Re: [PATCH 1/2] ext4: Don't count free clusters from a corrupt block group

[Zheng Liu <gnehzuil.liu@gmail.com>]

On Fri, Sep 27, 2013 at 05:13:57PM -0700, Darrick J. Wong wrote:
> A bg that's been flagged "corrupt" by definition has no free blocks, so that
> the allocator won't be tempted to use the damaged bg.  Therefore, we shouldn't
> count the clusters in the damaged group when calculating free counts.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>

                                                - Zheng

> ---
>  fs/ext4/balloc.c |   13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> 
> diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
> index dc5d572..6ea7b14 100644
> --- a/fs/ext4/balloc.c
> +++ b/fs/ext4/balloc.c
> @@ -640,6 +640,7 @@ ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
>  	struct ext4_group_desc *gdp;
>  	ext4_group_t i;
>  	ext4_group_t ngroups = ext4_get_groups_count(sb);
> +	struct ext4_group_info *grp;
>  #ifdef EXT4FS_DEBUG
>  	struct ext4_super_block *es;
>  	ext4_fsblk_t bitmap_count;
> @@ -655,7 +656,11 @@ ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
>  		gdp = ext4_get_group_desc(sb, i, NULL);
>  		if (!gdp)
>  			continue;
> -		desc_count += ext4_free_group_clusters(sb, gdp);
> +		grp = NULL;
> +		if (EXT4_SB(sb)->s_group_info)
> +			grp = ext4_get_group_info(sb, i);
> +		if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
> +			desc_count += ext4_free_group_clusters(sb, gdp);
>  		brelse(bitmap_bh);
>  		bitmap_bh = ext4_read_block_bitmap(sb, i);
>  		if (bitmap_bh == NULL)
> @@ -679,7 +684,11 @@ ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
>  		gdp = ext4_get_group_desc(sb, i, NULL);
>  		if (!gdp)
>  			continue;
> -		desc_count += ext4_free_group_clusters(sb, gdp);
> +		grp = NULL;
> +		if (EXT4_SB(sb)->s_group_info)
> +			grp = ext4_get_group_info(sb, i);
> +		if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
> +			desc_count += ext4_free_group_clusters(sb, gdp);
>  	}
>  
>  	return desc_count;
>