ext4: Fix online resize block group descriptor corruption From: Frederic Bohe This is the patch for the group descriptor table corruption during online resize pointed out by Theodore Tso. The problem was caused by the fact that the ext4 group descriptor can be either 32 or 64 bytes long. Only the 64 bytes structure was taken into account. Signed-off-by: Frederic Bohe Signed-off-by: Mingming Cao Signed-off-by: "Theodore Ts'o" --- fs/ext4/resize.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) Index: linux-2.6.26-rc6/fs/ext4/resize.c =================================================================== --- linux-2.6.26-rc6.orig/fs/ext4/resize.c 2008-06-17 10:43:22.000000000 -0700 +++ linux-2.6.26-rc6/fs/ext4/resize.c 2008-06-17 10:43:22.000000000 -0700 @@ -855,7 +855,8 @@ int ext4_group_add(struct super_block *s */ /* Update group descriptor block for new group */ - gdp = (struct ext4_group_desc *)primary->b_data + gdb_off; + gdp = (struct ext4_group_desc *)((char *)primary->b_data + + gdb_off * EXT4_DESC_SIZE(sb)); ext4_block_bitmap_set(sb, gdp, input->block_bitmap); /* LV FIXME */ ext4_inode_bitmap_set(sb, gdp, input->inode_bitmap); /* LV FIXME */