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Subject[PATCH 21/23] jbd2: Checksum commit blocks
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Calculate and verify the checksum of commit blocks.  In checksum v2, deprecate
most of the checksum v1 commit block checksum fields, since each block has its
own checksum.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
---
fs/jbd2/commit.c | 19 +++++++++++++++++++
fs/jbd2/recovery.c | 31 +++++++++++++++++++++++++++++++
2 files changed, 50 insertions(+), 0 deletions(-)

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 7acc318..fce7c53 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -86,6 +86,24 @@ nope:
__brelse(bh);
}

+static void jbd2_commit_block_csum_set(journal_t *j,
+ struct journal_head *descriptor)
+{
+ struct commit_header *h;
+ __u32 csum;
+
+ if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+ return;
+
+ h = (struct commit_header *)(jh2bh(descriptor)->b_data);
+ h->h_chksum_type = 0;
+ h->h_chksum_size = 0;
+ h->h_chksum[0] = 0;
+ csum = jbd2_chksum(j, j->j_csum_seed, jh2bh(descriptor)->b_data,
+ j->j_blocksize);
+ h->h_chksum[0] = cpu_to_be32(csum);
+}
+
/*
* Done it all: now submit the commit record. We should have
* cleaned up our previous buffers by now, so if we are in abort
@@ -129,6 +147,7 @@ static int journal_submit_commit_record(journal_t *journal,
tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
}
+ jbd2_commit_block_csum_set(journal, descriptor);

JBUFFER_TRACE(descriptor, "submit commit block");
lock_buffer(bh);
diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
index 513006b..a757d8d 100644
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -372,6 +372,24 @@ static int calc_chksums(journal_t *journal, struct buffer_head *bh,
return 0;
}

+static int jbd2_commit_block_csum_verify(journal_t *j, void *buf)
+{
+ struct commit_header *h;
+ __u32 provided, calculated;
+
+ if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+ return 1;
+
+ h = buf;
+ provided = h->h_chksum[0];
+ h->h_chksum[0] = 0;
+ calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
+ h->h_chksum[0] = provided;
+
+ provided = be32_to_cpu(provided);
+ return provided == calculated;
+}
+
static int do_one_pass(journal_t *journal,
struct recovery_info *info, enum passtype pass)
{
@@ -682,6 +700,19 @@ static int do_one_pass(journal_t *journal,
}
crc32_sum = ~0;
}
+ if (pass == PASS_SCAN &&
+ !jbd2_commit_block_csum_verify(journal,
+ bh->b_data)) {
+ info->end_transaction = next_commit_ID;
+
+ if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
+ JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
+ journal->j_failed_commit =
+ next_commit_ID;
+ brelse(bh);
+ break;
+ }
+ }
brelse(bh);
next_commit_ID++;
continue;


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