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btrfs: cleanup the reserved space inside loop of btrfs_buffered_write()

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Inside the main loop of btrfs_buffered_write(), if something wrong
happened, there is a out-of-loop cleanup path to release the reserved
space.

This behavior saves some code lines, but makes it much harder to read,
as we need to check release_bytes to make sure when we need to do the
cleanup.

Factor out the cleanup part into a helper, release_reserved_space(), to
do the cleanup inside the main loop, so that we can move @release_bytes
inside the loop.

This will make later refactoring of the main loop much easier.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Qu Wenruo
2025-03-20 13:07:31 +10:30
committed by David Sterba
parent 563bd2b785
commit afe990fb59
1 changed files with 28 additions and 17 deletions
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45
fs/btrfs/file.c
View File

@@ -1076,6 +1076,24 @@ int btrfs_write_check(struct kiocb *iocb, size_t count)
return 0;
}
static void release_space(struct btrfs_inode *inode, struct extent_changeset *data_reserved,
u64 start, u64 len, bool only_release_metadata)
{
if (len == 0)
return;
if (only_release_metadata) {
btrfs_check_nocow_unlock(inode);
btrfs_delalloc_release_metadata(inode, len, true);
} else {
const struct btrfs_fs_info *fs_info = inode->root->fs_info;
btrfs_delalloc_release_space(inode, data_reserved,
round_down(start, fs_info->sectorsize),
len, true);
}
}
ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i)
{
struct file *file = iocb->ki_filp;
@@ -1083,7 +1101,6 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i)
struct inode *inode = file_inode(file);
struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
struct extent_changeset *data_reserved = NULL;
u64 release_bytes = 0;
u64 lockstart;
u64 lockend;
size_t num_written = 0;
@@ -1092,7 +1109,6 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i)
unsigned int ilock_flags = 0;
const bool nowait = (iocb->ki_flags & IOCB_NOWAIT);
unsigned int bdp_flags = (nowait ? BDP_ASYNC : 0);
bool only_release_metadata = false;
if (nowait)
ilock_flags |= BTRFS_ILOCK_TRY;
@@ -1127,7 +1143,9 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i)
size_t dirty_sectors;
size_t num_sectors;
struct folio *folio = NULL;
u64 release_bytes;
int extents_locked;
bool only_release_metadata = false;
/*
* Fault pages before locking them in prepare_one_folio()
@@ -1138,7 +1156,6 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i)
break;
}
only_release_metadata = false;
sector_offset = pos & (fs_info->sectorsize - 1);
extent_changeset_release(data_reserved);
@@ -1193,6 +1210,8 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i)
ret = balance_dirty_pages_ratelimited_flags(inode->i_mapping, bdp_flags);
if (ret) {
btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes);
release_space(BTRFS_I(inode), data_reserved,
pos, release_bytes, only_release_metadata);
break;
}
@@ -1200,6 +1219,8 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i)
if (ret) {
btrfs_delalloc_release_extents(BTRFS_I(inode),
reserve_bytes);
release_space(BTRFS_I(inode), data_reserved,
pos, release_bytes, only_release_metadata);
break;
}
@@ -1212,6 +1233,8 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i)
btrfs_delalloc_release_extents(BTRFS_I(inode),
reserve_bytes);
release_space(BTRFS_I(inode), data_reserved,
pos, release_bytes, only_release_metadata);
ret = extents_locked;
break;
}
@@ -1279,10 +1302,11 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i)
btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes);
if (ret) {
btrfs_drop_folio(fs_info, folio, pos, copied);
release_space(BTRFS_I(inode), data_reserved,
pos, release_bytes, only_release_metadata);
break;
}
release_bytes = 0;
if (only_release_metadata)
btrfs_check_nocow_unlock(BTRFS_I(inode));
@@ -1294,19 +1318,6 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i)
num_written += copied;
}
if (release_bytes) {
if (only_release_metadata) {
btrfs_check_nocow_unlock(BTRFS_I(inode));
btrfs_delalloc_release_metadata(BTRFS_I(inode),
release_bytes, true);
} else {
btrfs_delalloc_release_space(BTRFS_I(inode),
data_reserved,
round_down(pos, fs_info->sectorsize),
release_bytes, true);
}
}
extent_changeset_free(data_reserved);
if (num_written > 0) {
pagecache_isize_extended(inode, old_isize, iocb->ki_pos);