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| author | Darrick J. Wong <djwong@us.ibm.com> | 2012-05-27 08:10:22 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2012-05-27 08:10:22 -0400 |
| commit | 3caa487f53f65fd1e3950a6b6ae1709e6c43b334 (patch) | |
| tree | 02ee3f18422d9ffed974eb1019e98b2ee1ade01c /fs/jbd2/recovery.c | |
| parent | 42a7106de636ebf9c0b93d25b4230e14f5f2682e (diff) | |
| download | linux-3caa487f53f65fd1e3950a6b6ae1709e6c43b334.tar.gz | |
jbd2: checksum descriptor blocks
Calculate and verify a checksum of each descriptor block.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/jbd2/recovery.c')
| -rw-r--r-- | fs/jbd2/recovery.c | 37 |
1 files changed, 36 insertions, 1 deletions
diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c index 728ecd0705d95..066ee603db50a 100644 --- a/fs/jbd2/recovery.c +++ b/fs/jbd2/recovery.c @@ -174,6 +174,25 @@ static int jread(struct buffer_head **bhp, journal_t *journal, return 0; } +static int jbd2_descr_block_csum_verify(journal_t *j, + void *buf) +{ + struct jbd2_journal_block_tail *tail; + __u32 provided, calculated; + + if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2)) + return 1; + + tail = (struct jbd2_journal_block_tail *)(buf + j->j_blocksize - + sizeof(struct jbd2_journal_block_tail)); + provided = tail->t_checksum; + tail->t_checksum = 0; + calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize); + tail->t_checksum = provided; + + provided = be32_to_cpu(provided); + return provided == calculated; +} /* * Count the number of in-use tags in a journal descriptor block. @@ -186,6 +205,9 @@ static int count_tags(journal_t *journal, struct buffer_head *bh) int nr = 0, size = journal->j_blocksize; int tag_bytes = journal_tag_bytes(journal); + if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2)) + size -= sizeof(struct jbd2_journal_block_tail); + tagp = &bh->b_data[sizeof(journal_header_t)]; while ((tagp - bh->b_data + tag_bytes) <= size) { @@ -366,6 +388,7 @@ static int do_one_pass(journal_t *journal, int blocktype; int tag_bytes = journal_tag_bytes(journal); __u32 crc32_sum = ~0; /* Transactional Checksums */ + int descr_csum_size = 0; /* * First thing is to establish what we expect to find in the log @@ -451,6 +474,18 @@ static int do_one_pass(journal_t *journal, switch(blocktype) { case JBD2_DESCRIPTOR_BLOCK: + /* Verify checksum first */ + if (JBD2_HAS_INCOMPAT_FEATURE(journal, + JBD2_FEATURE_INCOMPAT_CSUM_V2)) + descr_csum_size = + sizeof(struct jbd2_journal_block_tail); + if (descr_csum_size > 0 && + !jbd2_descr_block_csum_verify(journal, + bh->b_data)) { + err = -EIO; + goto failed; + } + /* If it is a valid descriptor block, replay it * in pass REPLAY; if journal_checksums enabled, then * calculate checksums in PASS_SCAN, otherwise, @@ -481,7 +516,7 @@ static int do_one_pass(journal_t *journal, tagp = &bh->b_data[sizeof(journal_header_t)]; while ((tagp - bh->b_data + tag_bytes) - <= journal->j_blocksize) { + <= journal->j_blocksize - descr_csum_size) { unsigned long io_block; tag = (journal_block_tag_t *) tagp; |