Commit 3d2660d0 authored Feb 15, 2014 by Theodore Ts'o

ext4: fix online resize with a non-standard blocks per group setting



The set_flexbg_block_bitmap() function assumed that the number of
blocks in a blockgroup was sb->blocksize * 8, which is normally true,
but not always!  Use EXT4_BLOCKS_PER_GROUP(sb) instead, to fix block
bitmap corruption after:

mke2fs -t ext4 -g 3072 -i 4096 /dev/vdd 1G
mount -t ext4 /dev/vdd /vdd
resize2fs /dev/vdd 8G

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: Jon Bernard <jbernard@tuxion.com>
Cc: stable@vger.kernel.org

parent b93c9535

fs/ext4/resize.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -409,7 +409,7 @@ static int set_flexbg_block_bitmap(struct super_block sb, handle_t handle,
		start = ext4_group_first_block_no(sb, group);
		group -= flex_gd->groups[0].group;

		count2 = sb->s_blocksize * 8 - (block - start);
		count2 = EXT4_BLOCKS_PER_GROUP(sb) - (block - start);
		if (count2 > count)
		count2 = count;