xfs: cross-reference the realtime bitmap

While we're scrubbing various btrees, cross-reference the records
with the other metadata.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/scrub/rtbitmap.c

@@ -98,3 +98,26 @@ xfs_scrub_rtsummary(
 	/* XXX: implement this some day */
 	return -ENOENT;
 }
+
+
+/* xref check that the extent is not free in the rtbitmap */
+void
+xfs_scrub_xref_is_used_rt_space(
+	struct xfs_scrub_context	*sc,
+	xfs_rtblock_t			fsbno,
+	xfs_extlen_t			len)
+{
+	bool				is_free;
+	int				error;
+
+	xfs_ilock(sc->mp->m_rbmip, XFS_ILOCK_SHARED | XFS_ILOCK_RTBITMAP);
+	error = xfs_rtalloc_extent_is_free(sc->mp, sc->tp, fsbno, len,
+			&is_free);
+	if (!xfs_scrub_should_check_xref(sc, &error, NULL))
+		goto out_unlock;
+	if (is_free)
+		xfs_scrub_ino_xref_set_corrupt(sc, sc->mp->m_rbmip->i_ino,
+				NULL);
+out_unlock:
+	xfs_iunlock(sc->mp->m_rbmip, XFS_ILOCK_SHARED | XFS_ILOCK_RTBITMAP);
+}