diff options
| author | Zhang Yi <yi.zhang@huawei.com> | 2025-09-12 18:58:41 +0800 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2025-09-26 08:36:08 -0400 |
| commit | 12e803c8827d049ae8f2c743ef66ab87ae898375 (patch) | |
| tree | 69d0e0e502391bf02b4d8680c4ee294398df05a7 | |
| parent | 9d80eaa1a1d37539224982b76c9ceeee736510b9 (diff) | |
ext4: fix an off-by-one issue during moving extents
During the movement of a written extent, mext_page_mkuptodate() is
called to read data in the range [from, to) into the page cache and to
update the corresponding buffers. Therefore, we should not wait on any
buffer whose start offset is >= 'to'. Otherwise, it will return -EIO and
fail the extents movement.
$ for i in `seq 3 -1 0`; \
do xfs_io -fs -c "pwrite -b 1024 $((i * 1024)) 1024" /mnt/foo; \
done
$ umount /mnt && mount /dev/pmem1s /mnt # drop cache
$ e4defrag /mnt/foo
e4defrag 1.47.0 (5-Feb-2023)
ext4 defragmentation for /mnt/foo
[1/1]/mnt/foo: 0% [ NG ]
Success: [0/1]
Cc: stable@kernel.org
Fixes: a40759fb16ae ("ext4: remove array of buffer_heads from mext_page_mkuptodate()")
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-ID: <20250912105841.1886799-1-yi.zhang@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/move_extent.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c index adae3caf175a..4b091c21908f 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -225,7 +225,7 @@ static int mext_page_mkuptodate(struct folio *folio, size_t from, size_t to) do { if (bh_offset(bh) + blocksize <= from) continue; - if (bh_offset(bh) > to) + if (bh_offset(bh) >= to) break; wait_on_buffer(bh); if (buffer_uptodate(bh)) |