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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>
This commit is contained in:
Darrick J. Wong 2013-05-28 07:31:59 -04:00 committed by Theodore Ts'o
parent 5d9cf9c625
commit eee06c5678
2 changed files with 12 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
fs/jbd2/commit.c
View File

@ -343,20 +343,21 @@ static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
{
struct page *page = bh->b_page;
__u8 *addr;
__u32 csum;
__u32 csum32;
if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
return;
sequence = cpu_to_be32(sequence);
addr = kmap_atomic(page);
csum = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&sequence,
sizeof(sequence));
csum = jbd2_chksum(j, csum, addr + offset_in_page(bh->b_data),
bh->b_size);
csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&sequence,
sizeof(sequence));
csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
bh->b_size);
kunmap_atomic(addr);
tag->t_checksum = cpu_to_be32(csum);
/* We only have space to store the lower 16 bits of the crc32c. */
tag->t_checksum = cpu_to_be16(csum32);
}
/*
* jbd2_journal_commit_transaction

11
fs/jbd2/recovery.c
View File

@ -399,18 +399,17 @@ static int jbd2_commit_block_csum_verify(journal_t *j, void *buf)
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,