unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
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ext4: fix online resize with a non-standard blocks per group setting

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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
This commit is contained in:
Theodore Ts'o 2014-02-15 22:42:25 -05:00
parent b93c953534
commit 3d2660d0c9
1 changed files with 1 additions and 1 deletions
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2
fs/ext4/resize.c
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@ -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;