For an NFSv4 mount with the "nocto" option, don't get the

up to date file attributes upon close. This reduces the
Getattr RPC count by about 65% for software builds.

MFC after:	2 weeks

sys/fs/nfsclient/nfs_clvnops.c

@@ -767,7 +767,9 @@ nfs_close(struct vop_close_args *ap)
 		/*
 		 * Get attributes so "change" is up to date.
 		 */
-		if (error == 0 && nfscl_mustflush(vp) != 0) {
+		if (error == 0 && nfscl_mustflush(vp) != 0 &&
+		    vp->v_type == VREG &&
+		    (VFSTONFS(vp->v_mount)->nm_flag & NFSMNT_NOCTO) == 0) {
 			ret = nfsrpc_getattr(vp, cred, ap->a_td, &nfsva,
 			    NULL);
 			if (!ret) {