Re: [PATCH v2 5/8] ext4: avoid dividing by 0 in mb_update_avg_fragment_size() when block bitmap corrupt

From: Jan Kara
Date: Thu Jan 04 2024 - 05:43:52 EST


On Thu 21-12-23 23:05:55, Baokun Li wrote:
> 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>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

Honza

> ---
> fs/ext4/mballoc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 1f15774971d7..03500aec43ac 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -842,7 +842,7 @@ mb_update_avg_fragment_size(struct super_block *sb, struct ext4_group_info *grp)
> struct ext4_sb_info *sbi = EXT4_SB(sb);
> int new_order;
>
> - if (!test_opt2(sb, MB_OPTIMIZE_SCAN) || grp->bb_free == 0)
> + if (!test_opt2(sb, MB_OPTIMIZE_SCAN) || grp->bb_fragments == 0)
> return;
>
> new_order = mb_avg_fragment_size_order(sb,
> --
> 2.31.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR