linux/fs/ext4/file.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
/*
* linux/fs/ext4/file.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/file.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* ext4 fs regular file handling primitives
*
* 64-bit file support on 64-bit platforms by Jakub Jelinek
* (jj@sunsite.ms.mff.cuni.cz)
*/
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/iomap.h>
#include <linux/mount.h>
#include <linux/path.h>
#include <linux/dax.h>
#include <linux/quotaops.h>
#include <linux/pagevec.h>
#include <linux/uio.h>
#include <linux/mman.h>
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
#include <linux/backing-dev.h>
#include "ext4.h"
#include "ext4_jbd2.h"
#include "xattr.h"
#include "acl.h"
#include "truncate.h"
/*
* Returns %true if the given DIO request should be attempted with DIO, or
* %false if it should fall back to buffered I/O.
*
* DIO isn't well specified; when it's unsupported (either due to the request
* being misaligned, or due to the file not supporting DIO at all), filesystems
* either fall back to buffered I/O or return EINVAL. For files that don't use
* any special features like encryption or verity, ext4 has traditionally
* returned EINVAL for misaligned DIO. iomap_dio_rw() uses this convention too.
* In this case, we should attempt the DIO, *not* fall back to buffered I/O.
*
* In contrast, in cases where DIO is unsupported due to ext4 features, ext4
* traditionally falls back to buffered I/O.
*
* This function implements the traditional ext4 behavior in all these cases.
*/
static bool ext4_should_use_dio(struct kiocb *iocb, struct iov_iter *iter)
{
struct inode *inode = file_inode(iocb->ki_filp);
u32 dio_align = ext4_dio_alignment(inode);
if (dio_align == 0)
return false;
if (dio_align == 1)
return true;
return IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(iter), dio_align);
}
static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
ssize_t ret;
struct inode *inode = file_inode(iocb->ki_filp);
if (iocb->ki_flags & IOCB_NOWAIT) {
if (!inode_trylock_shared(inode))
return -EAGAIN;
} else {
inode_lock_shared(inode);
}
if (!ext4_should_use_dio(iocb, to)) {
inode_unlock_shared(inode);
/*
* Fallback to buffered I/O if the operation being performed on
* the inode is not supported by direct I/O. The IOCB_DIRECT
* flag needs to be cleared here in order to ensure that the
* direct I/O path within generic_file_read_iter() is not
* taken.
*/
iocb->ki_flags &= ~IOCB_DIRECT;
return generic_file_read_iter(iocb, to);
}
ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, 0, NULL, 0);
inode_unlock_shared(inode);
file_accessed(iocb->ki_filp);
return ret;
}
#ifdef CONFIG_FS_DAX
static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct inode *inode = file_inode(iocb->ki_filp);
ssize_t ret;
if (iocb->ki_flags & IOCB_NOWAIT) {
if (!inode_trylock_shared(inode))
return -EAGAIN;
} else {
inode_lock_shared(inode);
}
/*
* Recheck under inode lock - at this point we are sure it cannot
* change anymore
*/
if (!IS_DAX(inode)) {
inode_unlock_shared(inode);
/* Fallback to buffered IO in case we cannot support DAX */
return generic_file_read_iter(iocb, to);
}
ret = dax_iomap_rw(iocb, to, &ext4_iomap_ops);
inode_unlock_shared(inode);
file_accessed(iocb->ki_filp);
return ret;
}
#endif
static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct inode *inode = file_inode(iocb->ki_filp);
if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
return -EIO;
if (!iov_iter_count(to))
return 0; /* skip atime */
#ifdef CONFIG_FS_DAX
if (IS_DAX(inode))
return ext4_dax_read_iter(iocb, to);
#endif
if (iocb->ki_flags & IOCB_DIRECT)
return ext4_dio_read_iter(iocb, to);
return generic_file_read_iter(iocb, to);
}
/*
* Called when an inode is released. Note that this is different
* from ext4_file_open: open gets called at every open, but release
* gets called only when /all/ the files are closed.
*/
static int ext4_release_file(struct inode *inode, struct file *filp)
{
if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
ext4_alloc_da_blocks(inode);
ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
}
/* if we are the last writer on the inode, drop the block reservation */
if ((filp->f_mode & FMODE_WRITE) &&
(atomic_read(&inode->i_writecount) == 1) &&
!EXT4_I(inode)->i_reserved_data_blocks) {
down_write(&EXT4_I(inode)->i_data_sem);
ext4_discard_preallocations(inode, 0);
up_write(&EXT4_I(inode)->i_data_sem);
}
if (is_dx(inode) && filp->private_data)
ext4_htree_free_dir_info(filp->private_data);
return 0;
}
ext4: serialize unaligned asynchronous DIO ext4 has a data corruption case when doing non-block-aligned asynchronous direct IO into a sparse file, as demonstrated by xfstest 240. The root cause is that while ext4 preallocates space in the hole, mappings of that space still look "new" and dio_zero_block() will zero out the unwritten portions. When more than one AIO thread is going, they both find this "new" block and race to zero out their portion; this is uncoordinated and causes data corruption. Dave Chinner fixed this for xfs by simply serializing all unaligned asynchronous direct IO. I've done the same here. The difference is that we only wait on conversions, not all IO. This is a very big hammer, and I'm not very pleased with stuffing this into ext4_file_write(). But since ext4 is DIO_LOCKING, we need to serialize it at this high level. I tried to move this into ext4_ext_direct_IO, but by then we have the i_mutex already, and we will wait on the work queue to do conversions - which must also take the i_mutex. So that won't work. This was originally exposed by qemu-kvm installing to a raw disk image with a normal sector-63 alignment. I've tested a backport of this patch with qemu, and it does avoid the corruption. It is also quite a lot slower (14 min for package installs, vs. 8 min for well-aligned) but I'll take slow correctness over fast corruption any day. Mingming suggested that we can track outstanding conversions, and wait on those so that non-sparse files won't be affected, and I've implemented that here; unaligned AIO to nonsparse files won't take a perf hit. [tytso@mit.edu: Keep the mutex as a hashed array instead of bloating the ext4 inode] [tytso@mit.edu: Fix up namespace issues so that global variables are protected with an "ext4_" prefix.] Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2011-02-12 13:17:34 +00:00
/*
* This tests whether the IO in question is block-aligned or not.
* Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
* are converted to written only after the IO is complete. Until they are
* mapped, these blocks appear as holes, so dio_zero_block() will assume that
* it needs to zero out portions of the start and/or end block. If 2 AIO
* threads are at work on the same unwritten block, they must be synchronized
* or one thread will zero the other's data, causing corruption.
*/
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
static bool
ext4_unaligned_io(struct inode *inode, struct iov_iter *from, loff_t pos)
ext4: serialize unaligned asynchronous DIO ext4 has a data corruption case when doing non-block-aligned asynchronous direct IO into a sparse file, as demonstrated by xfstest 240. The root cause is that while ext4 preallocates space in the hole, mappings of that space still look "new" and dio_zero_block() will zero out the unwritten portions. When more than one AIO thread is going, they both find this "new" block and race to zero out their portion; this is uncoordinated and causes data corruption. Dave Chinner fixed this for xfs by simply serializing all unaligned asynchronous direct IO. I've done the same here. The difference is that we only wait on conversions, not all IO. This is a very big hammer, and I'm not very pleased with stuffing this into ext4_file_write(). But since ext4 is DIO_LOCKING, we need to serialize it at this high level. I tried to move this into ext4_ext_direct_IO, but by then we have the i_mutex already, and we will wait on the work queue to do conversions - which must also take the i_mutex. So that won't work. This was originally exposed by qemu-kvm installing to a raw disk image with a normal sector-63 alignment. I've tested a backport of this patch with qemu, and it does avoid the corruption. It is also quite a lot slower (14 min for package installs, vs. 8 min for well-aligned) but I'll take slow correctness over fast corruption any day. Mingming suggested that we can track outstanding conversions, and wait on those so that non-sparse files won't be affected, and I've implemented that here; unaligned AIO to nonsparse files won't take a perf hit. [tytso@mit.edu: Keep the mutex as a hashed array instead of bloating the ext4 inode] [tytso@mit.edu: Fix up namespace issues so that global variables are protected with an "ext4_" prefix.] Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2011-02-12 13:17:34 +00:00
{
struct super_block *sb = inode->i_sb;
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
unsigned long blockmask = sb->s_blocksize - 1;
ext4: serialize unaligned asynchronous DIO ext4 has a data corruption case when doing non-block-aligned asynchronous direct IO into a sparse file, as demonstrated by xfstest 240. The root cause is that while ext4 preallocates space in the hole, mappings of that space still look "new" and dio_zero_block() will zero out the unwritten portions. When more than one AIO thread is going, they both find this "new" block and race to zero out their portion; this is uncoordinated and causes data corruption. Dave Chinner fixed this for xfs by simply serializing all unaligned asynchronous direct IO. I've done the same here. The difference is that we only wait on conversions, not all IO. This is a very big hammer, and I'm not very pleased with stuffing this into ext4_file_write(). But since ext4 is DIO_LOCKING, we need to serialize it at this high level. I tried to move this into ext4_ext_direct_IO, but by then we have the i_mutex already, and we will wait on the work queue to do conversions - which must also take the i_mutex. So that won't work. This was originally exposed by qemu-kvm installing to a raw disk image with a normal sector-63 alignment. I've tested a backport of this patch with qemu, and it does avoid the corruption. It is also quite a lot slower (14 min for package installs, vs. 8 min for well-aligned) but I'll take slow correctness over fast corruption any day. Mingming suggested that we can track outstanding conversions, and wait on those so that non-sparse files won't be affected, and I've implemented that here; unaligned AIO to nonsparse files won't take a perf hit. [tytso@mit.edu: Keep the mutex as a hashed array instead of bloating the ext4 inode] [tytso@mit.edu: Fix up namespace issues so that global variables are protected with an "ext4_" prefix.] Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2011-02-12 13:17:34 +00:00
if ((pos | iov_iter_alignment(from)) & blockmask)
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
return true;
ext4: serialize unaligned asynchronous DIO ext4 has a data corruption case when doing non-block-aligned asynchronous direct IO into a sparse file, as demonstrated by xfstest 240. The root cause is that while ext4 preallocates space in the hole, mappings of that space still look "new" and dio_zero_block() will zero out the unwritten portions. When more than one AIO thread is going, they both find this "new" block and race to zero out their portion; this is uncoordinated and causes data corruption. Dave Chinner fixed this for xfs by simply serializing all unaligned asynchronous direct IO. I've done the same here. The difference is that we only wait on conversions, not all IO. This is a very big hammer, and I'm not very pleased with stuffing this into ext4_file_write(). But since ext4 is DIO_LOCKING, we need to serialize it at this high level. I tried to move this into ext4_ext_direct_IO, but by then we have the i_mutex already, and we will wait on the work queue to do conversions - which must also take the i_mutex. So that won't work. This was originally exposed by qemu-kvm installing to a raw disk image with a normal sector-63 alignment. I've tested a backport of this patch with qemu, and it does avoid the corruption. It is also quite a lot slower (14 min for package installs, vs. 8 min for well-aligned) but I'll take slow correctness over fast corruption any day. Mingming suggested that we can track outstanding conversions, and wait on those so that non-sparse files won't be affected, and I've implemented that here; unaligned AIO to nonsparse files won't take a perf hit. [tytso@mit.edu: Keep the mutex as a hashed array instead of bloating the ext4 inode] [tytso@mit.edu: Fix up namespace issues so that global variables are protected with an "ext4_" prefix.] Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2011-02-12 13:17:34 +00:00
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
return false;
}
static bool
ext4_extending_io(struct inode *inode, loff_t offset, size_t len)
{
if (offset + len > i_size_read(inode) ||
offset + len > EXT4_I(inode)->i_disksize)
return true;
return false;
ext4: serialize unaligned asynchronous DIO ext4 has a data corruption case when doing non-block-aligned asynchronous direct IO into a sparse file, as demonstrated by xfstest 240. The root cause is that while ext4 preallocates space in the hole, mappings of that space still look "new" and dio_zero_block() will zero out the unwritten portions. When more than one AIO thread is going, they both find this "new" block and race to zero out their portion; this is uncoordinated and causes data corruption. Dave Chinner fixed this for xfs by simply serializing all unaligned asynchronous direct IO. I've done the same here. The difference is that we only wait on conversions, not all IO. This is a very big hammer, and I'm not very pleased with stuffing this into ext4_file_write(). But since ext4 is DIO_LOCKING, we need to serialize it at this high level. I tried to move this into ext4_ext_direct_IO, but by then we have the i_mutex already, and we will wait on the work queue to do conversions - which must also take the i_mutex. So that won't work. This was originally exposed by qemu-kvm installing to a raw disk image with a normal sector-63 alignment. I've tested a backport of this patch with qemu, and it does avoid the corruption. It is also quite a lot slower (14 min for package installs, vs. 8 min for well-aligned) but I'll take slow correctness over fast corruption any day. Mingming suggested that we can track outstanding conversions, and wait on those so that non-sparse files won't be affected, and I've implemented that here; unaligned AIO to nonsparse files won't take a perf hit. [tytso@mit.edu: Keep the mutex as a hashed array instead of bloating the ext4 inode] [tytso@mit.edu: Fix up namespace issues so that global variables are protected with an "ext4_" prefix.] Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2011-02-12 13:17:34 +00:00
}
/* Is IO overwriting allocated and initialized blocks? */
static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len)
{
struct ext4_map_blocks map;
unsigned int blkbits = inode->i_blkbits;
int err, blklen;
if (pos + len > i_size_read(inode))
return false;
map.m_lblk = pos >> blkbits;
map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits);
blklen = map.m_len;
err = ext4_map_blocks(NULL, inode, &map, 0);
/*
* 'err==len' means that all of the blocks have been preallocated,
* regardless of whether they have been initialized or not. To exclude
* unwritten extents, we need to check m_flags.
*/
return err == blklen && (map.m_flags & EXT4_MAP_MAPPED);
}
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
static ssize_t ext4_generic_write_checks(struct kiocb *iocb,
struct iov_iter *from)
{
struct inode *inode = file_inode(iocb->ki_filp);
ssize_t ret;
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
if (unlikely(IS_IMMUTABLE(inode)))
return -EPERM;
ret = generic_write_checks(iocb, from);
if (ret <= 0)
return ret;
/*
* If we have encountered a bitmap-format file, the size limit
* is smaller than s_maxbytes, which is for extent-mapped files.
*/
if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
if (iocb->ki_pos >= sbi->s_bitmap_maxbytes)
return -EFBIG;
iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
}
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
return iov_iter_count(from);
}
static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from)
{
ssize_t ret, count;
count = ext4_generic_write_checks(iocb, from);
if (count <= 0)
return count;
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
ret = file_modified(iocb->ki_filp);
if (ret)
return ret;
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
return count;
}
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
struct iov_iter *from)
{
ssize_t ret;
struct inode *inode = file_inode(iocb->ki_filp);
if (iocb->ki_flags & IOCB_NOWAIT)
return -EOPNOTSUPP;
inode_lock(inode);
ret = ext4_write_checks(iocb, from);
if (ret <= 0)
goto out;
current->backing_dev_info = inode_to_bdi(inode);
ret = generic_perform_write(iocb, from);
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
current->backing_dev_info = NULL;
out:
inode_unlock(inode);
if (likely(ret > 0)) {
iocb->ki_pos += ret;
ret = generic_write_sync(iocb, ret);
}
return ret;
}
static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset,
ssize_t written, size_t count)
{
handle_t *handle;
bool truncate = false;
u8 blkbits = inode->i_blkbits;
ext4_lblk_t written_blk, end_blk;
int ret;
/*
* Note that EXT4_I(inode)->i_disksize can get extended up to
* inode->i_size while the I/O was running due to writeback of delalloc
* blocks. But, the code in ext4_iomap_alloc() is careful to use
* zeroed/unwritten extents if this is possible; thus we won't leave
* uninitialized blocks in a file even if we didn't succeed in writing
* as much as we intended.
*/
WARN_ON_ONCE(i_size_read(inode) < EXT4_I(inode)->i_disksize);
if (offset + count <= EXT4_I(inode)->i_disksize) {
/*
* We need to ensure that the inode is removed from the orphan
* list if it has been added prematurely, due to writeback of
* delalloc blocks.
*/
if (!list_empty(&EXT4_I(inode)->i_orphan) && inode->i_nlink) {
handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
if (IS_ERR(handle)) {
ext4_orphan_del(NULL, inode);
return PTR_ERR(handle);
}
ext4_orphan_del(handle, inode);
ext4_journal_stop(handle);
}
return written;
}
if (written < 0)
goto truncate;
handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
if (IS_ERR(handle)) {
written = PTR_ERR(handle);
goto truncate;
}
if (ext4_update_inode_size(inode, offset + written)) {
ret = ext4_mark_inode_dirty(handle, inode);
if (unlikely(ret)) {
written = ret;
ext4_journal_stop(handle);
goto truncate;
}
}
/*
* We may need to truncate allocated but not written blocks beyond EOF.
*/
written_blk = ALIGN(offset + written, 1 << blkbits);
end_blk = ALIGN(offset + count, 1 << blkbits);
if (written_blk < end_blk && ext4_can_truncate(inode))
truncate = true;
/*
* Remove the inode from the orphan list if it has been extended and
* everything went OK.
*/
if (!truncate && inode->i_nlink)
ext4_orphan_del(handle, inode);
ext4_journal_stop(handle);
if (truncate) {
truncate:
ext4_truncate_failed_write(inode);
/*
* If the truncate operation failed early, then the inode may
* still be on the orphan list. In that case, we need to try
* remove the inode from the in-memory linked list.
*/
if (inode->i_nlink)
ext4_orphan_del(NULL, inode);
}
return written;
}
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size,
int error, unsigned int flags)
{
loff_t pos = iocb->ki_pos;
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
struct inode *inode = file_inode(iocb->ki_filp);
if (error)
return error;
if (size && flags & IOMAP_DIO_UNWRITTEN) {
error = ext4_convert_unwritten_extents(NULL, inode, pos, size);
if (error < 0)
return error;
}
/*
* If we are extending the file, we have to update i_size here before
* page cache gets invalidated in iomap_dio_rw(). Otherwise racing
* buffered reads could zero out too much from page cache pages. Update
* of on-disk size will happen later in ext4_dio_write_iter() where
* we have enough information to also perform orphan list handling etc.
* Note that we perform all extending writes synchronously under
* i_rwsem held exclusively so i_size update is safe here in that case.
* If the write was not extending, we cannot see pos > i_size here
* because operations reducing i_size like truncate wait for all
* outstanding DIO before updating i_size.
*/
pos += size;
if (pos > i_size_read(inode))
i_size_write(inode, pos);
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
return 0;
}
static const struct iomap_dio_ops ext4_dio_write_ops = {
.end_io = ext4_dio_write_end_io,
};
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
/*
* The intention here is to start with shared lock acquired then see if any
* condition requires an exclusive inode lock. If yes, then we restart the
* whole operation by releasing the shared lock and acquiring exclusive lock.
*
* - For unaligned_io we never take shared lock as it may cause data corruption
* when two unaligned IO tries to modify the same block e.g. while zeroing.
*
* - For extending writes case we don't take the shared lock, since it requires
* updating inode i_disksize and/or orphan handling with exclusive lock.
*
* - shared locking will only be true mostly with overwrites. Otherwise we will
* switch to exclusive i_rwsem lock.
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
*/
static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
bool *ilock_shared, bool *extend)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
loff_t offset;
size_t count;
ssize_t ret;
restart:
ret = ext4_generic_write_checks(iocb, from);
if (ret <= 0)
goto out;
offset = iocb->ki_pos;
count = ret;
if (ext4_extending_io(inode, offset, count))
*extend = true;
/*
* Determine whether the IO operation will overwrite allocated
* and initialized blocks.
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
* We need exclusive i_rwsem for changing security info
* in file_modified().
*/
if (*ilock_shared && (!IS_NOSEC(inode) || *extend ||
!ext4_overwrite_io(inode, offset, count))) {
if (iocb->ki_flags & IOCB_NOWAIT) {
ret = -EAGAIN;
goto out;
}
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
inode_unlock_shared(inode);
*ilock_shared = false;
inode_lock(inode);
goto restart;
}
ret = file_modified(file);
if (ret < 0)
goto out;
return count;
out:
if (*ilock_shared)
inode_unlock_shared(inode);
else
inode_unlock(inode);
return ret;
}
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
ssize_t ret;
handle_t *handle;
struct inode *inode = file_inode(iocb->ki_filp);
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
loff_t offset = iocb->ki_pos;
size_t count = iov_iter_count(from);
ext4: Optimize ext4 DIO overwrites Currently we start transaction for mapping every extent for writing using direct IO. This is unnecessary when we know we are overwriting already allocated blocks and the overhead of starting a transaction can be significant especially for multithreaded workloads doing small writes. Use iomap operations that avoid starting a transaction for direct IO overwrites. This improves throughput of 4k random writes - fio jobfile: [global] rw=randrw norandommap=1 invalidate=0 bs=4k numjobs=16 time_based=1 ramp_time=30 runtime=120 group_reporting=1 ioengine=psync direct=1 size=16G filename=file1.0.0:file1.0.1:file1.0.2:file1.0.3:file1.0.4:file1.0.5:file1.0.6:file1.0.7:file1.0.8:file1.0.9:file1.0.10:file1.0.11:file1.0.12:file1.0.13:file1.0.14:file1.0.15:file1.0.16:file1.0.17:file1.0.18:file1.0.19:file1.0.20:file1.0.21:file1.0.22:file1.0.23:file1.0.24:file1.0.25:file1.0.26:file1.0.27:file1.0.28:file1.0.29:file1.0.30:file1.0.31 file_service_type=random nrfiles=32 from 3018MB/s to 4059MB/s in my test VM running test against simulated pmem device (note that before iomap conversion, this workload was able to achieve 3708MB/s because old direct IO path avoided transaction start for overwrites as well). For dax, the win is even larger improving throughput from 3042MB/s to 4311MB/s. Reported-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20191218174433.19380-1-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-18 17:44:33 +00:00
const struct iomap_ops *iomap_ops = &ext4_iomap_ops;
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
bool extend = false, unaligned_io = false;
bool ilock_shared = true;
/*
* We initially start with shared inode lock unless it is
* unaligned IO which needs exclusive lock anyways.
*/
if (ext4_unaligned_io(inode, from, offset)) {
unaligned_io = true;
ilock_shared = false;
}
/*
* Quick check here without any i_rwsem lock to see if it is extending
* IO. A more reliable check is done in ext4_dio_write_checks() with
* proper locking in place.
*/
if (offset + count > i_size_read(inode))
ilock_shared = false;
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
if (iocb->ki_flags & IOCB_NOWAIT) {
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
if (ilock_shared) {
if (!inode_trylock_shared(inode))
return -EAGAIN;
} else {
if (!inode_trylock(inode))
return -EAGAIN;
}
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
} else {
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
if (ilock_shared)
inode_lock_shared(inode);
else
inode_lock(inode);
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
}
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
/* Fallback to buffered I/O if the inode does not support direct I/O. */
if (!ext4_should_use_dio(iocb, from)) {
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
if (ilock_shared)
inode_unlock_shared(inode);
else
inode_unlock(inode);
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
return ext4_buffered_write_iter(iocb, from);
}
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
ret = ext4_dio_write_checks(iocb, from, &ilock_shared, &extend);
if (ret <= 0)
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
return ret;
/* if we're going to block and IOCB_NOWAIT is set, return -EAGAIN */
if ((iocb->ki_flags & IOCB_NOWAIT) && (unaligned_io || extend)) {
ret = -EAGAIN;
goto out;
}
ext4: avoid crash when inline data creation follows DIO write When inode is created and written to using direct IO, there is nothing to clear the EXT4_STATE_MAY_INLINE_DATA flag. Thus when inode gets truncated later to say 1 byte and written using normal write, we will try to store the data as inline data. This confuses the code later because the inode now has both normal block and inline data allocated and the confusion manifests for example as: kernel BUG at fs/ext4/inode.c:2721! invalid opcode: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 359 Comm: repro Not tainted 5.19.0-rc8-00001-g31ba1e3b8305-dirty #15 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-1.fc36 04/01/2014 RIP: 0010:ext4_writepages+0x363d/0x3660 RSP: 0018:ffffc90000ccf260 EFLAGS: 00010293 RAX: ffffffff81e1abcd RBX: 0000008000000000 RCX: ffff88810842a180 RDX: 0000000000000000 RSI: 0000008000000000 RDI: 0000000000000000 RBP: ffffc90000ccf650 R08: ffffffff81e17d58 R09: ffffed10222c680b R10: dfffe910222c680c R11: 1ffff110222c680a R12: ffff888111634128 R13: ffffc90000ccf880 R14: 0000008410000000 R15: 0000000000000001 FS: 00007f72635d2640(0000) GS:ffff88811b000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000565243379180 CR3: 000000010aa74000 CR4: 0000000000150eb0 Call Trace: <TASK> do_writepages+0x397/0x640 filemap_fdatawrite_wbc+0x151/0x1b0 file_write_and_wait_range+0x1c9/0x2b0 ext4_sync_file+0x19e/0xa00 vfs_fsync_range+0x17b/0x190 ext4_buffered_write_iter+0x488/0x530 ext4_file_write_iter+0x449/0x1b90 vfs_write+0xbcd/0xf40 ksys_write+0x198/0x2c0 __x64_sys_write+0x7b/0x90 do_syscall_64+0x3d/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd </TASK> Fix the problem by clearing EXT4_STATE_MAY_INLINE_DATA when we are doing direct IO write to a file. Cc: stable@kernel.org Reported-by: Tadeusz Struk <tadeusz.struk@linaro.org> Reported-by: syzbot+bd13648a53ed6933ca49@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=a1e89d09bbbcbd5c4cb45db230ee28c822953984 Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Lukas Czerner <lczerner@redhat.com> Tested-by: Tadeusz Struk<tadeusz.struk@linaro.org> Link: https://lore.kernel.org/r/20220727155753.13969-1-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2022-07-27 15:57:53 +00:00
/*
* Make sure inline data cannot be created anymore since we are going
* to allocate blocks for DIO. We know the inode does not have any
* inline data now because ext4_dio_supported() checked for that.
*/
ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
offset = iocb->ki_pos;
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
count = ret;
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
/*
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
* Unaligned direct IO must be serialized among each other as zeroing
* of partial blocks of two competing unaligned IOs can result in data
* corruption.
*
* So we make sure we don't allow any unaligned IO in flight.
* For IOs where we need not wait (like unaligned non-AIO DIO),
* below inode_dio_wait() may anyway become a no-op, since we start
* with exclusive lock.
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
*/
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
if (unaligned_io)
inode_dio_wait(inode);
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
if (extend) {
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto out;
}
ret = ext4_orphan_add(handle, inode);
if (ret) {
ext4_journal_stop(handle);
goto out;
}
ext4_journal_stop(handle);
}
ext4: Optimize ext4 DIO overwrites Currently we start transaction for mapping every extent for writing using direct IO. This is unnecessary when we know we are overwriting already allocated blocks and the overhead of starting a transaction can be significant especially for multithreaded workloads doing small writes. Use iomap operations that avoid starting a transaction for direct IO overwrites. This improves throughput of 4k random writes - fio jobfile: [global] rw=randrw norandommap=1 invalidate=0 bs=4k numjobs=16 time_based=1 ramp_time=30 runtime=120 group_reporting=1 ioengine=psync direct=1 size=16G filename=file1.0.0:file1.0.1:file1.0.2:file1.0.3:file1.0.4:file1.0.5:file1.0.6:file1.0.7:file1.0.8:file1.0.9:file1.0.10:file1.0.11:file1.0.12:file1.0.13:file1.0.14:file1.0.15:file1.0.16:file1.0.17:file1.0.18:file1.0.19:file1.0.20:file1.0.21:file1.0.22:file1.0.23:file1.0.24:file1.0.25:file1.0.26:file1.0.27:file1.0.28:file1.0.29:file1.0.30:file1.0.31 file_service_type=random nrfiles=32 from 3018MB/s to 4059MB/s in my test VM running test against simulated pmem device (note that before iomap conversion, this workload was able to achieve 3708MB/s because old direct IO path avoided transaction start for overwrites as well). For dax, the win is even larger improving throughput from 3042MB/s to 4311MB/s. Reported-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20191218174433.19380-1-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-18 17:44:33 +00:00
if (ilock_shared)
iomap_ops = &ext4_iomap_overwrite_ops;
ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
(unaligned_io || extend) ? IOMAP_DIO_FORCE_WAIT : 0,
NULL, 0);
if (ret == -ENOTBLK)
ret = 0;
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
if (extend)
ret = ext4_handle_inode_extension(inode, offset, ret, count);
out:
ext4: Start with shared i_rwsem in case of DIO instead of exclusive Earlier there was no shared lock in DIO read path. But this patch (16c54688592ce: ext4: Allow parallel DIO reads) simplified some of the locking mechanism while still allowing for parallel DIO reads by adding shared lock in inode DIO read path. But this created problem with mixed read/write workload. It is due to the fact that in DIO path, we first start with exclusive lock and only when we determine that it is a ovewrite IO, we downgrade the lock. This causes the problem, since we still have shared locking in DIO reads. So, this patch tries to fix this issue by starting with shared lock and then switching to exclusive lock only when required based on ext4_dio_write_checks(). Other than that, it also simplifies below cases:- 1. Simplified ext4_unaligned_aio API to ext4_unaligned_io. Previous API was abused in the sense that it was not really checking for AIO anywhere also it used to check for extending writes. So this API was renamed and simplified to ext4_unaligned_io() which actully only checks if the IO is really unaligned. Now, in case of unaligned direct IO, iomap_dio_rw needs to do zeroing of partial block and that will require serialization against other direct IOs in the same block. So we take a exclusive inode lock for any unaligned DIO. In case of AIO we also need to wait for any outstanding IOs to complete so that conversion from unwritten to written is completed before anyone try to map the overlapping block. Hence we take exclusive inode lock and also wait for inode_dio_wait() for unaligned DIO case. Please note since we are anyway taking an exclusive lock in unaligned IO, inode_dio_wait() becomes a no-op in case of non-AIO DIO. 2. Added ext4_extending_io(). This checks if the IO is extending the file. 3. Added ext4_dio_write_checks(). In this we start with shared inode lock and only switch to exclusive lock if required. So in most cases with aligned, non-extending, dioread_nolock & overwrites, it tries to write with a shared lock. If not, then we restart the operation in ext4_dio_write_checks(), after acquiring exclusive lock. Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20191212055557.11151-3-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-12-12 05:55:56 +00:00
if (ilock_shared)
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
inode_unlock_shared(inode);
else
inode_unlock(inode);
if (ret >= 0 && iov_iter_count(from)) {
ssize_t err;
loff_t endbyte;
offset = iocb->ki_pos;
err = ext4_buffered_write_iter(iocb, from);
if (err < 0)
return err;
/*
* We need to ensure that the pages within the page cache for
* the range covered by this I/O are written to disk and
* invalidated. This is in attempt to preserve the expected
* direct I/O semantics in the case we fallback to buffered I/O
* to complete off the I/O request.
*/
ret += err;
endbyte = offset + err - 1;
err = filemap_write_and_wait_range(iocb->ki_filp->f_mapping,
offset, endbyte);
if (!err)
invalidate_mapping_pages(iocb->ki_filp->f_mapping,
offset >> PAGE_SHIFT,
endbyte >> PAGE_SHIFT);
}
return ret;
}
#ifdef CONFIG_FS_DAX
static ssize_t
ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
ssize_t ret;
size_t count;
loff_t offset;
handle_t *handle;
bool extend = false;
struct inode *inode = file_inode(iocb->ki_filp);
if (iocb->ki_flags & IOCB_NOWAIT) {
if (!inode_trylock(inode))
return -EAGAIN;
} else {
inode_lock(inode);
}
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
ret = ext4_write_checks(iocb, from);
if (ret <= 0)
goto out;
offset = iocb->ki_pos;
count = iov_iter_count(from);
if (offset + count > EXT4_I(inode)->i_disksize) {
handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto out;
}
ret = ext4_orphan_add(handle, inode);
if (ret) {
ext4_journal_stop(handle);
goto out;
}
extend = true;
ext4_journal_stop(handle);
}
ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops);
if (extend)
ret = ext4_handle_inode_extension(inode, offset, ret, count);
out:
inode_unlock(inode);
if (ret > 0)
ret = generic_write_sync(iocb, ret);
return ret;
}
#endif
static ssize_t
ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct inode *inode = file_inode(iocb->ki_filp);
if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
return -EIO;
#ifdef CONFIG_FS_DAX
if (IS_DAX(inode))
return ext4_dax_write_iter(iocb, from);
#endif
ext4: introduce direct I/O write using iomap infrastructure This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/e55db6f12ae6ff017f36774135e79f3e7b0333da.1572949325.git.mbobrowski@mbobrowski.org Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 12:02:39 +00:00
if (iocb->ki_flags & IOCB_DIRECT)
return ext4_dio_write_iter(iocb, from);
else
return ext4_buffered_write_iter(iocb, from);
}
#ifdef CONFIG_FS_DAX
static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf,
enum page_entry_size pe_size)
{
int error = 0;
vm_fault_t result;
int retries = 0;
handle_t *handle = NULL;
struct inode *inode = file_inode(vmf->vma->vm_file);
struct super_block *sb = inode->i_sb;
/*
* We have to distinguish real writes from writes which will result in a
* COW page; COW writes should *not* poke the journal (the file will not
* be changed). Doing so would cause unintended failures when mounted
* read-only.
*
* We check for VM_SHARED rather than vmf->cow_page since the latter is
* unset for pe_size != PE_SIZE_PTE (i.e. only in do_cow_fault); for
* other sizes, dax_iomap_fault will handle splitting / fallback so that
* we eventually come back with a COW page.
*/
bool write = (vmf->flags & FAULT_FLAG_WRITE) &&
(vmf->vma->vm_flags & VM_SHARED);
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
pfn_t pfn;
if (write) {
sb_start_pagefault(sb);
file_update_time(vmf->vma->vm_file);
filemap_invalidate_lock_shared(mapping);
retry:
handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
EXT4_DATA_TRANS_BLOCKS(sb));
if (IS_ERR(handle)) {
filemap_invalidate_unlock_shared(mapping);
sb_end_pagefault(sb);
return VM_FAULT_SIGBUS;
}
} else {
filemap_invalidate_lock_shared(mapping);
}
result = dax_iomap_fault(vmf, pe_size, &pfn, &error, &ext4_iomap_ops);
if (write) {
ext4_journal_stop(handle);
if ((result & VM_FAULT_ERROR) && error == -ENOSPC &&
ext4_should_retry_alloc(sb, &retries))
goto retry;
/* Handling synchronous page fault? */
if (result & VM_FAULT_NEEDDSYNC)
result = dax_finish_sync_fault(vmf, pe_size, pfn);
filemap_invalidate_unlock_shared(mapping);
sb_end_pagefault(sb);
} else {
filemap_invalidate_unlock_shared(mapping);
}
return result;
}
static vm_fault_t ext4_dax_fault(struct vm_fault *vmf)
{
return ext4_dax_huge_fault(vmf, PE_SIZE_PTE);
}
static const struct vm_operations_struct ext4_dax_vm_ops = {
.fault = ext4_dax_fault,
.huge_fault = ext4_dax_huge_fault,
.page_mkwrite = ext4_dax_fault,
dax: use common 4k zero page for dax mmap reads When servicing mmap() reads from file holes the current DAX code allocates a page cache page of all zeroes and places the struct page pointer in the mapping->page_tree radix tree. This has three major drawbacks: 1) It consumes memory unnecessarily. For every 4k page that is read via a DAX mmap() over a hole, we allocate a new page cache page. This means that if you read 1GiB worth of pages, you end up using 1GiB of zeroed memory. This is easily visible by looking at the overall memory consumption of the system or by looking at /proc/[pid]/smaps: 7f62e72b3000-7f63272b3000 rw-s 00000000 103:00 12 /root/dax/data Size: 1048576 kB Rss: 1048576 kB Pss: 1048576 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 1048576 kB Private_Dirty: 0 kB Referenced: 1048576 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB KernelPageSize: 4 kB MMUPageSize: 4 kB Locked: 0 kB 2) It is slower than using a common zero page because each page fault has more work to do. Instead of just inserting a common zero page we have to allocate a page cache page, zero it, and then insert it. Here are the average latencies of dax_load_hole() as measured by ftrace on a random test box: Old method, using zeroed page cache pages: 3.4 us New method, using the common 4k zero page: 0.8 us This was the average latency over 1 GiB of sequential reads done by this simple fio script: [global] size=1G filename=/root/dax/data fallocate=none [io] rw=read ioengine=mmap 3) The fact that we had to check for both DAX exceptional entries and for page cache pages in the radix tree made the DAX code more complex. Solve these issues by following the lead of the DAX PMD code and using a common 4k zero page instead. As with the PMD code we will now insert a DAX exceptional entry into the radix tree instead of a struct page pointer which allows us to remove all the special casing in the DAX code. Note that we do still pretty aggressively check for regular pages in the DAX radix tree, especially where we take action based on the bits set in the page. If we ever find a regular page in our radix tree now that most likely means that someone besides DAX is inserting pages (which has happened lots of times in the past), and we want to find that out early and fail loudly. This solution also removes the extra memory consumption. Here is that same /proc/[pid]/smaps after 1GiB of reading from a hole with the new code: 7f2054a74000-7f2094a74000 rw-s 00000000 103:00 12 /root/dax/data Size: 1048576 kB Rss: 0 kB Pss: 0 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 0 kB Anonymous: 0 kB LazyFree: 0 kB AnonHugePages: 0 kB ShmemPmdMapped: 0 kB Shared_Hugetlb: 0 kB Private_Hugetlb: 0 kB Swap: 0 kB SwapPss: 0 kB KernelPageSize: 4 kB MMUPageSize: 4 kB Locked: 0 kB Overall system memory consumption is similarly improved. Another major change is that we remove dax_pfn_mkwrite() from our fault flow, and instead rely on the page fault itself to make the PTE dirty and writeable. The following description from the patch adding the vm_insert_mixed_mkwrite() call explains this a little more: "To be able to use the common 4k zero page in DAX we need to have our PTE fault path look more like our PMD fault path where a PTE entry can be marked as dirty and writeable as it is first inserted rather than waiting for a follow-up dax_pfn_mkwrite() => finish_mkwrite_fault() call. Right now we can rely on having a dax_pfn_mkwrite() call because we can distinguish between these two cases in do_wp_page(): case 1: 4k zero page => writable DAX storage case 2: read-only DAX storage => writeable DAX storage This distinction is made by via vm_normal_page(). vm_normal_page() returns false for the common 4k zero page, though, just as it does for DAX ptes. Instead of special casing the DAX + 4k zero page case we will simplify our DAX PTE page fault sequence so that it matches our DAX PMD sequence, and get rid of the dax_pfn_mkwrite() helper. We will instead use dax_iomap_fault() to handle write-protection faults. This means that insert_pfn() needs to follow the lead of insert_pfn_pmd() and allow us to pass in a 'mkwrite' flag. If 'mkwrite' is set insert_pfn() will do the work that was previously done by wp_page_reuse() as part of the dax_pfn_mkwrite() call path" Link: http://lkml.kernel.org/r/20170724170616.25810-4-ross.zwisler@linux.intel.com Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: "Darrick J. Wong" <darrick.wong@oracle.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-06 23:18:43 +00:00
.pfn_mkwrite = ext4_dax_fault,
};
#else
#define ext4_dax_vm_ops ext4_file_vm_ops
#endif
static const struct vm_operations_struct ext4_file_vm_ops = {
.fault = filemap_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = ext4_page_mkwrite,
};
static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
{
struct inode *inode = file->f_mapping->host;
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
struct dax_device *dax_dev = sbi->s_daxdev;
if (unlikely(ext4_forced_shutdown(sbi)))
return -EIO;
/*
* We don't support synchronous mappings for non-DAX files and
* for DAX files if underneath dax_device is not synchronous.
*/
if (!daxdev_mapping_supported(vma, dax_dev))
return -EOPNOTSUPP;
file_accessed(file);
if (IS_DAX(file_inode(file))) {
vma->vm_ops = &ext4_dax_vm_ops;
dax: remove VM_MIXEDMAP for fsdax and device dax This patch is reworked from an earlier patch that Dan has posted: https://patchwork.kernel.org/patch/10131727/ VM_MIXEDMAP is used by dax to direct mm paths like vm_normal_page() that the memory page it is dealing with is not typical memory from the linear map. The get_user_pages_fast() path, since it does not resolve the vma, is already using {pte,pmd}_devmap() as a stand-in for VM_MIXEDMAP, so we use that as a VM_MIXEDMAP replacement in some locations. In the cases where there is no pte to consult we fallback to using vma_is_dax() to detect the VM_MIXEDMAP special case. Now that we have explicit driver pfn_t-flag opt-in/opt-out for get_user_pages() support for DAX we can stop setting VM_MIXEDMAP. This also means we no longer need to worry about safely manipulating vm_flags in a future where we support dynamically changing the dax mode of a file. DAX should also now be supported with madvise_behavior(), vma_merge(), and copy_page_range(). This patch has been tested against ndctl unit test. It has also been tested against xfstests commit: 625515d using fake pmem created by memmap and no additional issues have been observed. Link: http://lkml.kernel.org/r/152847720311.55924.16999195879201817653.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-17 22:43:40 +00:00
vma->vm_flags |= VM_HUGEPAGE;
} else {
vma->vm_ops = &ext4_file_vm_ops;
}
return 0;
}
static int ext4_sample_last_mounted(struct super_block *sb,
struct vfsmount *mnt)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct path path;
char buf[64], *cp;
handle_t *handle;
int err;
if (likely(ext4_test_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED)))
return 0;
if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb))
return 0;
ext4_set_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED);
/*
* Sample where the filesystem has been mounted and
* store it in the superblock for sysadmin convenience
* when trying to sort through large numbers of block
* devices or filesystem images.
*/
memset(buf, 0, sizeof(buf));
path.mnt = mnt;
path.dentry = mnt->mnt_root;
cp = d_path(&path, buf, sizeof(buf));
err = 0;
if (IS_ERR(cp))
goto out;
handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
err = PTR_ERR(handle);
if (IS_ERR(handle))
goto out;
BUFFER_TRACE(sbi->s_sbh, "get_write_access");
err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
EXT4_JTR_NONE);
if (err)
goto out_journal;
lock_buffer(sbi->s_sbh);
strncpy(sbi->s_es->s_last_mounted, cp,
sizeof(sbi->s_es->s_last_mounted));
ext4_superblock_csum_set(sb);
unlock_buffer(sbi->s_sbh);
ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
out_journal:
ext4_journal_stop(handle);
out:
sb_end_intwrite(sb);
return err;
}
static int ext4_file_open(struct inode *inode, struct file *filp)
{
int ret;
if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
return -EIO;
ret = ext4_sample_last_mounted(inode->i_sb, filp->f_path.mnt);
if (ret)
return ret;
ret = fscrypt_file_open(inode, filp);
if (ret)
ext4: add basic fs-verity support Add most of fs-verity support to ext4. fs-verity is a filesystem feature that enables transparent integrity protection and authentication of read-only files. It uses a dm-verity like mechanism at the file level: a Merkle tree is used to verify any block in the file in log(filesize) time. It is implemented mainly by helper functions in fs/verity/. See Documentation/filesystems/fsverity.rst for the full documentation. This commit adds all of ext4 fs-verity support except for the actual data verification, including: - Adding a filesystem feature flag and an inode flag for fs-verity. - Implementing the fsverity_operations to support enabling verity on an inode and reading/writing the verity metadata. - Updating ->write_begin(), ->write_end(), and ->writepages() to support writing verity metadata pages. - Calling the fs-verity hooks for ->open(), ->setattr(), and ->ioctl(). ext4 stores the verity metadata (Merkle tree and fsverity_descriptor) past the end of the file, starting at the first 64K boundary beyond i_size. This approach works because (a) verity files are readonly, and (b) pages fully beyond i_size aren't visible to userspace but can be read/written internally by ext4 with only some relatively small changes to ext4. This approach avoids having to depend on the EA_INODE feature and on rearchitecturing ext4's xattr support to support paging multi-gigabyte xattrs into memory, and to support encrypting xattrs. Note that the verity metadata *must* be encrypted when the file is, since it contains hashes of the plaintext data. This patch incorporates work by Theodore Ts'o and Chandan Rajendra. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-22 16:26:24 +00:00
return ret;
ret = fsverity_file_open(inode, filp);
if (ret)
return ret;
/*
* Set up the jbd2_inode if we are opening the inode for
* writing and the journal is present
*/
if (filp->f_mode & FMODE_WRITE) {
ret = ext4_inode_attach_jinode(inode);
if (ret < 0)
return ret;
}
filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
return dquot_file_open(inode, filp);
}
ext4: improve llseek error handling for overly large seek offsets The llseek system call should return EINVAL if passed a seek offset which results in a write error. What this maximum offset should be depends on whether or not the huge_file file system feature is set, and whether or not the file is extent based or not. If the file has no "EXT4_EXTENTS_FL" flag, the maximum size which can be written (write systemcall) is different from the maximum size which can be sought (lseek systemcall). For example, the following 2 cases demonstrates the differences between the maximum size which can be written, versus the seek offset allowed by the llseek system call: #1: mkfs.ext3 <dev>; mount -t ext4 <dev> #2: mkfs.ext3 <dev>; tune2fs -Oextent,huge_file <dev>; mount -t ext4 <dev> Table. the max file size which we can write or seek at each filesystem feature tuning and file flag setting +============+===============================+===============================+ | \ File flag| | | | \ | !EXT4_EXTENTS_FL | EXT4_EXTETNS_FL | |case \| | | +------------+-------------------------------+-------------------------------+ | #1 | write: 2194719883264 | write: -------------- | | | seek: 2199023251456 | seek: -------------- | +------------+-------------------------------+-------------------------------+ | #2 | write: 4402345721856 | write: 17592186044415 | | | seek: 17592186044415 | seek: 17592186044415 | +------------+-------------------------------+-------------------------------+ The differences exist because ext4 has 2 maxbytes which are sb->s_maxbytes (= extent-mapped maxbytes) and EXT4_SB(sb)->s_bitmap_maxbytes (= block-mapped maxbytes). Although generic_file_llseek uses only extent-mapped maxbytes. (llseek of ext4_file_operations is generic_file_llseek which uses sb->s_maxbytes.) Therefore we create ext4 llseek function which uses 2 maxbytes. The new own function originates from generic_file_llseek(). If the file flag, "EXT4_EXTENTS_FL" is not set, the function alters inode->i_sb->s_maxbytes into EXT4_SB(inode->i_sb)->s_bitmap_maxbytes. Signed-off-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca>
2010-10-28 01:30:06 +00:00
/*
* ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
* by calling generic_file_llseek_size() with the appropriate maxbytes
* value for each.
ext4: improve llseek error handling for overly large seek offsets The llseek system call should return EINVAL if passed a seek offset which results in a write error. What this maximum offset should be depends on whether or not the huge_file file system feature is set, and whether or not the file is extent based or not. If the file has no "EXT4_EXTENTS_FL" flag, the maximum size which can be written (write systemcall) is different from the maximum size which can be sought (lseek systemcall). For example, the following 2 cases demonstrates the differences between the maximum size which can be written, versus the seek offset allowed by the llseek system call: #1: mkfs.ext3 <dev>; mount -t ext4 <dev> #2: mkfs.ext3 <dev>; tune2fs -Oextent,huge_file <dev>; mount -t ext4 <dev> Table. the max file size which we can write or seek at each filesystem feature tuning and file flag setting +============+===============================+===============================+ | \ File flag| | | | \ | !EXT4_EXTENTS_FL | EXT4_EXTETNS_FL | |case \| | | +------------+-------------------------------+-------------------------------+ | #1 | write: 2194719883264 | write: -------------- | | | seek: 2199023251456 | seek: -------------- | +------------+-------------------------------+-------------------------------+ | #2 | write: 4402345721856 | write: 17592186044415 | | | seek: 17592186044415 | seek: 17592186044415 | +------------+-------------------------------+-------------------------------+ The differences exist because ext4 has 2 maxbytes which are sb->s_maxbytes (= extent-mapped maxbytes) and EXT4_SB(sb)->s_bitmap_maxbytes (= block-mapped maxbytes). Although generic_file_llseek uses only extent-mapped maxbytes. (llseek of ext4_file_operations is generic_file_llseek which uses sb->s_maxbytes.) Therefore we create ext4 llseek function which uses 2 maxbytes. The new own function originates from generic_file_llseek(). If the file flag, "EXT4_EXTENTS_FL" is not set, the function alters inode->i_sb->s_maxbytes into EXT4_SB(inode->i_sb)->s_bitmap_maxbytes. Signed-off-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca>
2010-10-28 01:30:06 +00:00
*/
loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
ext4: improve llseek error handling for overly large seek offsets The llseek system call should return EINVAL if passed a seek offset which results in a write error. What this maximum offset should be depends on whether or not the huge_file file system feature is set, and whether or not the file is extent based or not. If the file has no "EXT4_EXTENTS_FL" flag, the maximum size which can be written (write systemcall) is different from the maximum size which can be sought (lseek systemcall). For example, the following 2 cases demonstrates the differences between the maximum size which can be written, versus the seek offset allowed by the llseek system call: #1: mkfs.ext3 <dev>; mount -t ext4 <dev> #2: mkfs.ext3 <dev>; tune2fs -Oextent,huge_file <dev>; mount -t ext4 <dev> Table. the max file size which we can write or seek at each filesystem feature tuning and file flag setting +============+===============================+===============================+ | \ File flag| | | | \ | !EXT4_EXTENTS_FL | EXT4_EXTETNS_FL | |case \| | | +------------+-------------------------------+-------------------------------+ | #1 | write: 2194719883264 | write: -------------- | | | seek: 2199023251456 | seek: -------------- | +------------+-------------------------------+-------------------------------+ | #2 | write: 4402345721856 | write: 17592186044415 | | | seek: 17592186044415 | seek: 17592186044415 | +------------+-------------------------------+-------------------------------+ The differences exist because ext4 has 2 maxbytes which are sb->s_maxbytes (= extent-mapped maxbytes) and EXT4_SB(sb)->s_bitmap_maxbytes (= block-mapped maxbytes). Although generic_file_llseek uses only extent-mapped maxbytes. (llseek of ext4_file_operations is generic_file_llseek which uses sb->s_maxbytes.) Therefore we create ext4 llseek function which uses 2 maxbytes. The new own function originates from generic_file_llseek(). If the file flag, "EXT4_EXTENTS_FL" is not set, the function alters inode->i_sb->s_maxbytes into EXT4_SB(inode->i_sb)->s_bitmap_maxbytes. Signed-off-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca>
2010-10-28 01:30:06 +00:00
{
struct inode *inode = file->f_mapping->host;
loff_t maxbytes;
if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
else
maxbytes = inode->i_sb->s_maxbytes;
switch (whence) {
default:
return generic_file_llseek_size(file, offset, whence,
maxbytes, i_size_read(inode));
case SEEK_HOLE:
inode_lock_shared(inode);
offset = iomap_seek_hole(inode, offset,
&ext4_iomap_report_ops);
inode_unlock_shared(inode);
break;
case SEEK_DATA:
inode_lock_shared(inode);
offset = iomap_seek_data(inode, offset,
&ext4_iomap_report_ops);
inode_unlock_shared(inode);
break;
}
if (offset < 0)
return offset;
return vfs_setpos(file, offset, maxbytes);
ext4: improve llseek error handling for overly large seek offsets The llseek system call should return EINVAL if passed a seek offset which results in a write error. What this maximum offset should be depends on whether or not the huge_file file system feature is set, and whether or not the file is extent based or not. If the file has no "EXT4_EXTENTS_FL" flag, the maximum size which can be written (write systemcall) is different from the maximum size which can be sought (lseek systemcall). For example, the following 2 cases demonstrates the differences between the maximum size which can be written, versus the seek offset allowed by the llseek system call: #1: mkfs.ext3 <dev>; mount -t ext4 <dev> #2: mkfs.ext3 <dev>; tune2fs -Oextent,huge_file <dev>; mount -t ext4 <dev> Table. the max file size which we can write or seek at each filesystem feature tuning and file flag setting +============+===============================+===============================+ | \ File flag| | | | \ | !EXT4_EXTENTS_FL | EXT4_EXTETNS_FL | |case \| | | +------------+-------------------------------+-------------------------------+ | #1 | write: 2194719883264 | write: -------------- | | | seek: 2199023251456 | seek: -------------- | +------------+-------------------------------+-------------------------------+ | #2 | write: 4402345721856 | write: 17592186044415 | | | seek: 17592186044415 | seek: 17592186044415 | +------------+-------------------------------+-------------------------------+ The differences exist because ext4 has 2 maxbytes which are sb->s_maxbytes (= extent-mapped maxbytes) and EXT4_SB(sb)->s_bitmap_maxbytes (= block-mapped maxbytes). Although generic_file_llseek uses only extent-mapped maxbytes. (llseek of ext4_file_operations is generic_file_llseek which uses sb->s_maxbytes.) Therefore we create ext4 llseek function which uses 2 maxbytes. The new own function originates from generic_file_llseek(). If the file flag, "EXT4_EXTENTS_FL" is not set, the function alters inode->i_sb->s_maxbytes into EXT4_SB(inode->i_sb)->s_bitmap_maxbytes. Signed-off-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca>
2010-10-28 01:30:06 +00:00
}
const struct file_operations ext4_file_operations = {
ext4: improve llseek error handling for overly large seek offsets The llseek system call should return EINVAL if passed a seek offset which results in a write error. What this maximum offset should be depends on whether or not the huge_file file system feature is set, and whether or not the file is extent based or not. If the file has no "EXT4_EXTENTS_FL" flag, the maximum size which can be written (write systemcall) is different from the maximum size which can be sought (lseek systemcall). For example, the following 2 cases demonstrates the differences between the maximum size which can be written, versus the seek offset allowed by the llseek system call: #1: mkfs.ext3 <dev>; mount -t ext4 <dev> #2: mkfs.ext3 <dev>; tune2fs -Oextent,huge_file <dev>; mount -t ext4 <dev> Table. the max file size which we can write or seek at each filesystem feature tuning and file flag setting +============+===============================+===============================+ | \ File flag| | | | \ | !EXT4_EXTENTS_FL | EXT4_EXTETNS_FL | |case \| | | +------------+-------------------------------+-------------------------------+ | #1 | write: 2194719883264 | write: -------------- | | | seek: 2199023251456 | seek: -------------- | +------------+-------------------------------+-------------------------------+ | #2 | write: 4402345721856 | write: 17592186044415 | | | seek: 17592186044415 | seek: 17592186044415 | +------------+-------------------------------+-------------------------------+ The differences exist because ext4 has 2 maxbytes which are sb->s_maxbytes (= extent-mapped maxbytes) and EXT4_SB(sb)->s_bitmap_maxbytes (= block-mapped maxbytes). Although generic_file_llseek uses only extent-mapped maxbytes. (llseek of ext4_file_operations is generic_file_llseek which uses sb->s_maxbytes.) Therefore we create ext4 llseek function which uses 2 maxbytes. The new own function originates from generic_file_llseek(). If the file flag, "EXT4_EXTENTS_FL" is not set, the function alters inode->i_sb->s_maxbytes into EXT4_SB(inode->i_sb)->s_bitmap_maxbytes. Signed-off-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca>
2010-10-28 01:30:06 +00:00
.llseek = ext4_llseek,
.read_iter = ext4_file_read_iter,
.write_iter = ext4_file_write_iter,
.iopoll = iocb_bio_iopoll,
.unlocked_ioctl = ext4_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = ext4_compat_ioctl,
#endif
.mmap = ext4_file_mmap,
.mmap_supported_flags = MAP_SYNC,
.open = ext4_file_open,
.release = ext4_release_file,
.fsync = ext4_sync_file,
.get_unmapped_area = thp_get_unmapped_area,
.splice_read = generic_file_splice_read,
.splice_write = iter_file_splice_write,
.fallocate = ext4_fallocate,
};
const struct inode_operations ext4_file_inode_operations = {
.setattr = ext4_setattr,
.getattr = ext4_file_getattr,
.listxattr = ext4_listxattr,
fs: rename current get acl method The current way of setting and getting posix acls through the generic xattr interface is error prone and type unsafe. The vfs needs to interpret and fixup posix acls before storing or reporting it to userspace. Various hacks exist to make this work. The code is hard to understand and difficult to maintain in it's current form. Instead of making this work by hacking posix acls through xattr handlers we are building a dedicated posix acl api around the get and set inode operations. This removes a lot of hackiness and makes the codepaths easier to maintain. A lot of background can be found in [1]. The current inode operation for getting posix acls takes an inode argument but various filesystems (e.g., 9p, cifs, overlayfs) need access to the dentry. In contrast to the ->set_acl() inode operation we cannot simply extend ->get_acl() to take a dentry argument. The ->get_acl() inode operation is called from: acl_permission_check() -> check_acl() -> get_acl() which is part of generic_permission() which in turn is part of inode_permission(). Both generic_permission() and inode_permission() are called in the ->permission() handler of various filesystems (e.g., overlayfs). So simply passing a dentry argument to ->get_acl() would amount to also having to pass a dentry argument to ->permission(). We should avoid this unnecessary change. So instead of extending the existing inode operation rename it from ->get_acl() to ->get_inode_acl() and add a ->get_acl() method later that passes a dentry argument and which filesystems that need access to the dentry can implement instead of ->get_inode_acl(). Filesystems like cifs which allow setting and getting posix acls but not using them for permission checking during lookup can simply not implement ->get_inode_acl(). This is intended to be a non-functional change. Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1] Suggested-by/Inspired-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-09-22 15:17:00 +00:00
.get_inode_acl = ext4_get_acl,
.set_acl = ext4_set_acl,
.fiemap = ext4_fiemap,
.fileattr_get = ext4_fileattr_get,
.fileattr_set = ext4_fileattr_set,
};