jbd2: checksum revocation blocks

Compute and verify revoke blocks inside the journal.

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

diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
index 980f3d6..728ecd0 100644 (file)
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -706,6 +706,25 @@ static int do_one_pass(journal_t *journal,
        return err;
 }
 
+static int jbd2_revoke_block_csum_verify(journal_t *j,
+                                        void *buf)
+{
+       struct jbd2_journal_revoke_tail *tail;
+       __u32 provided, calculated;
+
+       if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+               return 1;
+
+       tail = (struct jbd2_journal_revoke_tail *)(buf + j->j_blocksize -
+                       sizeof(struct jbd2_journal_revoke_tail));
+       provided = tail->r_checksum;
+       tail->r_checksum = 0;
+       calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
+       tail->r_checksum = provided;
+
+       provided = be32_to_cpu(provided);
+       return provided == calculated;
+}
 
 /* Scan a revoke record, marking all blocks mentioned as revoked. */
 
@@ -720,6 +739,9 @@ static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
        offset = sizeof(jbd2_journal_revoke_header_t);
        max = be32_to_cpu(header->r_count);
 
+       if (!jbd2_revoke_block_csum_verify(journal, header))
+               return -EINVAL;
+
        if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
                record_len = 8;
 

diff --git a/fs/jbd2/revoke.c b/fs/jbd2/revoke.c
index 6973705..f30b80b 100644 (file)
--- a/fs/jbd2/revoke.c
+++ b/fs/jbd2/revoke.c
@@ -578,6 +578,7 @@ static void write_one_revoke_record(journal_t *journal,
                                    struct jbd2_revoke_record_s *record,
                                    int write_op)
 {
+       int csum_size = 0;
        struct journal_head *descriptor;
        int offset;
        journal_header_t *header;
@@ -592,9 +593,13 @@ static void write_one_revoke_record(journal_t *journal,
        descriptor = *descriptorp;
        offset = *offsetp;
 
+       /* Do we need to leave space at the end for a checksum? */
+       if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+               csum_size = sizeof(struct jbd2_journal_revoke_tail);
+
        /* Make sure we have a descriptor with space left for the record */
        if (descriptor) {
-               if (offset == journal->j_blocksize) {
+               if (offset >= journal->j_blocksize - csum_size) {
                        flush_descriptor(journal, descriptor, offset, write_op);
                        descriptor = NULL;
                }
@@ -631,6 +636,24 @@ static void write_one_revoke_record(journal_t *journal,
        *offsetp = offset;
 }
 
+static void jbd2_revoke_csum_set(journal_t *j,
+                                struct journal_head *descriptor)
+{
+       struct jbd2_journal_revoke_tail *tail;
+       __u32 csum;
+
+       if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+               return;
+
+       tail = (struct jbd2_journal_revoke_tail *)
+                       (jh2bh(descriptor)->b_data + j->j_blocksize -
+                       sizeof(struct jbd2_journal_revoke_tail));
+       tail->r_checksum = 0;
+       csum = jbd2_chksum(j, j->j_csum_seed, jh2bh(descriptor)->b_data,
+                          j->j_blocksize);
+       tail->r_checksum = cpu_to_be32(csum);
+}
+
 /*
  * Flush a revoke descriptor out to the journal.  If we are aborting,
  * this is a noop; otherwise we are generating a buffer which needs to
@@ -652,6 +675,8 @@ static void flush_descriptor(journal_t *journal,
 
        header = (jbd2_journal_revoke_header_t *) jh2bh(descriptor)->b_data;
        header->r_count = cpu_to_be32(offset);
+       jbd2_revoke_csum_set(journal, descriptor);
+
        set_buffer_jwrite(bh);
        BUFFER_TRACE(bh, "write");
        set_buffer_dirty(bh);