nfsd41: use SEQ4_STATUS_BACKCHANNEL_FAULT when cb_sequence is invalid

Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 1a58200..a3cf384 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -258,6 +258,7 @@
 #define NFSD4_CB_UP		0
 #define NFSD4_CB_UNKNOWN	1
 #define NFSD4_CB_DOWN		2
+#define NFSD4_CB_FAULT		3
 	int			cl_cb_state;
 	struct nfsd4_callback	cl_cb_null;
 	struct nfsd4_session	*cl_cb_session;