ext4: avoid modifying checksum fields directly during checksum verification
We temporally change checksum fields in buffers of some types of
metadata into '0' for verifying the checksum values. By doing this
without locking the buffer, some metadata's checksums, which are
being committed or written back to the storage, could be damaged.
In our test, several metadata blocks were found with damaged metadata
checksum value during recovery process. When we only verify the
checksum value, we have to avoid modifying checksum fields directly.
Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com>
Signed-off-by: Youngjin Gil <youngjin.gil@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index f7140ca6..44ee5d9 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -51,26 +51,32 @@
struct ext4_inode_info *ei)
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
- __u16 csum_lo;
- __u16 csum_hi = 0;
__u32 csum;
+ __u16 dummy_csum = 0;
+ int offset = offsetof(struct ext4_inode, i_checksum_lo);
+ unsigned int csum_size = sizeof(dummy_csum);
- csum_lo = le16_to_cpu(raw->i_checksum_lo);
- raw->i_checksum_lo = 0;
- if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
- EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
- csum_hi = le16_to_cpu(raw->i_checksum_hi);
- raw->i_checksum_hi = 0;
+ csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw, offset);
+ csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, csum_size);
+ offset += csum_size;
+ csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
+ EXT4_GOOD_OLD_INODE_SIZE - offset);
+
+ if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
+ offset = offsetof(struct ext4_inode, i_checksum_hi);
+ csum = ext4_chksum(sbi, csum, (__u8 *)raw +
+ EXT4_GOOD_OLD_INODE_SIZE,
+ offset - EXT4_GOOD_OLD_INODE_SIZE);
+ if (EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
+ 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, ei->i_csum_seed, (__u8 *)raw,
- EXT4_INODE_SIZE(inode->i_sb));
-
- raw->i_checksum_lo = cpu_to_le16(csum_lo);
- if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
- EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
- raw->i_checksum_hi = cpu_to_le16(csum_hi);
-
return csum;
}