xfs: don't allow reflink + realtime filesystems

We don't support realtime filesystems with reflink either, so fail
those mounts.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>

fs/xfs/xfs_super.c

@@ -1684,6 +1684,13 @@ xfs_fs_fill_super(
 		}
 	}
 
+	if (xfs_sb_version_hasreflink(&mp->m_sb) && mp->m_sb.sb_rblocks) {
+		xfs_alert(mp,
+	"reflink not compatible with realtime device!");
+		error = -EINVAL;
+		goto out_filestream_unmount;
+	}
+
 	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
 		if (mp->m_sb.sb_rblocks) {
 			xfs_alert(mp,