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Commit aec51758 authored by Jerry Lee's avatar Jerry Lee Committed by Theodore Ts'o
Browse files

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: 1c6bd717
Signed-off-by: default avatarJerry Lee <jerrylee@qnap.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org # 3.7+
parent c03b45b8

fs/ext4/resize.c

+2 −1
Original line number Diff line number Diff line
@@ -1927,7 +1927,8 @@ int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count) 
			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 */

		}