This is a note to let you know that I've just added the patch titled
ext4: avoid dividing by 0 in mb_update_avg_fragment_size() when block bitmap corrupt
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-avoid-dividing-by-0-in-mb_update_avg_fragment_s.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 19559be5d85e016f867b596f7fcd04c0f37c059d
Author: Baokun Li <libaokun1@xxxxxxxxxx>
Date: Thu Jan 4 22:20:37 2024 +0800
ext4: avoid dividing by 0 in mb_update_avg_fragment_size() when block bitmap corrupt
[ Upstream commit 993bf0f4c393b3667830918f9247438a8f6fdb5b ]
Determine if bb_fragments is 0 instead of determining bb_free to eliminate
the risk of dividing by zero when the block bitmap is corrupted.
Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Link: https://lore.kernel.org/r/20240104142040.2835097-6-libaokun1@xxxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 762c2f8b5b2a8..48930df9ae565 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -853,7 +853,7 @@ mb_update_avg_fragment_size(struct super_block *sb, struct ext4_group_info *grp)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
- if (!test_opt2(sb, MB_OPTIMIZE_SCAN) || grp->bb_free == 0)
+ if (!test_opt2(sb, MB_OPTIMIZE_SCAN) || grp->bb_fragments == 0)
return;
write_lock(&sbi->s_mb_rb_lock);
