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| author | Darrick J. Wong <darrick.wong@oracle.com> | 2013-05-28 07:31:59 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2013-05-28 07:31:59 -0400 |
| commit | eee06c56784496805b198964c59fa8cd7c00bf48 (patch) | |
| tree | cbdfeadc9a0ee81b83ef012f81dcae1acb0f660f /fs/jbd2/commit.c | |
| parent | 5d9cf9c6254ddc551fb51072f59dfae60e579736 (diff) | |
| download | linux-eee06c56784496805b198964c59fa8cd7c00bf48.tar.gz | |
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>
Diffstat (limited to 'fs/jbd2/commit.c')
| -rw-r--r-- | fs/jbd2/commit.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 0f53946f13c1..e61d7224a729 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -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 |