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authorDarrick J. Wong <darrick.wong@oracle.com>2013-05-28 07:31:59 -0400
committerTheodore Ts'o <tytso@mit.edu>2013-05-28 07:31:59 -0400
commiteee06c56784496805b198964c59fa8cd7c00bf48 (patch)
treecbdfeadc9a0ee81b83ef012f81dcae1acb0f660f /fs/jbd2/commit.c
parent5d9cf9c6254ddc551fb51072f59dfae60e579736 (diff)
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.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 0f53946f13c..e61d7224a72 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