Module Name: src
Committed By: hannken
Date: Sat Dec 7 10:03:28 UTC 2013
Modified Files:
src/sys/kern: vfs_vnode.c
Log Message:
When deciding to defer in vrelel():
- No need to always defer layer vnodes, if we get the vnode lock it
is safe to inactivate.
- Always use VOP_LOCK(), it makes no sense to use vn_lock() here.
- No need to drop v_interlock for VOP_LOCK(... LK_NOWAIT).
To generate a diff of this commit:
cvs rdiff -u -r1.29 -r1.30 src/sys/kern/vfs_vnode.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/vfs_vnode.c
diff -u src/sys/kern/vfs_vnode.c:1.29 src/sys/kern/vfs_vnode.c:1.30
--- src/sys/kern/vfs_vnode.c:1.29 Sun Dec 1 17:29:40 2013
+++ src/sys/kern/vfs_vnode.c Sat Dec 7 10:03:28 2013
@@ -1,4 +1,4 @@
-/* $NetBSD: vfs_vnode.c,v 1.29 2013/12/01 17:29:40 christos Exp $ */
+/* $NetBSD: vfs_vnode.c,v 1.30 2013/12/07 10:03:28 hannken Exp $ */
/*-
* Copyright (c) 1997-2011 The NetBSD Foundation, Inc.
@@ -116,7 +116,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.29 2013/12/01 17:29:40 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.30 2013/12/07 10:03:28 hannken Exp $");
#define _VFS_VNODE_PRIVATE
@@ -626,27 +626,22 @@ vrelel(vnode_t *vp, int flags)
* locking is pushed down into the file systems.
*
* Defer vnode release to vrele_thread if caller
- * requests it explicitly.
+ * requests it explicitly or is the pagedaemon.
*/
if ((curlwp == uvm.pagedaemon_lwp) ||
(flags & VRELEL_ASYNC_RELE) != 0) {
- /* The pagedaemon can't wait around; defer. */
defer = true;
} else if (curlwp == vrele_lwp) {
/*
* We have to try harder.
*/
mutex_exit(vp->v_interlock);
- error = vn_lock(vp, LK_EXCLUSIVE);
- if (error != 0) {
- /* XXX */
- vnpanic(vp, "%s: unable to lock %p",
- __func__, vp);
- }
+ error = VOP_LOCK(vp, LK_EXCLUSIVE);
+ KASSERT(error == 0);
mutex_enter(vp->v_interlock);
/*
- * if we did get another reference while
- * sleeping, don't try to inactivate it yet.
+ * If the node got another reference while sleeping,
+ * don't try to inactivate it yet.
*/
if (__predict_false(vtryrele(vp))) {
VOP_UNLOCK(vp);
@@ -659,31 +654,20 @@ vrelel(vnode_t *vp, int flags)
return;
}
defer = false;
- } else if ((vp->v_iflag & VI_LAYER) != 0) {
- /*
- * Acquiring the stack's lock in vclean() even
- * for an honest vput/vrele is dangerous because
- * our caller may hold other vnode locks; defer.
- */
- defer = true;
} else {
/* If we can't acquire the lock, then defer. */
- mutex_exit(vp->v_interlock);
- error = vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT);
- if (error != 0) {
- defer = true;
- } else {
- defer = false;
- }
- mutex_enter(vp->v_interlock);
+ error = VOP_LOCK(vp, LK_EXCLUSIVE | LK_NOWAIT);
+ defer = (error != 0);
}
+ KASSERT(mutex_owned(vp->v_interlock));
+ KASSERT(! (curlwp == vrele_lwp && defer));
+
if (defer) {
/*
* Defer reclaim to the kthread; it's not safe to
* clean it here. We donate it our last reference.
*/
- KASSERT(mutex_owned(vp->v_interlock));
if ((flags & VRELEL_CHANGING_SET) != 0) {
KASSERT((vp->v_iflag & VI_CHANGING) != 0);
vp->v_iflag &= ~VI_CHANGING;
