| Message ID | 20130510233807.GB5706@blackbox.djwong.org |
|---|---|
| State | Superseded, archived |
| Headers | show |
On Fri, May 10, 2013 at 04:38:07PM -0700, Darrick J. Wong wrote: > 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. > > v2: Eliminate unnecessary variables and make it clear(er) which values are 32 > bits wide. > > Reported-by: Al Viro <viro@ZenIV.linux.org.uk> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> ACKed-by: Al Viro <viro@ZenIV.linux.org.uk> -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2013-05-10, at 17:38, "Darrick J. Wong" <darrick.wong@oracle.com> wrote: > static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag, > { > > + tag->t_checksum = cpu_to_be16(csum32); > } It wouldn't be a terrible idea to add a comment in these spots, since it is a bit non-obvious to use cpu_to_be16() on a 32-bit variable. Cheers, Andreas -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 750c701..67a8a2f 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -343,20 +343,20 @@ 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); + tag->t_checksum = cpu_to_be16(csum32); } /* * jbd2_journal_commit_transaction 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_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,
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. v2: Eliminate unnecessary variables and make it clear(er) which values are 32 bits wide. Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> --- fs/jbd2/commit.c | 12 ++++++------ fs/jbd2/recovery.c | 11 +++++------ 2 files changed, 11 insertions(+), 12 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html