jbd2: checksum data blocks that are stored in the journal

Calculate and verify checksums of each data block being stored in the journal.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

3 files changed, 60 insertions, 2 deletions

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 16e1fe2a769f..216f4299f65e 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -338,6 +338,26 @@ static void jbd2_descr_block_csum_set(journal_t *j,
         tail->t_checksum = cpu_to_be32(csum);
 }
 
+static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
+                                    struct buffer_head *bh, __u32 sequence)
+{
+        struct page *page = bh->b_page;
+        __u8 *addr;
+        __u32 csum;
+
+        if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+                return;
+
+        sequence = cpu_to_be32(sequence);
+        addr = kmap_atomic(page, KM_USER0);
+        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);
+        kunmap_atomic(addr, KM_USER0);
+
+        tag->t_checksum = cpu_to_be32(csum);
+}
 /*
  * jbd2_journal_commit_transaction
  *
@@ -669,6 +689,8 @@ void jbd2_journal_commit_transaction(journal_t *journal)
                 tag = (journal_block_tag_t *) tagp;
                 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr);
                 tag->t_flags = cpu_to_be16(tag_flag);
+                jbd2_block_tag_csum_set(journal, tag, jh2bh(new_jh),
+                                        commit_transaction->t_tid);
                 tagp += tag_bytes;
                 space_left -= tag_bytes;
 
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 9072f03d30b5..e9a3c4c85594 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -2097,10 +2097,16 @@ int jbd2_journal_blocks_per_page(struct inode *inode)
  */
 size_t journal_tag_bytes(journal_t *journal)
 {
+        journal_block_tag_t tag;
+        size_t x = 0;
+
+        if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+                x += sizeof(tag.t_checksum);
+
         if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
-                return JBD2_TAG_SIZE64;
+                return x + JBD2_TAG_SIZE64;
         else
-                return JBD2_TAG_SIZE32;
+                return x + JBD2_TAG_SIZE32;
 }
 
 /*
diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
index df4a20e7d854..0131e4362534 100644
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -393,6 +393,23 @@ static int jbd2_commit_block_csum_verify(journal_t *j, void *buf)
         return provided == calculated;
 }
 
+static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag,
+                                      void *buf, __u32 sequence)
+{
+        __u32 provided, calculated;
+
+        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);
+
+        return provided == cpu_to_be32(calculated);
+}
+
 static int do_one_pass(journal_t *journal,
                         struct recovery_info *info, enum passtype pass)
 {
@@ -569,6 +586,19 @@ static int do_one_pass(journal_t *journal,
                                                 goto skip_write;
                                         }
 
+                                        /* Look for block corruption */
+                                        if (!jbd2_block_tag_csum_verify(
+                                                journal, tag, obh->b_data,
+                                                be32_to_cpu(tmp->h_sequence))) {
+                                                brelse(obh);
+                                                success = -EIO;
+                                                printk(KERN_ERR "JBD: Invalid "
+                                                       "checksum recovering "
+                                                       "block %llu in log\n",
+                                                       blocknr);
+                                                continue;
+                                        }
+
                                         /* Find a buffer for the new
                                          * data being restored */
                                         nbh = __getblk(journal->j_fs_dev,