Module Name: src
Committed By: ad
Date: Sun Jan 12 17:49:17 UTC 2020
Modified Files:
src/sys/kern: vfs_vnode.c
Log Message:
vput(): don't drop the vnode lock, carry the hold over into vrelel() which
might need it anyway.
To generate a diff of this commit:
cvs rdiff -u -r1.106 -r1.107 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:1.106 src/sys/kern/vfs_vnode.c:1.107
--- src/sys/kern/vfs_vnode.c:1.106 Wed Jan 8 12:04:56 2020
+++ src/sys/kern/vfs_vnode.c Sun Jan 12 17:49:17 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: vfs_vnode.c,v 1.106 2020/01/08 12:04:56 ad Exp $ */
+/* $NetBSD: vfs_vnode.c,v 1.107 2020/01/12 17:49:17 ad Exp $ */
/*-
* Copyright (c) 1997-2011, 2019 The NetBSD Foundation, Inc.
@@ -146,7 +146,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.106 2020/01/08 12:04:56 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.107 2020/01/12 17:49:17 ad Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
@@ -175,8 +175,6 @@ __KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,
/* Flags to vrelel. */
#define VRELEL_ASYNC 0x0001 /* Always defer to vrele thread. */
-#define VRELEL_FORCE 0x0002 /* Must always succeed. */
-#define VRELEL_NOINACT 0x0004 /* Don't bother calling VOP_INACTIVE(). */
#define LRU_VRELE 0
#define LRU_FREE 1
@@ -213,7 +211,7 @@ static void vcache_free(vnode_impl_t *)
static void vcache_init(void);
static void vcache_reinit(void);
static void vcache_reclaim(vnode_t *);
-static void vrelel(vnode_t *, int);
+static void vrelel(vnode_t *, int, int);
static void vdrain_thread(void *);
static void vnpanic(vnode_t *, const char *, ...)
__printflike(2, 3);
@@ -530,8 +528,9 @@ vrele_flush(struct mount *mp)
TAILQ_INSERT_TAIL(vip->vi_lrulisthd, vip, vi_lrulist);
mutex_exit(&vdrain_lock);
+ vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
mutex_enter(vp->v_interlock);
- vrelel(vp, VRELEL_FORCE);
+ vrelel(vp, 0, LK_EXCLUSIVE);
mutex_enter(&vdrain_lock);
}
@@ -573,8 +572,9 @@ vdrain_remove(vnode_t *vp)
if (vcache_vget(vp) == 0) {
if (!vrecycle(vp)) {
+ vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
mutex_enter(vp->v_interlock);
- vrelel(vp, VRELEL_FORCE);
+ vrelel(vp, 0, LK_EXCLUSIVE);
}
}
fstrans_done(mp);
@@ -612,8 +612,9 @@ vdrain_vrele(vnode_t *vp)
vdrain_retry = true;
mutex_exit(&vdrain_lock);
+ vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
mutex_enter(vp->v_interlock);
- vrelel(vp, VRELEL_FORCE);
+ vrelel(vp, 0, LK_EXCLUSIVE);
fstrans_done(mp);
mutex_enter(&vdrain_lock);
@@ -674,9 +675,16 @@ vdrain_thread(void *cookie)
void
vput(vnode_t *vp)
{
+ int lktype;
- VOP_UNLOCK(vp);
- vrele(vp);
+ if ((vp->v_vflag & VV_LOCKSWORK) == 0) {
+ lktype = LK_EXCLUSIVE;
+ } else {
+ lktype = VOP_ISLOCKED(vp);
+ KASSERT(lktype != LK_NONE);
+ }
+ mutex_enter(vp->v_interlock);
+ vrelel(vp, 0, lktype);
}
/*
@@ -684,10 +692,9 @@ vput(vnode_t *vp)
* routine and either return to freelist or free to the pool.
*/
static void
-vrelel(vnode_t *vp, int flags)
+vrelel(vnode_t *vp, int flags, int lktype)
{
const bool async = ((flags & VRELEL_ASYNC) != 0);
- const bool force = ((flags & VRELEL_FORCE) != 0);
bool recycle, defer;
int error;
@@ -703,6 +710,9 @@ vrelel(vnode_t *vp, int flags)
* and unlock.
*/
if (vp->v_usecount > 1) {
+ if (lktype != LK_NONE) {
+ VOP_UNLOCK(vp);
+ }
vp->v_usecount--;
mutex_exit(vp->v_interlock);
return;
@@ -723,39 +733,42 @@ vrelel(vnode_t *vp, int flags)
* Defer vnode release to vdrain_thread if caller requests
* it explicitly, is the pagedaemon or the lock failed.
*/
+ defer = false;
if ((curlwp == uvm.pagedaemon_lwp) || async) {
defer = true;
- } else if (force) {
- mutex_exit(vp->v_interlock);
- error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
- defer = (error != 0);
- mutex_enter(vp->v_interlock);
- } else {
- error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_NOWAIT);
- defer = (error != 0);
+ } else if (lktype == LK_SHARED) {
+ /* Excellent chance of getting, if the last ref. */
+ error = vn_lock(vp, LK_UPGRADE | LK_RETRY |
+ LK_NOWAIT);
+ if (error != 0) {
+ defer = true;
+ } else {
+ lktype = LK_EXCLUSIVE;
+ }
+ } else if (lktype == LK_NONE) {
+ /* Excellent chance of getting, if the last ref. */
+ error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY |
+ LK_NOWAIT);
+ if (error != 0) {
+ defer = true;
+ } else {
+ lktype = LK_EXCLUSIVE;
+ }
}
KASSERT(mutex_owned(vp->v_interlock));
- KASSERT(! (force && defer));
if (defer) {
/*
* Defer reclaim to the kthread; it's not safe to
* clean it here. We donate it our last reference.
*/
+ if (lktype != LK_NONE) {
+ VOP_UNLOCK(vp);
+ }
lru_requeue(vp, &lru_list[LRU_VRELE]);
mutex_exit(vp->v_interlock);
return;
}
-
- /*
- * If the node got another reference while we
- * released the interlock, don't try to inactivate it yet.
- */
- if (vp->v_usecount > 1) {
- vp->v_usecount--;
- VOP_UNLOCK(vp);
- mutex_exit(vp->v_interlock);
- return;
- }
+ KASSERT(lktype == LK_EXCLUSIVE);
/*
* If not clean, deactivate the vnode, but preserve
@@ -839,7 +852,7 @@ vrele(vnode_t *vp)
{
mutex_enter(vp->v_interlock);
- vrelel(vp, 0);
+ vrelel(vp, 0, LK_NONE);
}
/*
@@ -850,7 +863,7 @@ vrele_async(vnode_t *vp)
{
mutex_enter(vp->v_interlock);
- vrelel(vp, VRELEL_ASYNC);
+ vrelel(vp, VRELEL_ASYNC, LK_NONE);
}
/*
@@ -921,7 +934,7 @@ vrecycle(vnode_t *vp)
/* If the vnode is already clean we're done. */
if (VSTATE_GET(vp) != VS_LOADED) {
VSTATE_ASSERT(vp, VS_RECLAIMED);
- vrelel(vp, 0);
+ vrelel(vp, 0, LK_NONE);
return true;
}
@@ -947,7 +960,7 @@ vrecycle(vnode_t *vp)
KASSERT(vp->v_usecount == 1);
vcache_reclaim(vp);
- vrelel(vp, 0);
+ vrelel(vp, 0, LK_NONE);
return true;
}
@@ -1026,16 +1039,20 @@ vrevoke(vnode_t *vp)
void
vgone(vnode_t *vp)
{
+ int lktype;
KASSERT(vp->v_mount == dead_rootmount || fstrans_is_owner(vp->v_mount));
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+ lktype = LK_EXCLUSIVE;
mutex_enter(vp->v_interlock);
VSTATE_WAIT_STABLE(vp);
- if (VSTATE_GET(vp) == VS_LOADED)
+ if (VSTATE_GET(vp) == VS_LOADED) {
vcache_reclaim(vp);
+ lktype = LK_NONE;
+ }
VSTATE_ASSERT(vp, VS_RECLAIMED);
- vrelel(vp, 0);
+ vrelel(vp, 0, lktype);
}
static inline uint32_t
@@ -1164,7 +1181,7 @@ vcache_dealloc(vnode_impl_t *vip)
vp->v_op = dead_vnodeop_p;
VSTATE_CHANGE(vp, VS_LOADING, VS_RECLAIMED);
mutex_exit(&vcache_lock);
- vrelel(vp, 0);
+ vrelel(vp, 0, LK_NONE);
}
/*
