[src/trunk]: src/sys/kern Change vrecycle() and vgone() to lock with LK_RETRY...

[hannken <hannken%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c2afdd6693a1
branches:  trunk
changeset: 351932:c2afdd6693a1
user:      hannken <hannken%NetBSD.org@localhost>
date:      Mon Mar 06 10:07:52 2017 +0000

description:
Change vrecycle() and vgone() to lock with LK_RETRY.  If this node is
a layerfs node the lower node(s) may already be reclaimed.

diffstat:

 sys/kern/vfs_vnode.c |  17 ++++++++---------
 1 files changed, 8 insertions(+), 9 deletions(-)

diffs (46 lines):

diff -r 8fc52f07e645 -r c2afdd6693a1 sys/kern/vfs_vnode.c
--- a/sys/kern/vfs_vnode.c      Mon Mar 06 10:00:14 2017 +0000
+++ b/sys/kern/vfs_vnode.c      Mon Mar 06 10:07:52 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_vnode.c,v 1.75 2017/02/17 08:30:00 hannken Exp $   */
+/*     $NetBSD: vfs_vnode.c,v 1.76 2017/03/06 10:07:52 hannken Exp $   */
 
 /*-
  * Copyright (c) 1997-2011 The NetBSD Foundation, Inc.
@@ -156,7 +156,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.75 2017/02/17 08:30:00 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.76 2017/03/06 10:07:52 hannken Exp $");
 
 #include <sys/param.h>
 #include <sys/kernel.h>
@@ -919,7 +919,7 @@
         * On layered file systems waiting for the lock would open a can of
         * deadlocks as the lower vnodes may have other active references.
         */
-       error = vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT);
+       error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_NOWAIT);
 
        mutex_enter(vp->v_interlock);
        VSTATE_CHANGE(vp, VS_BLOCKED, VS_ACTIVE);
@@ -978,13 +978,12 @@
 vgone(vnode_t *vp)
 {
 
-       if (vn_lock(vp, LK_EXCLUSIVE) != 0) {
-               VSTATE_ASSERT(vp, VS_RECLAIMED);
-               vrele(vp);
-       }
-
+       vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        mutex_enter(vp->v_interlock);
-       vcache_reclaim(vp);
+       VSTATE_WAIT_STABLE(vp);
+       if (VSTATE_GET(vp) == VS_ACTIVE)
+               vcache_reclaim(vp);
+       VSTATE_ASSERT(vp, VS_RECLAIMED);
        vrelel(vp, 0);
 }