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
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 69a6261..f3b84cd 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -409,7 +409,7 @@
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;