linux/fs/btrfs/ordered-data.c
Filipe Manana f13e01b89d btrfs: ensure fast fsync waits for ordered extents after a write failure
If a write path in COW mode fails, either before submitting a bio for the
new extents or an actual IO error happens, we can end up allowing a fast
fsync to log file extent items that point to unwritten extents.

This is because dropping the extent maps happens when completing ordered
extents, at btrfs_finish_one_ordered(), and the completion of an ordered
extent is executed in a work queue.

This can result in a fast fsync to start logging file extent items based
on existing extent maps before the ordered extents complete, therefore
resulting in a log that has file extent items that point to unwritten
extents, resulting in a corrupt file if a crash happens after and the log
tree is replayed the next time the fs is mounted.

This can happen for both direct IO writes and buffered writes.

For example consider a direct IO write, in COW mode, that fails at
btrfs_dio_submit_io() because btrfs_extract_ordered_extent() returned an
error:

1) We call btrfs_finish_ordered_extent() with the 'uptodate' parameter
   set to false, meaning an error happened;

2) That results in marking the ordered extent with the BTRFS_ORDERED_IOERR
   flag;

3) btrfs_finish_ordered_extent() queues the completion of the ordered
   extent - so that btrfs_finish_one_ordered() will be executed later in
   a work queue. That function will drop extent maps in the range when
   it's executed, since the extent maps point to unwritten locations
   (signaled by the BTRFS_ORDERED_IOERR flag);

4) After calling btrfs_finish_ordered_extent() we keep going down the
   write path and unlock the inode;

5) After that a fast fsync starts and locks the inode;

6) Before the work queue executes btrfs_finish_one_ordered(), the fsync
   task sees the extent maps that point to the unwritten locations and
   logs file extent items based on them - it does not know they are
   unwritten, and the fast fsync path does not wait for ordered extents
   to complete, which is an intentional behaviour in order to reduce
   latency.

For the buffered write case, here's one example:

1) A fast fsync begins, and it starts by flushing delalloc and waiting for
   the writeback to complete by calling filemap_fdatawait_range();

2) Flushing the dellaloc created a new extent map X;

3) During the writeback some IO error happened, and at the end io callback
   (end_bbio_data_write()) we call btrfs_finish_ordered_extent(), which
   sets the BTRFS_ORDERED_IOERR flag in the ordered extent and queues its
   completion;

4) After queuing the ordered extent completion, the end io callback clears
   the writeback flag from all pages (or folios), and from that moment the
   fast fsync can proceed;

5) The fast fsync proceeds sees extent map X and logs a file extent item
   based on extent map X, resulting in a log that points to an unwritten
   data extent - because the ordered extent completion hasn't run yet, it
   happens only after the logging.

To fix this make btrfs_finish_ordered_extent() set the inode flag
BTRFS_INODE_NEEDS_FULL_SYNC in case an error happened for a COW write,
so that a fast fsync will wait for ordered extent completion.

Note that this issues of using extent maps that point to unwritten
locations can not happen for reads, because in read paths we start by
locking the extent range and wait for any ordered extents in the range
to complete before looking for extent maps.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-28 16:35:12 +02:00

1287 lines
37 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/writeback.h>
#include <linux/sched/mm.h>
#include "messages.h"
#include "misc.h"
#include "ctree.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "extent_io.h"
#include "disk-io.h"
#include "compression.h"
#include "delalloc-space.h"
#include "qgroup.h"
#include "subpage.h"
#include "file.h"
static struct kmem_cache *btrfs_ordered_extent_cache;
static u64 entry_end(struct btrfs_ordered_extent *entry)
{
if (entry->file_offset + entry->num_bytes < entry->file_offset)
return (u64)-1;
return entry->file_offset + entry->num_bytes;
}
/* returns NULL if the insertion worked, or it returns the node it did find
* in the tree
*/
static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
struct rb_node *node)
{
struct rb_node **p = &root->rb_node;
struct rb_node *parent = NULL;
struct btrfs_ordered_extent *entry;
while (*p) {
parent = *p;
entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
if (file_offset < entry->file_offset)
p = &(*p)->rb_left;
else if (file_offset >= entry_end(entry))
p = &(*p)->rb_right;
else
return parent;
}
rb_link_node(node, parent, p);
rb_insert_color(node, root);
return NULL;
}
/*
* look for a given offset in the tree, and if it can't be found return the
* first lesser offset
*/
static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
struct rb_node **prev_ret)
{
struct rb_node *n = root->rb_node;
struct rb_node *prev = NULL;
struct rb_node *test;
struct btrfs_ordered_extent *entry;
struct btrfs_ordered_extent *prev_entry = NULL;
while (n) {
entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
prev = n;
prev_entry = entry;
if (file_offset < entry->file_offset)
n = n->rb_left;
else if (file_offset >= entry_end(entry))
n = n->rb_right;
else
return n;
}
if (!prev_ret)
return NULL;
while (prev && file_offset >= entry_end(prev_entry)) {
test = rb_next(prev);
if (!test)
break;
prev_entry = rb_entry(test, struct btrfs_ordered_extent,
rb_node);
if (file_offset < entry_end(prev_entry))
break;
prev = test;
}
if (prev)
prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
rb_node);
while (prev && file_offset < entry_end(prev_entry)) {
test = rb_prev(prev);
if (!test)
break;
prev_entry = rb_entry(test, struct btrfs_ordered_extent,
rb_node);
prev = test;
}
*prev_ret = prev;
return NULL;
}
static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
u64 len)
{
if (file_offset + len <= entry->file_offset ||
entry->file_offset + entry->num_bytes <= file_offset)
return 0;
return 1;
}
/*
* look find the first ordered struct that has this offset, otherwise
* the first one less than this offset
*/
static inline struct rb_node *ordered_tree_search(struct btrfs_inode *inode,
u64 file_offset)
{
struct rb_node *prev = NULL;
struct rb_node *ret;
struct btrfs_ordered_extent *entry;
if (inode->ordered_tree_last) {
entry = rb_entry(inode->ordered_tree_last, struct btrfs_ordered_extent,
rb_node);
if (in_range(file_offset, entry->file_offset, entry->num_bytes))
return inode->ordered_tree_last;
}
ret = __tree_search(&inode->ordered_tree, file_offset, &prev);
if (!ret)
ret = prev;
if (ret)
inode->ordered_tree_last = ret;
return ret;
}
static struct btrfs_ordered_extent *alloc_ordered_extent(
struct btrfs_inode *inode, u64 file_offset, u64 num_bytes,
u64 ram_bytes, u64 disk_bytenr, u64 disk_num_bytes,
u64 offset, unsigned long flags, int compress_type)
{
struct btrfs_ordered_extent *entry;
int ret;
u64 qgroup_rsv = 0;
if (flags &
((1 << BTRFS_ORDERED_NOCOW) | (1 << BTRFS_ORDERED_PREALLOC))) {
/* For nocow write, we can release the qgroup rsv right now */
ret = btrfs_qgroup_free_data(inode, NULL, file_offset, num_bytes, &qgroup_rsv);
if (ret < 0)
return ERR_PTR(ret);
} else {
/*
* The ordered extent has reserved qgroup space, release now
* and pass the reserved number for qgroup_record to free.
*/
ret = btrfs_qgroup_release_data(inode, file_offset, num_bytes, &qgroup_rsv);
if (ret < 0)
return ERR_PTR(ret);
}
entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
if (!entry)
return ERR_PTR(-ENOMEM);
entry->file_offset = file_offset;
entry->num_bytes = num_bytes;
entry->ram_bytes = ram_bytes;
entry->disk_bytenr = disk_bytenr;
entry->disk_num_bytes = disk_num_bytes;
entry->offset = offset;
entry->bytes_left = num_bytes;
entry->inode = igrab(&inode->vfs_inode);
entry->compress_type = compress_type;
entry->truncated_len = (u64)-1;
entry->qgroup_rsv = qgroup_rsv;
entry->flags = flags;
refcount_set(&entry->refs, 1);
init_waitqueue_head(&entry->wait);
INIT_LIST_HEAD(&entry->list);
INIT_LIST_HEAD(&entry->log_list);
INIT_LIST_HEAD(&entry->root_extent_list);
INIT_LIST_HEAD(&entry->work_list);
INIT_LIST_HEAD(&entry->bioc_list);
init_completion(&entry->completion);
/*
* We don't need the count_max_extents here, we can assume that all of
* that work has been done at higher layers, so this is truly the
* smallest the extent is going to get.
*/
spin_lock(&inode->lock);
btrfs_mod_outstanding_extents(inode, 1);
spin_unlock(&inode->lock);
return entry;
}
static void insert_ordered_extent(struct btrfs_ordered_extent *entry)
{
struct btrfs_inode *inode = BTRFS_I(entry->inode);
struct btrfs_root *root = inode->root;
struct btrfs_fs_info *fs_info = root->fs_info;
struct rb_node *node;
trace_btrfs_ordered_extent_add(inode, entry);
percpu_counter_add_batch(&fs_info->ordered_bytes, entry->num_bytes,
fs_info->delalloc_batch);
/* One ref for the tree. */
refcount_inc(&entry->refs);
spin_lock_irq(&inode->ordered_tree_lock);
node = tree_insert(&inode->ordered_tree, entry->file_offset,
&entry->rb_node);
if (node)
btrfs_panic(fs_info, -EEXIST,
"inconsistency in ordered tree at offset %llu",
entry->file_offset);
spin_unlock_irq(&inode->ordered_tree_lock);
spin_lock(&root->ordered_extent_lock);
list_add_tail(&entry->root_extent_list,
&root->ordered_extents);
root->nr_ordered_extents++;
if (root->nr_ordered_extents == 1) {
spin_lock(&fs_info->ordered_root_lock);
BUG_ON(!list_empty(&root->ordered_root));
list_add_tail(&root->ordered_root, &fs_info->ordered_roots);
spin_unlock(&fs_info->ordered_root_lock);
}
spin_unlock(&root->ordered_extent_lock);
}
/*
* Add an ordered extent to the per-inode tree.
*
* @inode: Inode that this extent is for.
* @file_offset: Logical offset in file where the extent starts.
* @num_bytes: Logical length of extent in file.
* @ram_bytes: Full length of unencoded data.
* @disk_bytenr: Offset of extent on disk.
* @disk_num_bytes: Size of extent on disk.
* @offset: Offset into unencoded data where file data starts.
* @flags: Flags specifying type of extent (1 << BTRFS_ORDERED_*).
* @compress_type: Compression algorithm used for data.
*
* Most of these parameters correspond to &struct btrfs_file_extent_item. The
* tree is given a single reference on the ordered extent that was inserted, and
* the returned pointer is given a second reference.
*
* Return: the new ordered extent or error pointer.
*/
struct btrfs_ordered_extent *btrfs_alloc_ordered_extent(
struct btrfs_inode *inode, u64 file_offset,
u64 num_bytes, u64 ram_bytes, u64 disk_bytenr,
u64 disk_num_bytes, u64 offset, unsigned long flags,
int compress_type)
{
struct btrfs_ordered_extent *entry;
ASSERT((flags & ~BTRFS_ORDERED_TYPE_FLAGS) == 0);
entry = alloc_ordered_extent(inode, file_offset, num_bytes, ram_bytes,
disk_bytenr, disk_num_bytes, offset, flags,
compress_type);
if (!IS_ERR(entry))
insert_ordered_extent(entry);
return entry;
}
/*
* Add a struct btrfs_ordered_sum into the list of checksums to be inserted
* when an ordered extent is finished. If the list covers more than one
* ordered extent, it is split across multiples.
*/
void btrfs_add_ordered_sum(struct btrfs_ordered_extent *entry,
struct btrfs_ordered_sum *sum)
{
struct btrfs_inode *inode = BTRFS_I(entry->inode);
spin_lock_irq(&inode->ordered_tree_lock);
list_add_tail(&sum->list, &entry->list);
spin_unlock_irq(&inode->ordered_tree_lock);
}
void btrfs_mark_ordered_extent_error(struct btrfs_ordered_extent *ordered)
{
if (!test_and_set_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
mapping_set_error(ordered->inode->i_mapping, -EIO);
}
static void finish_ordered_fn(struct btrfs_work *work)
{
struct btrfs_ordered_extent *ordered_extent;
ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
btrfs_finish_ordered_io(ordered_extent);
}
static bool can_finish_ordered_extent(struct btrfs_ordered_extent *ordered,
struct page *page, u64 file_offset,
u64 len, bool uptodate)
{
struct btrfs_inode *inode = BTRFS_I(ordered->inode);
struct btrfs_fs_info *fs_info = inode->root->fs_info;
lockdep_assert_held(&inode->ordered_tree_lock);
if (page) {
ASSERT(page->mapping);
ASSERT(page_offset(page) <= file_offset);
ASSERT(file_offset + len <= page_offset(page) + PAGE_SIZE);
/*
* Ordered (Private2) bit indicates whether we still have
* pending io unfinished for the ordered extent.
*
* If there's no such bit, we need to skip to next range.
*/
if (!btrfs_folio_test_ordered(fs_info, page_folio(page),
file_offset, len))
return false;
btrfs_folio_clear_ordered(fs_info, page_folio(page), file_offset, len);
}
/* Now we're fine to update the accounting. */
if (WARN_ON_ONCE(len > ordered->bytes_left)) {
btrfs_crit(fs_info,
"bad ordered extent accounting, root=%llu ino=%llu OE offset=%llu OE len=%llu to_dec=%llu left=%llu",
btrfs_root_id(inode->root), btrfs_ino(inode),
ordered->file_offset, ordered->num_bytes,
len, ordered->bytes_left);
ordered->bytes_left = 0;
} else {
ordered->bytes_left -= len;
}
if (!uptodate)
set_bit(BTRFS_ORDERED_IOERR, &ordered->flags);
if (ordered->bytes_left)
return false;
/*
* All the IO of the ordered extent is finished, we need to queue
* the finish_func to be executed.
*/
set_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags);
cond_wake_up(&ordered->wait);
refcount_inc(&ordered->refs);
trace_btrfs_ordered_extent_mark_finished(inode, ordered);
return true;
}
static void btrfs_queue_ordered_fn(struct btrfs_ordered_extent *ordered)
{
struct btrfs_inode *inode = BTRFS_I(ordered->inode);
struct btrfs_fs_info *fs_info = inode->root->fs_info;
struct btrfs_workqueue *wq = btrfs_is_free_space_inode(inode) ?
fs_info->endio_freespace_worker : fs_info->endio_write_workers;
btrfs_init_work(&ordered->work, finish_ordered_fn, NULL);
btrfs_queue_work(wq, &ordered->work);
}
bool btrfs_finish_ordered_extent(struct btrfs_ordered_extent *ordered,
struct page *page, u64 file_offset, u64 len,
bool uptodate)
{
struct btrfs_inode *inode = BTRFS_I(ordered->inode);
unsigned long flags;
bool ret;
trace_btrfs_finish_ordered_extent(inode, file_offset, len, uptodate);
spin_lock_irqsave(&inode->ordered_tree_lock, flags);
ret = can_finish_ordered_extent(ordered, page, file_offset, len, uptodate);
spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
/*
* If this is a COW write it means we created new extent maps for the
* range and they point to unwritten locations if we got an error either
* before submitting a bio or during IO.
*
* We have marked the ordered extent with BTRFS_ORDERED_IOERR, and we
* are queuing its completion below. During completion, at
* btrfs_finish_one_ordered(), we will drop the extent maps for the
* unwritten extents.
*
* However because completion runs in a work queue we can end up having
* a fast fsync running before that. In the case of direct IO, once we
* unlock the inode the fsync might start, and we queue the completion
* before unlocking the inode. In the case of buffered IO when writeback
* finishes (end_bbio_data_write()) we queue the completion, so if the
* writeback was triggered by a fast fsync, the fsync might start
* logging before ordered extent completion runs in the work queue.
*
* The fast fsync will log file extent items based on the extent maps it
* finds, so if by the time it collects extent maps the ordered extent
* completion didn't happen yet, it will log file extent items that
* point to unwritten extents, resulting in a corruption if a crash
* happens and the log tree is replayed. Note that a fast fsync does not
* wait for completion of ordered extents in order to reduce latency.
*
* Set a flag in the inode so that the next fast fsync will wait for
* ordered extents to complete before starting to log.
*/
if (!uptodate && !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags))
set_bit(BTRFS_INODE_COW_WRITE_ERROR, &inode->runtime_flags);
if (ret)
btrfs_queue_ordered_fn(ordered);
return ret;
}
/*
* Mark all ordered extents io inside the specified range finished.
*
* @page: The involved page for the operation.
* For uncompressed buffered IO, the page status also needs to be
* updated to indicate whether the pending ordered io is finished.
* Can be NULL for direct IO and compressed write.
* For these cases, callers are ensured they won't execute the
* endio function twice.
*
* This function is called for endio, thus the range must have ordered
* extent(s) covering it.
*/
void btrfs_mark_ordered_io_finished(struct btrfs_inode *inode,
struct page *page, u64 file_offset,
u64 num_bytes, bool uptodate)
{
struct rb_node *node;
struct btrfs_ordered_extent *entry = NULL;
unsigned long flags;
u64 cur = file_offset;
trace_btrfs_writepage_end_io_hook(inode, file_offset,
file_offset + num_bytes - 1,
uptodate);
spin_lock_irqsave(&inode->ordered_tree_lock, flags);
while (cur < file_offset + num_bytes) {
u64 entry_end;
u64 end;
u32 len;
node = ordered_tree_search(inode, cur);
/* No ordered extents at all */
if (!node)
break;
entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
entry_end = entry->file_offset + entry->num_bytes;
/*
* |<-- OE --->| |
* cur
* Go to next OE.
*/
if (cur >= entry_end) {
node = rb_next(node);
/* No more ordered extents, exit */
if (!node)
break;
entry = rb_entry(node, struct btrfs_ordered_extent,
rb_node);
/* Go to next ordered extent and continue */
cur = entry->file_offset;
continue;
}
/*
* | |<--- OE --->|
* cur
* Go to the start of OE.
*/
if (cur < entry->file_offset) {
cur = entry->file_offset;
continue;
}
/*
* Now we are definitely inside one ordered extent.
*
* |<--- OE --->|
* |
* cur
*/
end = min(entry->file_offset + entry->num_bytes,
file_offset + num_bytes) - 1;
ASSERT(end + 1 - cur < U32_MAX);
len = end + 1 - cur;
if (can_finish_ordered_extent(entry, page, cur, len, uptodate)) {
spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
btrfs_queue_ordered_fn(entry);
spin_lock_irqsave(&inode->ordered_tree_lock, flags);
}
cur += len;
}
spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
}
/*
* Finish IO for one ordered extent across a given range. The range can only
* contain one ordered extent.
*
* @cached: The cached ordered extent. If not NULL, we can skip the tree
* search and use the ordered extent directly.
* Will be also used to store the finished ordered extent.
* @file_offset: File offset for the finished IO
* @io_size: Length of the finish IO range
*
* Return true if the ordered extent is finished in the range, and update
* @cached.
* Return false otherwise.
*
* NOTE: The range can NOT cross multiple ordered extents.
* Thus caller should ensure the range doesn't cross ordered extents.
*/
bool btrfs_dec_test_ordered_pending(struct btrfs_inode *inode,
struct btrfs_ordered_extent **cached,
u64 file_offset, u64 io_size)
{
struct rb_node *node;
struct btrfs_ordered_extent *entry = NULL;
unsigned long flags;
bool finished = false;
spin_lock_irqsave(&inode->ordered_tree_lock, flags);
if (cached && *cached) {
entry = *cached;
goto have_entry;
}
node = ordered_tree_search(inode, file_offset);
if (!node)
goto out;
entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
have_entry:
if (!in_range(file_offset, entry->file_offset, entry->num_bytes))
goto out;
if (io_size > entry->bytes_left)
btrfs_crit(inode->root->fs_info,
"bad ordered accounting left %llu size %llu",
entry->bytes_left, io_size);
entry->bytes_left -= io_size;
if (entry->bytes_left == 0) {
/*
* Ensure only one caller can set the flag and finished_ret
* accordingly
*/
finished = !test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
/* test_and_set_bit implies a barrier */
cond_wake_up_nomb(&entry->wait);
}
out:
if (finished && cached && entry) {
*cached = entry;
refcount_inc(&entry->refs);
trace_btrfs_ordered_extent_dec_test_pending(inode, entry);
}
spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
return finished;
}
/*
* used to drop a reference on an ordered extent. This will free
* the extent if the last reference is dropped
*/
void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
{
struct list_head *cur;
struct btrfs_ordered_sum *sum;
trace_btrfs_ordered_extent_put(BTRFS_I(entry->inode), entry);
if (refcount_dec_and_test(&entry->refs)) {
ASSERT(list_empty(&entry->root_extent_list));
ASSERT(list_empty(&entry->log_list));
ASSERT(RB_EMPTY_NODE(&entry->rb_node));
if (entry->inode)
btrfs_add_delayed_iput(BTRFS_I(entry->inode));
while (!list_empty(&entry->list)) {
cur = entry->list.next;
sum = list_entry(cur, struct btrfs_ordered_sum, list);
list_del(&sum->list);
kvfree(sum);
}
kmem_cache_free(btrfs_ordered_extent_cache, entry);
}
}
/*
* remove an ordered extent from the tree. No references are dropped
* and waiters are woken up.
*/
void btrfs_remove_ordered_extent(struct btrfs_inode *btrfs_inode,
struct btrfs_ordered_extent *entry)
{
struct btrfs_root *root = btrfs_inode->root;
struct btrfs_fs_info *fs_info = root->fs_info;
struct rb_node *node;
bool pending;
bool freespace_inode;
/*
* If this is a free space inode the thread has not acquired the ordered
* extents lockdep map.
*/
freespace_inode = btrfs_is_free_space_inode(btrfs_inode);
btrfs_lockdep_acquire(fs_info, btrfs_trans_pending_ordered);
/* This is paired with btrfs_alloc_ordered_extent. */
spin_lock(&btrfs_inode->lock);
btrfs_mod_outstanding_extents(btrfs_inode, -1);
spin_unlock(&btrfs_inode->lock);
if (root != fs_info->tree_root) {
u64 release;
if (test_bit(BTRFS_ORDERED_ENCODED, &entry->flags))
release = entry->disk_num_bytes;
else
release = entry->num_bytes;
btrfs_delalloc_release_metadata(btrfs_inode, release,
test_bit(BTRFS_ORDERED_IOERR,
&entry->flags));
}
percpu_counter_add_batch(&fs_info->ordered_bytes, -entry->num_bytes,
fs_info->delalloc_batch);
spin_lock_irq(&btrfs_inode->ordered_tree_lock);
node = &entry->rb_node;
rb_erase(node, &btrfs_inode->ordered_tree);
RB_CLEAR_NODE(node);
if (btrfs_inode->ordered_tree_last == node)
btrfs_inode->ordered_tree_last = NULL;
set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
pending = test_and_clear_bit(BTRFS_ORDERED_PENDING, &entry->flags);
spin_unlock_irq(&btrfs_inode->ordered_tree_lock);
/*
* The current running transaction is waiting on us, we need to let it
* know that we're complete and wake it up.
*/
if (pending) {
struct btrfs_transaction *trans;
/*
* The checks for trans are just a formality, it should be set,
* but if it isn't we don't want to deref/assert under the spin
* lock, so be nice and check if trans is set, but ASSERT() so
* if it isn't set a developer will notice.
*/
spin_lock(&fs_info->trans_lock);
trans = fs_info->running_transaction;
if (trans)
refcount_inc(&trans->use_count);
spin_unlock(&fs_info->trans_lock);
ASSERT(trans || BTRFS_FS_ERROR(fs_info));
if (trans) {
if (atomic_dec_and_test(&trans->pending_ordered))
wake_up(&trans->pending_wait);
btrfs_put_transaction(trans);
}
}
btrfs_lockdep_release(fs_info, btrfs_trans_pending_ordered);
spin_lock(&root->ordered_extent_lock);
list_del_init(&entry->root_extent_list);
root->nr_ordered_extents--;
trace_btrfs_ordered_extent_remove(btrfs_inode, entry);
if (!root->nr_ordered_extents) {
spin_lock(&fs_info->ordered_root_lock);
BUG_ON(list_empty(&root->ordered_root));
list_del_init(&root->ordered_root);
spin_unlock(&fs_info->ordered_root_lock);
}
spin_unlock(&root->ordered_extent_lock);
wake_up(&entry->wait);
if (!freespace_inode)
btrfs_lockdep_release(fs_info, btrfs_ordered_extent);
}
static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
{
struct btrfs_ordered_extent *ordered;
ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
btrfs_start_ordered_extent(ordered);
complete(&ordered->completion);
}
/*
* wait for all the ordered extents in a root. This is done when balancing
* space between drives.
*/
u64 btrfs_wait_ordered_extents(struct btrfs_root *root, u64 nr,
const u64 range_start, const u64 range_len)
{
struct btrfs_fs_info *fs_info = root->fs_info;
LIST_HEAD(splice);
LIST_HEAD(skipped);
LIST_HEAD(works);
struct btrfs_ordered_extent *ordered, *next;
u64 count = 0;
const u64 range_end = range_start + range_len;
mutex_lock(&root->ordered_extent_mutex);
spin_lock(&root->ordered_extent_lock);
list_splice_init(&root->ordered_extents, &splice);
while (!list_empty(&splice) && nr) {
ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
root_extent_list);
if (range_end <= ordered->disk_bytenr ||
ordered->disk_bytenr + ordered->disk_num_bytes <= range_start) {
list_move_tail(&ordered->root_extent_list, &skipped);
cond_resched_lock(&root->ordered_extent_lock);
continue;
}
list_move_tail(&ordered->root_extent_list,
&root->ordered_extents);
refcount_inc(&ordered->refs);
spin_unlock(&root->ordered_extent_lock);
btrfs_init_work(&ordered->flush_work,
btrfs_run_ordered_extent_work, NULL);
list_add_tail(&ordered->work_list, &works);
btrfs_queue_work(fs_info->flush_workers, &ordered->flush_work);
cond_resched();
spin_lock(&root->ordered_extent_lock);
if (nr != U64_MAX)
nr--;
count++;
}
list_splice_tail(&skipped, &root->ordered_extents);
list_splice_tail(&splice, &root->ordered_extents);
spin_unlock(&root->ordered_extent_lock);
list_for_each_entry_safe(ordered, next, &works, work_list) {
list_del_init(&ordered->work_list);
wait_for_completion(&ordered->completion);
btrfs_put_ordered_extent(ordered);
cond_resched();
}
mutex_unlock(&root->ordered_extent_mutex);
return count;
}
void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, u64 nr,
const u64 range_start, const u64 range_len)
{
struct btrfs_root *root;
LIST_HEAD(splice);
u64 done;
mutex_lock(&fs_info->ordered_operations_mutex);
spin_lock(&fs_info->ordered_root_lock);
list_splice_init(&fs_info->ordered_roots, &splice);
while (!list_empty(&splice) && nr) {
root = list_first_entry(&splice, struct btrfs_root,
ordered_root);
root = btrfs_grab_root(root);
BUG_ON(!root);
list_move_tail(&root->ordered_root,
&fs_info->ordered_roots);
spin_unlock(&fs_info->ordered_root_lock);
done = btrfs_wait_ordered_extents(root, nr,
range_start, range_len);
btrfs_put_root(root);
spin_lock(&fs_info->ordered_root_lock);
if (nr != U64_MAX) {
nr -= done;
}
}
list_splice_tail(&splice, &fs_info->ordered_roots);
spin_unlock(&fs_info->ordered_root_lock);
mutex_unlock(&fs_info->ordered_operations_mutex);
}
/*
* Start IO and wait for a given ordered extent to finish.
*
* Wait on page writeback for all the pages in the extent and the IO completion
* code to insert metadata into the btree corresponding to the extent.
*/
void btrfs_start_ordered_extent(struct btrfs_ordered_extent *entry)
{
u64 start = entry->file_offset;
u64 end = start + entry->num_bytes - 1;
struct btrfs_inode *inode = BTRFS_I(entry->inode);
bool freespace_inode;
trace_btrfs_ordered_extent_start(inode, entry);
/*
* If this is a free space inode do not take the ordered extents lockdep
* map.
*/
freespace_inode = btrfs_is_free_space_inode(inode);
/*
* pages in the range can be dirty, clean or writeback. We
* start IO on any dirty ones so the wait doesn't stall waiting
* for the flusher thread to find them
*/
if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
filemap_fdatawrite_range(inode->vfs_inode.i_mapping, start, end);
if (!freespace_inode)
btrfs_might_wait_for_event(inode->root->fs_info, btrfs_ordered_extent);
wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE, &entry->flags));
}
/*
* Used to wait on ordered extents across a large range of bytes.
*/
int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
{
int ret = 0;
int ret_wb = 0;
u64 end;
u64 orig_end;
struct btrfs_ordered_extent *ordered;
if (start + len < start) {
orig_end = OFFSET_MAX;
} else {
orig_end = start + len - 1;
if (orig_end > OFFSET_MAX)
orig_end = OFFSET_MAX;
}
/* start IO across the range first to instantiate any delalloc
* extents
*/
ret = btrfs_fdatawrite_range(inode, start, orig_end);
if (ret)
return ret;
/*
* If we have a writeback error don't return immediately. Wait first
* for any ordered extents that haven't completed yet. This is to make
* sure no one can dirty the same page ranges and call writepages()
* before the ordered extents complete - to avoid failures (-EEXIST)
* when adding the new ordered extents to the ordered tree.
*/
ret_wb = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
end = orig_end;
while (1) {
ordered = btrfs_lookup_first_ordered_extent(BTRFS_I(inode), end);
if (!ordered)
break;
if (ordered->file_offset > orig_end) {
btrfs_put_ordered_extent(ordered);
break;
}
if (ordered->file_offset + ordered->num_bytes <= start) {
btrfs_put_ordered_extent(ordered);
break;
}
btrfs_start_ordered_extent(ordered);
end = ordered->file_offset;
/*
* If the ordered extent had an error save the error but don't
* exit without waiting first for all other ordered extents in
* the range to complete.
*/
if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
ret = -EIO;
btrfs_put_ordered_extent(ordered);
if (end == 0 || end == start)
break;
end--;
}
return ret_wb ? ret_wb : ret;
}
/*
* find an ordered extent corresponding to file_offset. return NULL if
* nothing is found, otherwise take a reference on the extent and return it
*/
struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct btrfs_inode *inode,
u64 file_offset)
{
struct rb_node *node;
struct btrfs_ordered_extent *entry = NULL;
unsigned long flags;
spin_lock_irqsave(&inode->ordered_tree_lock, flags);
node = ordered_tree_search(inode, file_offset);
if (!node)
goto out;
entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
if (!in_range(file_offset, entry->file_offset, entry->num_bytes))
entry = NULL;
if (entry) {
refcount_inc(&entry->refs);
trace_btrfs_ordered_extent_lookup(inode, entry);
}
out:
spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
return entry;
}
/* Since the DIO code tries to lock a wide area we need to look for any ordered
* extents that exist in the range, rather than just the start of the range.
*/
struct btrfs_ordered_extent *btrfs_lookup_ordered_range(
struct btrfs_inode *inode, u64 file_offset, u64 len)
{
struct rb_node *node;
struct btrfs_ordered_extent *entry = NULL;
spin_lock_irq(&inode->ordered_tree_lock);
node = ordered_tree_search(inode, file_offset);
if (!node) {
node = ordered_tree_search(inode, file_offset + len);
if (!node)
goto out;
}
while (1) {
entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
if (range_overlaps(entry, file_offset, len))
break;
if (entry->file_offset >= file_offset + len) {
entry = NULL;
break;
}
entry = NULL;
node = rb_next(node);
if (!node)
break;
}
out:
if (entry) {
refcount_inc(&entry->refs);
trace_btrfs_ordered_extent_lookup_range(inode, entry);
}
spin_unlock_irq(&inode->ordered_tree_lock);
return entry;
}
/*
* Adds all ordered extents to the given list. The list ends up sorted by the
* file_offset of the ordered extents.
*/
void btrfs_get_ordered_extents_for_logging(struct btrfs_inode *inode,
struct list_head *list)
{
struct rb_node *n;
ASSERT(inode_is_locked(&inode->vfs_inode));
spin_lock_irq(&inode->ordered_tree_lock);
for (n = rb_first(&inode->ordered_tree); n; n = rb_next(n)) {
struct btrfs_ordered_extent *ordered;
ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
if (test_bit(BTRFS_ORDERED_LOGGED, &ordered->flags))
continue;
ASSERT(list_empty(&ordered->log_list));
list_add_tail(&ordered->log_list, list);
refcount_inc(&ordered->refs);
trace_btrfs_ordered_extent_lookup_for_logging(inode, ordered);
}
spin_unlock_irq(&inode->ordered_tree_lock);
}
/*
* lookup and return any extent before 'file_offset'. NULL is returned
* if none is found
*/
struct btrfs_ordered_extent *
btrfs_lookup_first_ordered_extent(struct btrfs_inode *inode, u64 file_offset)
{
struct rb_node *node;
struct btrfs_ordered_extent *entry = NULL;
spin_lock_irq(&inode->ordered_tree_lock);
node = ordered_tree_search(inode, file_offset);
if (!node)
goto out;
entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
refcount_inc(&entry->refs);
trace_btrfs_ordered_extent_lookup_first(inode, entry);
out:
spin_unlock_irq(&inode->ordered_tree_lock);
return entry;
}
/*
* Lookup the first ordered extent that overlaps the range
* [@file_offset, @file_offset + @len).
*
* The difference between this and btrfs_lookup_first_ordered_extent() is
* that this one won't return any ordered extent that does not overlap the range.
* And the difference against btrfs_lookup_ordered_extent() is, this function
* ensures the first ordered extent gets returned.
*/
struct btrfs_ordered_extent *btrfs_lookup_first_ordered_range(
struct btrfs_inode *inode, u64 file_offset, u64 len)
{
struct rb_node *node;
struct rb_node *cur;
struct rb_node *prev;
struct rb_node *next;
struct btrfs_ordered_extent *entry = NULL;
spin_lock_irq(&inode->ordered_tree_lock);
node = inode->ordered_tree.rb_node;
/*
* Here we don't want to use tree_search() which will use tree->last
* and screw up the search order.
* And __tree_search() can't return the adjacent ordered extents
* either, thus here we do our own search.
*/
while (node) {
entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
if (file_offset < entry->file_offset) {
node = node->rb_left;
} else if (file_offset >= entry_end(entry)) {
node = node->rb_right;
} else {
/*
* Direct hit, got an ordered extent that starts at
* @file_offset
*/
goto out;
}
}
if (!entry) {
/* Empty tree */
goto out;
}
cur = &entry->rb_node;
/* We got an entry around @file_offset, check adjacent entries */
if (entry->file_offset < file_offset) {
prev = cur;
next = rb_next(cur);
} else {
prev = rb_prev(cur);
next = cur;
}
if (prev) {
entry = rb_entry(prev, struct btrfs_ordered_extent, rb_node);
if (range_overlaps(entry, file_offset, len))
goto out;
}
if (next) {
entry = rb_entry(next, struct btrfs_ordered_extent, rb_node);
if (range_overlaps(entry, file_offset, len))
goto out;
}
/* No ordered extent in the range */
entry = NULL;
out:
if (entry) {
refcount_inc(&entry->refs);
trace_btrfs_ordered_extent_lookup_first_range(inode, entry);
}
spin_unlock_irq(&inode->ordered_tree_lock);
return entry;
}
/*
* Lock the passed range and ensures all pending ordered extents in it are run
* to completion.
*
* @inode: Inode whose ordered tree is to be searched
* @start: Beginning of range to flush
* @end: Last byte of range to lock
* @cached_state: If passed, will return the extent state responsible for the
* locked range. It's the caller's responsibility to free the
* cached state.
*
* Always return with the given range locked, ensuring after it's called no
* order extent can be pending.
*/
void btrfs_lock_and_flush_ordered_range(struct btrfs_inode *inode, u64 start,
u64 end,
struct extent_state **cached_state)
{
struct btrfs_ordered_extent *ordered;
struct extent_state *cache = NULL;
struct extent_state **cachedp = &cache;
if (cached_state)
cachedp = cached_state;
while (1) {
lock_extent(&inode->io_tree, start, end, cachedp);
ordered = btrfs_lookup_ordered_range(inode, start,
end - start + 1);
if (!ordered) {
/*
* If no external cached_state has been passed then
* decrement the extra ref taken for cachedp since we
* aren't exposing it outside of this function
*/
if (!cached_state)
refcount_dec(&cache->refs);
break;
}
unlock_extent(&inode->io_tree, start, end, cachedp);
btrfs_start_ordered_extent(ordered);
btrfs_put_ordered_extent(ordered);
}
}
/*
* Lock the passed range and ensure all pending ordered extents in it are run
* to completion in nowait mode.
*
* Return true if btrfs_lock_ordered_range does not return any extents,
* otherwise false.
*/
bool btrfs_try_lock_ordered_range(struct btrfs_inode *inode, u64 start, u64 end,
struct extent_state **cached_state)
{
struct btrfs_ordered_extent *ordered;
if (!try_lock_extent(&inode->io_tree, start, end, cached_state))
return false;
ordered = btrfs_lookup_ordered_range(inode, start, end - start + 1);
if (!ordered)
return true;
btrfs_put_ordered_extent(ordered);
unlock_extent(&inode->io_tree, start, end, cached_state);
return false;
}
/* Split out a new ordered extent for this first @len bytes of @ordered. */
struct btrfs_ordered_extent *btrfs_split_ordered_extent(
struct btrfs_ordered_extent *ordered, u64 len)
{
struct btrfs_inode *inode = BTRFS_I(ordered->inode);
struct btrfs_root *root = inode->root;
struct btrfs_fs_info *fs_info = root->fs_info;
u64 file_offset = ordered->file_offset;
u64 disk_bytenr = ordered->disk_bytenr;
unsigned long flags = ordered->flags;
struct btrfs_ordered_sum *sum, *tmpsum;
struct btrfs_ordered_extent *new;
struct rb_node *node;
u64 offset = 0;
trace_btrfs_ordered_extent_split(inode, ordered);
ASSERT(!(flags & (1U << BTRFS_ORDERED_COMPRESSED)));
/*
* The entire bio must be covered by the ordered extent, but we can't
* reduce the original extent to a zero length either.
*/
if (WARN_ON_ONCE(len >= ordered->num_bytes))
return ERR_PTR(-EINVAL);
/* We cannot split partially completed ordered extents. */
if (ordered->bytes_left) {
ASSERT(!(flags & ~BTRFS_ORDERED_TYPE_FLAGS));
if (WARN_ON_ONCE(ordered->bytes_left != ordered->disk_num_bytes))
return ERR_PTR(-EINVAL);
}
/* We cannot split a compressed ordered extent. */
if (WARN_ON_ONCE(ordered->disk_num_bytes != ordered->num_bytes))
return ERR_PTR(-EINVAL);
new = alloc_ordered_extent(inode, file_offset, len, len, disk_bytenr,
len, 0, flags, ordered->compress_type);
if (IS_ERR(new))
return new;
/* One ref for the tree. */
refcount_inc(&new->refs);
spin_lock_irq(&root->ordered_extent_lock);
spin_lock(&inode->ordered_tree_lock);
/* Remove from tree once */
node = &ordered->rb_node;
rb_erase(node, &inode->ordered_tree);
RB_CLEAR_NODE(node);
if (inode->ordered_tree_last == node)
inode->ordered_tree_last = NULL;
ordered->file_offset += len;
ordered->disk_bytenr += len;
ordered->num_bytes -= len;
ordered->disk_num_bytes -= len;
ordered->ram_bytes -= len;
if (test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags)) {
ASSERT(ordered->bytes_left == 0);
new->bytes_left = 0;
} else {
ordered->bytes_left -= len;
}
if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags)) {
if (ordered->truncated_len > len) {
ordered->truncated_len -= len;
} else {
new->truncated_len = ordered->truncated_len;
ordered->truncated_len = 0;
}
}
list_for_each_entry_safe(sum, tmpsum, &ordered->list, list) {
if (offset == len)
break;
list_move_tail(&sum->list, &new->list);
offset += sum->len;
}
/* Re-insert the node */
node = tree_insert(&inode->ordered_tree, ordered->file_offset,
&ordered->rb_node);
if (node)
btrfs_panic(fs_info, -EEXIST,
"zoned: inconsistency in ordered tree at offset %llu",
ordered->file_offset);
node = tree_insert(&inode->ordered_tree, new->file_offset, &new->rb_node);
if (node)
btrfs_panic(fs_info, -EEXIST,
"zoned: inconsistency in ordered tree at offset %llu",
new->file_offset);
spin_unlock(&inode->ordered_tree_lock);
list_add_tail(&new->root_extent_list, &root->ordered_extents);
root->nr_ordered_extents++;
spin_unlock_irq(&root->ordered_extent_lock);
return new;
}
int __init ordered_data_init(void)
{
btrfs_ordered_extent_cache = KMEM_CACHE(btrfs_ordered_extent, 0);
if (!btrfs_ordered_extent_cache)
return -ENOMEM;
return 0;
}
void __cold ordered_data_exit(void)
{
kmem_cache_destroy(btrfs_ordered_extent_cache);
}