dont-count-free-clusters-from-a-corrupt-block-group

   1 ext4: don't count free clusters from a corrupt block group
   2
   3 From: "Darrick J. Wong" <darrick.wong@oracle.com>
   4
   5 A bg that's been flagged "corrupt" by definition has no free blocks,
   6 so that the allocator won't be tempted to use the damaged bg.
   7 Therefore, we shouldn't count the clusters in the damaged group when
   8 calculating free counts.
   9
  10 Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
  11 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
  12 Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
  13 ---
  14  fs/ext4/balloc.c | 13 +++++++++++--
  15  1 file changed, 11 insertions(+), 2 deletions(-)
  16
  17 diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
  18 index dc5d572..6ea7b14 100644
  19 --- a/fs/ext4/balloc.c
  20 +++ b/fs/ext4/balloc.c
  21 @@ -640,6 +640,7 @@ ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
  22         struct ext4_group_desc *gdp;
  23         ext4_group_t i;
  24         ext4_group_t ngroups = ext4_get_groups_count(sb);
  25 +       struct ext4_group_info *grp;
  26  #ifdef EXT4FS_DEBUG
  27         struct ext4_super_block *es;
  28         ext4_fsblk_t bitmap_count;
  29 @@ -655,7 +656,11 @@ ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
  30                 gdp = ext4_get_group_desc(sb, i, NULL);
  31                 if (!gdp)
  32                         continue;
  33 -               desc_count += ext4_free_group_clusters(sb, gdp);
  34 +               grp = NULL;
  35 +               if (EXT4_SB(sb)->s_group_info)
  36 +                       grp = ext4_get_group_info(sb, i);
  37 +               if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
  38 +                       desc_count += ext4_free_group_clusters(sb, gdp);
  39                 brelse(bitmap_bh);
  40                 bitmap_bh = ext4_read_block_bitmap(sb, i);
  41                 if (bitmap_bh == NULL)
  42 @@ -679,7 +684,11 @@ ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb)
  43                 gdp = ext4_get_group_desc(sb, i, NULL);
  44                 if (!gdp)
  45                         continue;
  46 -               desc_count += ext4_free_group_clusters(sb, gdp);
  47 +               grp = NULL;
  48 +               if (EXT4_SB(sb)->s_group_info)
  49 +                       grp = ext4_get_group_info(sb, i);
  50 +               if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
  51 +                       desc_count += ext4_free_group_clusters(sb, gdp);
  52         }
  53
  54         return desc_count;