ext4: fix an off-by-one issue during moving extents

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commit 12e803c882 upstream.

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: a40759fb16 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Zhang Yi 2025-09-12 18:58:41 +08:00 • committed by Greg Kroah-Hartman

parent a6e94557cd

commit 3fb2b7550d

1 changed files with 1 additions and 1 deletions

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fs/ext4/move_extent.c

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