jbd2: checksum commit blocks

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>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 5d505cfd21c28b8458c837424fb3b4ef423538f6..16e1fe2a769f0bb123b69e823d81a750a743e65a 100644 (file)
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -85,6 +85,24 @@ 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
@@ -128,6 +146,7 @@ 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 066ee603db50ad2aef1f5a135b9e0314d2d9355d..df4a20e7d854e51add551ea2990b675c64a0d9a9 100644 (file)
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -375,6 +375,24 @@ 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)
 {
@@ -685,6 +703,19 @@ 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;