd" -X 100 umount /mnt done Which usually triggers the BUG_ON within less than 24 hours: [49558.618097] ------------[ cut here ]------------ [49558.619732] kernel BUG at fs/btrfs/extent_io.c:4551! (...) [49558.620031] CPU: 3 PID: 23908 Comm: fsstress Tainted: G W 3.19.0-btrfs-next-7+ #3 [49558.620031] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [49558.620031] task: ffff8800319fc0d0 ti: ffff880220da8000 task.ti: ffff880220da8000 [49558.620031] RIP: 0010:[<ffffffffa0476b1a>] [<ffffffffa0476b1a>] btrfs_release_extent_buffer_page+0x20/0xe9 [btrfs] (...) [49558.620031] Call Trace: [49558.620031] [<ffffffffa0476c73>] release_extent_buffer+0x90/0xd3 [btrfs] [49558.620031] [<ffffffff8142b10c>] ? _raw_spin_lock+0x3b/0x43 [49558.620031] [<ffffffffa0477052>] ? free_extent_buffer+0x37/0x94 [btrfs] [49558.620031] [<ffffffffa04770ab>] free_extent_buffer+0x90/0x94 [btrfs] [49558.620031] [<ffffffffa04396d5>] btrfs_release_path+0x4a/0x69 [btrfs] [49558.620031] [<ffffffffa0444907>] __btrfs_free_extent+0x778/0x80c [btrfs] [49558.620031] [<ffffffffa044a485>] __btrfs_run_delayed_refs+0xad2/0xc62 [btrfs] [49558.728054] [<ffffffff811420d5>] ? kmemleak_alloc_recursive.constprop.52+0x16/0x18 [49558.728054] [<ffffffffa044c1e8>] btrfs_run_delayed_refs+0x6d/0x1ba [btrfs] [49558.728054] [<ffffffffa045917f>] ? join_transaction.isra.9+0xb9/0x36b [btrfs] [49558.728054] [<ffffffffa045a75c>] btrfs_commit_transaction+0x4c/0x981 [btrfs] [49558.728054] [<ffffffffa0434f86>] btrfs_sync_fs+0xd5/0x10d [btrfs] [49558.728054] [<ffffffff81155923>] ? iterate_supers+0x60/0xc4 [49558.728054] [<ffffffff8117966a>] ? do_sync_work+0x91/0x91 [49558.728054] [<ffffffff8117968a>] sync_fs_one_sb+0x20/0x22 [49558.728054] [<ffffffff81155939>] iterate_supers+0x76/0xc4 [49558.728054] [<ffffffff811798e8>] sys_sync+0x55/0x83 [49558.728054] [<ffffffff8142bbd2>] system_call_fastpath+0x12/0x17 Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
2015-04-23 10:28:48 +00:00
/*
* Lock our eb's refs_lock to avoid races with
* free_extent_buffer. When we get our eb it might be flagged
* with EXTENT_BUFFER_STALE and another task running
* free_extent_buffer might have seen that flag set,
* eb->refs == 2, that the buffer isn't under IO (dirty and
* writeback flags not set) and it's still in the tree (flag
* EXTENT_BUFFER_TREE_REF set), therefore being in the process
* of decrementing the extent buffer's reference count twice.
* So here we could race and increment the eb's reference count,
* clear its stale flag, mark it as dirty and drop our reference
* before the other task finishes executing free_extent_buffer,
* which would later result in an attempt to free an extent
* buffer that is dirty.
*/
if (test_bit(EXTENT_BUFFER_STALE, &eb->bflags)) {
spin_lock(&eb->refs_lock);
spin_unlock(&eb->refs_lock);
}
mm: non-atomically mark page accessed during page cache allocation where possible aops->write_begin may allocate a new page and make it visible only to have mark_page_accessed called almost immediately after. Once the page is visible the atomic operations are necessary which is noticable overhead when writing to an in-memory filesystem like tmpfs but should also be noticable with fast storage. The objective of the patch is to initialse the accessed information with non-atomic operations before the page is visible. The bulk of filesystems directly or indirectly use grab_cache_page_write_begin or find_or_create_page for the initial allocation of a page cache page. This patch adds an init_page_accessed() helper which behaves like the first call to mark_page_accessed() but may called before the page is visible and can be done non-atomically. The primary APIs of concern in this care are the following and are used by most filesystems. find_get_page find_lock_page find_or_create_page grab_cache_page_nowait grab_cache_page_write_begin All of them are very similar in detail to the patch creates a core helper pagecache_get_page() which takes a flags parameter that affects its behavior such as whether the page should be marked accessed or not. Then old API is preserved but is basically a thin wrapper around this core function. Each of the filesystems are then updated to avoid calling mark_page_accessed when it is known that the VM interfaces have already done the job. There is a slight snag in that the timing of the mark_page_accessed() has now changed so in rare cases it's possible a page gets to the end of the LRU as PageReferenced where as previously it might have been repromoted. This is expected to be rare but it's worth the filesystem people thinking about it in case they see a problem with the timing change. It is also the case that some filesystems may be marking pages accessed that previously did not but it makes sense that filesystems have consistent behaviour in this regard. The test case used to evaulate this is a simple dd of a large file done multiple times with the file deleted on each iterations. The size of the file is 1/10th physical memory to avoid dirty page balancing. In the async case it will be possible that the workload completes without even hitting the disk and will have variable results but highlight the impact of mark_page_accessed for async IO. The sync results are expected to be more stable. The exception is tmpfs where the normal case is for the "IO" to not hit the disk. The test machine was single socket and UMA to avoid any scheduling or NUMA artifacts. Throughput and wall times are presented for sync IO, only wall times are shown for async as the granularity reported by dd and the variability is unsuitable for comparison. As async results were variable do to writback timings, I'm only reporting the maximum figures. The sync results were stable enough to make the mean and stddev uninteresting. The performance results are reported based on a run with no profiling. Profile data is based on a separate run with oprofile running. async dd 3.15.0-rc3 3.15.0-rc3 vanilla accessed-v2 ext3 Max elapsed 13.9900 ( 0.00%) 11.5900 ( 17.16%) tmpfs Max elapsed 0.5100 ( 0.00%) 0.4900 ( 3.92%) btrfs Max elapsed 12.8100 ( 0.00%) 12.7800 ( 0.23%) ext4 Max elapsed 18.6000 ( 0.00%) 13.3400 ( 28.28%) xfs Max elapsed 12.5600 ( 0.00%) 2.0900 ( 83.36%) The XFS figure is a bit strange as it managed to avoid a worst case by sheer luck but the average figures looked reasonable. samples percentage ext3 86107 0.9783 vmlinux-3.15.0-rc4-vanilla mark_page_accessed ext3 23833 0.2710 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed ext3 5036 0.0573 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed ext4 64566 0.8961 vmlinux-3.15.0-rc4-vanilla mark_page_accessed ext4 5322 0.0713 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed ext4 2869 0.0384 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed xfs 62126 1.7675 vmlinux-3.15.0-rc4-vanilla mark_page_accessed xfs 1904 0.0554 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed xfs 103 0.0030 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed btrfs 10655 0.1338 vmlinux-3.15.0-rc4-vanilla mark_page_accessed btrfs 2020 0.0273 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed btrfs 587 0.0079 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed tmpfs 59562 3.2628 vmlinux-3.15.0-rc4-vanilla mark_page_accessed tmpfs 1210 0.0696 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed tmpfs 94 0.0054 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed [akpm@linux-foundation.org: don't run init_page_accessed() against an uninitialised pointer] Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Tested-by: Prabhakar Lad <prabhakar.csengg@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 23:10:31 +00:00
mark_extent_buffer_accessed(eb, NULL);
return eb;
}
rcu_read_unlock();
return NULL;
}
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
u64 start)
{
struct extent_buffer *eb, *exists = NULL;
int ret;
eb = find_extent_buffer(fs_info, start);
if (eb)
return eb;
eb = alloc_dummy_extent_buffer(fs_info, start);
if (!eb)
return ERR_PTR(-ENOMEM);
eb->fs_info = fs_info;
again:
ret = radix_tree_preload(GFP_NOFS);
if (ret) {
exists = ERR_PTR(ret);
goto free_eb;
}
spin_lock(&fs_info->buffer_lock);
ret = radix_tree_insert(&fs_info->buffer_radix,
start >> fs_info->sectorsize_bits, eb);
spin_unlock(&fs_info->buffer_lock);
radix_tree_preload_end();
if (ret == -EEXIST) {
exists = find_extent_buffer(fs_info, start);
if (exists)
goto free_eb;
else
goto again;
}
check_buffer_tree_ref(eb);
set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
return eb;
free_eb:
btrfs_release_extent_buffer(eb);
return exists;
}
#endif
static struct extent_buffer *grab_extent_buffer(
struct btrfs_fs_info *fs_info, struct page *page)
{
struct extent_buffer *exists;
/*
* For subpage case, we completely rely on radix tree to ensure we
* don't try to insert two ebs for the same bytenr. So here we always
* return NULL and just continue.
*/
if (fs_info->sectorsize < PAGE_SIZE)
return NULL;
/* Page not yet attached to an extent buffer */
if (!PagePrivate(page))
return NULL;
/*
* We could have already allocated an eb for this page and attached one
* so lets see if we can get a ref on the existing eb, and if we can we
* know it's good and we can just return that one, else we know we can
* just overwrite page->private.
*/
exists = (struct extent_buffer *)page->private;
if (atomic_inc_not_zero(&exists->refs))
return exists;
WARN_ON(PageDirty(page));
detach_page_private(page);
return NULL;
}
struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info,
u64 start, u64 owner_root, int level)
{
unsigned long len = fs_info->nodesize;
int num_pages;
int i;
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
unsigned long index = start >> PAGE_SHIFT;
struct extent_buffer *eb;
struct extent_buffer *exists = NULL;
struct page *p;
struct address_space *mapping = fs_info->btree_inode->i_mapping;
int uptodate = 1;
int ret;
if (!IS_ALIGNED(start, fs_info->sectorsize)) {
btrfs_err(fs_info, "bad tree block start %llu", start);
return ERR_PTR(-EINVAL);
}
if (fs_info->sectorsize < PAGE_SIZE &&
offset_in_page(start) + len > PAGE_SIZE) {
btrfs_err(fs_info,
"tree block crosses page boundary, start %llu nodesize %lu",
start, len);
return ERR_PTR(-EINVAL);
}
eb = find_extent_buffer(fs_info, start);
if (eb)
return eb;
eb = __alloc_extent_buffer(fs_info, start, len);
if (!eb)
return ERR_PTR(-ENOMEM);
btrfs: set the lockdep class for extent buffers on creation Both Filipe and Fedora QA recently hit the following lockdep splat: WARNING: possible recursive locking detected 5.10.0-0.rc1.20201028gited8780e3f2ec.57.fc34.x86_64 #1 Not tainted -------------------------------------------- rsync/2610 is trying to acquire lock: ffff89617ed48f20 (&eb->lock){++++}-{2:2}, at: btrfs_tree_read_lock_atomic+0x34/0x140 but task is already holding lock: ffff8961757b1130 (&eb->lock){++++}-{2:2}, at: btrfs_tree_read_lock_atomic+0x34/0x140 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&eb->lock); lock(&eb->lock); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by rsync/2610: #0: ffff896107212b90 (&type->i_mutex_dir_key#10){++++}-{3:3}, at: walk_component+0x10c/0x190 #1: ffff8961757b1130 (&eb->lock){++++}-{2:2}, at: btrfs_tree_read_lock_atomic+0x34/0x140 stack backtrace: CPU: 1 PID: 2610 Comm: rsync Not tainted 5.10.0-0.rc1.20201028gited8780e3f2ec.57.fc34.x86_64 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 Call Trace: dump_stack+0x8b/0xb0 __lock_acquire.cold+0x12d/0x2a4 ? kvm_sched_clock_read+0x14/0x30 ? sched_clock+0x5/0x10 lock_acquire+0xc8/0x400 ? btrfs_tree_read_lock_atomic+0x34/0x140 ? read_block_for_search.isra.0+0xdd/0x320 _raw_read_lock+0x3d/0xa0 ? btrfs_tree_read_lock_atomic+0x34/0x140 btrfs_tree_read_lock_atomic+0x34/0x140 btrfs_search_slot+0x616/0x9a0 btrfs_lookup_dir_item+0x6c/0xb0 btrfs_lookup_dentry+0xa8/0x520 ? lockdep_init_map_waits+0x4c/0x210 btrfs_lookup+0xe/0x30 __lookup_slow+0x10f/0x1e0 walk_component+0x11b/0x190 path_lookupat+0x72/0x1c0 filename_lookup+0x97/0x180 ? strncpy_from_user+0x96/0x1e0 ? getname_flags.part.0+0x45/0x1a0 vfs_statx+0x64/0x100 ? lockdep_hardirqs_on_prepare+0xff/0x180 ? _raw_spin_unlock_irqrestore+0x41/0x50 __do_sys_newlstat+0x26/0x40 ? lockdep_hardirqs_on_prepare+0xff/0x180 ? syscall_enter_from_user_mode+0x27/0x80 ? syscall_enter_from_user_mode+0x27/0x80 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 I have also seen a report of lockdep complaining about the lock class that was looked up being the same as the lock class on the lock we were using, but I can't find the report. These are problems that occur because we do not have the lockdep class set on the extent buffer until _after_ we read the eb in properly. This is problematic for concurrent readers, because we will create the extent buffer, lock it, and then attempt to read the extent buffer. If a second thread comes in and tries to do a search down the same path they'll get the above lockdep splat because the class isn't set properly on the extent buffer. There was a good reason for this, we generally didn't know the real owner of the eb until we read it, specifically in refcounted roots. However now all refcounted roots have the same class name, so we no longer need to worry about this. For non-refcounted trees we know which root we're on based on the parent. Fix this by setting the lockdep class on the eb at creation time instead of read time. This will fix the splat and the weirdness where the class changes in the middle of locking the block. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-05 15:45:21 +00:00
btrfs_set_buffer_lockdep_class(owner_root, eb, level);
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++, index++) {
struct btrfs_subpage *prealloc = NULL;
btrfs: Prevent from early transaction abort Btrfs relies on GFP_NOFS allocation when committing the transaction but this allocation context is rather weak wrt. reclaim capabilities. The page allocator currently tries hard to not fail these allocations if they are small (<=PAGE_ALLOC_COSTLY_ORDER) so this is not a problem currently but there is an attempt to move away from the default no-fail behavior and allow these allocation to fail more eagerly. And this would lead to a pre-mature transaction abort as follows: [ 55.328093] Call Trace: [ 55.328890] [<ffffffff8154e6f0>] dump_stack+0x4f/0x7b [ 55.330518] [<ffffffff8108fa28>] ? console_unlock+0x334/0x363 [ 55.332738] [<ffffffff8110873e>] __alloc_pages_nodemask+0x81d/0x8d4 [ 55.334910] [<ffffffff81100752>] pagecache_get_page+0x10e/0x20c [ 55.336844] [<ffffffffa007d916>] alloc_extent_buffer+0xd0/0x350 [btrfs] [ 55.338973] [<ffffffffa0059d8c>] btrfs_find_create_tree_block+0x15/0x17 [btrfs] [ 55.341329] [<ffffffffa004f728>] btrfs_alloc_tree_block+0x18c/0x405 [btrfs] [ 55.343566] [<ffffffffa003fa34>] split_leaf+0x1e4/0x6a6 [btrfs] [ 55.345577] [<ffffffffa0040567>] btrfs_search_slot+0x671/0x831 [btrfs] [ 55.347679] [<ffffffff810682d7>] ? get_parent_ip+0xe/0x3e [ 55.349434] [<ffffffffa0041cb2>] btrfs_insert_empty_items+0x5d/0xa8 [btrfs] [ 55.351681] [<ffffffffa004ecfb>] __btrfs_run_delayed_refs+0x7a6/0xf35 [btrfs] [ 55.353979] [<ffffffffa00512ea>] btrfs_run_delayed_refs+0x6e/0x226 [btrfs] [ 55.356212] [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs] [ 55.358378] [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs] [ 55.360626] [<ffffffffa0060221>] btrfs_commit_transaction+0x4c/0xaba [btrfs] [ 55.362894] [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs] [ 55.365221] [<ffffffffa0073428>] btrfs_sync_file+0x29c/0x310 [btrfs] [ 55.367273] [<ffffffff81186808>] vfs_fsync_range+0x8f/0x9e [ 55.369047] [<ffffffff81186833>] vfs_fsync+0x1c/0x1e [ 55.370654] [<ffffffff81186869>] do_fsync+0x34/0x4e [ 55.372246] [<ffffffff81186ab3>] SyS_fsync+0x10/0x14 [ 55.373851] [<ffffffff81554f97>] system_call_fastpath+0x12/0x6f [ 55.381070] BTRFS: error (device hdb1) in btrfs_run_delayed_refs:2821: errno=-12 Out of memory [ 55.382431] BTRFS warning (device hdb1): Skipping commit of aborted transaction. [ 55.382433] BTRFS warning (device hdb1): cleanup_transaction:1692: Aborting unused transaction(IO failure). [ 55.384280] ------------[ cut here ]------------ [ 55.384312] WARNING: CPU: 0 PID: 3010 at fs/btrfs/delayed-ref.c:438 btrfs_select_ref_head+0xd9/0xfe [btrfs]() [...] [ 55.384337] Call Trace: [ 55.384353] [<ffffffff8154e6f0>] dump_stack+0x4f/0x7b [ 55.384357] [<ffffffff8107f717>] ? down_trylock+0x2d/0x37 [ 55.384359] [<ffffffff81046977>] warn_slowpath_common+0xa1/0xbb [ 55.384398] [<ffffffffa00a1d6b>] ? btrfs_select_ref_head+0xd9/0xfe [btrfs] [ 55.384400] [<ffffffff81046a34>] warn_slowpath_null+0x1a/0x1c [ 55.384423] [<ffffffffa00a1d6b>] btrfs_select_ref_head+0xd9/0xfe [btrfs] [ 55.384446] [<ffffffffa004e5f7>] ? __btrfs_run_delayed_refs+0xa2/0xf35 [btrfs] [ 55.384455] [<ffffffffa004e600>] __btrfs_run_delayed_refs+0xab/0xf35 [btrfs] [ 55.384476] [<ffffffffa00512ea>] btrfs_run_delayed_refs+0x6e/0x226 [btrfs] [ 55.384499] [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs] [ 55.384521] [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs] [ 55.384543] [<ffffffffa0060221>] btrfs_commit_transaction+0x4c/0xaba [btrfs] [ 55.384565] [<ffffffffa0060e21>] ? start_transaction+0x192/0x534 [btrfs] [ 55.384588] [<ffffffffa0073428>] btrfs_sync_file+0x29c/0x310 [btrfs] [ 55.384591] [<ffffffff81186808>] vfs_fsync_range+0x8f/0x9e [ 55.384592] [<ffffffff81186833>] vfs_fsync+0x1c/0x1e [ 55.384593] [<ffffffff81186869>] do_fsync+0x34/0x4e [ 55.384594] [<ffffffff81186ab3>] SyS_fsync+0x10/0x14 [ 55.384595] [<ffffffff81554f97>] system_call_fastpath+0x12/0x6f [...] [ 55.384608] ---[ end trace c29799da1d4dd621 ]--- [ 55.437323] BTRFS info (device hdb1): forced readonly [ 55.438815] BTRFS info (device hdb1): delayed_refs has NO entry Fix this by being explicit about the no-fail behavior of this allocation path and use __GFP_NOFAIL. Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2015-08-19 12:17:40 +00:00
p = find_or_create_page(mapping, index, GFP_NOFS|__GFP_NOFAIL);
if (!p) {
exists = ERR_PTR(-ENOMEM);
goto free_eb;
}
/*
* Preallocate page->private for subpage case, so that we won't
* allocate memory with private_lock hold. The memory will be
* freed by attach_extent_buffer_page() or freed manually if
* we exit earlier.
*
* Although we have ensured one subpage eb can only have one
* page, but it may change in the future for 16K page size
* support, so we still preallocate the memory in the loop.
*/
ret = btrfs_alloc_subpage(fs_info, &prealloc,
BTRFS_SUBPAGE_METADATA);
if (ret < 0) {
unlock_page(p);
put_page(p);
exists = ERR_PTR(ret);
goto free_eb;
}
spin_lock(&mapping->private_lock);
exists = grab_extent_buffer(fs_info, p);
if (exists) {
spin_unlock(&mapping->private_lock);
unlock_page(p);
put_page(p);
mark_extent_buffer_accessed(exists, p);
btrfs_free_subpage(prealloc);
goto free_eb;
}
/* Should not fail, as we have preallocated the memory */
ret = attach_extent_buffer_page(eb, p, prealloc);
ASSERT(!ret);
btrfs: support subpage for extent buffer page release In btrfs_release_extent_buffer_pages(), we need to add extra handling for subpage. Introduce a helper, detach_extent_buffer_page(), to do different handling for regular and subpage cases. For subpage case, handle detaching page private. For unmapped (dummy or cloned) ebs, we can detach the page private immediately as the page can only be attached to one unmapped eb. For mapped ebs, we have to ensure there are no eb in the page range before we delete it, as page->private is shared between all ebs in the same page. But there is a subpage specific race, where we can race with extent buffer allocation, and clear the page private while new eb is still being utilized, like this: Extent buffer A is the new extent buffer which will be allocated, while extent buffer B is the last existing extent buffer of the page. T1 (eb A) | T2 (eb B) -------------------------------+------------------------------ alloc_extent_buffer() | btrfs_release_extent_buffer_pages() |- p = find_or_create_page() | | |- attach_extent_buffer_page() | | | | |- detach_extent_buffer_page() | | |- if (!page_range_has_eb()) | | | No new eb in the page range yet | | | As new eb A hasn't yet been | | | inserted into radix tree. | | |- btrfs_detach_subpage() | | |- detach_page_private(); |- radix_tree_insert() | Then we have a metadata eb whose page has no private bit. To avoid such race, we introduce a subpage metadata-specific member, btrfs_subpage::eb_refs. In alloc_extent_buffer() we increase eb_refs in the critical section of private_lock. Then page_range_has_eb() will return true for detach_extent_buffer_page(), and will not detach page private. The section is marked by: - btrfs_page_inc_eb_refs() - btrfs_page_dec_eb_refs() Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-26 08:33:50 +00:00
/*
* To inform we have extra eb under allocation, so that
* detach_extent_buffer_page() won't release the page private
* when the eb hasn't yet been inserted into radix tree.
*
* The ref will be decreased when the eb released the page, in
* detach_extent_buffer_page().
* Thus needs no special handling in error path.
*/
btrfs_page_inc_eb_refs(fs_info, p);
spin_unlock(&mapping->private_lock);
WARN_ON(btrfs_page_test_dirty(fs_info, p, eb->start, eb->len));
eb->pages[i] = p;
if (!PageUptodate(p))
uptodate = 0;
/*
* We can't unlock the pages just yet since the extent buffer
* hasn't been properly inserted in the radix tree, this
* opens a race with btree_releasepage which can free a page
* while we are still filling in all pages for the buffer and
* we could crash.
*/
}
if (uptodate)
Btrfs: Change btree locking to use explicit blocking points Most of the btrfs metadata operations can be protected by a spinlock, but some operations still need to schedule. So far, btrfs has been using a mutex along with a trylock loop, most of the time it is able to avoid going for the full mutex, so the trylock loop is a big performance gain. This commit is step one for getting rid of the blocking locks entirely. btrfs_tree_lock takes a spinlock, and the code explicitly switches to a blocking lock when it starts an operation that can schedule. We'll be able get rid of the blocking locks in smaller pieces over time. Tracing allows us to find the most common cause of blocking, so we can start with the hot spots first. The basic idea is: btrfs_tree_lock() returns with the spin lock held btrfs_set_lock_blocking() sets the EXTENT_BUFFER_BLOCKING bit in the extent buffer flags, and then drops the spin lock. The buffer is still considered locked by all of the btrfs code. If btrfs_tree_lock gets the spinlock but finds the blocking bit set, it drops the spin lock and waits on a wait queue for the blocking bit to go away. Much of the code that needs to set the blocking bit finishes without actually blocking a good percentage of the time. So, an adaptive spin is still used against the blocking bit to avoid very high context switch rates. btrfs_clear_lock_blocking() clears the blocking bit and returns with the spinlock held again. btrfs_tree_unlock() can be called on either blocking or spinning locks, it does the right thing based on the blocking bit. ctree.c has a helper function to set/clear all the locked buffers in a path as blocking. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 14:25:08 +00:00
set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
again:
ret = radix_tree_preload(GFP_NOFS);
if (ret) {
exists = ERR_PTR(ret);
goto free_eb;
}
spin_lock(&fs_info->buffer_lock);
ret = radix_tree_insert(&fs_info->buffer_radix,
start >> fs_info->sectorsize_bits, eb);
spin_unlock(&fs_info->buffer_lock);
radix_tree_preload_end();
if (ret == -EEXIST) {
exists = find_extent_buffer(fs_info, start);
if (exists)
goto free_eb;
else
goto again;
}
/* add one reference for the tree */
check_buffer_tree_ref(eb);
set_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags);
/*
* Now it's safe to unlock the pages because any calls to
* btree_releasepage will correctly detect that a page belongs to a
* live buffer and won't free them prematurely.
*/
for (i = 0; i < num_pages; i++)
unlock_page(eb->pages[i]);
return eb;
free_eb:
WARN_ON(!atomic_dec_and_test(&eb->refs));
for (i = 0; i < num_pages; i++) {
if (eb->pages[i])
unlock_page(eb->pages[i]);
}
btrfs_release_extent_buffer(eb);
return exists;
}
static inline void btrfs_release_extent_buffer_rcu(struct rcu_head *head)
{
struct extent_buffer *eb =
container_of(head, struct extent_buffer, rcu_head);
__free_extent_buffer(eb);
}
static int release_extent_buffer(struct extent_buffer *eb)
__releases(&eb->refs_lock)
{
lockdep_assert_held(&eb->refs_lock);
WARN_ON(atomic_read(&eb->refs) == 0);
if (atomic_dec_and_test(&eb->refs)) {
if (test_and_clear_bit(EXTENT_BUFFER_IN_TREE, &eb->bflags)) {
struct btrfs_fs_info *fs_info = eb->fs_info;
spin_unlock(&eb->refs_lock);
spin_lock(&fs_info->buffer_lock);
radix_tree_delete(&fs_info->buffer_radix,
eb->start >> fs_info->sectorsize_bits);
spin_unlock(&fs_info->buffer_lock);
} else {
spin_unlock(&eb->refs_lock);
}
btrfs_leak_debug_del(&eb->fs_info->eb_leak_lock, &eb->leak_list);
/* Should be safe to release our pages at this point */
btrfs_release_extent_buffer_pages(eb);
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
if (unlikely(test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags))) {
__free_extent_buffer(eb);
return 1;
}
#endif
call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
return 1;
}
spin_unlock(&eb->refs_lock);
return 0;
}
void free_extent_buffer(struct extent_buffer *eb)
{
int refs;
int old;
if (!eb)
return;
while (1) {
refs = atomic_read(&eb->refs);
if ((!test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags) && refs <= 3)
|| (test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags) &&
refs == 1))
break;
old = atomic_cmpxchg(&eb->refs, refs, refs - 1);
if (old == refs)
return;
}
spin_lock(&eb->refs_lock);
if (atomic_read(&eb->refs) == 2 &&
test_bit(EXTENT_BUFFER_STALE, &eb->bflags) &&
!extent_buffer_under_io(eb) &&
test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
atomic_dec(&eb->refs);
/*
* I know this is terrible, but it's temporary until we stop tracking
* the uptodate bits and such for the extent buffers.
*/
release_extent_buffer(eb);
}
void free_extent_buffer_stale(struct extent_buffer *eb)
{
if (!eb)
return;
spin_lock(&eb->refs_lock);
set_bit(EXTENT_BUFFER_STALE, &eb->bflags);
if (atomic_read(&eb->refs) == 2 && !extent_buffer_under_io(eb) &&
test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags))
atomic_dec(&eb->refs);
release_extent_buffer(eb);
}
btrfs: make set/clear_extent_buffer_dirty() subpage compatible For set_extent_buffer_dirty() to support subpage sized metadata, just call btrfs_page_set_dirty() to handle both cases. For clear_extent_buffer_dirty(), it needs to clear the page dirty if and only if all extent buffers in the page range are no longer dirty. Also do the same for page error. This is pretty different from the existing clear_extent_buffer_dirty() routine, so add a new helper function, clear_subpage_extent_buffer_dirty() to do this for subpage metadata. Also since the main part of clearing page dirty code is still the same, extract that into btree_clear_page_dirty() so that it can be utilized for both cases. But there is a special race between set_extent_buffer_dirty() and clear_extent_buffer_dirty(), where we can clear the page dirty. [POSSIBLE RACE WINDOW] For the race window between clear_subpage_extent_buffer_dirty() and set_extent_buffer_dirty(), due to the fact that we can't call clear_page_dirty_for_io() under subpage spin lock, we can race like below: T1 (eb1 in the same page) | T2 (eb2 in the same page) -------------------------------+------------------------------ set_extent_buffer_dirty() | clear_extent_buffer_dirty() |- was_dirty = false; | |- clear_subpagE_extent_buffer_dirty() | | |- btrfs_clear_and_test_dirty() | | | Since eb2 is the last dirty page | | | we got: | | | last == true; | | | |- btrfs_page_set_dirty() | | | We set the page dirty and | | | subpage dirty bitmap | | | | |- if (last) | | | Since we don't have subpage lock | | | held, now @last is no longer | | | correct | | |- btree_clear_page_dirty() | | Now PageDirty == false, even if | | we have dirty_bitmap not zero. |- ASSERT(PageDirty()); | ^^^^ CRASH The solution here is to also lock the eb->pages[0] for subpage case of set_extent_buffer_dirty(), to prevent racing with clear_extent_buffer_dirty(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-03-25 07:14:43 +00:00
static void btree_clear_page_dirty(struct page *page)
{
ASSERT(PageDirty(page));
ASSERT(PageLocked(page));
clear_page_dirty_for_io(page);
xa_lock_irq(&page->mapping->i_pages);
if (!PageDirty(page))
__xa_clear_mark(&page->mapping->i_pages,
page_index(page), PAGECACHE_TAG_DIRTY);
xa_unlock_irq(&page->mapping->i_pages);
}
static void clear_subpage_extent_buffer_dirty(const struct extent_buffer *eb)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
struct page *page = eb->pages[0];
bool last;
/* btree_clear_page_dirty() needs page locked */
lock_page(page);
last = btrfs_subpage_clear_and_test_dirty(fs_info, page, eb->start,
eb->len);
if (last)
btree_clear_page_dirty(page);
unlock_page(page);
WARN_ON(atomic_read(&eb->refs) == 0);
}
void clear_extent_buffer_dirty(const struct extent_buffer *eb)
{
int i;
int num_pages;
struct page *page;
btrfs: make set/clear_extent_buffer_dirty() subpage compatible For set_extent_buffer_dirty() to support subpage sized metadata, just call btrfs_page_set_dirty() to handle both cases. For clear_extent_buffer_dirty(), it needs to clear the page dirty if and only if all extent buffers in the page range are no longer dirty. Also do the same for page error. This is pretty different from the existing clear_extent_buffer_dirty() routine, so add a new helper function, clear_subpage_extent_buffer_dirty() to do this for subpage metadata. Also since the main part of clearing page dirty code is still the same, extract that into btree_clear_page_dirty() so that it can be utilized for both cases. But there is a special race between set_extent_buffer_dirty() and clear_extent_buffer_dirty(), where we can clear the page dirty. [POSSIBLE RACE WINDOW] For the race window between clear_subpage_extent_buffer_dirty() and set_extent_buffer_dirty(), due to the fact that we can't call clear_page_dirty_for_io() under subpage spin lock, we can race like below: T1 (eb1 in the same page) | T2 (eb2 in the same page) -------------------------------+------------------------------ set_extent_buffer_dirty() | clear_extent_buffer_dirty() |- was_dirty = false; | |- clear_subpagE_extent_buffer_dirty() | | |- btrfs_clear_and_test_dirty() | | | Since eb2 is the last dirty page | | | we got: | | | last == true; | | | |- btrfs_page_set_dirty() | | | We set the page dirty and | | | subpage dirty bitmap | | | | |- if (last) | | | Since we don't have subpage lock | | | held, now @last is no longer | | | correct | | |- btree_clear_page_dirty() | | Now PageDirty == false, even if | | we have dirty_bitmap not zero. |- ASSERT(PageDirty()); | ^^^^ CRASH The solution here is to also lock the eb->pages[0] for subpage case of set_extent_buffer_dirty(), to prevent racing with clear_extent_buffer_dirty(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-03-25 07:14:43 +00:00
if (eb->fs_info->sectorsize < PAGE_SIZE)
return clear_subpage_extent_buffer_dirty(eb);
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
page = eb->pages[i];
if (!PageDirty(page))
continue;
lock_page(page);
btrfs: make set/clear_extent_buffer_dirty() subpage compatible For set_extent_buffer_dirty() to support subpage sized metadata, just call btrfs_page_set_dirty() to handle both cases. For clear_extent_buffer_dirty(), it needs to clear the page dirty if and only if all extent buffers in the page range are no longer dirty. Also do the same for page error. This is pretty different from the existing clear_extent_buffer_dirty() routine, so add a new helper function, clear_subpage_extent_buffer_dirty() to do this for subpage metadata. Also since the main part of clearing page dirty code is still the same, extract that into btree_clear_page_dirty() so that it can be utilized for both cases. But there is a special race between set_extent_buffer_dirty() and clear_extent_buffer_dirty(), where we can clear the page dirty. [POSSIBLE RACE WINDOW] For the race window between clear_subpage_extent_buffer_dirty() and set_extent_buffer_dirty(), due to the fact that we can't call clear_page_dirty_for_io() under subpage spin lock, we can race like below: T1 (eb1 in the same page) | T2 (eb2 in the same page) -------------------------------+------------------------------ set_extent_buffer_dirty() | clear_extent_buffer_dirty() |- was_dirty = false; | |- clear_subpagE_extent_buffer_dirty() | | |- btrfs_clear_and_test_dirty() | | | Since eb2 is the last dirty page | | | we got: | | | last == true; | | | |- btrfs_page_set_dirty() | | | We set the page dirty and | | | subpage dirty bitmap | | | | |- if (last) | | | Since we don't have subpage lock | | | held, now @last is no longer | | | correct | | |- btree_clear_page_dirty() | | Now PageDirty == false, even if | | we have dirty_bitmap not zero. |- ASSERT(PageDirty()); | ^^^^ CRASH The solution here is to also lock the eb->pages[0] for subpage case of set_extent_buffer_dirty(), to prevent racing with clear_extent_buffer_dirty(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-03-25 07:14:43 +00:00
btree_clear_page_dirty(page);
ClearPageError(page);
unlock_page(page);
}
WARN_ON(atomic_read(&eb->refs) == 0);
}
bool set_extent_buffer_dirty(struct extent_buffer *eb)
{
int i;
int num_pages;
bool was_dirty;
check_buffer_tree_ref(eb);
was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
num_pages = num_extent_pages(eb);
WARN_ON(atomic_read(&eb->refs) == 0);
WARN_ON(!test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags));
btrfs: make set/clear_extent_buffer_dirty() subpage compatible For set_extent_buffer_dirty() to support subpage sized metadata, just call btrfs_page_set_dirty() to handle both cases. For clear_extent_buffer_dirty(), it needs to clear the page dirty if and only if all extent buffers in the page range are no longer dirty. Also do the same for page error. This is pretty different from the existing clear_extent_buffer_dirty() routine, so add a new helper function, clear_subpage_extent_buffer_dirty() to do this for subpage metadata. Also since the main part of clearing page dirty code is still the same, extract that into btree_clear_page_dirty() so that it can be utilized for both cases. But there is a special race between set_extent_buffer_dirty() and clear_extent_buffer_dirty(), where we can clear the page dirty. [POSSIBLE RACE WINDOW] For the race window between clear_subpage_extent_buffer_dirty() and set_extent_buffer_dirty(), due to the fact that we can't call clear_page_dirty_for_io() under subpage spin lock, we can race like below: T1 (eb1 in the same page) | T2 (eb2 in the same page) -------------------------------+------------------------------ set_extent_buffer_dirty() | clear_extent_buffer_dirty() |- was_dirty = false; | |- clear_subpagE_extent_buffer_dirty() | | |- btrfs_clear_and_test_dirty() | | | Since eb2 is the last dirty page | | | we got: | | | last == true; | | | |- btrfs_page_set_dirty() | | | We set the page dirty and | | | subpage dirty bitmap | | | | |- if (last) | | | Since we don't have subpage lock | | | held, now @last is no longer | | | correct | | |- btree_clear_page_dirty() | | Now PageDirty == false, even if | | we have dirty_bitmap not zero. |- ASSERT(PageDirty()); | ^^^^ CRASH The solution here is to also lock the eb->pages[0] for subpage case of set_extent_buffer_dirty(), to prevent racing with clear_extent_buffer_dirty(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-03-25 07:14:43 +00:00
if (!was_dirty) {
bool subpage = eb->fs_info->sectorsize < PAGE_SIZE;
btrfs: make set/clear_extent_buffer_dirty() subpage compatible For set_extent_buffer_dirty() to support subpage sized metadata, just call btrfs_page_set_dirty() to handle both cases. For clear_extent_buffer_dirty(), it needs to clear the page dirty if and only if all extent buffers in the page range are no longer dirty. Also do the same for page error. This is pretty different from the existing clear_extent_buffer_dirty() routine, so add a new helper function, clear_subpage_extent_buffer_dirty() to do this for subpage metadata. Also since the main part of clearing page dirty code is still the same, extract that into btree_clear_page_dirty() so that it can be utilized for both cases. But there is a special race between set_extent_buffer_dirty() and clear_extent_buffer_dirty(), where we can clear the page dirty. [POSSIBLE RACE WINDOW] For the race window between clear_subpage_extent_buffer_dirty() and set_extent_buffer_dirty(), due to the fact that we can't call clear_page_dirty_for_io() under subpage spin lock, we can race like below: T1 (eb1 in the same page) | T2 (eb2 in the same page) -------------------------------+------------------------------ set_extent_buffer_dirty() | clear_extent_buffer_dirty() |- was_dirty = false; | |- clear_subpagE_extent_buffer_dirty() | | |- btrfs_clear_and_test_dirty() | | | Since eb2 is the last dirty page | | | we got: | | | last == true; | | | |- btrfs_page_set_dirty() | | | We set the page dirty and | | | subpage dirty bitmap | | | | |- if (last) | | | Since we don't have subpage lock | | | held, now @last is no longer | | | correct | | |- btree_clear_page_dirty() | | Now PageDirty == false, even if | | we have dirty_bitmap not zero. |- ASSERT(PageDirty()); | ^^^^ CRASH The solution here is to also lock the eb->pages[0] for subpage case of set_extent_buffer_dirty(), to prevent racing with clear_extent_buffer_dirty(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-03-25 07:14:43 +00:00
/*
* For subpage case, we can have other extent buffers in the
* same page, and in clear_subpage_extent_buffer_dirty() we
* have to clear page dirty without subpage lock held.
* This can cause race where our page gets dirty cleared after
* we just set it.
*
* Thankfully, clear_subpage_extent_buffer_dirty() has locked
* its page for other reasons, we can use page lock to prevent
* the above race.
*/
if (subpage)
lock_page(eb->pages[0]);
for (i = 0; i < num_pages; i++)
btrfs_page_set_dirty(eb->fs_info, eb->pages[i],
eb->start, eb->len);
if (subpage)
unlock_page(eb->pages[0]);
}
#ifdef CONFIG_BTRFS_DEBUG
for (i = 0; i < num_pages; i++)
ASSERT(PageDirty(eb->pages[i]));
#endif
return was_dirty;
}
void clear_extent_buffer_uptodate(struct extent_buffer *eb)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
struct page *page;
int num_pages;
int i;
Btrfs: Change btree locking to use explicit blocking points Most of the btrfs metadata operations can be protected by a spinlock, but some operations still need to schedule. So far, btrfs has been using a mutex along with a trylock loop, most of the time it is able to avoid going for the full mutex, so the trylock loop is a big performance gain. This commit is step one for getting rid of the blocking locks entirely. btrfs_tree_lock takes a spinlock, and the code explicitly switches to a blocking lock when it starts an operation that can schedule. We'll be able get rid of the blocking locks in smaller pieces over time. Tracing allows us to find the most common cause of blocking, so we can start with the hot spots first. The basic idea is: btrfs_tree_lock() returns with the spin lock held btrfs_set_lock_blocking() sets the EXTENT_BUFFER_BLOCKING bit in the extent buffer flags, and then drops the spin lock. The buffer is still considered locked by all of the btrfs code. If btrfs_tree_lock gets the spinlock but finds the blocking bit set, it drops the spin lock and waits on a wait queue for the blocking bit to go away. Much of the code that needs to set the blocking bit finishes without actually blocking a good percentage of the time. So, an adaptive spin is still used against the blocking bit to avoid very high context switch rates. btrfs_clear_lock_blocking() clears the blocking bit and returns with the spinlock held again. btrfs_tree_unlock() can be called on either blocking or spinning locks, it does the right thing based on the blocking bit. ctree.c has a helper function to set/clear all the locked buffers in a path as blocking. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 14:25:08 +00:00
clear_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
page = eb->pages[i];
if (page)
btrfs_page_clear_uptodate(fs_info, page,
eb->start, eb->len);
}
}
void set_extent_buffer_uptodate(struct extent_buffer *eb)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
struct page *page;
int num_pages;
int i;
set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
page = eb->pages[i];
btrfs_page_set_uptodate(fs_info, page, eb->start, eb->len);
}
}
static int read_extent_buffer_subpage(struct extent_buffer *eb, int wait,
int mirror_num)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
struct extent_io_tree *io_tree;
struct page *page = eb->pages[0];
struct bio *bio = NULL;
int ret = 0;
ASSERT(!test_bit(EXTENT_BUFFER_UNMAPPED, &eb->bflags));
ASSERT(PagePrivate(page));
io_tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
if (wait == WAIT_NONE) {
ret = try_lock_extent(io_tree, eb->start,
eb->start + eb->len - 1);
if (ret <= 0)
return ret;
} else {
ret = lock_extent(io_tree, eb->start, eb->start + eb->len - 1);
if (ret < 0)
return ret;
}
ret = 0;
if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags) ||
PageUptodate(page) ||
btrfs_subpage_test_uptodate(fs_info, page, eb->start, eb->len)) {
set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
unlock_extent(io_tree, eb->start, eb->start + eb->len - 1);
return ret;
}
clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
eb->read_mirror = 0;
atomic_set(&eb->io_pages, 1);
check_buffer_tree_ref(eb);
btrfs_subpage_clear_error(fs_info, page, eb->start, eb->len);
ret = submit_extent_page(REQ_OP_READ | REQ_META, NULL, page, eb->start,
eb->len, eb->start - page_offset(page), &bio,
end_bio_extent_readpage, mirror_num, 0, 0,
true);
if (ret) {
/*
* In the endio function, if we hit something wrong we will
* increase the io_pages, so here we need to decrease it for
* error path.
*/
atomic_dec(&eb->io_pages);
}
if (bio) {
int tmp;
tmp = submit_one_bio(bio, mirror_num, 0);
if (tmp < 0)
return tmp;
}
if (ret || wait != WAIT_COMPLETE)
return ret;
wait_extent_bit(io_tree, eb->start, eb->start + eb->len - 1, EXTENT_LOCKED);
if (!test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
ret = -EIO;
return ret;
}
int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num)
{
int i;
struct page *page;
int err;
int ret = 0;
int locked_pages = 0;
int all_uptodate = 1;
int num_pages;
unsigned long num_reads = 0;
struct bio *bio = NULL;
Btrfs: Add zlib compression support This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
unsigned long bio_flags = 0;
Btrfs: Change btree locking to use explicit blocking points Most of the btrfs metadata operations can be protected by a spinlock, but some operations still need to schedule. So far, btrfs has been using a mutex along with a trylock loop, most of the time it is able to avoid going for the full mutex, so the trylock loop is a big performance gain. This commit is step one for getting rid of the blocking locks entirely. btrfs_tree_lock takes a spinlock, and the code explicitly switches to a blocking lock when it starts an operation that can schedule. We'll be able get rid of the blocking locks in smaller pieces over time. Tracing allows us to find the most common cause of blocking, so we can start with the hot spots first. The basic idea is: btrfs_tree_lock() returns with the spin lock held btrfs_set_lock_blocking() sets the EXTENT_BUFFER_BLOCKING bit in the extent buffer flags, and then drops the spin lock. The buffer is still considered locked by all of the btrfs code. If btrfs_tree_lock gets the spinlock but finds the blocking bit set, it drops the spin lock and waits on a wait queue for the blocking bit to go away. Much of the code that needs to set the blocking bit finishes without actually blocking a good percentage of the time. So, an adaptive spin is still used against the blocking bit to avoid very high context switch rates. btrfs_clear_lock_blocking() clears the blocking bit and returns with the spinlock held again. btrfs_tree_unlock() can be called on either blocking or spinning locks, it does the right thing based on the blocking bit. ctree.c has a helper function to set/clear all the locked buffers in a path as blocking. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 14:25:08 +00:00
if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
return 0;
if (eb->fs_info->sectorsize < PAGE_SIZE)
return read_extent_buffer_subpage(eb, wait, mirror_num);
num_pages = num_extent_pages(eb);
for (i = 0; i < num_pages; i++) {
page = eb->pages[i];
if (wait == WAIT_NONE) {
/*
* WAIT_NONE is only utilized by readahead. If we can't
* acquire the lock atomically it means either the eb
* is being read out or under modification.
* Either way the eb will be or has been cached,
* readahead can exit safely.
*/
if (!trylock_page(page))
goto unlock_exit;
} else {
lock_page(page);
}
locked_pages++;
Btrfs: fix memory leak in reading btree blocks So we can read a btree block via readahead or intentional read, and we can end up with a memory leak when something happens as follows, 1) readahead starts to read block A but does not wait for read completion, 2) btree_readpage_end_io_hook finds that block A is corrupted, and it needs to clear all block A's pages' uptodate bit. 3) meanwhile an intentional read kicks in and checks block A's pages' uptodate to decide which page needs to be read. 4) when some pages have the uptodate bit during 3)'s check so 3) doesn't count them for eb->io_pages, but they are later cleared by 2) so we has to readpage on the page, we get the wrong eb->io_pages which results in a memory leak of this block. This fixes the problem by firstly getting all pages's locking and then checking pages' uptodate bit. t1(readahead) t2(readahead endio) t3(the following read) read_extent_buffer_pages end_bio_extent_readpage for pg in eb: for page 0,1,2 in eb: if pg is uptodate: btree_readpage_end_io_hook(pg) num_reads++ if uptodate: eb->io_pages = num_reads SetPageUptodate(pg) _______________ for pg in eb: for page 3 in eb: read_extent_buffer_pages if pg is NOT uptodate: btree_readpage_end_io_hook(pg) for pg in eb: __extent_read_full_page(pg) sanity check reports something wrong if pg is uptodate: clear_extent_buffer_uptodate(eb) num_reads++ for pg in eb: eb->io_pages = num_reads ClearPageUptodate(page) _______________ for pg in eb: if pg is NOT uptodate: __extent_read_full_page(pg) So t3's eb->io_pages is not consistent with the number of pages it's reading, and during endio(), atomic_dec_and_test(&eb->io_pages) will get a negative number so that we're not able to free the eb. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-08-03 19:33:01 +00:00
}
/*
* We need to firstly lock all pages to make sure that
* the uptodate bit of our pages won't be affected by
* clear_extent_buffer_uptodate().
*/
for (i = 0; i < num_pages; i++) {
Btrfs: fix memory leak in reading btree blocks So we can read a btree block via readahead or intentional read, and we can end up with a memory leak when something happens as follows, 1) readahead starts to read block A but does not wait for read completion, 2) btree_readpage_end_io_hook finds that block A is corrupted, and it needs to clear all block A's pages' uptodate bit. 3) meanwhile an intentional read kicks in and checks block A's pages' uptodate to decide which page needs to be read. 4) when some pages have the uptodate bit during 3)'s check so 3) doesn't count them for eb->io_pages, but they are later cleared by 2) so we has to readpage on the page, we get the wrong eb->io_pages which results in a memory leak of this block. This fixes the problem by firstly getting all pages's locking and then checking pages' uptodate bit. t1(readahead) t2(readahead endio) t3(the following read) read_extent_buffer_pages end_bio_extent_readpage for pg in eb: for page 0,1,2 in eb: if pg is uptodate: btree_readpage_end_io_hook(pg) num_reads++ if uptodate: eb->io_pages = num_reads SetPageUptodate(pg) _______________ for pg in eb: for page 3 in eb: read_extent_buffer_pages if pg is NOT uptodate: btree_readpage_end_io_hook(pg) for pg in eb: __extent_read_full_page(pg) sanity check reports something wrong if pg is uptodate: clear_extent_buffer_uptodate(eb) num_reads++ for pg in eb: eb->io_pages = num_reads ClearPageUptodate(page) _______________ for pg in eb: if pg is NOT uptodate: __extent_read_full_page(pg) So t3's eb->io_pages is not consistent with the number of pages it's reading, and during endio(), atomic_dec_and_test(&eb->io_pages) will get a negative number so that we're not able to free the eb. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-08-03 19:33:01 +00:00
page = eb->pages[i];
if (!PageUptodate(page)) {
num_reads++;
all_uptodate = 0;
}
}
Btrfs: fix memory leak in reading btree blocks So we can read a btree block via readahead or intentional read, and we can end up with a memory leak when something happens as follows, 1) readahead starts to read block A but does not wait for read completion, 2) btree_readpage_end_io_hook finds that block A is corrupted, and it needs to clear all block A's pages' uptodate bit. 3) meanwhile an intentional read kicks in and checks block A's pages' uptodate to decide which page needs to be read. 4) when some pages have the uptodate bit during 3)'s check so 3) doesn't count them for eb->io_pages, but they are later cleared by 2) so we has to readpage on the page, we get the wrong eb->io_pages which results in a memory leak of this block. This fixes the problem by firstly getting all pages's locking and then checking pages' uptodate bit. t1(readahead) t2(readahead endio) t3(the following read) read_extent_buffer_pages end_bio_extent_readpage for pg in eb: for page 0,1,2 in eb: if pg is uptodate: btree_readpage_end_io_hook(pg) num_reads++ if uptodate: eb->io_pages = num_reads SetPageUptodate(pg) _______________ for pg in eb: for page 3 in eb: read_extent_buffer_pages if pg is NOT uptodate: btree_readpage_end_io_hook(pg) for pg in eb: __extent_read_full_page(pg) sanity check reports something wrong if pg is uptodate: clear_extent_buffer_uptodate(eb) num_reads++ for pg in eb: eb->io_pages = num_reads ClearPageUptodate(page) _______________ for pg in eb: if pg is NOT uptodate: __extent_read_full_page(pg) So t3's eb->io_pages is not consistent with the number of pages it's reading, and during endio(), atomic_dec_and_test(&eb->io_pages) will get a negative number so that we're not able to free the eb. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-08-03 19:33:01 +00:00
if (all_uptodate) {
set_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags);
goto unlock_exit;
}
Btrfs: be aware of btree inode write errors to avoid fs corruption While we have a transaction ongoing, the VM might decide at any time to call btree_inode->i_mapping->a_ops->writepages(), which will start writeback of dirty pages belonging to btree nodes/leafs. This call might return an error or the writeback might finish with an error before we attempt to commit the running transaction. If this happens, we might have no way of knowing that such error happened when we are committing the transaction - because the pages might no longer be marked dirty nor tagged for writeback (if a subsequent modification to the extent buffer didn't happen before the transaction commit) which makes filemap_fdata[write|wait]_range unable to find such pages (even if they're marked with SetPageError). So if this happens we must abort the transaction, otherwise we commit a super block with btree roots that point to btree nodes/leafs whose content on disk is invalid - either garbage or the content of some node/leaf from a past generation that got cowed or deleted and is no longer valid (for this later case we end up getting error messages like "parent transid verify failed on 10826481664 wanted 25748 found 29562" when reading btree nodes/leafs from disk). Note that setting and checking AS_EIO/AS_ENOSPC in the btree inode's i_mapping would not be enough because we need to distinguish between log tree extents (not fatal) vs non-log tree extents (fatal) and because the next call to filemap_fdatawait_range() will catch and clear such errors in the mapping - and that call might be from a log sync and not from a transaction commit, which means we would not know about the error at transaction commit time. Also, checking for the eb flag EXTENT_BUFFER_IOERR at transaction commit time isn't done and would not be completely reliable, as the eb might be removed from memory and read back when trying to get it, which clears that flag right before reading the eb's pages from disk, making us not know about the previous write error. Using the new 3 flags for the btree inode also makes us achieve the goal of AS_EIO/AS_ENOSPC when writepages() returns success, started writeback for all dirty pages and before filemap_fdatawait_range() is called, the writeback for all dirty pages had already finished with errors - because we were not using AS_EIO/AS_ENOSPC, filemap_fdatawait_range() would return success, as it could not know that writeback errors happened (the pages were no longer tagged for writeback). Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-26 11:25:56 +00:00
clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
eb->read_mirror = 0;
atomic_set(&eb->io_pages, num_reads);
btrfs: fix fatal extent_buffer readahead vs releasepage race Under somewhat convoluted conditions, it is possible to attempt to release an extent_buffer that is under io, which triggers a BUG_ON in btrfs_release_extent_buffer_pages. This relies on a few different factors. First, extent_buffer reads done as readahead for searching use WAIT_NONE, so they free the local extent buffer reference while the io is outstanding. However, they should still be protected by TREE_REF. However, if the system is doing signficant reclaim, and simultaneously heavily accessing the extent_buffers, it is possible for releasepage to race with two concurrent readahead attempts in a way that leaves TREE_REF unset when the readahead extent buffer is released. Essentially, if two tasks race to allocate a new extent_buffer, but the winner who attempts the first io is rebuffed by a page being locked (likely by the reclaim itself) then the loser will still go ahead with issuing the readahead. The loser's call to find_extent_buffer must also race with the reclaim task reading the extent_buffer's refcount as 1 in a way that allows the reclaim to re-clear the TREE_REF checked by find_extent_buffer. The following represents an example execution demonstrating the race: CPU0 CPU1 CPU2 reada_for_search reada_for_search readahead_tree_block readahead_tree_block find_create_tree_block find_create_tree_block alloc_extent_buffer alloc_extent_buffer find_extent_buffer // not found allocates eb lock pages associate pages to eb insert eb into radix tree set TREE_REF, refs == 2 unlock pages read_extent_buffer_pages // WAIT_NONE not uptodate (brand new eb) lock_page if !trylock_page goto unlock_exit // not an error free_extent_buffer release_extent_buffer atomic_dec_and_test refs to 1 find_extent_buffer // found try_release_extent_buffer take refs_lock reads refs == 1; no io atomic_inc_not_zero refs to 2 mark_buffer_accessed check_buffer_tree_ref // not STALE, won't take refs_lock refs == 2; TREE_REF set // no action read_extent_buffer_pages // WAIT_NONE clear TREE_REF release_extent_buffer atomic_dec_and_test refs to 1 unlock_page still not uptodate (CPU1 read failed on trylock_page) locks pages set io_pages > 0 submit io return free_extent_buffer release_extent_buffer dec refs to 0 delete from radix tree btrfs_release_extent_buffer_pages BUG_ON(io_pages > 0)!!! We observe this at a very low rate in production and were also able to reproduce it in a test environment by introducing some spurious delays and by introducing probabilistic trylock_page failures. To fix it, we apply check_tree_ref at a point where it could not possibly be unset by a competing task: after io_pages has been incremented. All the codepaths that clear TREE_REF check for io, so they would not be able to clear it after this point until the io is done. Stack trace, for reference: [1417839.424739] ------------[ cut here ]------------ [1417839.435328] kernel BUG at fs/btrfs/extent_io.c:4841! [1417839.447024] invalid opcode: 0000 [#1] SMP [1417839.502972] RIP: 0010:btrfs_release_extent_buffer_pages+0x20/0x1f0 [1417839.517008] Code: ed e9 ... [1417839.558895] RSP: 0018:ffffc90020bcf798 EFLAGS: 00010202 [1417839.570816] RAX: 0000000000000002 RBX: ffff888102d6def0 RCX: 0000000000000028 [1417839.586962] RDX: 0000000000000002 RSI: ffff8887f0296482 RDI: ffff888102d6def0 [1417839.603108] RBP: ffff88885664a000 R08: 0000000000000046 R09: 0000000000000238 [1417839.619255] R10: 0000000000000028 R11: ffff88885664af68 R12: 0000000000000000 [1417839.635402] R13: 0000000000000000 R14: ffff88875f573ad0 R15: ffff888797aafd90 [1417839.651549] FS: 00007f5a844fa700(0000) GS:ffff88885f680000(0000) knlGS:0000000000000000 [1417839.669810] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1417839.682887] CR2: 00007f7884541fe0 CR3: 000000049f609002 CR4: 00000000003606e0 [1417839.699037] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [1417839.715187] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [1417839.731320] Call Trace: [1417839.737103] release_extent_buffer+0x39/0x90 [1417839.746913] read_block_for_search.isra.38+0x2a3/0x370 [1417839.758645] btrfs_search_slot+0x260/0x9b0 [1417839.768054] btrfs_lookup_file_extent+0x4a/0x70 [1417839.778427] btrfs_get_extent+0x15f/0x830 [1417839.787665] ? submit_extent_page+0xc4/0x1c0 [1417839.797474] ? __do_readpage+0x299/0x7a0 [1417839.806515] __do_readpage+0x33b/0x7a0 [1417839.815171] ? btrfs_releasepage+0x70/0x70 [1417839.824597] extent_readpages+0x28f/0x400 [1417839.833836] read_pages+0x6a/0x1c0 [1417839.841729] ? startup_64+0x2/0x30 [1417839.849624] __do_page_cache_readahead+0x13c/0x1a0 [1417839.860590] filemap_fault+0x6c7/0x990 [1417839.869252] ? xas_load+0x8/0x80 [1417839.876756] ? xas_find+0x150/0x190 [1417839.884839] ? filemap_map_pages+0x295/0x3b0 [1417839.894652] __do_fault+0x32/0x110 [1417839.902540] __handle_mm_fault+0xacd/0x1000 [1417839.912156] handle_mm_fault+0xaa/0x1c0 [1417839.921004] __do_page_fault+0x242/0x4b0 [1417839.930044] ? page_fault+0x8/0x30 [1417839.937933] page_fault+0x1e/0x30 [1417839.945631] RIP: 0033:0x33c4bae [1417839.952927] Code: Bad RIP value. [1417839.960411] RSP: 002b:00007f5a844f7350 EFLAGS: 00010206 [1417839.972331] RAX: 000000000000006e RBX: 1614b3ff6a50398a RCX: 0000000000000000 [1417839.988477] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002 [1417840.004626] RBP: 00007f5a844f7420 R08: 000000000000006e R09: 00007f5a94aeccb8 [1417840.020784] R10: 00007f5a844f7350 R11: 0000000000000000 R12: 00007f5a94aecc79 [1417840.036932] R13: 00007f5a94aecc78 R14: 00007f5a94aecc90 R15: 00007f5a94aecc40 CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2020-06-17 18:35:19 +00:00
/*
* It is possible for releasepage to clear the TREE_REF bit before we
* set io_pages. See check_buffer_tree_ref for a more detailed comment.
*/
check_buffer_tree_ref(eb);
for (i = 0; i < num_pages; i++) {
page = eb->pages[i];
if (!PageUptodate(page)) {
if (ret) {
atomic_dec(&eb->io_pages);
unlock_page(page);
continue;
}
ClearPageError(page);
err = submit_extent_page(REQ_OP_READ | REQ_META, NULL,
page, page_offset(page), PAGE_SIZE, 0,
&bio, end_bio_extent_readpage,
mirror_num, 0, 0, false);
if (err) {
/*
* We failed to submit the bio so it's the
* caller's responsibility to perform cleanup
* i.e unlock page/set error bit.
*/
ret = err;
SetPageError(page);
unlock_page(page);
atomic_dec(&eb->io_pages);
}
} else {
unlock_page(page);
}
}
if (bio) {
err = submit_one_bio(bio, mirror_num, bio_flags);
if (err)
return err;
}
if (ret || wait != WAIT_COMPLETE)
return ret;
for (i = 0; i < num_pages; i++) {
page = eb->pages[i];
wait_on_page_locked(page);
if (!PageUptodate(page))
ret = -EIO;
}
return ret;
unlock_exit:
while (locked_pages > 0) {
locked_pages--;
page = eb->pages[locked_pages];
unlock_page(page);
}
return ret;
}
btrfs: extent_io: do extra check for extent buffer read write functions Although we have start, len check for extent buffer reader/write (e.g. read_extent_buffer()), these checks have limitations: - No overflow check Values like start = 1024 len = -1024 can still pass the basic (start + len) > eb->len check. - Checks are not consistent For read_extent_buffer() we only check (start + len) against eb->len. While for memcmp_extent_buffer() we also check start against eb->len. - Different error reporting mechanism We use WARN() in read_extent_buffer() but BUG() in memcpy_extent_buffer(). - Still modify memory if the request is obviously wrong In read_extent_buffer() even we find (start + len) > eb->len, we still call memset(dst, 0, len), which can easily cause memory access error if start + len overflows. To address above problems, this patch creates a new common function to check such access, check_eb_range(). - Add overflow check This function checks start, start + len against eb->len and overflow check. - Unified checks - Unified error reports Will call WARN() if CONFIG_BTRFS_DEBUG is configured. And also do btrfs_warn() message for non-debug build. - Exit ASAP if check fails No more possible memory corruption. - Add extra comment for @start @len used in those functions as it's sometimes confused with the logical addressing instead of a range inside the eb space Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202817 [ Inspired by above report, the report itself is already addressed ] Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ use check_add_overflow ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 06:35:47 +00:00
static bool report_eb_range(const struct extent_buffer *eb, unsigned long start,
unsigned long len)
{
btrfs_warn(eb->fs_info,
"access to eb bytenr %llu len %lu out of range start %lu len %lu",
eb->start, eb->len, start, len);
WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
return true;
}
/*
* Check if the [start, start + len) range is valid before reading/writing
* the eb.
* NOTE: @start and @len are offset inside the eb, not logical address.
*
* Caller should not touch the dst/src memory if this function returns error.
*/
static inline int check_eb_range(const struct extent_buffer *eb,
unsigned long start, unsigned long len)
{
unsigned long offset;
/* start, start + len should not go beyond eb->len nor overflow */
if (unlikely(check_add_overflow(start, len, &offset) || offset > eb->len))
return report_eb_range(eb, start, len);
return false;
}
void read_extent_buffer(const struct extent_buffer *eb, void *dstv,
unsigned long start, unsigned long len)
{
size_t cur;
size_t offset;
struct page *page;
char *kaddr;
char *dst = (char *)dstv;
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
unsigned long i = get_eb_page_index(start);
btrfs: extent_io: do extra check for extent buffer read write functions Although we have start, len check for extent buffer reader/write (e.g. read_extent_buffer()), these checks have limitations: - No overflow check Values like start = 1024 len = -1024 can still pass the basic (start + len) > eb->len check. - Checks are not consistent For read_extent_buffer() we only check (start + len) against eb->len. While for memcmp_extent_buffer() we also check start against eb->len. - Different error reporting mechanism We use WARN() in read_extent_buffer() but BUG() in memcpy_extent_buffer(). - Still modify memory if the request is obviously wrong In read_extent_buffer() even we find (start + len) > eb->len, we still call memset(dst, 0, len), which can easily cause memory access error if start + len overflows. To address above problems, this patch creates a new common function to check such access, check_eb_range(). - Add overflow check This function checks start, start + len against eb->len and overflow check. - Unified checks - Unified error reports Will call WARN() if CONFIG_BTRFS_DEBUG is configured. And also do btrfs_warn() message for non-debug build. - Exit ASAP if check fails No more possible memory corruption. - Add extra comment for @start @len used in those functions as it's sometimes confused with the logical addressing instead of a range inside the eb space Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202817 [ Inspired by above report, the report itself is already addressed ] Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ use check_add_overflow ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 06:35:47 +00:00
if (check_eb_range(eb, start, len))
return;
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
offset = get_eb_offset_in_page(eb, start);
while (len > 0) {
page = eb->pages[i];
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
cur = min(len, (PAGE_SIZE - offset));
kaddr = page_address(page);
memcpy(dst, kaddr + offset, cur);
dst += cur;
len -= cur;
offset = 0;
i++;
}
}
btrfs: fix potential deadlock in the search ioctl With the conversion of the tree locks to rwsem I got the following lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00165-g04ec4da5f45f-dirty #922 Not tainted ------------------------------------------------------ compsize/11122 is trying to acquire lock: ffff889fabca8768 (&mm->mmap_lock#2){++++}-{3:3}, at: __might_fault+0x3e/0x90 but task is already holding lock: ffff889fe720fe40 (btrfs-fs-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (btrfs-fs-00){++++}-{3:3}: down_write_nested+0x3b/0x70 __btrfs_tree_lock+0x24/0x120 btrfs_search_slot+0x756/0x990 btrfs_lookup_inode+0x3a/0xb4 __btrfs_update_delayed_inode+0x93/0x270 btrfs_async_run_delayed_root+0x168/0x230 btrfs_work_helper+0xd4/0x570 process_one_work+0x2ad/0x5f0 worker_thread+0x3a/0x3d0 kthread+0x133/0x150 ret_from_fork+0x1f/0x30 -> #1 (&delayed_node->mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_delayed_update_inode+0x50/0x440 btrfs_update_inode+0x8a/0xf0 btrfs_dirty_inode+0x5b/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&mm->mmap_lock#2){++++}-{3:3}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 copy_to_sk.isra.32+0x121/0x300 search_ioctl+0x106/0x200 btrfs_ioctl_tree_search_v2+0x7b/0xf0 btrfs_ioctl+0x106f/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: &mm->mmap_lock#2 --> &delayed_node->mutex --> btrfs-fs-00 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(btrfs-fs-00); lock(&delayed_node->mutex); lock(btrfs-fs-00); lock(&mm->mmap_lock#2); *** DEADLOCK *** 1 lock held by compsize/11122: #0: ffff889fe720fe40 (btrfs-fs-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 stack backtrace: CPU: 17 PID: 11122 Comm: compsize Kdump: loaded Not tainted 5.8.0-rc7-00165-g04ec4da5f45f-dirty #922 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? __might_fault+0x3e/0x90 ? find_held_lock+0x72/0x90 __might_fault+0x68/0x90 ? __might_fault+0x3e/0x90 _copy_to_user+0x1e/0x80 copy_to_sk.isra.32+0x121/0x300 ? btrfs_search_forward+0x2a6/0x360 search_ioctl+0x106/0x200 btrfs_ioctl_tree_search_v2+0x7b/0xf0 btrfs_ioctl+0x106f/0x30a0 ? __do_sys_newfstat+0x5a/0x70 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The problem is we're doing a copy_to_user() while holding tree locks, which can deadlock if we have to do a page fault for the copy_to_user(). This exists even without my locking changes, so it needs to be fixed. Rework the search ioctl to do the pre-fault and then copy_to_user_nofault for the copying. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 15:42:27 +00:00
int read_extent_buffer_to_user_nofault(const struct extent_buffer *eb,
void __user *dstv,
unsigned long start, unsigned long len)
{
size_t cur;
size_t offset;
struct page *page;
char *kaddr;
char __user *dst = (char __user *)dstv;
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
unsigned long i = get_eb_page_index(start);
int ret = 0;
WARN_ON(start > eb->len);
WARN_ON(start + len > eb->start + eb->len);
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
offset = get_eb_offset_in_page(eb, start);
while (len > 0) {
page = eb->pages[i];
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
cur = min(len, (PAGE_SIZE - offset));
kaddr = page_address(page);
btrfs: fix potential deadlock in the search ioctl With the conversion of the tree locks to rwsem I got the following lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00165-g04ec4da5f45f-dirty #922 Not tainted ------------------------------------------------------ compsize/11122 is trying to acquire lock: ffff889fabca8768 (&mm->mmap_lock#2){++++}-{3:3}, at: __might_fault+0x3e/0x90 but task is already holding lock: ffff889fe720fe40 (btrfs-fs-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (btrfs-fs-00){++++}-{3:3}: down_write_nested+0x3b/0x70 __btrfs_tree_lock+0x24/0x120 btrfs_search_slot+0x756/0x990 btrfs_lookup_inode+0x3a/0xb4 __btrfs_update_delayed_inode+0x93/0x270 btrfs_async_run_delayed_root+0x168/0x230 btrfs_work_helper+0xd4/0x570 process_one_work+0x2ad/0x5f0 worker_thread+0x3a/0x3d0 kthread+0x133/0x150 ret_from_fork+0x1f/0x30 -> #1 (&delayed_node->mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_delayed_update_inode+0x50/0x440 btrfs_update_inode+0x8a/0xf0 btrfs_dirty_inode+0x5b/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&mm->mmap_lock#2){++++}-{3:3}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 copy_to_sk.isra.32+0x121/0x300 search_ioctl+0x106/0x200 btrfs_ioctl_tree_search_v2+0x7b/0xf0 btrfs_ioctl+0x106f/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: &mm->mmap_lock#2 --> &delayed_node->mutex --> btrfs-fs-00 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(btrfs-fs-00); lock(&delayed_node->mutex); lock(btrfs-fs-00); lock(&mm->mmap_lock#2); *** DEADLOCK *** 1 lock held by compsize/11122: #0: ffff889fe720fe40 (btrfs-fs-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 stack backtrace: CPU: 17 PID: 11122 Comm: compsize Kdump: loaded Not tainted 5.8.0-rc7-00165-g04ec4da5f45f-dirty #922 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? __might_fault+0x3e/0x90 ? find_held_lock+0x72/0x90 __might_fault+0x68/0x90 ? __might_fault+0x3e/0x90 _copy_to_user+0x1e/0x80 copy_to_sk.isra.32+0x121/0x300 ? btrfs_search_forward+0x2a6/0x360 search_ioctl+0x106/0x200 btrfs_ioctl_tree_search_v2+0x7b/0xf0 btrfs_ioctl+0x106f/0x30a0 ? __do_sys_newfstat+0x5a/0x70 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The problem is we're doing a copy_to_user() while holding tree locks, which can deadlock if we have to do a page fault for the copy_to_user(). This exists even without my locking changes, so it needs to be fixed. Rework the search ioctl to do the pre-fault and then copy_to_user_nofault for the copying. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 15:42:27 +00:00
if (copy_to_user_nofault(dst, kaddr + offset, cur)) {
ret = -EFAULT;
break;
}
dst += cur;
len -= cur;
offset = 0;
i++;
}
return ret;
}
int memcmp_extent_buffer(const struct extent_buffer *eb, const void *ptrv,
unsigned long start, unsigned long len)
{
size_t cur;
size_t offset;
struct page *page;
char *kaddr;
char *ptr = (char *)ptrv;
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
unsigned long i = get_eb_page_index(start);
int ret = 0;
btrfs: extent_io: do extra check for extent buffer read write functions Although we have start, len check for extent buffer reader/write (e.g. read_extent_buffer()), these checks have limitations: - No overflow check Values like start = 1024 len = -1024 can still pass the basic (start + len) > eb->len check. - Checks are not consistent For read_extent_buffer() we only check (start + len) against eb->len. While for memcmp_extent_buffer() we also check start against eb->len. - Different error reporting mechanism We use WARN() in read_extent_buffer() but BUG() in memcpy_extent_buffer(). - Still modify memory if the request is obviously wrong In read_extent_buffer() even we find (start + len) > eb->len, we still call memset(dst, 0, len), which can easily cause memory access error if start + len overflows. To address above problems, this patch creates a new common function to check such access, check_eb_range(). - Add overflow check This function checks start, start + len against eb->len and overflow check. - Unified checks - Unified error reports Will call WARN() if CONFIG_BTRFS_DEBUG is configured. And also do btrfs_warn() message for non-debug build. - Exit ASAP if check fails No more possible memory corruption. - Add extra comment for @start @len used in those functions as it's sometimes confused with the logical addressing instead of a range inside the eb space Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202817 [ Inspired by above report, the report itself is already addressed ] Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ use check_add_overflow ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 06:35:47 +00:00
if (check_eb_range(eb, start, len))
return -EINVAL;
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
offset = get_eb_offset_in_page(eb, start);
while (len > 0) {
page = eb->pages[i];
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
cur = min(len, (PAGE_SIZE - offset));
kaddr = page_address(page);
ret = memcmp(ptr, kaddr + offset, cur);
if (ret)
break;
ptr += cur;
len -= cur;
offset = 0;
i++;
}
return ret;
}
/*
* Check that the extent buffer is uptodate.
*
* For regular sector size == PAGE_SIZE case, check if @page is uptodate.
* For subpage case, check if the range covered by the eb has EXTENT_UPTODATE.
*/
static void assert_eb_page_uptodate(const struct extent_buffer *eb,
struct page *page)
{
struct btrfs_fs_info *fs_info = eb->fs_info;
if (fs_info->sectorsize < PAGE_SIZE) {
bool uptodate;
uptodate = btrfs_subpage_test_uptodate(fs_info, page,
eb->start, eb->len);
WARN_ON(!uptodate);
} else {
WARN_ON(!PageUptodate(page));
}
}
void write_extent_buffer_chunk_tree_uuid(const struct extent_buffer *eb,
const void *srcv)
{
char *kaddr;
assert_eb_page_uptodate(eb, eb->pages[0]);
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
kaddr = page_address(eb->pages[0]) + get_eb_offset_in_page(eb, 0);
memcpy(kaddr + offsetof(struct btrfs_header, chunk_tree_uuid), srcv,
BTRFS_FSID_SIZE);
}
void write_extent_buffer_fsid(const struct extent_buffer *eb, const void *srcv)
{
char *kaddr;
assert_eb_page_uptodate(eb, eb->pages[0]);
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
kaddr = page_address(eb->pages[0]) + get_eb_offset_in_page(eb, 0);
memcpy(kaddr + offsetof(struct btrfs_header, fsid), srcv,
BTRFS_FSID_SIZE);
}
void write_extent_buffer(const struct extent_buffer *eb, const void *srcv,
unsigned long start, unsigned long len)
{
size_t cur;
size_t offset;
struct page *page;
char *kaddr;
char *src = (char *)srcv;
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
unsigned long i = get_eb_page_index(start);
WARN_ON(test_bit(EXTENT_BUFFER_NO_CHECK, &eb->bflags));
btrfs: extent_io: do extra check for extent buffer read write functions Although we have start, len check for extent buffer reader/write (e.g. read_extent_buffer()), these checks have limitations: - No overflow check Values like start = 1024 len = -1024 can still pass the basic (start + len) > eb->len check. - Checks are not consistent For read_extent_buffer() we only check (start + len) against eb->len. While for memcmp_extent_buffer() we also check start against eb->len. - Different error reporting mechanism We use WARN() in read_extent_buffer() but BUG() in memcpy_extent_buffer(). - Still modify memory if the request is obviously wrong In read_extent_buffer() even we find (start + len) > eb->len, we still call memset(dst, 0, len), which can easily cause memory access error if start + len overflows. To address above problems, this patch creates a new common function to check such access, check_eb_range(). - Add overflow check This function checks start, start + len against eb->len and overflow check. - Unified checks - Unified error reports Will call WARN() if CONFIG_BTRFS_DEBUG is configured. And also do btrfs_warn() message for non-debug build. - Exit ASAP if check fails No more possible memory corruption. - Add extra comment for @start @len used in those functions as it's sometimes confused with the logical addressing instead of a range inside the eb space Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202817 [ Inspired by above report, the report itself is already addressed ] Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ use check_add_overflow ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 06:35:47 +00:00
if (check_eb_range(eb, start, len))
return;
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
offset = get_eb_offset_in_page(eb, start);
while (len > 0) {
page = eb->pages[i];
assert_eb_page_uptodate(eb, page);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
cur = min(len, PAGE_SIZE - offset);
kaddr = page_address(page);
memcpy(kaddr + offset, src, cur);
src += cur;
len -= cur;
offset = 0;
i++;
}
}
void memzero_extent_buffer(const struct extent_buffer *eb, unsigned long start,
unsigned long len)
{
size_t cur;
size_t offset;
struct page *page;
char *kaddr;
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
unsigned long i = get_eb_page_index(start);
btrfs: extent_io: do extra check for extent buffer read write functions Although we have start, len check for extent buffer reader/write (e.g. read_extent_buffer()), these checks have limitations: - No overflow check Values like start = 1024 len = -1024 can still pass the basic (start + len) > eb->len check. - Checks are not consistent For read_extent_buffer() we only check (start + len) against eb->len. While for memcmp_extent_buffer() we also check start against eb->len. - Different error reporting mechanism We use WARN() in read_extent_buffer() but BUG() in memcpy_extent_buffer(). - Still modify memory if the request is obviously wrong In read_extent_buffer() even we find (start + len) > eb->len, we still call memset(dst, 0, len), which can easily cause memory access error if start + len overflows. To address above problems, this patch creates a new common function to check such access, check_eb_range(). - Add overflow check This function checks start, start + len against eb->len and overflow check. - Unified checks - Unified error reports Will call WARN() if CONFIG_BTRFS_DEBUG is configured. And also do btrfs_warn() message for non-debug build. - Exit ASAP if check fails No more possible memory corruption. - Add extra comment for @start @len used in those functions as it's sometimes confused with the logical addressing instead of a range inside the eb space Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202817 [ Inspired by above report, the report itself is already addressed ] Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ use check_add_overflow ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 06:35:47 +00:00
if (check_eb_range(eb, start, len))
return;
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
offset = get_eb_offset_in_page(eb, start);
while (len > 0) {
page = eb->pages[i];
assert_eb_page_uptodate(eb, page);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
cur = min(len, PAGE_SIZE - offset);
kaddr = page_address(page);
memset(kaddr + offset, 0, cur);
len -= cur;
offset = 0;
i++;
}
}
void copy_extent_buffer_full(const struct extent_buffer *dst,
const struct extent_buffer *src)
{
int i;
int num_pages;
ASSERT(dst->len == src->len);
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
if (dst->fs_info->sectorsize == PAGE_SIZE) {
num_pages = num_extent_pages(dst);
for (i = 0; i < num_pages; i++)
copy_page(page_address(dst->pages[i]),
page_address(src->pages[i]));
} else {
size_t src_offset = get_eb_offset_in_page(src, 0);
size_t dst_offset = get_eb_offset_in_page(dst, 0);
ASSERT(src->fs_info->sectorsize < PAGE_SIZE);
memcpy(page_address(dst->pages[0]) + dst_offset,
page_address(src->pages[0]) + src_offset,
src->len);
}
}
void copy_extent_buffer(const struct extent_buffer *dst,
const struct extent_buffer *src,
unsigned long dst_offset, unsigned long src_offset,
unsigned long len)
{
u64 dst_len = dst->len;
size_t cur;
size_t offset;
struct page *page;
char *kaddr;
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
unsigned long i = get_eb_page_index(dst_offset);
btrfs: extent_io: do extra check for extent buffer read write functions Although we have start, len check for extent buffer reader/write (e.g. read_extent_buffer()), these checks have limitations: - No overflow check Values like start = 1024 len = -1024 can still pass the basic (start + len) > eb->len check. - Checks are not consistent For read_extent_buffer() we only check (start + len) against eb->len. While for memcmp_extent_buffer() we also check start against eb->len. - Different error reporting mechanism We use WARN() in read_extent_buffer() but BUG() in memcpy_extent_buffer(). - Still modify memory if the request is obviously wrong In read_extent_buffer() even we find (start + len) > eb->len, we still call memset(dst, 0, len), which can easily cause memory access error if start + len overflows. To address above problems, this patch creates a new common function to check such access, check_eb_range(). - Add overflow check This function checks start, start + len against eb->len and overflow check. - Unified checks - Unified error reports Will call WARN() if CONFIG_BTRFS_DEBUG is configured. And also do btrfs_warn() message for non-debug build. - Exit ASAP if check fails No more possible memory corruption. - Add extra comment for @start @len used in those functions as it's sometimes confused with the logical addressing instead of a range inside the eb space Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202817 [ Inspired by above report, the report itself is already addressed ] Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ use check_add_overflow ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 06:35:47 +00:00
if (check_eb_range(dst, dst_offset, len) ||
check_eb_range(src, src_offset, len))
return;
WARN_ON(src->len != dst_len);
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
offset = get_eb_offset_in_page(dst, dst_offset);
while (len > 0) {
page = dst->pages[i];
assert_eb_page_uptodate(dst, page);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
cur = min(len, (unsigned long)(PAGE_SIZE - offset));
kaddr = page_address(page);
read_extent_buffer(src, kaddr + offset, src_offset, cur);
src_offset += cur;
len -= cur;
offset = 0;
i++;
}
}
/*
* eb_bitmap_offset() - calculate the page and offset of the byte containing the
* given bit number
* @eb: the extent buffer
* @start: offset of the bitmap item in the extent buffer
* @nr: bit number
* @page_index: return index of the page in the extent buffer that contains the
* given bit number
* @page_offset: return offset into the page given by page_index
*
* This helper hides the ugliness of finding the byte in an extent buffer which
* contains a given bit.
*/
static inline void eb_bitmap_offset(const struct extent_buffer *eb,
unsigned long start, unsigned long nr,
unsigned long *page_index,
size_t *page_offset)
{
size_t byte_offset = BIT_BYTE(nr);
size_t offset;
/*
* The byte we want is the offset of the extent buffer + the offset of
* the bitmap item in the extent buffer + the offset of the byte in the
* bitmap item.
*/
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
offset = start + offset_in_page(eb->start) + byte_offset;
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
*page_index = offset >> PAGE_SHIFT;
*page_offset = offset_in_page(offset);
}
/**
* extent_buffer_test_bit - determine whether a bit in a bitmap item is set
* @eb: the extent buffer
* @start: offset of the bitmap item in the extent buffer
* @nr: bit number to test
*/
int extent_buffer_test_bit(const struct extent_buffer *eb, unsigned long start,
unsigned long nr)
{
u8 *kaddr;
struct page *page;
unsigned long i;
size_t offset;
eb_bitmap_offset(eb, start, nr, &i, &offset);
page = eb->pages[i];
assert_eb_page_uptodate(eb, page);
kaddr = page_address(page);
return 1U & (kaddr[offset] >> (nr & (BITS_PER_BYTE - 1)));
}
/**
* extent_buffer_bitmap_set - set an area of a bitmap
* @eb: the extent buffer
* @start: offset of the bitmap item in the extent buffer
* @pos: bit number of the first bit
* @len: number of bits to set
*/
void extent_buffer_bitmap_set(const struct extent_buffer *eb, unsigned long start,
unsigned long pos, unsigned long len)
{
u8 *kaddr;
struct page *page;
unsigned long i;
size_t offset;
const unsigned int size = pos + len;
int bits_to_set = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(pos);
eb_bitmap_offset(eb, start, pos, &i, &offset);
page = eb->pages[i];
assert_eb_page_uptodate(eb, page);
kaddr = page_address(page);
while (len >= bits_to_set) {
kaddr[offset] |= mask_to_set;
len -= bits_to_set;
bits_to_set = BITS_PER_BYTE;
mask_to_set = ~0;
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
if (++offset >= PAGE_SIZE && len > 0) {
offset = 0;
page = eb->pages[++i];
assert_eb_page_uptodate(eb, page);
kaddr = page_address(page);
}
}
if (len) {
mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
kaddr[offset] |= mask_to_set;
}
}
/**
* extent_buffer_bitmap_clear - clear an area of a bitmap
* @eb: the extent buffer
* @start: offset of the bitmap item in the extent buffer
* @pos: bit number of the first bit
* @len: number of bits to clear
*/
void extent_buffer_bitmap_clear(const struct extent_buffer *eb,
unsigned long start, unsigned long pos,
unsigned long len)
{
u8 *kaddr;
struct page *page;
unsigned long i;
size_t offset;
const unsigned int size = pos + len;
int bits_to_clear = BITS_PER_BYTE - (pos % BITS_PER_BYTE);
u8 mask_to_clear = BITMAP_FIRST_BYTE_MASK(pos);
eb_bitmap_offset(eb, start, pos, &i, &offset);
page = eb->pages[i];
assert_eb_page_uptodate(eb, page);
kaddr = page_address(page);
while (len >= bits_to_clear) {
kaddr[offset] &= ~mask_to_clear;
len -= bits_to_clear;
bits_to_clear = BITS_PER_BYTE;
mask_to_clear = ~0;
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
if (++offset >= PAGE_SIZE && len > 0) {
offset = 0;
page = eb->pages[++i];
assert_eb_page_uptodate(eb, page);
kaddr = page_address(page);
}
}
if (len) {
mask_to_clear &= BITMAP_LAST_BYTE_MASK(size);
kaddr[offset] &= ~mask_to_clear;
}
}
btrfs: properly handle overlapping areas in memmove_extent_buffer Fix data corruption caused by memcpy() usage on overlapping data. I've observed it first when found out usermode linux crash on btrfs. ?all chain is the following: ------------[ cut here ]------------ WARNING: at /home/slyfox/linux-2.6/fs/btrfs/extent_io.c:3900 memcpy_extent_buffer+0x1a5/0x219() Call Trace: 6fa39a58: [<601b495e>] _raw_spin_unlock_irqrestore+0x18/0x1c 6fa39a68: [<60029ad9>] warn_slowpath_common+0x59/0x70 6fa39aa8: [<60029b05>] warn_slowpath_null+0x15/0x17 6fa39ab8: [<600efc97>] memcpy_extent_buffer+0x1a5/0x219 6fa39b48: [<600efd9f>] memmove_extent_buffer+0x94/0x208 6fa39bc8: [<600becbf>] btrfs_del_items+0x214/0x473 6fa39c78: [<600ce1b0>] btrfs_delete_one_dir_name+0x7c/0xda 6fa39cc8: [<600dad6b>] __btrfs_unlink_inode+0xad/0x25d 6fa39d08: [<600d7864>] btrfs_start_transaction+0xe/0x10 6fa39d48: [<600dc9ff>] btrfs_unlink_inode+0x1b/0x3b 6fa39d78: [<600e04bc>] btrfs_unlink+0x70/0xef 6fa39dc8: [<6007f0d0>] vfs_unlink+0x58/0xa3 6fa39df8: [<60080278>] do_unlinkat+0xd4/0x162 6fa39e48: [<600517db>] call_rcu_sched+0xe/0x10 6fa39e58: [<600452a8>] __put_cred+0x58/0x5a 6fa39e78: [<6007446c>] sys_faccessat+0x154/0x166 6fa39ed8: [<60080317>] sys_unlink+0x11/0x13 6fa39ee8: [<60016b80>] handle_syscall+0x58/0x70 6fa39f08: [<60021377>] userspace+0x2d4/0x381 6fa39fc8: [<60014507>] fork_handler+0x62/0x69 ---[ end trace 70b0ca2ef0266b93 ]--- http://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg09302.html Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> Reviewed-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-04-11 21:52:52 +00:00
static inline bool areas_overlap(unsigned long src, unsigned long dst, unsigned long len)
{
unsigned long distance = (src > dst) ? src - dst : dst - src;
return distance < len;
}
static void copy_pages(struct page *dst_page, struct page *src_page,
unsigned long dst_off, unsigned long src_off,
unsigned long len)
{
char *dst_kaddr = page_address(dst_page);
char *src_kaddr;
int must_memmove = 0;
btrfs: properly handle overlapping areas in memmove_extent_buffer Fix data corruption caused by memcpy() usage on overlapping data. I've observed it first when found out usermode linux crash on btrfs. ?all chain is the following: ------------[ cut here ]------------ WARNING: at /home/slyfox/linux-2.6/fs/btrfs/extent_io.c:3900 memcpy_extent_buffer+0x1a5/0x219() Call Trace: 6fa39a58: [<601b495e>] _raw_spin_unlock_irqrestore+0x18/0x1c 6fa39a68: [<60029ad9>] warn_slowpath_common+0x59/0x70 6fa39aa8: [<60029b05>] warn_slowpath_null+0x15/0x17 6fa39ab8: [<600efc97>] memcpy_extent_buffer+0x1a5/0x219 6fa39b48: [<600efd9f>] memmove_extent_buffer+0x94/0x208 6fa39bc8: [<600becbf>] btrfs_del_items+0x214/0x473 6fa39c78: [<600ce1b0>] btrfs_delete_one_dir_name+0x7c/0xda 6fa39cc8: [<600dad6b>] __btrfs_unlink_inode+0xad/0x25d 6fa39d08: [<600d7864>] btrfs_start_transaction+0xe/0x10 6fa39d48: [<600dc9ff>] btrfs_unlink_inode+0x1b/0x3b 6fa39d78: [<600e04bc>] btrfs_unlink+0x70/0xef 6fa39dc8: [<6007f0d0>] vfs_unlink+0x58/0xa3 6fa39df8: [<60080278>] do_unlinkat+0xd4/0x162 6fa39e48: [<600517db>] call_rcu_sched+0xe/0x10 6fa39e58: [<600452a8>] __put_cred+0x58/0x5a 6fa39e78: [<6007446c>] sys_faccessat+0x154/0x166 6fa39ed8: [<60080317>] sys_unlink+0x11/0x13 6fa39ee8: [<60016b80>] handle_syscall+0x58/0x70 6fa39f08: [<60021377>] userspace+0x2d4/0x381 6fa39fc8: [<60014507>] fork_handler+0x62/0x69 ---[ end trace 70b0ca2ef0266b93 ]--- http://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg09302.html Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> Reviewed-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-04-11 21:52:52 +00:00
if (dst_page != src_page) {
src_kaddr = page_address(src_page);
btrfs: properly handle overlapping areas in memmove_extent_buffer Fix data corruption caused by memcpy() usage on overlapping data. I've observed it first when found out usermode linux crash on btrfs. ?all chain is the following: ------------[ cut here ]------------ WARNING: at /home/slyfox/linux-2.6/fs/btrfs/extent_io.c:3900 memcpy_extent_buffer+0x1a5/0x219() Call Trace: 6fa39a58: [<601b495e>] _raw_spin_unlock_irqrestore+0x18/0x1c 6fa39a68: [<60029ad9>] warn_slowpath_common+0x59/0x70 6fa39aa8: [<60029b05>] warn_slowpath_null+0x15/0x17 6fa39ab8: [<600efc97>] memcpy_extent_buffer+0x1a5/0x219 6fa39b48: [<600efd9f>] memmove_extent_buffer+0x94/0x208 6fa39bc8: [<600becbf>] btrfs_del_items+0x214/0x473 6fa39c78: [<600ce1b0>] btrfs_delete_one_dir_name+0x7c/0xda 6fa39cc8: [<600dad6b>] __btrfs_unlink_inode+0xad/0x25d 6fa39d08: [<600d7864>] btrfs_start_transaction+0xe/0x10 6fa39d48: [<600dc9ff>] btrfs_unlink_inode+0x1b/0x3b 6fa39d78: [<600e04bc>] btrfs_unlink+0x70/0xef 6fa39dc8: [<6007f0d0>] vfs_unlink+0x58/0xa3 6fa39df8: [<60080278>] do_unlinkat+0xd4/0x162 6fa39e48: [<600517db>] call_rcu_sched+0xe/0x10 6fa39e58: [<600452a8>] __put_cred+0x58/0x5a 6fa39e78: [<6007446c>] sys_faccessat+0x154/0x166 6fa39ed8: [<60080317>] sys_unlink+0x11/0x13 6fa39ee8: [<60016b80>] handle_syscall+0x58/0x70 6fa39f08: [<60021377>] userspace+0x2d4/0x381 6fa39fc8: [<60014507>] fork_handler+0x62/0x69 ---[ end trace 70b0ca2ef0266b93 ]--- http://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg09302.html Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> Reviewed-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-04-11 21:52:52 +00:00
} else {
src_kaddr = dst_kaddr;
if (areas_overlap(src_off, dst_off, len))
must_memmove = 1;
btrfs: properly handle overlapping areas in memmove_extent_buffer Fix data corruption caused by memcpy() usage on overlapping data. I've observed it first when found out usermode linux crash on btrfs. ?all chain is the following: ------------[ cut here ]------------ WARNING: at /home/slyfox/linux-2.6/fs/btrfs/extent_io.c:3900 memcpy_extent_buffer+0x1a5/0x219() Call Trace: 6fa39a58: [<601b495e>] _raw_spin_unlock_irqrestore+0x18/0x1c 6fa39a68: [<60029ad9>] warn_slowpath_common+0x59/0x70 6fa39aa8: [<60029b05>] warn_slowpath_null+0x15/0x17 6fa39ab8: [<600efc97>] memcpy_extent_buffer+0x1a5/0x219 6fa39b48: [<600efd9f>] memmove_extent_buffer+0x94/0x208 6fa39bc8: [<600becbf>] btrfs_del_items+0x214/0x473 6fa39c78: [<600ce1b0>] btrfs_delete_one_dir_name+0x7c/0xda 6fa39cc8: [<600dad6b>] __btrfs_unlink_inode+0xad/0x25d 6fa39d08: [<600d7864>] btrfs_start_transaction+0xe/0x10 6fa39d48: [<600dc9ff>] btrfs_unlink_inode+0x1b/0x3b 6fa39d78: [<600e04bc>] btrfs_unlink+0x70/0xef 6fa39dc8: [<6007f0d0>] vfs_unlink+0x58/0xa3 6fa39df8: [<60080278>] do_unlinkat+0xd4/0x162 6fa39e48: [<600517db>] call_rcu_sched+0xe/0x10 6fa39e58: [<600452a8>] __put_cred+0x58/0x5a 6fa39e78: [<6007446c>] sys_faccessat+0x154/0x166 6fa39ed8: [<60080317>] sys_unlink+0x11/0x13 6fa39ee8: [<60016b80>] handle_syscall+0x58/0x70 6fa39f08: [<60021377>] userspace+0x2d4/0x381 6fa39fc8: [<60014507>] fork_handler+0x62/0x69 ---[ end trace 70b0ca2ef0266b93 ]--- http://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg09302.html Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> Reviewed-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2011-04-11 21:52:52 +00:00
}
if (must_memmove)
memmove(dst_kaddr + dst_off, src_kaddr + src_off, len);
else
memcpy(dst_kaddr + dst_off, src_kaddr + src_off, len);
}
void memcpy_extent_buffer(const struct extent_buffer *dst,
unsigned long dst_offset, unsigned long src_offset,
unsigned long len)
{
size_t cur;
size_t dst_off_in_page;
size_t src_off_in_page;
unsigned long dst_i;
unsigned long src_i;
btrfs: extent_io: do extra check for extent buffer read write functions Although we have start, len check for extent buffer reader/write (e.g. read_extent_buffer()), these checks have limitations: - No overflow check Values like start = 1024 len = -1024 can still pass the basic (start + len) > eb->len check. - Checks are not consistent For read_extent_buffer() we only check (start + len) against eb->len. While for memcmp_extent_buffer() we also check start against eb->len. - Different error reporting mechanism We use WARN() in read_extent_buffer() but BUG() in memcpy_extent_buffer(). - Still modify memory if the request is obviously wrong In read_extent_buffer() even we find (start + len) > eb->len, we still call memset(dst, 0, len), which can easily cause memory access error if start + len overflows. To address above problems, this patch creates a new common function to check such access, check_eb_range(). - Add overflow check This function checks start, start + len against eb->len and overflow check. - Unified checks - Unified error reports Will call WARN() if CONFIG_BTRFS_DEBUG is configured. And also do btrfs_warn() message for non-debug build. - Exit ASAP if check fails No more possible memory corruption. - Add extra comment for @start @len used in those functions as it's sometimes confused with the logical addressing instead of a range inside the eb space Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202817 [ Inspired by above report, the report itself is already addressed ] Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ use check_add_overflow ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 06:35:47 +00:00
if (check_eb_range(dst, dst_offset, len) ||
check_eb_range(dst, src_offset, len))
return;
while (len > 0) {
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
dst_off_in_page = get_eb_offset_in_page(dst, dst_offset);
src_off_in_page = get_eb_offset_in_page(dst, src_offset);
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
dst_i = get_eb_page_index(dst_offset);
src_i = get_eb_page_index(src_offset);
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
cur = min(len, (unsigned long)(PAGE_SIZE -
src_off_in_page));
cur = min_t(unsigned long, cur,
mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-01 12:29:47 +00:00
(unsigned long)(PAGE_SIZE - dst_off_in_page));
copy_pages(dst->pages[dst_i], dst->pages[src_i],
dst_off_in_page, src_off_in_page, cur);
src_offset += cur;
dst_offset += cur;
len -= cur;
}
}
void memmove_extent_buffer(const struct extent_buffer *dst,
unsigned long dst_offset, unsigned long src_offset,
unsigned long len)
{
size_t cur;
size_t dst_off_in_page;
size_t src_off_in_page;
unsigned long dst_end = dst_offset + len - 1;
unsigned long src_end = src_offset + len - 1;
unsigned long dst_i;
unsigned long src_i;
btrfs: extent_io: do extra check for extent buffer read write functions Although we have start, len check for extent buffer reader/write (e.g. read_extent_buffer()), these checks have limitations: - No overflow check Values like start = 1024 len = -1024 can still pass the basic (start + len) > eb->len check. - Checks are not consistent For read_extent_buffer() we only check (start + len) against eb->len. While for memcmp_extent_buffer() we also check start against eb->len. - Different error reporting mechanism We use WARN() in read_extent_buffer() but BUG() in memcpy_extent_buffer(). - Still modify memory if the request is obviously wrong In read_extent_buffer() even we find (start + len) > eb->len, we still call memset(dst, 0, len), which can easily cause memory access error if start + len overflows. To address above problems, this patch creates a new common function to check such access, check_eb_range(). - Add overflow check This function checks start, start + len against eb->len and overflow check. - Unified checks - Unified error reports Will call WARN() if CONFIG_BTRFS_DEBUG is configured. And also do btrfs_warn() message for non-debug build. - Exit ASAP if check fails No more possible memory corruption. - Add extra comment for @start @len used in those functions as it's sometimes confused with the logical addressing instead of a range inside the eb space Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202817 [ Inspired by above report, the report itself is already addressed ] Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ use check_add_overflow ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 06:35:47 +00:00
if (check_eb_range(dst, dst_offset, len) ||
check_eb_range(dst, src_offset, len))
return;
if (dst_offset < src_offset) {
memcpy_extent_buffer(dst, dst_offset, src_offset, len);
return;
}
while (len > 0) {
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
dst_i = get_eb_page_index(dst_end);
src_i = get_eb_page_index(src_end);
btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors To support sectorsize < PAGE_SIZE case, we need to take extra care of extent buffer accessors. Since sectorsize is smaller than PAGE_SIZE, one page can contain multiple tree blocks, we must use eb->start to determine the real offset to read/write for extent buffer accessors. This patch introduces two helpers to do this: - get_eb_page_index() This is to calculate the index to access extent_buffer::pages. It's just a simple wrapper around "start >> PAGE_SHIFT". For sectorsize == PAGE_SIZE case, nothing is changed. For sectorsize < PAGE_SIZE case, we always get index as 0, and the existing page shift also works. - get_eb_offset_in_page() This is to calculate the offset to access extent_buffer::pages. This needs to take extent_buffer::start into consideration. For sectorsize == PAGE_SIZE case, extent_buffer::start is always aligned to PAGE_SIZE, thus adding extent_buffer::start to offset_in_page() won't change the result. For sectorsize < PAGE_SIZE case, adding extent_buffer::start gives us the correct offset to access. This patch will touch the following parts to cover all extent buffer accessors: - BTRFS_SETGET_HEADER_FUNCS() - read_extent_buffer() - read_extent_buffer_to_user() - memcmp_extent_buffer() - write_extent_buffer_chunk_tree_uuid() - write_extent_buffer_fsid() - write_extent_buffer() - memzero_extent_buffer() - copy_extent_buffer_full() - copy_extent_buffer() - memcpy_extent_buffer() - memmove_extent_buffer() - btrfs_get_token_##bits() - btrfs_get_##bits() - btrfs_set_token_##bits() - btrfs_set_##bits() - generic_bin_search() Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-02 06:48:04 +00:00
dst_off_in_page = get_eb_offset_in_page(dst, dst_end);
src_off_in_page = get_eb_offset_in_page(dst, src_end);
cur = min_t(unsigned long, len, src_off_in_page + 1);
cur = min(cur, dst_off_in_page + 1);
copy_pages(dst->pages[dst_i], dst->pages[src_i],
dst_off_in_page - cur + 1,
src_off_in_page - cur + 1, cur);
dst_end -= cur;
src_end -= cur;
len -= cur;
}
}
static struct extent_buffer *get_next_extent_buffer(
struct btrfs_fs_info *fs_info, struct page *page, u64 bytenr)
{
struct extent_buffer *gang[BTRFS_SUBPAGE_BITMAP_SIZE];
struct extent_buffer *found = NULL;
u64 page_start = page_offset(page);
int ret;
int i;
ASSERT(in_range(bytenr, page_start, PAGE_SIZE));
ASSERT(PAGE_SIZE / fs_info->nodesize <= BTRFS_SUBPAGE_BITMAP_SIZE);
lockdep_assert_held(&fs_info->buffer_lock);
ret = radix_tree_gang_lookup(&fs_info->buffer_radix, (void **)gang,
bytenr >> fs_info->sectorsize_bits,
PAGE_SIZE / fs_info->nodesize);
for (i = 0; i < ret; i++) {
/* Already beyond page end */
if (gang[i]->start >= page_start + PAGE_SIZE)
break;
/* Found one */
if (gang[i]->start >= bytenr) {
found = gang[i];
break;
}
}
return found;
}
static int try_release_subpage_extent_buffer(struct page *page)
{
struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
u64 cur = page_offset(page);
const u64 end = page_offset(page) + PAGE_SIZE;
int ret;
while (cur < end) {
struct extent_buffer *eb = NULL;
/*
* Unlike try_release_extent_buffer() which uses page->private
* to grab buffer, for subpage case we rely on radix tree, thus
* we need to ensure radix tree consistency.
*
* We also want an atomic snapshot of the radix tree, thus go
* with spinlock rather than RCU.
*/
spin_lock(&fs_info->buffer_lock);
eb = get_next_extent_buffer(fs_info, page, cur);
if (!eb) {
/* No more eb in the page range after or at cur */
spin_unlock(&fs_info->buffer_lock);
break;
}
cur = eb->start + eb->len;
/*
* The same as try_release_extent_buffer(), to ensure the eb
* won't disappear out from under us.
*/
spin_lock(&eb->refs_lock);
if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
spin_unlock(&eb->refs_lock);
spin_unlock(&fs_info->buffer_lock);
break;
}
spin_unlock(&fs_info->buffer_lock);
/*
* If tree ref isn't set then we know the ref on this eb is a
* real ref, so just return, this eb will likely be freed soon
* anyway.
*/
if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
spin_unlock(&eb->refs_lock);
break;
}
/*
* Here we don't care about the return value, we will always
* check the page private at the end. And
* release_extent_buffer() will release the refs_lock.
*/
release_extent_buffer(eb);
}
/*
* Finally to check if we have cleared page private, as if we have
* released all ebs in the page, the page private should be cleared now.
*/
spin_lock(&page->mapping->private_lock);
if (!PagePrivate(page))
ret = 1;
else
ret = 0;
spin_unlock(&page->mapping->private_lock);
return ret;
}
int try_release_extent_buffer(struct page *page)
{
struct extent_buffer *eb;
if (btrfs_sb(page->mapping->host->i_sb)->sectorsize < PAGE_SIZE)
return try_release_subpage_extent_buffer(page);
/*
* We need to make sure nobody is changing page->private, as we rely on
* page->private as the pointer to extent buffer.
*/
spin_lock(&page->mapping->private_lock);
if (!PagePrivate(page)) {
spin_unlock(&page->mapping->private_lock);
return 1;
}
eb = (struct extent_buffer *)page->private;
BUG_ON(!eb);
/*
* This is a little awful but should be ok, we need to make sure that
* the eb doesn't disappear out from under us while we're looking at
* this page.
*/
spin_lock(&eb->refs_lock);
if (atomic_read(&eb->refs) != 1 || extent_buffer_under_io(eb)) {
spin_unlock(&eb->refs_lock);
spin_unlock(&page->mapping->private_lock);
return 0;
}
spin_unlock(&page->mapping->private_lock);
/*
* If tree ref isn't set then we know the ref on this eb is a real ref,
* so just return, this page will likely be freed soon anyway.
*/
if (!test_and_clear_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) {
spin_unlock(&eb->refs_lock);
return 0;
}
return release_extent_buffer(eb);
}
/*
* btrfs_readahead_tree_block - attempt to readahead a child block
* @fs_info: the fs_info
* @bytenr: bytenr to read
* @owner_root: objectid of the root that owns this eb
* @gen: generation for the uptodate check, can be 0
* @level: level for the eb
*
* Attempt to readahead a tree block at @bytenr. If @gen is 0 then we do a
* normal uptodate check of the eb, without checking the generation. If we have
* to read the block we will not block on anything.
*/
void btrfs_readahead_tree_block(struct btrfs_fs_info *fs_info,
u64 bytenr, u64 owner_root, u64 gen, int level)
{
struct extent_buffer *eb;
int ret;
eb = btrfs_find_create_tree_block(fs_info, bytenr, owner_root, level);
if (IS_ERR(eb))
return;
if (btrfs_buffer_uptodate(eb, gen, 1)) {
free_extent_buffer(eb);
return;
}
ret = read_extent_buffer_pages(eb, WAIT_NONE, 0);
if (ret < 0)
free_extent_buffer_stale(eb);
else
free_extent_buffer(eb);
}
/*
* btrfs_readahead_node_child - readahead a node's child block
* @node: parent node we're reading from
* @slot: slot in the parent node for the child we want to read
*
* A helper for btrfs_readahead_tree_block, we simply read the bytenr pointed at
* the slot in the node provided.
*/
void btrfs_readahead_node_child(struct extent_buffer *node, int slot)
{
btrfs_readahead_tree_block(node->fs_info,
btrfs_node_blockptr(node, slot),
btrfs_header_owner(node),
btrfs_node_ptr_generation(node, slot),
btrfs_header_level(node) - 1);
}