aboutsummaryrefslogtreecommitdiff
path: root/fs/jbd2
diff options
context:
space:
mode:
authorDarrick J. Wong <djwong@us.ibm.com>2012-05-27 08:08:22 -0400
committerTheodore Ts'o <tytso@mit.edu>2012-05-27 08:08:22 -0400
commit4fd5ea43bc11602bfabe2c8f5378586d34bd2b0a (patch)
tree2a5e49a91ecb67c5a89eb0abe55f2b15495f738f /fs/jbd2
parent01b5adcebb977bc61b64167adce6d8260c9da33c (diff)
downloadvexpress-lsk-4fd5ea43bc11602bfabe2c8f5378586d34bd2b0a.tar.gz
jbd2: checksum journal superblock
Calculate and verify a checksum covering the journal superblock. Signed-off-by: Darrick J. Wong <djwong@us.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/jbd2')
-rw-r--r--fs/jbd2/journal.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index f04ab6c4b42..9072f03d30b 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -106,6 +106,34 @@ int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb)
return sb->s_checksum_type == JBD2_CRC32C_CHKSUM;
}
+static __u32 jbd2_superblock_csum(journal_t *j, journal_superblock_t *sb)
+{
+ __u32 csum, old_csum;
+
+ old_csum = sb->s_checksum;
+ sb->s_checksum = 0;
+ csum = jbd2_chksum(j, ~0, (char *)sb, sizeof(journal_superblock_t));
+ sb->s_checksum = old_csum;
+
+ return cpu_to_be32(csum);
+}
+
+int jbd2_superblock_csum_verify(journal_t *j, journal_superblock_t *sb)
+{
+ if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+ return 1;
+
+ return sb->s_checksum == jbd2_superblock_csum(j, sb);
+}
+
+void jbd2_superblock_csum_set(journal_t *j, journal_superblock_t *sb)
+{
+ if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+ return;
+
+ sb->s_checksum = jbd2_superblock_csum(j, sb);
+}
+
/*
* Helper function used to manage commit timeouts
*/
@@ -1357,6 +1385,7 @@ static void jbd2_journal_update_sb_errno(journal_t *journal)
jbd_debug(1, "JBD2: updating superblock error (errno %d)\n",
journal->j_errno);
sb->s_errno = cpu_to_be32(journal->j_errno);
+ jbd2_superblock_csum_set(journal, sb);
read_unlock(&journal->j_state_lock);
jbd2_write_superblock(journal, WRITE_SYNC);
@@ -1449,6 +1478,17 @@ static int journal_get_superblock(journal_t *journal)
}
}
+ /* Check superblock checksum */
+ if (!jbd2_superblock_csum_verify(journal, sb)) {
+ printk(KERN_ERR "JBD: journal checksum error\n");
+ goto out;
+ }
+
+ /* Precompute checksum seed for all metadata */
+ if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+ journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
+ sizeof(sb->s_uuid));
+
set_buffer_verified(bh);
return 0;
@@ -1732,6 +1772,13 @@ int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
return 0;
}
}
+
+ /* Precompute checksum seed for all metadata */
+ if (JBD2_HAS_INCOMPAT_FEATURE(journal,
+ JBD2_FEATURE_INCOMPAT_CSUM_V2))
+ journal->j_csum_seed = jbd2_chksum(journal, ~0,
+ sb->s_uuid,
+ sizeof(sb->s_uuid));
}
/* If enabling v1 checksums, downgrade superblock */