Aren
/
NetBSD
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
NetBSD/sys/kern/vfs_vnode.c

1821 lines
46 KiB
C
Raw Blame History

/* $NetBSD: vfs_vnode.c,v 1.100 2017/09/22 06:05:20 joerg Exp $ */
/*-
* Copyright (c) 1997-2011 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center, by Charles M. Hannum, and by Andrew Doran.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vfs_subr.c 8.13 (Berkeley) 4/18/94
*/
/*
* The vnode cache subsystem.
*
* Life-cycle
*
* Normally, there are two points where new vnodes are created:
* VOP_CREATE(9) and VOP_LOOKUP(9). The life-cycle of a vnode
* starts in one of the following ways:
*
* - Allocation, via vcache_get(9) or vcache_new(9).
* - Reclamation of inactive vnode, via vcache_vget(9).
*
* Recycle from a free list, via getnewvnode(9) -> getcleanvnode(9)
* was another, traditional way. Currently, only the draining thread
* recycles the vnodes. This behaviour might be revisited.
*
* The life-cycle ends when the last reference is dropped, usually
* in VOP_REMOVE(9). In such case, VOP_INACTIVE(9) is called to inform
* the file system that vnode is inactive. Via this call, file system
* indicates whether vnode can be recycled (usually, it checks its own
* references, e.g. count of links, whether the file was removed).
*
* Depending on indication, vnode can be put into a free list (cache),
* or cleaned via vcache_reclaim, which calls VOP_RECLAIM(9) to
* disassociate underlying file system from the vnode, and finally
* destroyed.
*
* Vnode state
*
* Vnode is always in one of six states:
* - MARKER This is a marker vnode to help list traversal. It
* will never change its state.
* - LOADING Vnode is associating underlying file system and not
* yet ready to use.
* - LOADED Vnode has associated underlying file system and is
* ready to use.
* - BLOCKED Vnode is active but cannot get new references.
* - RECLAIMING Vnode is disassociating from the underlying file
* system.
* - RECLAIMED Vnode has disassociated from underlying file system
* and is dead.
*
* Valid state changes are:
* LOADING -> LOADED
* Vnode has been initialised in vcache_get() or
* vcache_new() and is ready to use.
* LOADED -> RECLAIMING
* Vnode starts disassociation from underlying file
* system in vcache_reclaim().
* RECLAIMING -> RECLAIMED
* Vnode finished disassociation from underlying file
* system in vcache_reclaim().
* LOADED -> BLOCKED
* Either vcache_rekey*() is changing the vnode key or
* vrelel() is about to call VOP_INACTIVE().
* BLOCKED -> LOADED
* The block condition is over.
* LOADING -> RECLAIMED
* Either vcache_get() or vcache_new() failed to
* associate the underlying file system or vcache_rekey*()
* drops a vnode used as placeholder.
*
* Of these states LOADING, BLOCKED and RECLAIMING are intermediate
* and it is possible to wait for state change.
*
* State is protected with v_interlock with one exception:
* to change from LOADING both v_interlock and vcache_lock must be held
* so it is possible to check "state == LOADING" without holding
* v_interlock. See vcache_get() for details.
*
* Reference counting
*
* Vnode is considered active, if reference count (vnode_t::v_usecount)
* is non-zero. It is maintained using: vref(9) and vrele(9), as well
* as vput(9), routines. Common points holding references are e.g.
* file openings, current working directory, mount points, etc.
*
* Note on v_usecount and its locking
*
* At nearly all points it is known that v_usecount could be zero,
* the vnode_t::v_interlock will be held. To change v_usecount away
* from zero, the interlock must be held. To change from a non-zero
* value to zero, again the interlock must be held.
*
* Changing the usecount from a non-zero value to a non-zero value can
* safely be done using atomic operations, without the interlock held.
*
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_vnode.c,v 1.100 2017/09/22 06:05:20 joerg Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/atomic.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/device.h>
#include <sys/hash.h>
#include <sys/kauth.h>
#include <sys/kmem.h>
#include <sys/kthread.h>
#include <sys/module.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/syscallargs.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/vnode_impl.h>
#include <sys/wapbl.h>
#include <sys/fstrans.h>
#include <uvm/uvm.h>
#include <uvm/uvm_readahead.h>
/* Flags to vrelel. */
#define VRELEL_ASYNC_RELE 0x0001 /* Always defer to vrele thread. */
#define VRELEL_FORCE_RELE 0x0002 /* Must always succeed. */
u_int numvnodes __cacheline_aligned;
/*
* There are three lru lists: one holds vnodes waiting for async release,
* one is for vnodes which have no buffer/page references and
* one for those which do (i.e. v_holdcnt is non-zero).
*/
static vnodelst_t lru_vrele_list __cacheline_aligned;
static vnodelst_t lru_free_list __cacheline_aligned;
static vnodelst_t lru_hold_list __cacheline_aligned;
static kmutex_t vdrain_lock __cacheline_aligned;
static kcondvar_t vdrain_cv __cacheline_aligned;
static int vdrain_gen;
static kcondvar_t vdrain_gen_cv;
static bool vdrain_retry;
static lwp_t * vdrain_lwp;
SLIST_HEAD(hashhead, vnode_impl);
static kmutex_t vcache_lock __cacheline_aligned;
static kcondvar_t vcache_cv __cacheline_aligned;
static u_int vcache_hashsize;
static u_long vcache_hashmask;
static struct hashhead *vcache_hashtab __cacheline_aligned;
static pool_cache_t vcache_pool;
static void lru_requeue(vnode_t *, vnodelst_t *);
static vnodelst_t * lru_which(vnode_t *);
static vnode_impl_t * vcache_alloc(void);
static void vcache_dealloc(vnode_impl_t *);
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 vdrain_thread(void *);
static void vnpanic(vnode_t *, const char *, ...)
__printflike(2, 3);
/* Routines having to do with the management of the vnode table. */
extern struct mount *dead_rootmount;
extern int (**dead_vnodeop_p)(void *);
extern int (**spec_vnodeop_p)(void *);
extern struct vfsops dead_vfsops;
/* Vnode state operations and diagnostics. */
#if defined(DIAGNOSTIC)
#define VSTATE_VALID(state) \
((state) != VS_ACTIVE && (state) != VS_MARKER)
#define VSTATE_GET(vp) \
vstate_assert_get((vp), __func__, __LINE__)
#define VSTATE_CHANGE(vp, from, to) \
vstate_assert_change((vp), (from), (to), __func__, __LINE__)
#define VSTATE_WAIT_STABLE(vp) \
vstate_assert_wait_stable((vp), __func__, __LINE__)
void
_vstate_assert(vnode_t *vp, enum vnode_state state, const char *func, int line,
bool has_lock)
{
vnode_impl_t *vip = VNODE_TO_VIMPL(vp);
if (!has_lock) {
/*
* Prevent predictive loads from the CPU, but check the state
* without loooking first.
*/
membar_enter();
if (state == VS_ACTIVE && vp->v_usecount > 0 &&
(vip->vi_state == VS_LOADED || vip->vi_state == VS_BLOCKED))
return;
if (vip->vi_state == state)
return;
mutex_enter((vp)->v_interlock);
}
KASSERTMSG(mutex_owned(vp->v_interlock), "at %s:%d", func, line);
if ((state == VS_ACTIVE && vp->v_usecount > 0 &&
(vip->vi_state == VS_LOADED || vip->vi_state == VS_BLOCKED)) ||
vip->vi_state == state) {
if (!has_lock)
mutex_exit((vp)->v_interlock);
return;
}
vnpanic(vp, "state is %s, usecount %d, expected %s at %s:%d",
vstate_name(vip->vi_state), vp->v_usecount,
vstate_name(state), func, line);
}
static enum vnode_state
vstate_assert_get(vnode_t *vp, const char *func, int line)
{
vnode_impl_t *vip = VNODE_TO_VIMPL(vp);
KASSERTMSG(mutex_owned(vp->v_interlock), "at %s:%d", func, line);
if (! VSTATE_VALID(vip->vi_state))
vnpanic(vp, "state is %s at %s:%d",
vstate_name(vip->vi_state), func, line);
return vip->vi_state;
}
static void
vstate_assert_wait_stable(vnode_t *vp, const char *func, int line)
{
vnode_impl_t *vip = VNODE_TO_VIMPL(vp);
KASSERTMSG(mutex_owned(vp->v_interlock), "at %s:%d", func, line);
if (! VSTATE_VALID(vip->vi_state))
vnpanic(vp, "state is %s at %s:%d",
vstate_name(vip->vi_state), func, line);
while (vip->vi_state != VS_LOADED && vip->vi_state != VS_RECLAIMED)
cv_wait(&vp->v_cv, vp->v_interlock);
if (! VSTATE_VALID(vip->vi_state))
vnpanic(vp, "state is %s at %s:%d",
vstate_name(vip->vi_state), func, line);
}
static void
vstate_assert_change(vnode_t *vp, enum vnode_state from, enum vnode_state to,
const char *func, int line)
{
vnode_impl_t *vip = VNODE_TO_VIMPL(vp);
KASSERTMSG(mutex_owned(vp->v_interlock), "at %s:%d", func, line);
if (from == VS_LOADING)
KASSERTMSG(mutex_owned(&vcache_lock), "at %s:%d", func, line);
if (! VSTATE_VALID(from))
vnpanic(vp, "from is %s at %s:%d",
vstate_name(from), func, line);
if (! VSTATE_VALID(to))
vnpanic(vp, "to is %s at %s:%d",
vstate_name(to), func, line);
if (vip->vi_state != from)
vnpanic(vp, "from is %s, expected %s at %s:%d\n",
vstate_name(vip->vi_state), vstate_name(from), func, line);
if ((from == VS_BLOCKED || to == VS_BLOCKED) && vp->v_usecount != 1)
vnpanic(vp, "%s to %s with usecount %d at %s:%d",
vstate_name(from), vstate_name(to), vp->v_usecount,
func, line);
vip->vi_state = to;
if (from == VS_LOADING)
cv_broadcast(&vcache_cv);
if (to == VS_LOADED || to == VS_RECLAIMED)
cv_broadcast(&vp->v_cv);
}
#else /* defined(DIAGNOSTIC) */
#define VSTATE_GET(vp) \
(VNODE_TO_VIMPL((vp))->vi_state)
#define VSTATE_CHANGE(vp, from, to) \
vstate_change((vp), (from), (to))
#define VSTATE_WAIT_STABLE(vp) \
vstate_wait_stable((vp))
void
_vstate_assert(vnode_t *vp, enum vnode_state state, const char *func, int line,
bool has_lock)
{
}
static void
vstate_wait_stable(vnode_t *vp)
{
vnode_impl_t *vip = VNODE_TO_VIMPL(vp);
while (vip->vi_state != VS_LOADED && vip->vi_state != VS_RECLAIMED)
cv_wait(&vp->v_cv, vp->v_interlock);
}
static void
vstate_change(vnode_t *vp, enum vnode_state from, enum vnode_state to)
{
vnode_impl_t *vip = VNODE_TO_VIMPL(vp);
vip->vi_state = to;
if (from == VS_LOADING)
cv_broadcast(&vcache_cv);
if (to == VS_LOADED || to == VS_RECLAIMED)
cv_broadcast(&vp->v_cv);
}
#endif /* defined(DIAGNOSTIC) */
void
vfs_vnode_sysinit(void)
{
int error __diagused;
dead_rootmount = vfs_mountalloc(&dead_vfsops, NULL);
KASSERT(dead_rootmount != NULL);
dead_rootmount->mnt_iflag = IMNT_MPSAFE;
mutex_init(&vdrain_lock, MUTEX_DEFAULT, IPL_NONE);
TAILQ_INIT(&lru_free_list);
TAILQ_INIT(&lru_hold_list);
TAILQ_INIT(&lru_vrele_list);
vcache_init();
cv_init(&vdrain_cv, "vdrain");
cv_init(&vdrain_gen_cv, "vdrainwt");
error = kthread_create(PRI_VM, KTHREAD_MPSAFE, NULL, vdrain_thread,
NULL, &vdrain_lwp, "vdrain");
KASSERTMSG((error == 0), "kthread_create(vdrain) failed: %d", error);
}
/*
* Allocate a new marker vnode.
*/
vnode_t *
vnalloc_marker(struct mount *mp)
{
vnode_impl_t *vip;
vnode_t *vp;
vip = pool_cache_get(vcache_pool, PR_WAITOK);
memset(vip, 0, sizeof(*vip));
vp = VIMPL_TO_VNODE(vip);
uvm_obj_init(&vp->v_uobj, &uvm_vnodeops, true, 0);
vp->v_mount = mp;
vp->v_type = VBAD;
vip->vi_state = VS_MARKER;
return vp;
}
/*
* Free a marker vnode.
*/
void
vnfree_marker(vnode_t *vp)
{
vnode_impl_t *vip;
vip = VNODE_TO_VIMPL(vp);
KASSERT(vip->vi_state == VS_MARKER);
uvm_obj_destroy(&vp->v_uobj, true);
pool_cache_put(vcache_pool, vip);
}
/*
* Test a vnode for being a marker vnode.
*/
bool
vnis_marker(vnode_t *vp)
{
return (VNODE_TO_VIMPL(vp)->vi_state == VS_MARKER);
}
/*
* Return the lru list this node should be on.
*/
static vnodelst_t *
lru_which(vnode_t *vp)
{
KASSERT(mutex_owned(vp->v_interlock));
if (vp->v_holdcnt > 0)
return &lru_hold_list;
else
return &lru_free_list;
}
/*
* Put vnode to end of given list.
* Both the current and the new list may be NULL, used on vnode alloc/free.
* Adjust numvnodes and signal vdrain thread if there is work.
*/
static void
lru_requeue(vnode_t *vp, vnodelst_t *listhd)
{
vnode_impl_t *vip;
mutex_enter(&vdrain_lock);
vip = VNODE_TO_VIMPL(vp);
if (vip->vi_lrulisthd != NULL)
TAILQ_REMOVE(vip->vi_lrulisthd, vip, vi_lrulist);
else
numvnodes++;
vip->vi_lrulisthd = listhd;
if (vip->vi_lrulisthd != NULL)
TAILQ_INSERT_TAIL(vip->vi_lrulisthd, vip, vi_lrulist);
else
numvnodes--;
if (numvnodes > desiredvnodes || listhd == &lru_vrele_list)
cv_broadcast(&vdrain_cv);
mutex_exit(&vdrain_lock);
}
/*
* Release deferred vrele vnodes for this mount.
* Called with file system suspended.
*/
void
vrele_flush(struct mount *mp)
{
vnode_impl_t *vip, *marker;
KASSERT(fstrans_is_owner(mp));
marker = VNODE_TO_VIMPL(vnalloc_marker(NULL));
mutex_enter(&vdrain_lock);
TAILQ_INSERT_HEAD(&lru_vrele_list, marker, vi_lrulist);
while ((vip = TAILQ_NEXT(marker, vi_lrulist))) {
TAILQ_REMOVE(&lru_vrele_list, marker, vi_lrulist);
TAILQ_INSERT_AFTER(&lru_vrele_list, vip, marker, vi_lrulist);
if (vnis_marker(VIMPL_TO_VNODE(vip)))
continue;
KASSERT(vip->vi_lrulisthd == &lru_vrele_list);
TAILQ_REMOVE(vip->vi_lrulisthd, vip, vi_lrulist);
vip->vi_lrulisthd = &lru_hold_list;
TAILQ_INSERT_TAIL(vip->vi_lrulisthd, vip, vi_lrulist);
mutex_exit(&vdrain_lock);
mutex_enter(VIMPL_TO_VNODE(vip)->v_interlock);
vrelel(VIMPL_TO_VNODE(vip), VRELEL_FORCE_RELE);
mutex_enter(&vdrain_lock);
}
TAILQ_REMOVE(&lru_vrele_list, marker, vi_lrulist);
mutex_exit(&vdrain_lock);
vnfree_marker(VIMPL_TO_VNODE(marker));
}
/*
* Reclaim a cached vnode. Used from vdrain_thread only.
*/
static __inline void
vdrain_remove(vnode_t *vp)
{
struct mount *mp;
KASSERT(mutex_owned(&vdrain_lock));
/* Probe usecount (unlocked). */
if (vp->v_usecount > 0)
return;
/* Try v_interlock -- we lock the wrong direction! */
if (!mutex_tryenter(vp->v_interlock))
return;
/* Probe usecount and state. */
if (vp->v_usecount > 0 || VSTATE_GET(vp) != VS_LOADED) {
mutex_exit(vp->v_interlock);
return;
}
mp = vp->v_mount;
if (fstrans_start_nowait(mp) != 0) {
mutex_exit(vp->v_interlock);
return;
}
vdrain_retry = true;
mutex_exit(&vdrain_lock);
if (vcache_vget(vp) == 0) {
if (!vrecycle(vp)) {
mutex_enter(vp->v_interlock);
vrelel(vp, VRELEL_FORCE_RELE);
}
}
fstrans_done(mp);
mutex_enter(&vdrain_lock);
}
/*
* Release a cached vnode. Used from vdrain_thread only.
*/
static __inline void
vdrain_vrele(vnode_t *vp)
{
vnode_impl_t *vip = VNODE_TO_VIMPL(vp);
struct mount *mp;
KASSERT(mutex_owned(&vdrain_lock));
mp = vp->v_mount;
if (fstrans_start_nowait(mp) != 0)
return;
/*
* First remove the vnode from the vrele list.
* Put it on the last lru list, the last vrele()
* will put it back onto the right list before
* its v_usecount reaches zero.
*/
KASSERT(vip->vi_lrulisthd == &lru_vrele_list);
TAILQ_REMOVE(vip->vi_lrulisthd, vip, vi_lrulist);
vip->vi_lrulisthd = &lru_hold_list;
TAILQ_INSERT_TAIL(vip->vi_lrulisthd, vip, vi_lrulist);
vdrain_retry = true;
mutex_exit(&vdrain_lock);
mutex_enter(vp->v_interlock);
vrelel(vp, VRELEL_FORCE_RELE);
fstrans_done(mp);
mutex_enter(&vdrain_lock);
}
/*
* Helper thread to keep the number of vnodes below desiredvnodes
* and release vnodes from asynchronous vrele.
*/
static void
vdrain_thread(void *cookie)
{
vnodelst_t *listhd[] = {
&lru_vrele_list, &lru_free_list, &lru_hold_list
};
int i;
u_int target;
vnode_impl_t *vip, *marker;
marker = VNODE_TO_VIMPL(vnalloc_marker(NULL));
mutex_enter(&vdrain_lock);
for (;;) {
vdrain_retry = false;
target = desiredvnodes - desiredvnodes/10;
for (i = 0; i < __arraycount(listhd); i++) {
TAILQ_INSERT_HEAD(listhd[i], marker, vi_lrulist);
while ((vip = TAILQ_NEXT(marker, vi_lrulist))) {
TAILQ_REMOVE(listhd[i], marker, vi_lrulist);
TAILQ_INSERT_AFTER(listhd[i], vip, marker,
vi_lrulist);
if (vnis_marker(VIMPL_TO_VNODE(vip)))
continue;
if (listhd[i] == &lru_vrele_list)
vdrain_vrele(VIMPL_TO_VNODE(vip));
else if (numvnodes < target)
break;
else
vdrain_remove(VIMPL_TO_VNODE(vip));
}
TAILQ_REMOVE(listhd[i], marker, vi_lrulist);
}
if (vdrain_retry) {
mutex_exit(&vdrain_lock);
yield();
mutex_enter(&vdrain_lock);
} else {
vdrain_gen++;
cv_broadcast(&vdrain_gen_cv);
cv_wait(&vdrain_cv, &vdrain_lock);
}
}
}
/*
* vput: unlock and release the reference.
*/
void
vput(vnode_t *vp)
{
VOP_UNLOCK(vp);
vrele(vp);
}
/*
* Try to drop reference on a vnode. Abort if we are releasing the
* last reference. Note: this _must_ succeed if not the last reference.
*/
static inline bool
vtryrele(vnode_t *vp)
{
u_int use, next;
for (use = vp->v_usecount;; use = next) {
if (use == 1) {
return false;
}
KASSERT(use > 1);
next = atomic_cas_uint(&vp->v_usecount, use, use - 1);
if (__predict_true(next == use)) {
return true;
}
}
}
/*
* Vnode release. If reference count drops to zero, call inactive
* routine and either return to freelist or free to the pool.
*/
static void
vrelel(vnode_t *vp, int flags)
{
const bool async = ((flags & VRELEL_ASYNC_RELE) != 0);
const bool force = ((flags & VRELEL_FORCE_RELE) != 0);
bool recycle, defer;
int error;
KASSERT(mutex_owned(vp->v_interlock));
if (__predict_false(vp->v_op == dead_vnodeop_p &&
VSTATE_GET(vp) != VS_RECLAIMED)) {
vnpanic(vp, "dead but not clean");
}
/*
* If not the last reference, just drop the reference count
* and unlock.
*/
if (vtryrele(vp)) {
mutex_exit(vp->v_interlock);
return;
}
if (vp->v_usecount <= 0 || vp->v_writecount != 0) {
vnpanic(vp, "%s: bad ref count", __func__);
}
#ifdef DIAGNOSTIC
if ((vp->v_type == VBLK || vp->v_type == VCHR) &&
vp->v_specnode != NULL && vp->v_specnode->sn_opencnt != 0) {
vprint("vrelel: missing VOP_CLOSE()", vp);
}
#endif
/*
* First try to get the vnode locked for VOP_INACTIVE().
* Defer vnode release to vdrain_thread if caller requests
* it explicitly, is the pagedaemon or the lock failed.
*/
if ((curlwp == uvm.pagedaemon_lwp) || async) {
defer = true;
} else {
mutex_exit(vp->v_interlock);
error = vn_lock(vp,
LK_EXCLUSIVE | LK_RETRY | (force ? 0 : LK_NOWAIT));
defer = (error != 0);
mutex_enter(vp->v_interlock);
}
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.
*/
lru_requeue(vp, &lru_vrele_list);
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 (__predict_false(vtryrele(vp))) {
VOP_UNLOCK(vp);
mutex_exit(vp->v_interlock);
return;
}
/*
* If not clean, deactivate the vnode, but preserve
* our reference across the call to VOP_INACTIVE().
*/
if (VSTATE_GET(vp) == VS_RECLAIMED) {
VOP_UNLOCK(vp);
} else {
VSTATE_CHANGE(vp, VS_LOADED, VS_BLOCKED);
mutex_exit(vp->v_interlock);
/*
* The vnode must not gain another reference while being
* deactivated. If VOP_INACTIVE() indicates that
* the described file has been deleted, then recycle
* the vnode.
*
* Note that VOP_INACTIVE() will not drop the vnode lock.
*/
recycle = false;
VOP_INACTIVE(vp, &recycle);
if (!recycle)
VOP_UNLOCK(vp);
mutex_enter(vp->v_interlock);
VSTATE_CHANGE(vp, VS_BLOCKED, VS_LOADED);
if (!recycle) {
if (vtryrele(vp)) {
mutex_exit(vp->v_interlock);
return;
}
}
/* Take care of space accounting. */
if (vp->v_iflag & VI_EXECMAP) {
atomic_add_int(&uvmexp.execpages,
-vp->v_uobj.uo_npages);
atomic_add_int(&uvmexp.filepages,
vp->v_uobj.uo_npages);
}
vp->v_iflag &= ~(VI_TEXT|VI_EXECMAP|VI_WRMAP);
vp->v_vflag &= ~VV_MAPPED;
/*
* Recycle the vnode if the file is now unused (unlinked),
* otherwise just free it.
*/
if (recycle) {
VSTATE_ASSERT(vp, VS_LOADED);
/* vcache_reclaim drops the lock. */
vcache_reclaim(vp);
}
KASSERT(vp->v_usecount > 0);
}
if (atomic_dec_uint_nv(&vp->v_usecount) != 0) {
/* Gained another reference while being reclaimed. */
mutex_exit(vp->v_interlock);
return;
}
if (VSTATE_GET(vp) == VS_RECLAIMED && vp->v_holdcnt == 0) {
/*
* It's clean so destroy it. It isn't referenced
* anywhere since it has been reclaimed.
*/
vcache_free(VNODE_TO_VIMPL(vp));
} else {
/*
* Otherwise, put it back onto the freelist. It
* can't be destroyed while still associated with
* a file system.
*/
lru_requeue(vp, lru_which(vp));
mutex_exit(vp->v_interlock);
}
}
void
vrele(vnode_t *vp)
{
if (vtryrele(vp)) {
return;
}
mutex_enter(vp->v_interlock);
vrelel(vp, 0);
}
/*
* Asynchronous vnode release, vnode is released in different context.
*/
void
vrele_async(vnode_t *vp)
{
if (vtryrele(vp)) {
return;
}
mutex_enter(vp->v_interlock);
vrelel(vp, VRELEL_ASYNC_RELE);
}
/*
* Vnode reference, where a reference is already held by some other
* object (for example, a file structure).
*/
void
vref(vnode_t *vp)
{
KASSERT(vp->v_usecount != 0);
atomic_inc_uint(&vp->v_usecount);
}
/*
* Page or buffer structure gets a reference.
* Called with v_interlock held.
*/
void
vholdl(vnode_t *vp)
{
KASSERT(mutex_owned(vp->v_interlock));
if (vp->v_holdcnt++ == 0 && vp->v_usecount == 0)
lru_requeue(vp, lru_which(vp));
}
/*
* Page or buffer structure frees a reference.
* Called with v_interlock held.
*/
void
holdrelel(vnode_t *vp)
{
KASSERT(mutex_owned(vp->v_interlock));
if (vp->v_holdcnt <= 0) {
vnpanic(vp, "%s: holdcnt vp %p", __func__, vp);
}
vp->v_holdcnt--;
if (vp->v_holdcnt == 0 && vp->v_usecount == 0)
lru_requeue(vp, lru_which(vp));
}
/*
* Recycle an unused vnode if caller holds the last reference.
*/
bool
vrecycle(vnode_t *vp)
{
int error __diagused;
mutex_enter(vp->v_interlock);
/* Make sure we hold the last reference. */
VSTATE_WAIT_STABLE(vp);
if (vp->v_usecount != 1) {
mutex_exit(vp->v_interlock);
return false;
}
/* If the vnode is already clean we're done. */
if (VSTATE_GET(vp) != VS_LOADED) {
VSTATE_ASSERT(vp, VS_RECLAIMED);
vrelel(vp, 0);
return true;
}
/* Prevent further references until the vnode is locked. */
VSTATE_CHANGE(vp, VS_LOADED, VS_BLOCKED);
mutex_exit(vp->v_interlock);
/*
* On a leaf file system this lock will always succeed as we hold
* the last reference and prevent further references.
* 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_RETRY | LK_NOWAIT);
mutex_enter(vp->v_interlock);
VSTATE_CHANGE(vp, VS_BLOCKED, VS_LOADED);
if (error) {
mutex_exit(vp->v_interlock);
return false;
}
KASSERT(vp->v_usecount == 1);
vcache_reclaim(vp);
vrelel(vp, 0);
return true;
}
/*
* Helper for vrevoke() to propagate suspension from lastmp
* to thismp. Both args may be NULL.
* Returns the currently suspended file system or NULL.
*/
static struct mount *
vrevoke_suspend_next(struct mount *lastmp, struct mount *thismp)
{
int error;
if (lastmp == thismp)
return thismp;
if (lastmp != NULL)
vfs_resume(lastmp);
if (thismp == NULL)
return NULL;
do {
error = vfs_suspend(thismp, 0);
} while (error == EINTR || error == ERESTART);
if (error == 0)
return thismp;
KASSERT(error == EOPNOTSUPP);
return NULL;
}
/*
* Eliminate all activity associated with the requested vnode
* and with all vnodes aliased to the requested vnode.
*/
void
vrevoke(vnode_t *vp)
{
struct mount *mp;
vnode_t *vq;
enum vtype type;
dev_t dev;
KASSERT(vp->v_usecount > 0);
mp = vrevoke_suspend_next(NULL, vp->v_mount);
mutex_enter(vp->v_interlock);
VSTATE_WAIT_STABLE(vp);
if (VSTATE_GET(vp) == VS_RECLAIMED) {
mutex_exit(vp->v_interlock);
} else if (vp->v_type != VBLK && vp->v_type != VCHR) {
atomic_inc_uint(&vp->v_usecount);
mutex_exit(vp->v_interlock);
vgone(vp);
} else {
dev = vp->v_rdev;
type = vp->v_type;
mutex_exit(vp->v_interlock);
while (spec_node_lookup_by_dev(type, dev, &vq) == 0) {
mp = vrevoke_suspend_next(mp, vq->v_mount);
vgone(vq);
}
}
vrevoke_suspend_next(mp, NULL);
}
/*
* Eliminate all activity associated with a vnode in preparation for
* reuse. Drops a reference from the vnode.
*/
void
vgone(vnode_t *vp)
{
KASSERT((vp->v_mount->mnt_iflag & IMNT_HAS_TRANS) == 0 ||
fstrans_is_owner(vp->v_mount));
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
mutex_enter(vp->v_interlock);
VSTATE_WAIT_STABLE(vp);
if (VSTATE_GET(vp) == VS_LOADED)
vcache_reclaim(vp);
VSTATE_ASSERT(vp, VS_RECLAIMED);
vrelel(vp, 0);
}
static inline uint32_t
vcache_hash(const struct vcache_key *key)
{
uint32_t hash = HASH32_BUF_INIT;
KASSERT(key->vk_key_len > 0);
hash = hash32_buf(&key->vk_mount, sizeof(struct mount *), hash);
hash = hash32_buf(key->vk_key, key->vk_key_len, hash);
return hash;
}
static void
vcache_init(void)
{
vcache_pool = pool_cache_init(sizeof(vnode_impl_t), 0, 0, 0,
"vcachepl", NULL, IPL_NONE, NULL, NULL, NULL);
KASSERT(vcache_pool != NULL);
mutex_init(&vcache_lock, MUTEX_DEFAULT, IPL_NONE);
cv_init(&vcache_cv, "vcache");
vcache_hashsize = desiredvnodes;
vcache_hashtab = hashinit(desiredvnodes, HASH_SLIST, true,
&vcache_hashmask);
}
static void
vcache_reinit(void)
{
int i;
uint32_t hash;
u_long oldmask, newmask;
struct hashhead *oldtab, *newtab;
vnode_impl_t *vip;
newtab = hashinit(desiredvnodes, HASH_SLIST, true, &newmask);
mutex_enter(&vcache_lock);
oldtab = vcache_hashtab;
oldmask = vcache_hashmask;
vcache_hashsize = desiredvnodes;
vcache_hashtab = newtab;
vcache_hashmask = newmask;
for (i = 0; i <= oldmask; i++) {
while ((vip = SLIST_FIRST(&oldtab[i])) != NULL) {
SLIST_REMOVE(&oldtab[i], vip, vnode_impl, vi_hash);
hash = vcache_hash(&vip->vi_key);
SLIST_INSERT_HEAD(&newtab[hash & vcache_hashmask],
vip, vi_hash);
}
}
mutex_exit(&vcache_lock);
hashdone(oldtab, HASH_SLIST, oldmask);
}
static inline vnode_impl_t *
vcache_hash_lookup(const struct vcache_key *key, uint32_t hash)
{
struct hashhead *hashp;
vnode_impl_t *vip;
KASSERT(mutex_owned(&vcache_lock));
hashp = &vcache_hashtab[hash & vcache_hashmask];
SLIST_FOREACH(vip, hashp, vi_hash) {
if (key->vk_mount != vip->vi_key.vk_mount)
continue;
if (key->vk_key_len != vip->vi_key.vk_key_len)
continue;
if (memcmp(key->vk_key, vip->vi_key.vk_key, key->vk_key_len))
continue;
return vip;
}
return NULL;
}
/*
* Allocate a new, uninitialized vcache node.
*/
static vnode_impl_t *
vcache_alloc(void)
{
vnode_impl_t *vip;
vnode_t *vp;
vip = pool_cache_get(vcache_pool, PR_WAITOK);
memset(vip, 0, sizeof(*vip));
rw_init(&vip->vi_lock);
/* SLIST_INIT(&vip->vi_hash); */
/* LIST_INIT(&vip->vi_nclist); */
/* LIST_INIT(&vip->vi_dnclist); */
vp = VIMPL_TO_VNODE(vip);
uvm_obj_init(&vp->v_uobj, &uvm_vnodeops, true, 0);
cv_init(&vp->v_cv, "vnode");
vp->v_usecount = 1;
vp->v_type = VNON;
vp->v_size = vp->v_writesize = VSIZENOTSET;
vip->vi_state = VS_LOADING;
lru_requeue(vp, &lru_free_list);
return vip;
}
/*
* Deallocate a vcache node in state VS_LOADING.
*
* vcache_lock held on entry and released on return.
*/
static void
vcache_dealloc(vnode_impl_t *vip)
{
vnode_t *vp;
KASSERT(mutex_owned(&vcache_lock));
vp = VIMPL_TO_VNODE(vip);
mutex_enter(vp->v_interlock);
vp->v_op = dead_vnodeop_p;
VSTATE_CHANGE(vp, VS_LOADING, VS_RECLAIMED);
mutex_exit(&vcache_lock);
vrelel(vp, 0);
}
/*
* Free an unused, unreferenced vcache node.
* v_interlock locked on entry.
*/
static void
vcache_free(vnode_impl_t *vip)
{
vnode_t *vp;
vp = VIMPL_TO_VNODE(vip);
KASSERT(mutex_owned(vp->v_interlock));
KASSERT(vp->v_usecount == 0);
KASSERT(vp->v_holdcnt == 0);
KASSERT(vp->v_writecount == 0);
lru_requeue(vp, NULL);
mutex_exit(vp->v_interlock);
vfs_insmntque(vp, NULL);
if (vp->v_type == VBLK || vp->v_type == VCHR)
spec_node_destroy(vp);
rw_destroy(&vip->vi_lock);
uvm_obj_destroy(&vp->v_uobj, true);
cv_destroy(&vp->v_cv);
pool_cache_put(vcache_pool, vip);
}
/*
* Try to get an initial reference on this cached vnode.
* Returns zero on success, ENOENT if the vnode has been reclaimed and
* EBUSY if the vnode state is unstable.
*
* v_interlock locked on entry and unlocked on exit.
*/
int
vcache_tryvget(vnode_t *vp)
{
int error = 0;
KASSERT(mutex_owned(vp->v_interlock));
if (__predict_false(VSTATE_GET(vp) == VS_RECLAIMED))
error = ENOENT;
else if (__predict_false(VSTATE_GET(vp) != VS_LOADED))
error = EBUSY;
else if (vp->v_usecount == 0)
vp->v_usecount = 1;
else
atomic_inc_uint(&vp->v_usecount);
mutex_exit(vp->v_interlock);
return error;
}
/*
* Try to get an initial reference on this cached vnode.
* Returns zero on success and ENOENT if the vnode has been reclaimed.
* Will wait for the vnode state to be stable.
*
* v_interlock locked on entry and unlocked on exit.
*/
int
vcache_vget(vnode_t *vp)
{
KASSERT(mutex_owned(vp->v_interlock));
/* Increment hold count to prevent vnode from disappearing. */
vp->v_holdcnt++;
VSTATE_WAIT_STABLE(vp);
vp->v_holdcnt--;
/* If this was the last reference to a reclaimed vnode free it now. */
if (__predict_false(VSTATE_GET(vp) == VS_RECLAIMED)) {
if (vp->v_holdcnt == 0 && vp->v_usecount == 0)
vcache_free(VNODE_TO_VIMPL(vp));
else
mutex_exit(vp->v_interlock);
return ENOENT;
}
VSTATE_ASSERT(vp, VS_LOADED);
if (vp->v_usecount == 0)
vp->v_usecount = 1;
else
atomic_inc_uint(&vp->v_usecount);
mutex_exit(vp->v_interlock);
return 0;
}
/*
* Get a vnode / fs node pair by key and return it referenced through vpp.
*/
int
vcache_get(struct mount *mp, const void *key, size_t key_len,
struct vnode **vpp)
{
int error;
uint32_t hash;
const void *new_key;
struct vnode *vp;
struct vcache_key vcache_key;
vnode_impl_t *vip, *new_vip;
new_key = NULL;
*vpp = NULL;
vcache_key.vk_mount = mp;
vcache_key.vk_key = key;
vcache_key.vk_key_len = key_len;
hash = vcache_hash(&vcache_key);
again:
mutex_enter(&vcache_lock);
vip = vcache_hash_lookup(&vcache_key, hash);
/* If found, take a reference or retry. */
if (__predict_true(vip != NULL)) {
/*
* If the vnode is loading we cannot take the v_interlock
* here as it might change during load (see uvm_obj_setlock()).
* As changing state from VS_LOADING requires both vcache_lock
* and v_interlock it is safe to test with vcache_lock held.
*
* Wait for vnodes changing state from VS_LOADING and retry.
*/
if (__predict_false(vip->vi_state == VS_LOADING)) {
cv_wait(&vcache_cv, &vcache_lock);
mutex_exit(&vcache_lock);
goto again;
}
vp = VIMPL_TO_VNODE(vip);
mutex_enter(vp->v_interlock);
mutex_exit(&vcache_lock);
error = vcache_vget(vp);
if (error == ENOENT)
goto again;
if (error == 0)
*vpp = vp;
KASSERT((error != 0) == (*vpp == NULL));
return error;
}
mutex_exit(&vcache_lock);
/* Allocate and initialize a new vcache / vnode pair. */
error = vfs_busy(mp);
if (error)
return error;
new_vip = vcache_alloc();
new_vip->vi_key = vcache_key;
vp = VIMPL_TO_VNODE(new_vip);
mutex_enter(&vcache_lock);
vip = vcache_hash_lookup(&vcache_key, hash);
if (vip == NULL) {
SLIST_INSERT_HEAD(&vcache_hashtab[hash & vcache_hashmask],
new_vip, vi_hash);
vip = new_vip;
}
/* If another thread beat us inserting this node, retry. */
if (vip != new_vip) {
vcache_dealloc(new_vip);
vfs_unbusy(mp);
goto again;
}
mutex_exit(&vcache_lock);
/* Load the fs node. Exclusive as new_node is VS_LOADING. */
error = VFS_LOADVNODE(mp, vp, key, key_len, &new_key);
if (error) {
mutex_enter(&vcache_lock);
SLIST_REMOVE(&vcache_hashtab[hash & vcache_hashmask],
new_vip, vnode_impl, vi_hash);
vcache_dealloc(new_vip);
vfs_unbusy(mp);
KASSERT(*vpp == NULL);
return error;
}
KASSERT(new_key != NULL);
KASSERT(memcmp(key, new_key, key_len) == 0);
KASSERT(vp->v_op != NULL);
vfs_insmntque(vp, mp);
if ((mp->mnt_iflag & IMNT_MPSAFE) != 0)
vp->v_vflag |= VV_MPSAFE;
vfs_ref(mp);
vfs_unbusy(mp);
/* Finished loading, finalize node. */
mutex_enter(&vcache_lock);
new_vip->vi_key.vk_key = new_key;
mutex_enter(vp->v_interlock);
VSTATE_CHANGE(vp, VS_LOADING, VS_LOADED);
mutex_exit(vp->v_interlock);
mutex_exit(&vcache_lock);
*vpp = vp;
return 0;
}
/*
* Create a new vnode / fs node pair and return it referenced through vpp.
*/
int
vcache_new(struct mount *mp, struct vnode *dvp, struct vattr *vap,
kauth_cred_t cred, struct vnode **vpp)
{
int error;
uint32_t hash;
struct vnode *vp, *ovp;
vnode_impl_t *vip, *ovip;
*vpp = NULL;
/* Allocate and initialize a new vcache / vnode pair. */
error = vfs_busy(mp);
if (error)
return error;
vip = vcache_alloc();
vip->vi_key.vk_mount = mp;
vp = VIMPL_TO_VNODE(vip);
/* Create and load the fs node. */
error = VFS_NEWVNODE(mp, dvp, vp, vap, cred,
&vip->vi_key.vk_key_len, &vip->vi_key.vk_key);
if (error) {
mutex_enter(&vcache_lock);
vcache_dealloc(vip);
vfs_unbusy(mp);
KASSERT(*vpp == NULL);
return error;
}
KASSERT(vp->v_op != NULL);
KASSERT((vip->vi_key.vk_key_len == 0) == (mp == dead_rootmount));
if (vip->vi_key.vk_key_len > 0) {
KASSERT(vip->vi_key.vk_key != NULL);
hash = vcache_hash(&vip->vi_key);
/*
* Wait for previous instance to be reclaimed,
* then insert new node.
*/
mutex_enter(&vcache_lock);
while ((ovip = vcache_hash_lookup(&vip->vi_key, hash))) {
ovp = VIMPL_TO_VNODE(ovip);
mutex_enter(ovp->v_interlock);
mutex_exit(&vcache_lock);
error = vcache_vget(ovp);
KASSERT(error == ENOENT);
mutex_enter(&vcache_lock);
}
SLIST_INSERT_HEAD(&vcache_hashtab[hash & vcache_hashmask],
vip, vi_hash);
mutex_exit(&vcache_lock);
}
vfs_insmntque(vp, mp);
if ((mp->mnt_iflag & IMNT_MPSAFE) != 0)
vp->v_vflag |= VV_MPSAFE;
vfs_ref(mp);
vfs_unbusy(mp);
/* Finished loading, finalize node. */
mutex_enter(&vcache_lock);
mutex_enter(vp->v_interlock);
VSTATE_CHANGE(vp, VS_LOADING, VS_LOADED);
mutex_exit(&vcache_lock);
mutex_exit(vp->v_interlock);
*vpp = vp;
return 0;
}
/*
* Prepare key change: update old cache nodes key and lock new cache node.
* Return an error if the new node already exists.
*/
int
vcache_rekey_enter(struct mount *mp, struct vnode *vp,
const void *old_key, size_t old_key_len,
const void *new_key, size_t new_key_len)
{
uint32_t old_hash, new_hash;
struct vcache_key old_vcache_key, new_vcache_key;
vnode_impl_t *vip, *new_vip;
old_vcache_key.vk_mount = mp;
old_vcache_key.vk_key = old_key;
old_vcache_key.vk_key_len = old_key_len;
old_hash = vcache_hash(&old_vcache_key);
new_vcache_key.vk_mount = mp;
new_vcache_key.vk_key = new_key;
new_vcache_key.vk_key_len = new_key_len;
new_hash = vcache_hash(&new_vcache_key);
new_vip = vcache_alloc();
new_vip->vi_key = new_vcache_key;
/* Insert locked new node used as placeholder. */
mutex_enter(&vcache_lock);
vip = vcache_hash_lookup(&new_vcache_key, new_hash);
if (vip != NULL) {
vcache_dealloc(new_vip);
return EEXIST;
}
SLIST_INSERT_HEAD(&vcache_hashtab[new_hash & vcache_hashmask],
new_vip, vi_hash);
/* Replace old nodes key with the temporary copy. */
vip = vcache_hash_lookup(&old_vcache_key, old_hash);
KASSERT(vip != NULL);
KASSERT(VIMPL_TO_VNODE(vip) == vp);
KASSERT(vip->vi_key.vk_key != old_vcache_key.vk_key);
vip->vi_key = old_vcache_key;
mutex_exit(&vcache_lock);
return 0;
}
/*
* Key change complete: update old node and remove placeholder.
*/
void
vcache_rekey_exit(struct mount *mp, struct vnode *vp,
const void *old_key, size_t old_key_len,
const void *new_key, size_t new_key_len)
{
uint32_t old_hash, new_hash;
struct vcache_key old_vcache_key, new_vcache_key;
vnode_impl_t *vip, *new_vip;
struct vnode *new_vp;
old_vcache_key.vk_mount = mp;
old_vcache_key.vk_key = old_key;
old_vcache_key.vk_key_len = old_key_len;
old_hash = vcache_hash(&old_vcache_key);
new_vcache_key.vk_mount = mp;
new_vcache_key.vk_key = new_key;
new_vcache_key.vk_key_len = new_key_len;
new_hash = vcache_hash(&new_vcache_key);
mutex_enter(&vcache_lock);
/* Lookup old and new node. */
vip = vcache_hash_lookup(&old_vcache_key, old_hash);
KASSERT(vip != NULL);
KASSERT(VIMPL_TO_VNODE(vip) == vp);
new_vip = vcache_hash_lookup(&new_vcache_key, new_hash);
KASSERT(new_vip != NULL);
KASSERT(new_vip->vi_key.vk_key_len == new_key_len);
new_vp = VIMPL_TO_VNODE(new_vip);
mutex_enter(new_vp->v_interlock);
VSTATE_ASSERT(VIMPL_TO_VNODE(new_vip), VS_LOADING);
mutex_exit(new_vp->v_interlock);
/* Rekey old node and put it onto its new hashlist. */
vip->vi_key = new_vcache_key;
if (old_hash != new_hash) {
SLIST_REMOVE(&vcache_hashtab[old_hash & vcache_hashmask],
vip, vnode_impl, vi_hash);
SLIST_INSERT_HEAD(&vcache_hashtab[new_hash & vcache_hashmask],
vip, vi_hash);
}
/* Remove new node used as placeholder. */
SLIST_REMOVE(&vcache_hashtab[new_hash & vcache_hashmask],
new_vip, vnode_impl, vi_hash);
vcache_dealloc(new_vip);
}
/*
* Disassociate the underlying file system from a vnode.
*
* Must be called with vnode locked and will return unlocked.
* Must be called with the interlock held, and will return with it held.
*/
static void
vcache_reclaim(vnode_t *vp)
{
lwp_t *l = curlwp;
vnode_impl_t *vip = VNODE_TO_VIMPL(vp);
struct mount *mp = vp->v_mount;
uint32_t hash;
uint8_t temp_buf[64], *temp_key;
size_t temp_key_len;
bool recycle, active;
int error;
KASSERT((vp->v_vflag & VV_LOCKSWORK) == 0 ||
VOP_ISLOCKED(vp) == LK_EXCLUSIVE);
KASSERT(mutex_owned(vp->v_interlock));
KASSERT(vp->v_usecount != 0);
active = (vp->v_usecount > 1);
temp_key_len = vip->vi_key.vk_key_len;
/*
* Prevent the vnode from being recycled or brought into use
* while we clean it out.
*/
VSTATE_CHANGE(vp, VS_LOADED, VS_RECLAIMING);
if (vp->v_iflag & VI_EXECMAP) {
atomic_add_int(&uvmexp.execpages, -vp->v_uobj.uo_npages);
atomic_add_int(&uvmexp.filepages, vp->v_uobj.uo_npages);
}
vp->v_iflag &= ~(VI_TEXT|VI_EXECMAP);
mutex_exit(vp->v_interlock);
/* Replace the vnode key with a temporary copy. */
if (vip->vi_key.vk_key_len > sizeof(temp_buf)) {
temp_key = kmem_alloc(temp_key_len, KM_SLEEP);
} else {
temp_key = temp_buf;
}
if (vip->vi_key.vk_key_len > 0) {
mutex_enter(&vcache_lock);
memcpy(temp_key, vip->vi_key.vk_key, temp_key_len);
vip->vi_key.vk_key = temp_key;
mutex_exit(&vcache_lock);
}
fstrans_start(mp);
/*
* Clean out any cached data associated with the vnode.
* If purging an active vnode, it must be closed and
* deactivated before being reclaimed.
*/
error = vinvalbuf(vp, V_SAVE, NOCRED, l, 0, 0);
if (error != 0) {
if (wapbl_vphaswapbl(vp))
WAPBL_DISCARD(wapbl_vptomp(vp));
error = vinvalbuf(vp, 0, NOCRED, l, 0, 0);
}
KASSERTMSG((error == 0), "vinvalbuf failed: %d", error);
KASSERT((vp->v_iflag & VI_ONWORKLST) == 0);
if (active && (vp->v_type == VBLK || vp->v_type == VCHR)) {
spec_node_revoke(vp);
}
/*
* Disassociate the underlying file system from the vnode.
* VOP_INACTIVE leaves the vnode locked; VOP_RECLAIM unlocks
* the vnode, and may destroy the vnode so that VOP_UNLOCK
* would no longer function.
*/
VOP_INACTIVE(vp, &recycle);
KASSERT((vp->v_vflag & VV_LOCKSWORK) == 0 ||
VOP_ISLOCKED(vp) == LK_EXCLUSIVE);
if (VOP_RECLAIM(vp)) {
vnpanic(vp, "%s: cannot reclaim", __func__);
}
KASSERT(vp->v_data == NULL);
KASSERT(vp->v_uobj.uo_npages == 0);
if (vp->v_type == VREG && vp->v_ractx != NULL) {
uvm_ra_freectx(vp->v_ractx);
vp->v_ractx = NULL;
}
/* Purge name cache. */
cache_purge(vp);
if (vip->vi_key.vk_key_len > 0) {
/* Remove from vnode cache. */
hash = vcache_hash(&vip->vi_key);
mutex_enter(&vcache_lock);
KASSERT(vip == vcache_hash_lookup(&vip->vi_key, hash));
SLIST_REMOVE(&vcache_hashtab[hash & vcache_hashmask],
vip, vnode_impl, vi_hash);
mutex_exit(&vcache_lock);
}
if (temp_key != temp_buf)
kmem_free(temp_key, temp_key_len);
/* Done with purge, notify sleepers of the grim news. */
mutex_enter(vp->v_interlock);
vp->v_op = dead_vnodeop_p;
vp->v_vflag |= VV_LOCKSWORK;
VSTATE_CHANGE(vp, VS_RECLAIMING, VS_RECLAIMED);
vp->v_tag = VT_NON;
KNOTE(&vp->v_klist, NOTE_REVOKE);
mutex_exit(vp->v_interlock);
/*
* Move to dead mount. Must be after changing the operations
* vector as vnode operations enter the mount before using the
* operations vector. See sys/kern/vnode_if.c.
*/
vp->v_vflag &= ~VV_ROOT;
vfs_ref(dead_rootmount);
vfs_insmntque(vp, dead_rootmount);
mutex_enter(vp->v_interlock);
fstrans_done(mp);
KASSERT((vp->v_iflag & VI_ONWORKLST) == 0);
}
/*
* Disassociate the underlying file system from an open device vnode
* and make it anonymous.
*
* Vnode unlocked on entry, drops a reference to the vnode.
*/
void
vcache_make_anon(vnode_t *vp)
{
vnode_impl_t *vip = VNODE_TO_VIMPL(vp);
uint32_t hash;
bool recycle;
KASSERT(vp->v_type == VBLK || vp->v_type == VCHR);
KASSERT((vp->v_mount->mnt_iflag & IMNT_HAS_TRANS) == 0 ||
fstrans_is_owner(vp->v_mount));
VSTATE_ASSERT_UNLOCKED(vp, VS_ACTIVE);
/* Remove from vnode cache. */
hash = vcache_hash(&vip->vi_key);
mutex_enter(&vcache_lock);
KASSERT(vip == vcache_hash_lookup(&vip->vi_key, hash));
SLIST_REMOVE(&vcache_hashtab[hash & vcache_hashmask],
vip, vnode_impl, vi_hash);
vip->vi_key.vk_mount = dead_rootmount;
vip->vi_key.vk_key_len = 0;
vip->vi_key.vk_key = NULL;
mutex_exit(&vcache_lock);
/*
* Disassociate the underlying file system from the vnode.
* VOP_INACTIVE leaves the vnode locked; VOP_RECLAIM unlocks
* the vnode, and may destroy the vnode so that VOP_UNLOCK
* would no longer function.
*/
if (vn_lock(vp, LK_EXCLUSIVE)) {
vnpanic(vp, "%s: cannot lock", __func__);
}
VOP_INACTIVE(vp, &recycle);
KASSERT((vp->v_vflag & VV_LOCKSWORK) == 0 ||
VOP_ISLOCKED(vp) == LK_EXCLUSIVE);
if (VOP_RECLAIM(vp)) {
vnpanic(vp, "%s: cannot reclaim", __func__);
}
/* Purge name cache. */
cache_purge(vp);
/* Done with purge, change operations vector. */
mutex_enter(vp->v_interlock);
vp->v_op = spec_vnodeop_p;
vp->v_vflag |= VV_MPSAFE;
vp->v_vflag &= ~VV_LOCKSWORK;
mutex_exit(vp->v_interlock);
/*
* Move to dead mount. Must be after changing the operations
* vector as vnode operations enter the mount before using the
* operations vector. See sys/kern/vnode_if.c.
*/
vfs_ref(dead_rootmount);
vfs_insmntque(vp, dead_rootmount);
vrele(vp);
}
/*
* Update outstanding I/O count and do wakeup if requested.
*/
void
vwakeup(struct buf *bp)
{
vnode_t *vp;
if ((vp = bp->b_vp) == NULL)
return;
KASSERT(bp->b_objlock == vp->v_interlock);
KASSERT(mutex_owned(bp->b_objlock));
if (--vp->v_numoutput < 0)
vnpanic(vp, "%s: neg numoutput, vp %p", __func__, vp);
if (vp->v_numoutput == 0)
cv_broadcast(&vp->v_cv);
}
/*
* Test a vnode for being or becoming dead. Returns one of:
* EBUSY: vnode is becoming dead, with "flags == VDEAD_NOWAIT" only.
* ENOENT: vnode is dead.
* 0: otherwise.
*
* Whenever this function returns a non-zero value all future
* calls will also return a non-zero value.
*/
int
vdead_check(struct vnode *vp, int flags)
{
KASSERT(mutex_owned(vp->v_interlock));
if (! ISSET(flags, VDEAD_NOWAIT))
VSTATE_WAIT_STABLE(vp);
if (VSTATE_GET(vp) == VS_RECLAIMING) {
KASSERT(ISSET(flags, VDEAD_NOWAIT));
return EBUSY;
} else if (VSTATE_GET(vp) == VS_RECLAIMED) {
return ENOENT;
}
return 0;
}
int
vfs_drainvnodes(void)
{
int i, gen;
mutex_enter(&vdrain_lock);
for (i = 0; i < 2; i++) {
gen = vdrain_gen;
while (gen == vdrain_gen) {
cv_broadcast(&vdrain_cv);
cv_wait(&vdrain_gen_cv, &vdrain_lock);
}
}
mutex_exit(&vdrain_lock);
if (numvnodes >= desiredvnodes)
return EBUSY;
if (vcache_hashsize != desiredvnodes)
vcache_reinit();
return 0;
}
void
vnpanic(vnode_t *vp, const char *fmt, ...)
{
va_list ap;
#ifdef DIAGNOSTIC
vprint(NULL, vp);
#endif
va_start(ap, fmt);
vpanic(fmt, ap);
va_end(ap);
}
Reference in New Issue View Git Blame Copy Permalink