ext4-online-resize-fix-for-group-descriptor-corruption.patch

   1 ext4: Fix online resize block group descriptor corruption
   2
   3 From: Frederic Bohe <frederic.bohe@bull.net>
   4
   5 This is the patch for the group descriptor table corruption during
   6 online resize pointed out by Theodore Tso.  The problem was caused by
   7 the fact that the ext4 group descriptor can be either 32 or 64 bytes
   8 long.  Only the 64 bytes structure was taken into account.
   9
  10 Signed-off-by: Frederic Bohe <frederic.bohe@bull.net>
  11 Signed-off-by: Mingming Cao <cmm@us.ibm.com>
  12 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
  13 ---
  14  fs/ext4/resize.c |    3 ++-
  15  1 file changed, 2 insertions(+), 1 deletion(-)
  16
  17 Index: linux-2.6.26-rc6/fs/ext4/resize.c
  18 ===================================================================
  19 --- linux-2.6.26-rc6.orig/fs/ext4/resize.c      2008-06-17 10:43:22.000000000 -0700
  20 +++ linux-2.6.26-rc6/fs/ext4/resize.c   2008-06-17 10:43:22.000000000 -0700
  21 @@ -855,7 +855,8 @@ int ext4_group_add(struct super_block *s
  22          */
  23
  24         /* Update group descriptor block for new group */
  25 -       gdp = (struct ext4_group_desc *)primary->b_data + gdb_off;
  26 +       gdp = (struct ext4_group_desc *)((char *)primary->b_data +
  27 +                                        gdb_off * EXT4_DESC_SIZE(sb));
  28
  29         ext4_block_bitmap_set(sb, gdp, input->block_bitmap); /* LV FIXME */
  30         ext4_inode_bitmap_set(sb, gdp, input->inode_bitmap); /* LV FIXME */