jbd2: fix block tag checksum verification brokenness
Al Viro complained of a ton of bogosity with regards to the jbd2 block
tag header checksum. This one checksum is 16 bits, so cut off the
upper 16 bits and treat it as a 16-bit value and don't mess around
with be32* conversions. Fortunately metadata checksumming is still
"experimental" and not in a shipping e2fsprogs, so there should be few
users affected by this.
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
index 626846b..d4851464 100644
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -399,18 +399,17 @@
static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag,
void *buf, __u32 sequence)
{
- __u32 provided, calculated;
+ __u32 csum32;
if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
return 1;
sequence = cpu_to_be32(sequence);
- calculated = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&sequence,
- sizeof(sequence));
- calculated = jbd2_chksum(j, calculated, buf, j->j_blocksize);
- provided = be32_to_cpu(tag->t_checksum);
+ csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&sequence,
+ sizeof(sequence));
+ csum32 = jbd2_chksum(j, csum32, buf, j->j_blocksize);
- return provided == cpu_to_be32(calculated);
+ return tag->t_checksum == cpu_to_be16(csum32);
}
static int do_one_pass(journal_t *journal,
