Sandro/linux
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-09-18 23:09:29 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

ext4: write back partial-zeroed edges in WRITE_ZEROES

Browse Source 
FALLOC_FL_WRITE_ZEROES requires that all blocks in the requested range
end up as written extents with zeroed content. For unaligned edges that
were partial-zeroed in dirty unwritten or delalloc state, the buffer
is left dirty while the underlying extent may not yet be converted to
written. As a result, a subsequent SYNC write to this range would still
trigger metadata changes, which violates the semantics of WRITE_ZEROES.

Fix this by calling filemap_write_and_wait_range() for partial-zeroed
edges to flush out the zeroed data and ensure the extent conversion
is complete.

Fixes: f4265b8d32 ("ext4: add FALLOC_FL_WRITE_ZEROES support")
Cc: stable@vger.kernel.org
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260714080044.4038124-9-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Zhang Yi
2026-07-22 12:57:16 -04:00
committed by Theodore Ts'o
parent a5179156ac
commit d19d239ada
1 changed files with 9 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files
fs/ext4/extents.c
+9 -1
View File
@@ -4791,7 +4791,15 @@ static long ext4_zero_range(struct file *file, loff_t offset,
if (IS_ALIGNED(offset | end, blocksize))
return ret;
if (((file->f_flags & O_SYNC) || IS_SYNC(inode)) && partial_zeroed) {
/*
* In FALLOC_FL_WRITE_ZEROES mode, edges that have been partially
* zeroed must be written back to ensure the entire zeroed range
* is converted to the written state. In SYNC mode, writeback is
* also required to persist the zeroed data to disk.
*/
if (partial_zeroed &&
((mode & FALLOC_FL_WRITE_ZEROES) ||
(file->f_flags & O_SYNC) || IS_SYNC(inode))) {
ret = filemap_write_and_wait_range(inode->i_mapping, offset,
end - 1);
if (ret)