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>

1 files changed, 22 insertions, 0 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;