ldiskfs/kernel_patches/patches/ext3-block-bitmap-validation-2.6-rhel5.patch

   1  fs/ext3/balloc.c |   99 ++++++++++++++++++++++++++++++++++++++++++++----------
   2  1 files changed, 81 insertions(+), 18 deletions(-)
   3 diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c
   4 index ff3428e..a9140ea 100644
   5 Index: linux-stage/fs/ext3/balloc.c
   6 ===================================================================
   7 --- linux-stage.orig/fs/ext3/balloc.c
   8 +++ linux-stage/fs/ext3/balloc.c
   9 @@ -143,9 +143,96 @@ unsigned ext3_init_block_bitmap(struct s
  10         return free_blocks - sbi->s_itb_per_group - 2;
  11  }
  12
  13 -/*
  14 - * Read the bitmap for a given block_group, reading into the specified
  15 - * slot in the superblock's bitmap cache.
  16 +/**
  17 +* bh_uptodate_or_lock: Test whether the buffer is uptodate
  18 +* @bh: struct buffer_head
  19 +*
  20 +* Return true if the buffer is up-to-date and false,
  21 +* with the buffer locked, if not.
  22 +*/
  23 +int bh_uptodate_or_lock(struct buffer_head *bh)
  24 +{
  25 +       if (!buffer_uptodate(bh)) {
  26 +               lock_buffer(bh);
  27 +               if (!buffer_uptodate(bh))
  28 +                       return 0;
  29 +               unlock_buffer(bh);
  30 +       }
  31 +       return 1;
  32 +}
  33 +
  34 +/**
  35 +* bh_submit_read: Submit a locked buffer for reading
  36 +* @bh: struct buffer_head
  37 +*
  38 +* Returns a negative error
  39 +*/
  40 +int bh_submit_read(struct buffer_head *bh)
  41 +{
  42 +       if (!buffer_locked(bh))
  43 +               lock_buffer(bh);
  44 +       if (buffer_uptodate(bh))
  45 +               return 0;
  46 +       get_bh(bh);
  47 +       bh->b_end_io = end_buffer_read_sync;
  48 +       submit_bh(READ, bh);
  49 +       wait_on_buffer(bh);
  50 +       if (buffer_uptodate(bh))
  51 +               return 0;
  52 +       return -EIO;
  53 +}
  54 +
  55 +static int ext3_valid_block_bitmap(struct super_block *sb,
  56 +                                  struct ext3_group_desc *desc,
  57 +                                  unsigned int block_group,
  58 +                                  struct buffer_head *bh)
  59 +{
  60 +       ext3_grpblk_t offset;
  61 +       ext3_grpblk_t next_zero_bit;
  62 +       ext3_fsblk_t bitmap_blk;
  63 +       ext3_fsblk_t group_first_block;
  64 +
  65 +       group_first_block = ext3_group_first_block_no(sb, block_group);
  66 +
  67 +       /* check whether block bitmap block number is set */
  68 +       bitmap_blk = le32_to_cpu(desc->bg_block_bitmap);
  69 +       offset = bitmap_blk - group_first_block;
  70 +       if (!ext3_test_bit(offset, bh->b_data))
  71 +               /* bad block bitmap */
  72 +               goto err_out;
  73 +
  74 +       /* check whether the inode bitmap block number is set */
  75 +       bitmap_blk = le32_to_cpu(desc->bg_inode_bitmap);
  76 +       offset = bitmap_blk - group_first_block;
  77 +       if (!ext3_test_bit(offset, bh->b_data))
  78 +               /* bad block bitmap */
  79 +               goto err_out;
  80 +
  81 +       /* check whether the inode table block number is set */
  82 +       bitmap_blk = le32_to_cpu(desc->bg_inode_table);
  83 +       offset = bitmap_blk - group_first_block;
  84 +       next_zero_bit = ext3_find_next_zero_bit(bh->b_data,
  85 +                               offset + EXT3_SB(sb)->s_itb_per_group,
  86 +                               offset);
  87 +       if (next_zero_bit >= offset + EXT3_SB(sb)->s_itb_per_group)
  88 +               /* good bitmap for inode tables */
  89 +               return 1;
  90 +
  91 +err_out:
  92 +       ext3_error(sb, __FUNCTION__,
  93 +                  "Invalid block bitmap - "
  94 +                  "block_group = %d, block = %lu",
  95 +                  (int)block_group, bitmap_blk);
  96 +       return 0;
  97 +}
  98 +
  99 +/**
 100 + * read_block_bitmap()
 101 + * @sb:                 super block
 102 + * @block_group: given block group
 103 + *
 104 + * Read the bitmap for a given block_group,and validate the
 105 + * bits for block/inode/inode tables are set in the bitmaps.
 106   *
 107   * Return buffer_head on success or NULL in case of failure.
 108   */
 109 @@ -154,29 +241,42 @@ read_block_bitmap(struct super_block *sb
 110  {
 111         struct ext3_group_desc * desc;
 112         struct buffer_head * bh = NULL;
 113 +       ext3_fsblk_t bitmap_blk;
 114
 115         desc = ext3_get_group_desc (sb, block_group, NULL);
 116         if (!desc)
 117 -               goto error_out;
 118 +               return NULL;
 119 +       bitmap_blk = desc->bg_block_bitmap;
 120 +       bh = sb_getblk(sb, bitmap_blk);
 121 +       if (unlikely(!bh)) {
 122 +               ext3_error(sb, __FUNCTION__,
 123 +                          "Can not read block bitmap - "
 124 +                          "block group = %d, block_bitmap = %lu",
 125 +                          (int)block_group, bitmap_blk);
 126 +               return NULL;
 127 +       }
 128 +       if (bh_uptodate_or_lock(bh))
 129 +               return bh;
 130 +
 131         if (desc->bg_flags & cpu_to_le16(EXT3_BG_BLOCK_UNINIT)) {
 132 -               bh = sb_getblk(sb, le32_to_cpu(desc->bg_block_bitmap));
 133 -               if (!buffer_uptodate(bh)) {
 134 -                       lock_buffer(bh);
 135 -                       if (!buffer_uptodate(bh)) {
 136 -                               ext3_init_block_bitmap(sb, bh,block_group,desc);
 137 -                               set_buffer_uptodate(bh);
 138 -                       }
 139 -                       unlock_buffer(bh);
 140 -               }
 141 -       } else {
 142 -               bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap));
 143 +               ext3_init_block_bitmap(sb, bh, block_group, desc);
 144 +               set_buffer_uptodate(bh);
 145 +               unlock_buffer(bh);
 146 +               return bh;
 147 +       }
 148 +       if (bh_submit_read(bh) < 0) {
 149 +               brelse(bh);
 150 +               ext3_error(sb, __FUNCTION__,
 151 +                          "Cannot read block bitmap - "
 152 +                          "block group = %d block_bitmap = %lu",
 153 +                          (int)block_group, bitmap_blk);
 154 +               return NULL;
 155 +       }
 156 +       if (!ext3_valid_block_bitmap(sb, desc, block_group, bh)) {
 157 +               brelse(bh);
 158 +               return NULL;
 159         }
 160 -       if (!bh)
 161 -               ext3_error (sb, "read_block_bitmap",
 162 -                           "Cannot read block bitmap - "
 163 -                           "block_group = %d, block_bitmap = %u",
 164 -                           block_group, le32_to_cpu(desc->bg_block_bitmap));
 165 -error_out:
 166 +
 167         return bh;
 168  }
 169  /*