As VOP_ADVLOCK() may block indefinitely we cannot take fstrans here.

Fixes PR kern/52364: System hangs not much before showing the login prompt

sys/kern/vnode_if.src

@@ -1,4 +1,4 @@
-#	$NetBSD: vnode_if.src,v 1.76 2017/06/04 07:59:17 hannken Exp $
+#	$NetBSD: vnode_if.src,v 1.77 2017/07/12 09:31:07 hannken Exp $
 #
 # Copyright (c) 1992, 1993
 #	The Regents of the University of California.  All rights reserved.
@@ -468,6 +468,7 @@ vop_pathconf {
 #% advlock    vp      U U U
 #
 vop_advlock {
+	FSTRANS=NO
 	IN LOCKED=NO struct vnode *vp;
 	IN void *id;
 	IN int op;