From: "Ritesh Harjani (IBM)" ritesh.list@gmail.com

mainline inclusion from mainline-v6.10-rc1 commit c2a09f3d782de952f09a3962d03b939e7fa7ffa4 category: bugfix bugzilla: 190028

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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Truncate operation can race with writeback, in which inode->i_size can get truncated and therefore size - folio_pos() can be negative. This fixes the len calculation. However this path doesn't get easily triggered even with data journaling.

Cc: stable@kernel.org # v6.5 Fixes: 80be8c5cc925 ("Fixes: ext4: Make mpage_journal_page_buffers use folio") Signed-off-by: Ritesh Harjani (IBM) ritesh.list@gmail.com Reviewed-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/cff4953b5c9306aba71e944ab176a5d396b9a1b7.170918225... Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Yifan Qiao qiaoyifan4@huawei.com --- fs/ext4/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 2c0e61f531f1..642522ace038 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2410,7 +2410,7 @@ static int mpage_journal_page_buffers(handle_t *handle,

if (folio_pos(folio) + len > size && !ext4_verity_in_progress(inode)) - len = size - folio_pos(folio); + len = size & (len - 1);

return ext4_journal_folio_buffers(handle, folio, len); }