ext4: fix overflow caused by missing cast in ext4_resize_fs()

On a 32-bit platform, the value of n_blcoks_count may be wrong during
the file system is resized to size larger than 2^32 blocks.  This may
caused the superblock being corrupted with zero blocks count.

Fixes: 1c6bd7173d
Signed-off-by: Jerry Lee <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>
Cc: [email protected] # 3.7+
This commit is contained in:
Jerry Lee 2017-08-06 01:18:31 -04:00 • committed by Theodore Ts'o
commit aec51758ce

View file

@ -1927,7 +1927,8 @@ retry:
n_desc_blocks = o_desc_blocks +
le16_to_cpu(es->s_reserved_gdt_blocks);
n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
n_blocks_count = n_group * EXT4_BLOCKS_PER_GROUP(sb);
n_blocks_count = (ext4_fsblk_t)n_group *
EXT4_BLOCKS_PER_GROUP(sb);
n_group--; /* set to last group number */
}