From 3093e586b019c65b9975bb1ad0760c4273dce839 Mon Sep 17 00:00:00 2001 From: "Ritesh Harjani (IBM)" Date: Thu, 29 Feb 2024 11:40:13 +0530 Subject: [PATCH] ext4: Fixes len calculation in mpage_journal_page_buffers commit c2a09f3d782de952f09a3962d03b939e7fa7ffa4 upstream. 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) Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/cff4953b5c9306aba71e944ab176a5d396b9a1b7.1709182250.git.ritesh.list@gmail.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- 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 abb49f6c6ff4..d5eb8d44c6c8 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2342,7 +2342,7 @@ 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); }