xfs: RT bitmap and summary buffers need verifiers

Buffers without verifiers issue runtime warnings on XFS. We don't
have anything we can actually verify in the RT buffers (no CRCs, not
magic numbers, etc), but we still need verifiers to avoid the
warnings.

Add a set of dummy verifier operations for the realtime buffers and
apply them in the appropriate places.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/libxfs/xfs_rtbitmap.c

@@ -41,6 +41,31 @@
  * Realtime allocator bitmap functions shared with userspace.
  */
 
+/*
+ * Real time buffers need verifiers to avoid runtime warnings during IO.
+ * We don't have anything to verify, however, so these are just dummy
+ * operations.
+ */
+static void
+xfs_rtbuf_verify_read(
+	struct xfs_buf	*bp)
+{
+	return;
+}
+
+static void
+xfs_rtbuf_verify_write(
+	struct xfs_buf	*bp)
+{
+	return;
+}
+
+const struct xfs_buf_ops xfs_rtbuf_ops = {
+	.name = "rtbuf",
+	.verify_read = xfs_rtbuf_verify_read,
+	.verify_write = xfs_rtbuf_verify_write,
+};
+
 /*
  * Get a buffer for the bitmap or summary file block specified.
  * The buffer is returned read and locked.
@@ -68,7 +93,7 @@ xfs_rtbuf_get(
 	ASSERT(map.br_startblock != NULLFSBLOCK);
 	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
 				   XFS_FSB_TO_DADDR(mp, map.br_startblock),
-				   mp->m_bsize, 0, &bp, NULL);
+				   mp->m_bsize, 0, &bp, &xfs_rtbuf_ops);
 	if (error)
 		return error;
 

fs/xfs/libxfs/xfs_shared.h

@@ -53,6 +53,7 @@ extern const struct xfs_buf_ops xfs_dquot_buf_ra_ops;
 extern const struct xfs_buf_ops xfs_sb_buf_ops;
 extern const struct xfs_buf_ops xfs_sb_quiet_buf_ops;
 extern const struct xfs_buf_ops xfs_symlink_buf_ops;
+extern const struct xfs_buf_ops xfs_rtbuf_ops;
 
 /*
  * Transaction types.  Used to distinguish types of buffers. These never reach

fs/xfs/xfs_log_recover.c

@@ -2476,8 +2476,8 @@ xlog_recover_validate_buf_type(
 #ifdef CONFIG_XFS_RT
 	case XFS_BLFT_RTBITMAP_BUF:
 	case XFS_BLFT_RTSUMMARY_BUF:
-		/* no verification of RT buffers is done */
-		bp->b_ops = NULL;
+		/* no magic numbers for verification of RT buffers */
+		bp->b_ops = &xfs_rtbuf_ops;
 		break;
 #endif /* CONFIG_XFS_RT */
 	default: