Commit 05ac5aa1 authored Dec 01, 2016 by Daeho Jeong Committed by Theodore Ts'o Dec 01, 2016

ext4: fix inode checksum calculation problem if i_extra_size is small



We've fixed the race condition problem in calculating ext4 checksum
value in commit b47820ed ("ext4: avoid modifying checksum fields
directly during checksum veficationon"). However, by this change,
when calculating the checksum value of inode whose i_extra_size is
less than 4, we couldn't calculate the checksum value in a proper way.
This problem was found and reported by Nix, Thank you.

Reported-by: Nix <nix@esperi.org.uk>
Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com>
Signed-off-by: Youngjin Gil <youngjin.gil@samsung.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

parent 6dcc693b

fs/ext4/inode.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -72,10 +72,9 @@ static __u32 ext4_inode_csum(struct inode inode, struct ext4_inode raw,
		csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum,
		csum_size);
		offset += csum_size;
		csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
		EXT4_INODE_SIZE(inode->i_sb) -
		offset);
		}
		csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
		EXT4_INODE_SIZE(inode->i_sb) - offset);
		}

		return csum;

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