NFSv4: Fix an Oopsable condition if we fail to get the

root directory under NFSv4.

fs/nfs/nfs4proc.c

@@ -851,6 +851,7 @@ nfs4_proc_get_root(struct nfs_server *server, struct nfs_fh *fhandle,
 out_unlock:
 	up_write(&clp->cl_sem);
 	nfs4_put_client(clp);
+	server->nfs4_state = NULL;
 	return status;
 }