ldiskfs/kernel_patches/patches/ext3-sector_t-overflow-2.6.12.patch

   1 Subject: Avoid disk sector_t overflow for >2TB ext3 filesystem
   2 From: Mingming Cao <cmm@us.ibm.com>
   3
   4
   5 If ext3 filesystem is larger than 2TB, and sector_t is a u32 (i.e.
   6 CONFIG_LBD not defined in the kernel), the calculation of the disk sector
   7 will overflow.  Add check at ext3_fill_super() and ext3_group_extend() to
   8 prevent mount/remount/resize >2TB ext3 filesystem if sector_t size is 4
   9 bytes.
  10
  11 Verified this patch on a 32 bit platform without CONFIG_LBD defined
  12 (sector_t is 32 bits long), mount refuse to mount a 10TB ext3.
  13
  14 Signed-off-by: Mingming Cao<cmm@us.ibm.com>
  15 Acked-by: Andreas Dilger <adilger@clusterfs.com>
  16 Signed-off-by: Andrew Morton <akpm@osdl.org>
  17 ---
  18
  19  fs/ext3/resize.c |   10 ++++++++++
  20  fs/ext3/super.c  |   10 ++++++++++
  21  2 files changed, 20 insertions(+)
  22
  23 diff -puN fs/ext3/resize.c~avoid-disk-sector_t-overflow-for-2tb-ext3-filesystem fs/ext3/resize.c
  24 --- devel/fs/ext3/resize.c~avoid-disk-sector_t-overflow-for-2tb-ext3-filesystem 2006-05-22 14:09:53.000000000 -0700
  25 +++ devel-akpm/fs/ext3/resize.c 2006-05-22 14:10:56.000000000 -0700
  26 @@ -926,6 +926,16 @@ int ext3_group_extend(struct super_block
  27         if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
  28                 return 0;
  29
  30 +       if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
  31 +               printk(KERN_ERR "EXT3-fs: filesystem on %s: "
  32 +                      "too large to resize to %lu blocks safely\n",
  33 +                      sb->s_id, n_blocks_count);
  34 +               if (sizeof(sector_t) < 8)
  35 +                       ext3_warning(sb, __FUNCTION__,
  36 +                                    "CONFIG_LBD not enabled\n");
  37 +               return -EINVAL;
  38 +       }
  39 +
  40         if (n_blocks_count < o_blocks_count) {
  41                 ext3_warning(sb, __FUNCTION__,
  42                              "can't shrink FS - resize aborted");
  43 diff -puN fs/ext3/super.c~avoid-disk-sector_t-overflow-for-2tb-ext3-filesystem fs/ext3/super.c
  44 --- devel/fs/ext3/super.c~avoid-disk-sector_t-overflow-for-2tb-ext3-filesystem  2006-05-22 14:09:53.000000000 -0700
  45 +++ devel-akpm/fs/ext3/super.c  2006-05-22 14:11:10.000000000 -0700
  46 @@ -1565,6 +1565,17 @@ static int ext3_fill_super (struct super
  47                 goto failed_mount;
  48         }
  49
  50 +       if (le32_to_cpu(es->s_blocks_count) >
  51 +           (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
  52 +               printk(KERN_ERR "EXT3-fs: filesystem on %s: "
  53 +                      "too large to mount safely - %u blocks\n", sb->s_id,
  54 +                      le32_to_cpu(es->s_blocks_count));
  55 +               if (sizeof(sector_t) < 8)
  56 +                       printk(KERN_WARNING
  57 +                              "EXT3-fs: CONFIG_LBD not enabled\n");
  58 +               goto failed_mount;
  59 +       }
  60 +
  61         if (EXT3_BLOCKS_PER_GROUP(sb) == 0)
  62                 goto cantfind_ext3;
  63         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
  64 _