re #13613 rb4516 Tunables needs volatile keyword

@@ -20,10 +20,13 @@
  */
 /*
  *      Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  *      Use is subject to license terms.
  */
+/*
+ * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
+ */
 
 /*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T     */
 /*        All Rights Reserved   */
 
 #ifndef _NFS_RNODE4_H

@@ -385,11 +388,11 @@
         nfs4_open_stream_t      **re_osp; /* held reference */
 } nfs4_opinst_t;
 
 #ifdef _KERNEL
 
-extern long nrnode;
+extern volatile long nrnode;
 
 /* Used for r_delay_interval */
 #define NFS4_INITIAL_DELAY_INTERVAL      1
 #define NFS4_MAX_DELAY_INTERVAL         20