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NetBSD/sys/kern/vfs_subr.c

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/* $NetBSD: vfs_subr.c,v 1.305 2007/11/04 17:31:16 pooka Exp $ */
/*-
* Copyright (c) 1997, 1998, 2004, 2005, 2007 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation 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 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
*/
/*
* External virtual filesystem routines.
*
* This file contains vfs subroutines which are heavily dependant on
* the kernel and are not suitable for standalone use. Examples include
* routines involved vnode and mountpoint management.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_subr.c,v 1.305 2007/11/04 17:31:16 pooka Exp $");
#include "opt_inet.h"
#include "opt_ddb.h"
#include "opt_compat_netbsd.h"
#include "opt_compat_43.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/kernel.h>
#include <sys/mount.h>
#include <sys/fcntl.h>
#include <sys/vnode.h>
#include <sys/stat.h>
#include <sys/namei.h>
#include <sys/ucred.h>
#include <sys/buf.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/syscallargs.h>
#include <sys/device.h>
#include <sys/filedesc.h>
#include <sys/kauth.h>
#include <miscfs/specfs/specdev.h>
#include <miscfs/syncfs/syncfs.h>
#include <uvm/uvm.h>
#include <uvm/uvm_readahead.h>
#include <uvm/uvm_ddb.h>
#include <sys/sysctl.h>
extern int dovfsusermount; /* 1 => permit any user to mount filesystems */
extern int vfs_magiclinks; /* 1 => expand "magic" symlinks */
/* TAILQ_HEAD(freelst, vnode) vnode_free_list = vnode free list (in vnode.h) */
struct freelst vnode_free_list = TAILQ_HEAD_INITIALIZER(vnode_free_list);
struct freelst vnode_hold_list = TAILQ_HEAD_INITIALIZER(vnode_hold_list);
struct simplelock vnode_free_list_slock = SIMPLELOCK_INITIALIZER;
POOL_INIT(vnode_pool, sizeof(struct vnode), 0, 0, 0, "vnodepl",
&pool_allocator_nointr, IPL_NONE);
MALLOC_DEFINE(M_VNODE, "vnodes", "Dynamically allocated vnodes");
/*
* Local declarations.
*/
static void insmntque(struct vnode *, struct mount *);
static int getdevvp(dev_t, struct vnode **, enum vtype);
static void vclean(struct vnode *, int, struct lwp *);
static struct vnode *getcleanvnode(struct lwp *);
int
vfs_drainvnodes(long target, struct lwp *l)
{
simple_lock(&vnode_free_list_slock);
while (numvnodes > target) {
struct vnode *vp;
vp = getcleanvnode(l);
if (vp == NULL)
return EBUSY; /* give up */
pool_put(&vnode_pool, vp);
simple_lock(&vnode_free_list_slock);
numvnodes--;
}
simple_unlock(&vnode_free_list_slock);
return 0;
}
/*
* grab a vnode from freelist and clean it.
*/
struct vnode *
getcleanvnode(struct lwp *l)
{
struct vnode *vp;
struct freelst *listhd;
LOCK_ASSERT(simple_lock_held(&vnode_free_list_slock));
listhd = &vnode_free_list;
try_nextlist:
TAILQ_FOREACH(vp, listhd, v_freelist) {
if (!simple_lock_try(&vp->v_interlock))
continue;
/*
* as our lwp might hold the underlying vnode locked,
* don't try to reclaim the VLAYER vnode if it's locked.
*/
if ((vp->v_iflag & VI_XLOCK) == 0 &&
((vp->v_iflag & VI_LAYER) == 0 || VOP_ISLOCKED(vp) == 0)) {
break;
}
simple_unlock(&vp->v_interlock);
}
if (vp == NULLVP) {
if (listhd == &vnode_free_list) {
listhd = &vnode_hold_list;
goto try_nextlist;
}
simple_unlock(&vnode_free_list_slock);
return NULLVP;
}
if (vp->v_usecount)
panic("free vnode isn't, vp %p", vp);
TAILQ_REMOVE(listhd, vp, v_freelist);
/* see comment on why 0xdeadb is set at end of vgone (below) */
vp->v_freelist.tqe_prev = (struct vnode **)0xdeadb;
simple_unlock(&vnode_free_list_slock);
if (vp->v_type != VBAD)
vgonel(vp, l);
else
simple_unlock(&vp->v_interlock);
#ifdef DIAGNOSTIC
if (vp->v_data || vp->v_uobj.uo_npages ||
TAILQ_FIRST(&vp->v_uobj.memq))
panic("cleaned vnode isn't, vp %p", vp);
if (vp->v_numoutput)
panic("clean vnode has pending I/O's, vp %p", vp);
#endif
KASSERT((vp->v_iflag & VI_ONWORKLST) == 0);
return vp;
}
/*
* Mark a mount point as busy. Used to synchronize access and to delay
* unmounting. Interlock is not released on failure.
*/
int
vfs_busy(struct mount *mp, int flags, kmutex_t *interlkp)
{
int lkflags;
while (mp->mnt_iflag & IMNT_UNMOUNT) {
int gone, n;
if (flags & LK_NOWAIT)
return (ENOENT);
if ((flags & LK_RECURSEFAIL) && mp->mnt_unmounter != NULL
&& mp->mnt_unmounter == curlwp)
return (EDEADLK);
if (interlkp)
mutex_exit(interlkp);
/*
* Since all busy locks are shared except the exclusive
* lock granted when unmounting, the only place that a
* wakeup needs to be done is at the release of the
* exclusive lock at the end of dounmount.
*/
simple_lock(&mp->mnt_slock);
mp->mnt_wcnt++;
ltsleep((void *)mp, PVFS, "vfs_busy", 0, &mp->mnt_slock);
n = --mp->mnt_wcnt;
simple_unlock(&mp->mnt_slock);
gone = mp->mnt_iflag & IMNT_GONE;
if (n == 0)
wakeup(&mp->mnt_wcnt);
if (interlkp)
mutex_enter(interlkp);
if (gone)
return (ENOENT);
}
lkflags = LK_SHARED;
if (interlkp) {
/* lkflags |= LK_INTERLOCK; XXX */
mutex_exit(interlkp); /* XXX */
}
if (lockmgr(&mp->mnt_lock, lkflags, NULL))
panic("vfs_busy: unexpected lock failure");
return (0);
}
/*
* Free a busy filesystem.
*/
void
vfs_unbusy(struct mount *mp)
{
lockmgr(&mp->mnt_lock, LK_RELEASE, NULL);
}
/*
* Lookup a filesystem type, and if found allocate and initialize
* a mount structure for it.
*
* Devname is usually updated by mount(8) after booting.
*/
int
vfs_rootmountalloc(const char *fstypename, const char *devname,
struct mount **mpp)
{
struct vfsops *vfsp = NULL;
struct mount *mp;
LIST_FOREACH(vfsp, &vfs_list, vfs_list)
if (!strncmp(vfsp->vfs_name, fstypename,
sizeof(mp->mnt_stat.f_fstypename)))
break;
if (vfsp == NULL)
return (ENODEV);
mp = malloc((u_long)sizeof(struct mount), M_MOUNT, M_WAITOK);
memset((char *)mp, 0, (u_long)sizeof(struct mount));
lockinit(&mp->mnt_lock, PVFS, "vfslock", 0, 0);
simple_lock_init(&mp->mnt_slock);
(void)vfs_busy(mp, LK_NOWAIT, 0);
TAILQ_INIT(&mp->mnt_vnodelist);
mp->mnt_op = vfsp;
mp->mnt_flag = MNT_RDONLY;
mp->mnt_vnodecovered = NULLVP;
vfsp->vfs_refcount++;
(void)strlcpy(mp->mnt_stat.f_fstypename, vfsp->vfs_name,
sizeof(mp->mnt_stat.f_fstypename));
mp->mnt_stat.f_mntonname[0] = '/';
mp->mnt_stat.f_mntonname[1] = '\0';
mp->mnt_stat.f_mntfromname[sizeof(mp->mnt_stat.f_mntfromname) - 1] =
'\0';
(void)copystr(devname, mp->mnt_stat.f_mntfromname,
sizeof(mp->mnt_stat.f_mntfromname) - 1, 0);
mount_initspecific(mp);
*mpp = mp;
return (0);
}
/*
* Routines having to do with the management of the vnode table.
*/
extern int (**dead_vnodeop_p)(void *);
/*
* Return the next vnode from the free list.
*/
int
getnewvnode(enum vtagtype tag, struct mount *mp, int (**vops)(void *),
struct vnode **vpp)
{
extern struct uvm_pagerops uvm_vnodeops;
struct uvm_object *uobj;
struct lwp *l = curlwp; /* XXX */
static int toggle;
struct vnode *vp;
int error = 0, tryalloc;
try_again:
if (mp) {
/*
* Mark filesystem busy while we're creating a vnode.
* If unmount is in progress, this will wait; if the
* unmount succeeds (only if umount -f), this will
* return an error. If the unmount fails, we'll keep
* going afterwards.
* (This puts the per-mount vnode list logically under
* the protection of the vfs_busy lock).
*/
error = vfs_busy(mp, LK_RECURSEFAIL, 0);
if (error && error != EDEADLK)
return error;
}
/*
* We must choose whether to allocate a new vnode or recycle an
* existing one. The criterion for allocating a new one is that
* the total number of vnodes is less than the number desired or
* there are no vnodes on either free list. Generally we only
* want to recycle vnodes that have no buffers associated with
* them, so we look first on the vnode_free_list. If it is empty,
* we next consider vnodes with referencing buffers on the
* vnode_hold_list. The toggle ensures that half the time we
* will use a buffer from the vnode_hold_list, and half the time
* we will allocate a new one unless the list has grown to twice
* the desired size. We are reticent to recycle vnodes from the
* vnode_hold_list because we will lose the identity of all its
* referencing buffers.
*/
vp = NULL;
simple_lock(&vnode_free_list_slock);
toggle ^= 1;
if (numvnodes > 2 * desiredvnodes)
toggle = 0;
tryalloc = numvnodes < desiredvnodes ||
(TAILQ_FIRST(&vnode_free_list) == NULL &&
(TAILQ_FIRST(&vnode_hold_list) == NULL || toggle));
if (tryalloc &&
(vp = pool_get(&vnode_pool, PR_NOWAIT)) != NULL) {
numvnodes++;
simple_unlock(&vnode_free_list_slock);
memset(vp, 0, sizeof(*vp));
UVM_OBJ_INIT(&vp->v_uobj, &uvm_vnodeops, 1);
/*
* done by memset() above.
* LIST_INIT(&vp->v_nclist);
* LIST_INIT(&vp->v_dnclist);
*/
} else {
vp = getcleanvnode(l);
/*
* Unless this is a bad time of the month, at most
* the first NCPUS items on the free list are
* locked, so this is close enough to being empty.
*/
if (vp == NULLVP) {
if (mp && error != EDEADLK)
vfs_unbusy(mp);
if (tryalloc) {
printf("WARNING: unable to allocate new "
"vnode, retrying...\n");
(void) tsleep(&lbolt, PRIBIO, "newvn", hz);
goto try_again;
}
tablefull("vnode", "increase kern.maxvnodes or NVNODE");
*vpp = 0;
return (ENFILE);
}
vp->v_usecount = 1;
vp->v_iflag = 0;
vp->v_vflag = 0;
vp->v_uflag = 0;
vp->v_socket = NULL;
}
vp->v_type = VNON;
vp->v_vnlock = &vp->v_lock;
lockinit(vp->v_vnlock, PVFS, "vnlock", 0, 0);
KASSERT(LIST_EMPTY(&vp->v_nclist));
KASSERT(LIST_EMPTY(&vp->v_dnclist));
vp->v_tag = tag;
vp->v_op = vops;
insmntque(vp, mp);
*vpp = vp;
vp->v_data = 0;
simple_lock_init(&vp->v_interlock);
/*
* initialize uvm_object within vnode.
*/
uobj = &vp->v_uobj;
KASSERT(uobj->pgops == &uvm_vnodeops);
KASSERT(uobj->uo_npages == 0);
KASSERT(TAILQ_FIRST(&uobj->memq) == NULL);
vp->v_size = vp->v_writesize = VSIZENOTSET;
if (mp && error != EDEADLK)
vfs_unbusy(mp);
return (0);
}
/*
* This is really just the reverse of getnewvnode(). Needed for
* VFS_VGET functions who may need to push back a vnode in case
* of a locking race.
*/
void
ungetnewvnode(struct vnode *vp)
{
#ifdef DIAGNOSTIC
if (vp->v_usecount != 1)
panic("ungetnewvnode: busy vnode");
#endif
vp->v_usecount--;
insmntque(vp, NULL);
vp->v_type = VBAD;
simple_lock(&vp->v_interlock);
/*
* Insert at head of LRU list
*/
simple_lock(&vnode_free_list_slock);
if (vp->v_holdcnt > 0)
TAILQ_INSERT_HEAD(&vnode_hold_list, vp, v_freelist);
else
TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
simple_unlock(&vnode_free_list_slock);
simple_unlock(&vp->v_interlock);
}
/*
* Move a vnode from one mount queue to another.
*/
static void
insmntque(struct vnode *vp, struct mount *mp)
{
#ifdef DIAGNOSTIC
if ((mp != NULL) &&
(mp->mnt_iflag & IMNT_UNMOUNT) &&
!(mp->mnt_flag & MNT_SOFTDEP) &&
vp->v_tag != VT_VFS) {
panic("insmntque into dying filesystem");
}
#endif
simple_lock(&mntvnode_slock);
/*
* Delete from old mount point vnode list, if on one.
*/
if (vp->v_mount != NULL)
TAILQ_REMOVE(&vp->v_mount->mnt_vnodelist, vp, v_mntvnodes);
/*
* Insert into list of vnodes for the new mount point, if available.
*/
if ((vp->v_mount = mp) != NULL)
TAILQ_INSERT_TAIL(&mp->mnt_vnodelist, vp, v_mntvnodes);
simple_unlock(&mntvnode_slock);
}
/*
* Create a vnode for a block device.
* Used for root filesystem and swap areas.
* Also used for memory file system special devices.
*/
int
bdevvp(dev_t dev, struct vnode **vpp)
{
return (getdevvp(dev, vpp, VBLK));
}
/*
* Create a vnode for a character device.
* Used for kernfs and some console handling.
*/
int
cdevvp(dev_t dev, struct vnode **vpp)
{
return (getdevvp(dev, vpp, VCHR));
}
/*
* Create a vnode for a device.
* Used by bdevvp (block device) for root file system etc.,
* and by cdevvp (character device) for console and kernfs.
*/
static int
getdevvp(dev_t dev, struct vnode **vpp, enum vtype type)
{
struct vnode *vp;
struct vnode *nvp;
int error;
if (dev == NODEV) {
*vpp = NULL;
return (0);
}
error = getnewvnode(VT_NON, NULL, spec_vnodeop_p, &nvp);
if (error) {
*vpp = NULL;
return (error);
}
vp = nvp;
vp->v_type = type;
uvm_vnp_setsize(vp, 0);
if ((nvp = checkalias(vp, dev, NULL)) != 0) {
vput(vp);
vp = nvp;
}
*vpp = vp;
return (0);
}
/*
* Check to see if the new vnode represents a special device
* for which we already have a vnode (either because of
* bdevvp() or because of a different vnode representing
* the same block device). If such an alias exists, deallocate
* the existing contents and return the aliased vnode. The
* caller is responsible for filling it with its new contents.
*/
struct vnode *
checkalias(struct vnode *nvp, dev_t nvp_rdev, struct mount *mp)
{
struct lwp *l = curlwp; /* XXX */
struct vnode *vp;
struct vnode **vpp;
if (nvp->v_type != VBLK && nvp->v_type != VCHR)
return (NULLVP);
vpp = &speclisth[SPECHASH(nvp_rdev)];
loop:
simple_lock(&spechash_slock);
for (vp = *vpp; vp; vp = vp->v_specnext) {
if (nvp_rdev != vp->v_rdev || nvp->v_type != vp->v_type)
continue;
/*
* Alias, but not in use, so flush it out.
*/
simple_lock(&vp->v_interlock);
simple_unlock(&spechash_slock);
if (vp->v_usecount == 0) {
vgonel(vp, l);
goto loop;
}
/*
* What we're interested to know here is if someone else has
* removed this vnode from the device hash list while we were
* waiting. This can only happen if vclean() did it, and
* this requires the vnode to be locked.
*/
if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK))
goto loop;
if (vp->v_specinfo == NULL) {
vput(vp);
goto loop;
}
simple_lock(&spechash_slock);
break;
}
if (vp == NULL || vp->v_tag != VT_NON || vp->v_type != VBLK) {
MALLOC(nvp->v_specinfo, struct specinfo *,
sizeof(struct specinfo), M_VNODE, M_NOWAIT);
/* XXX Erg. */
if (nvp->v_specinfo == NULL) {
simple_unlock(&spechash_slock);
uvm_wait("checkalias");
goto loop;
}
nvp->v_rdev = nvp_rdev;
nvp->v_hashchain = vpp;
nvp->v_specnext = *vpp;
nvp->v_specmountpoint = NULL;
simple_unlock(&spechash_slock);
nvp->v_speclockf = NULL;
*vpp = nvp;
if (vp != NULLVP) {
nvp->v_iflag |= VI_ALIASED;
vp->v_iflag |= VI_ALIASED;
vput(vp);
}
return (NULLVP);
}
simple_unlock(&spechash_slock);
VOP_UNLOCK(vp, 0);
simple_lock(&vp->v_interlock);
vclean(vp, 0, l);
vp->v_op = nvp->v_op;
vp->v_tag = nvp->v_tag;
vp->v_vnlock = &vp->v_lock;
lockinit(vp->v_vnlock, PVFS, "vnlock", 0, 0);
nvp->v_type = VNON;
insmntque(vp, mp);
return (vp);
}
/*
* Grab a particular vnode from the free list, increment its
* reference count and lock it. If the vnode lock bit is set the
* vnode is being eliminated in vgone. In that case, we can not
* grab the vnode, so the process is awakened when the transition is
* completed, and an error returned to indicate that the vnode is no
* longer usable (possibly having been changed to a new file system type).
*/
int
vget(struct vnode *vp, int flags)
{
int error;
/*
* If the vnode is in the process of being cleaned out for
* another use, we wait for the cleaning to finish and then
* return failure. Cleaning is determined by checking that
* the VI_XLOCK flag is set.
*/
if ((flags & LK_INTERLOCK) == 0)
simple_lock(&vp->v_interlock);
if ((vp->v_iflag & (VI_XLOCK | VI_FREEING)) != 0) {
if (flags & LK_NOWAIT) {
simple_unlock(&vp->v_interlock);
return EBUSY;
}
vp->v_iflag |= VI_XWANT;
ltsleep(vp, PINOD|PNORELOCK, "vget", 0, &vp->v_interlock);
return (ENOENT);
}
if (vp->v_usecount == 0) {
simple_lock(&vnode_free_list_slock);
if (vp->v_holdcnt > 0)
TAILQ_REMOVE(&vnode_hold_list, vp, v_freelist);
else
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
simple_unlock(&vnode_free_list_slock);
}
vp->v_usecount++;
#ifdef DIAGNOSTIC
if (vp->v_usecount == 0) {
vprint("vget", vp);
panic("vget: usecount overflow, vp %p", vp);
}
#endif
if (flags & LK_TYPE_MASK) {
if ((error = vn_lock(vp, flags | LK_INTERLOCK))) {
vrele(vp);
}
return (error);
}
simple_unlock(&vp->v_interlock);
return (0);
}
/*
* vput(), just unlock and vrele()
*/
void
vput(struct vnode *vp)
{
struct lwp *l = curlwp; /* XXX */
#ifdef DIAGNOSTIC
if (vp == NULL)
panic("vput: null vp");
#endif
simple_lock(&vp->v_interlock);
vp->v_usecount--;
if (vp->v_usecount > 0) {
simple_unlock(&vp->v_interlock);
VOP_UNLOCK(vp, 0);
return;
}
#ifdef DIAGNOSTIC
if (vp->v_usecount < 0 || vp->v_writecount != 0) {
vprint("vput: bad ref count", vp);
panic("vput: ref cnt");
}
#endif
/*
* Insert at tail of LRU list.
*/
simple_lock(&vnode_free_list_slock);
if (vp->v_holdcnt > 0)
TAILQ_INSERT_TAIL(&vnode_hold_list, vp, v_freelist);
else
TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
simple_unlock(&vnode_free_list_slock);
if (vp->v_iflag & VI_EXECMAP) {
uvmexp.execpages -= vp->v_uobj.uo_npages;
uvmexp.filepages += vp->v_uobj.uo_npages;
}
vp->v_iflag &= ~(VI_TEXT|VI_EXECMAP|VI_WRMAP|VI_MAPPED);
vp->v_vflag &= ~VV_MAPPED;
simple_unlock(&vp->v_interlock);
VOP_INACTIVE(vp, l);
}
/*
* Vnode release.
* If count drops to zero, call inactive routine and return to freelist.
*/
static void
do_vrele(struct vnode *vp, int doinactive, int onhead)
{
struct lwp *l = curlwp; /* XXX */
#ifdef DIAGNOSTIC
if (vp == NULL)
panic("vrele: null vp");
#endif
simple_lock(&vp->v_interlock);
vp->v_usecount--;
if (vp->v_usecount > 0) {
simple_unlock(&vp->v_interlock);
return;
}
#ifdef DIAGNOSTIC
if (vp->v_usecount < 0 || vp->v_writecount != 0) {
vprint("vrele: bad ref count", vp);
panic("vrele: ref cnt vp %p", vp);
}
#endif
/*
* Insert at tail of LRU list.
*/
simple_lock(&vnode_free_list_slock);
if (vp->v_holdcnt > 0) {
TAILQ_INSERT_TAIL(&vnode_hold_list, vp, v_freelist);
} else {
if (onhead)
TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
else
TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
}
simple_unlock(&vnode_free_list_slock);
if (vp->v_iflag & VI_EXECMAP) {
uvmexp.execpages -= vp->v_uobj.uo_npages;
uvmexp.filepages += vp->v_uobj.uo_npages;
}
vp->v_iflag &= ~(VI_TEXT|VI_EXECMAP|VI_WRMAP|VI_MAPPED);
vp->v_vflag &= ~VV_MAPPED;
if (doinactive) {
if (vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK) == 0)
VOP_INACTIVE(vp, l);
} else {
simple_unlock(&vp->v_interlock);
}
}
void
vrele(struct vnode *vp)
{
do_vrele(vp, 1, 0);
}
void
vrele2(struct vnode *vp, int onhead)
{
do_vrele(vp, 0, onhead);
}
/*
* Page or buffer structure gets a reference.
* Called with v_interlock held.
*/
void
vholdl(struct vnode *vp)
{
/*
* If it is on the freelist and the hold count is currently
* zero, move it to the hold list. The test of the back
* pointer and the use reference count of zero is because
* it will be removed from a free list by getnewvnode,
* but will not have its reference count incremented until
* after calling vgone. If the reference count were
* incremented first, vgone would (incorrectly) try to
* close the previous instance of the underlying object.
* So, the back pointer is explicitly set to `0xdeadb' in
* getnewvnode after removing it from a freelist to ensure
* that we do not try to move it here.
*/
if ((vp->v_freelist.tqe_prev != (struct vnode **)0xdeadb) &&
vp->v_holdcnt == 0 && vp->v_usecount == 0) {
simple_lock(&vnode_free_list_slock);
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
TAILQ_INSERT_TAIL(&vnode_hold_list, vp, v_freelist);
simple_unlock(&vnode_free_list_slock);
}
vp->v_holdcnt++;
}
/*
* Page or buffer structure frees a reference.
* Called with v_interlock held.
*/
void
holdrelel(struct vnode *vp)
{
if (vp->v_holdcnt <= 0)
panic("holdrelel: holdcnt vp %p", vp);
vp->v_holdcnt--;
/*
* If it is on the holdlist and the hold count drops to
* zero, move it to the free list. The test of the back
* pointer and the use reference count of zero is because
* it will be removed from a free list by getnewvnode,
* but will not have its reference count incremented until
* after calling vgone. If the reference count were
* incremented first, vgone would (incorrectly) try to
* close the previous instance of the underlying object.
* So, the back pointer is explicitly set to `0xdeadb' in
* getnewvnode after removing it from a freelist to ensure
* that we do not try to move it here.
*/
if ((vp->v_freelist.tqe_prev != (struct vnode **)0xdeadb) &&
vp->v_holdcnt == 0 && vp->v_usecount == 0) {
simple_lock(&vnode_free_list_slock);
TAILQ_REMOVE(&vnode_hold_list, vp, v_freelist);
TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
simple_unlock(&vnode_free_list_slock);
}
}
/*
* Vnode reference.
*/
void
vref(struct vnode *vp)
{
simple_lock(&vp->v_interlock);
if (vp->v_usecount <= 0)
panic("vref used where vget required, vp %p", vp);
vp->v_usecount++;
#ifdef DIAGNOSTIC
if (vp->v_usecount == 0) {
vprint("vref", vp);
panic("vref: usecount overflow, vp %p", vp);
}
#endif
simple_unlock(&vp->v_interlock);
}
/*
* Remove any vnodes in the vnode table belonging to mount point mp.
*
* If FORCECLOSE is not specified, there should not be any active ones,
* return error if any are found (nb: this is a user error, not a
* system error). If FORCECLOSE is specified, detach any active vnodes
* that are found.
*
* If WRITECLOSE is set, only flush out regular file vnodes open for
* writing.
*
* SKIPSYSTEM causes any vnodes marked V_SYSTEM to be skipped.
*/
#ifdef DEBUG
int busyprt = 0; /* print out busy vnodes */
struct ctldebug debug1 = { "busyprt", &busyprt };
#endif
int
vflush(struct mount *mp, struct vnode *skipvp, int flags)
{
struct lwp *l = curlwp; /* XXX */
struct vnode *vp, *nvp;
int busy = 0;
simple_lock(&mntvnode_slock);
loop:
/*
* NOTE: not using the TAILQ_FOREACH here since in this loop vgone()
* and vclean() are called
*/
for (vp = TAILQ_FIRST(&mp->mnt_vnodelist); vp; vp = nvp) {
if (vp->v_mount != mp)
goto loop;
nvp = TAILQ_NEXT(vp, v_mntvnodes);
/*
* Skip over a selected vnode.
*/
if (vp == skipvp)
continue;
simple_lock(&vp->v_interlock);
/*
* Skip over a vnodes marked VV_SYSTEM.
*/
if ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) {
simple_unlock(&vp->v_interlock);
continue;
}
/*
* If WRITECLOSE is set, only flush out regular file
* vnodes open for writing.
*/
if ((flags & WRITECLOSE) &&
(vp->v_writecount == 0 || vp->v_type != VREG)) {
simple_unlock(&vp->v_interlock);
continue;
}
/*
* With v_usecount == 0, all we need to do is clear
* out the vnode data structures and we are done.
*/
if (vp->v_usecount == 0) {
simple_unlock(&mntvnode_slock);
vgonel(vp, l);
simple_lock(&mntvnode_slock);
continue;
}
/*
* If FORCECLOSE is set, forcibly close the vnode.
* For block or character devices, revert to an
* anonymous device. For all other files, just kill them.
*/
if (flags & FORCECLOSE) {
simple_unlock(&mntvnode_slock);
if (vp->v_type != VBLK && vp->v_type != VCHR) {
vgonel(vp, l);
} else {
vclean(vp, 0, l);
vp->v_op = spec_vnodeop_p;
insmntque(vp, (struct mount *)0);
}
simple_lock(&mntvnode_slock);
continue;
}
#ifdef DEBUG
if (busyprt)
vprint("vflush: busy vnode", vp);
#endif
simple_unlock(&vp->v_interlock);
busy++;
}
simple_unlock(&mntvnode_slock);
if (busy)
return (EBUSY);
return (0);
}
/*
* Disassociate the underlying file system from a vnode.
*/
static void
vclean(struct vnode *vp, int flags, struct lwp *l)
{
int active;
LOCK_ASSERT(simple_lock_held(&vp->v_interlock));
/*
* Check to see if the vnode is in use.
* If so we have to reference it before we clean it out
* so that its count cannot fall to zero and generate a
* race against ourselves to recycle it.
*/
if ((active = vp->v_usecount) != 0) {
vp->v_usecount++;
#ifdef DIAGNOSTIC
if (vp->v_usecount == 0) {
vprint("vclean", vp);
panic("vclean: usecount overflow");
}
#endif
}
/*
* Prevent the vnode from being recycled or
* brought into use while we clean it out.
*/
if (vp->v_iflag & VI_XLOCK)
panic("vclean: deadlock, vp %p", vp);
vp->v_iflag |= VI_XLOCK;
if (vp->v_iflag & VI_EXECMAP) {
uvmexp.execpages -= vp->v_uobj.uo_npages;
uvmexp.filepages += vp->v_uobj.uo_npages;
}
vp->v_iflag &= ~(VI_TEXT|VI_EXECMAP);
/*
* Even if the count is zero, the VOP_INACTIVE routine may still
* have the object locked while it cleans it out. For
* active vnodes, it ensures that no other activity can
* occur while the underlying object is being cleaned out.
*
* We drain the lock to make sure we are the last one trying to
* get it and immediately resurrect the lock. Future accesses
* for locking this _vnode_ will be protected by VI_XLOCK. However,
* upper layers might be using the _lock_ in case the file system
* exported it and might access it while the vnode lingers in
* deadfs.
*/
VOP_LOCK(vp, LK_DRAIN | LK_RESURRECT | LK_INTERLOCK);
/*
* Clean out any cached data associated with the vnode.
* If special device, remove it from special device alias list.
* if it is on one.
*/
if (flags & DOCLOSE) {
int error;
struct vnode *vq, *vx;
error = vinvalbuf(vp, V_SAVE, NOCRED, l, 0, 0);
if (error)
error = vinvalbuf(vp, 0, NOCRED, l, 0, 0);
KASSERT(error == 0);
KASSERT((vp->v_iflag & VI_ONWORKLST) == 0);
if (active)
VOP_CLOSE(vp, FNONBLOCK, NOCRED, NULL);
if ((vp->v_type == VBLK || vp->v_type == VCHR) &&
vp->v_specinfo != 0) {
simple_lock(&spechash_slock);
if (vp->v_hashchain != NULL) {
if (*vp->v_hashchain == vp) {
*vp->v_hashchain = vp->v_specnext;
} else {
for (vq = *vp->v_hashchain; vq;
vq = vq->v_specnext) {
if (vq->v_specnext != vp)
continue;
vq->v_specnext = vp->v_specnext;
break;
}
if (vq == NULL)
panic("missing bdev");
}
if (vp->v_iflag & VI_ALIASED) {
vx = NULL;
for (vq = *vp->v_hashchain; vq;
vq = vq->v_specnext) {
if (vq->v_rdev != vp->v_rdev ||
vq->v_type != vp->v_type)
continue;
if (vx)
break;
vx = vq;
}
if (vx == NULL)
panic("missing alias");
if (vq == NULL)
vx->v_iflag &= ~VI_ALIASED;
vp->v_iflag &= ~VI_ALIASED;
}
}
simple_unlock(&spechash_slock);
FREE(vp->v_specinfo, M_VNODE);
vp->v_specinfo = NULL;
}
}
/*
* If purging an active vnode, it must be closed and
* deactivated before being reclaimed. Note that the
* VOP_INACTIVE will unlock the vnode.
*/
if (active) {
VOP_INACTIVE(vp, l);
} else {
/*
* Any other processes trying to obtain this lock must first
* wait for VI_XLOCK to clear, then call the new lock operation.
*/
VOP_UNLOCK(vp, 0);
}
/*
* Reclaim the vnode.
*/
if (VOP_RECLAIM(vp, l))
panic("vclean: cannot reclaim, vp %p", vp);
if (active) {
/*
* Inline copy of vrele() since VOP_INACTIVE
* has already been called.
*/
simple_lock(&vp->v_interlock);
if (--vp->v_usecount <= 0) {
#ifdef DIAGNOSTIC
if (vp->v_usecount < 0 || vp->v_writecount != 0) {
vprint("vclean: bad ref count", vp);
panic("vclean: ref cnt");
}
#endif
/*
* Insert at tail of LRU list.
*/
simple_unlock(&vp->v_interlock);
simple_lock(&vnode_free_list_slock);
#ifdef DIAGNOSTIC
if (vp->v_holdcnt > 0)
panic("vclean: not clean, vp %p", vp);
#endif
TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
simple_unlock(&vnode_free_list_slock);
} else
simple_unlock(&vp->v_interlock);
}
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;
}
cache_purge(vp);
/*
* Done with purge, notify sleepers of the grim news.
*/
vp->v_op = dead_vnodeop_p;
vp->v_tag = VT_NON;
vp->v_vnlock = NULL;
simple_lock(&vp->v_interlock);
VN_KNOTE(vp, NOTE_REVOKE); /* FreeBSD has this in vn_pollgone() */
vp->v_iflag &= ~VI_XLOCK;
vp->v_vflag &= ~VV_LOCKSWORK;
if (vp->v_iflag & VI_XWANT) {
vp->v_iflag &= ~VI_XWANT;
simple_unlock(&vp->v_interlock);
wakeup((void *)vp);
} else
simple_unlock(&vp->v_interlock);
}
/*
* Recycle an unused vnode to the front of the free list.
* Release the passed interlock if the vnode will be recycled.
*/
int
vrecycle(struct vnode *vp, struct simplelock *inter_lkp, struct lwp *l)
{
simple_lock(&vp->v_interlock);
if (vp->v_usecount == 0) {
if (inter_lkp)
simple_unlock(inter_lkp);
vgonel(vp, l);
return (1);
}
simple_unlock(&vp->v_interlock);
return (0);
}
/*
* Eliminate all activity associated with a vnode
* in preparation for reuse.
*/
void
vgone(struct vnode *vp)
{
struct lwp *l = curlwp; /* XXX */
simple_lock(&vp->v_interlock);
vgonel(vp, l);
}
/*
* vgone, with the vp interlock held.
*/
void
vgonel(struct vnode *vp, struct lwp *l)
{
LOCK_ASSERT(simple_lock_held(&vp->v_interlock));
/*
* If a vgone (or vclean) is already in progress,
* wait until it is done and return.
*/
if (vp->v_iflag & VI_XLOCK) {
vp->v_iflag |= VI_XWANT;
ltsleep(vp, PINOD | PNORELOCK, "vgone", 0, &vp->v_interlock);
return;
}
/*
* Clean out the filesystem specific data.
*/
vclean(vp, DOCLOSE, l);
KASSERT((vp->v_iflag & VI_ONWORKLST) == 0);
/*
* Delete from old mount point vnode list, if on one.
*/
if (vp->v_mount != NULL)
insmntque(vp, (struct mount *)0);
/*
* The test of the back pointer and the reference count of
* zero is because it will be removed from the free list by
* getcleanvnode, but will not have its reference count
* incremented until after calling vgone. If the reference
* count were incremented first, vgone would (incorrectly)
* try to close the previous instance of the underlying object.
* So, the back pointer is explicitly set to `0xdeadb' in
* getnewvnode after removing it from the freelist to ensure
* that we do not try to move it here.
*/
vp->v_type = VBAD;
if (vp->v_usecount == 0) {
bool dofree;
simple_lock(&vnode_free_list_slock);
if (vp->v_holdcnt > 0)
panic("vgonel: not clean, vp %p", vp);
/*
* if it isn't on the freelist, we're called by getcleanvnode
* and vnode is being re-used. otherwise, we'll free it.
*/
dofree = vp->v_freelist.tqe_prev != (struct vnode **)0xdeadb;
if (dofree) {
TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
numvnodes--;
}
simple_unlock(&vnode_free_list_slock);
if (dofree)
pool_put(&vnode_pool, vp);
}
}
/*
* Lookup a vnode by device number.
*/
int
vfinddev(dev_t dev, enum vtype type, struct vnode **vpp)
{
struct vnode *vp;
int rc = 0;
simple_lock(&spechash_slock);
for (vp = speclisth[SPECHASH(dev)]; vp; vp = vp->v_specnext) {
if (dev != vp->v_rdev || type != vp->v_type)
continue;
*vpp = vp;
rc = 1;
break;
}
simple_unlock(&spechash_slock);
return (rc);
}
/*
* Revoke all the vnodes corresponding to the specified minor number
* range (endpoints inclusive) of the specified major.
*/
void
vdevgone(int maj, int minl, int minh, enum vtype type)
{
struct vnode *vp;
int mn;
vp = NULL; /* XXX gcc */
for (mn = minl; mn <= minh; mn++)
if (vfinddev(makedev(maj, mn), type, &vp))
VOP_REVOKE(vp, REVOKEALL);
}
/*
* Calculate the total number of references to a special device.
*/
int
vcount(struct vnode *vp)
{
struct vnode *vq, *vnext;
int count;
loop:
if ((vp->v_iflag & VI_ALIASED) == 0)
return (vp->v_usecount);
simple_lock(&spechash_slock);
for (count = 0, vq = *vp->v_hashchain; vq; vq = vnext) {
vnext = vq->v_specnext;
if (vq->v_rdev != vp->v_rdev || vq->v_type != vp->v_type)
continue;
/*
* Alias, but not in use, so flush it out.
*/
if (vq->v_usecount == 0 && vq != vp &&
(vq->v_iflag & VI_XLOCK) == 0) {
simple_unlock(&spechash_slock);
vgone(vq);
goto loop;
}
count += vq->v_usecount;
}
simple_unlock(&spechash_slock);
return (count);
}
/*
* sysctl helper routine to return list of supported fstypes
*/
static int
sysctl_vfs_generic_fstypes(SYSCTLFN_ARGS)
{
char bf[sizeof(((struct statvfs *)NULL)->f_fstypename)];
char *where = oldp;
struct vfsops *v;
size_t needed, left, slen;
int error, first;
if (newp != NULL)
return (EPERM);
if (namelen != 0)
return (EINVAL);
first = 1;
error = 0;
needed = 0;
left = *oldlenp;
mutex_enter(&vfs_list_lock);
LIST_FOREACH(v, &vfs_list, vfs_list) {
if (where == NULL)
needed += strlen(v->vfs_name) + 1;
else {
memset(bf, 0, sizeof(bf));
if (first) {
strncpy(bf, v->vfs_name, sizeof(bf));
first = 0;
} else {
bf[0] = ' ';
strncpy(bf + 1, v->vfs_name, sizeof(bf) - 1);
}
bf[sizeof(bf)-1] = '\0';
slen = strlen(bf);
if (left < slen + 1)
break;
/* +1 to copy out the trailing NUL byte */
v->vfs_refcount++;
mutex_exit(&vfs_list_lock);
error = copyout(bf, where, slen + 1);
mutex_enter(&vfs_list_lock);
v->vfs_refcount--;
if (error)
break;
where += slen;
needed += slen;
left -= slen;
}
}
mutex_exit(&vfs_list_lock);
*oldlenp = needed;
return (error);
}
/*
* Top level filesystem related information gathering.
*/
SYSCTL_SETUP(sysctl_vfs_setup, "sysctl vfs subtree setup")
{
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "vfs", NULL,
NULL, 0, NULL, 0,
CTL_VFS, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "generic",
SYSCTL_DESCR("Non-specific vfs related information"),
NULL, 0, NULL, 0,
CTL_VFS, VFS_GENERIC, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "usermount",
SYSCTL_DESCR("Whether unprivileged users may mount "
"filesystems"),
NULL, 0, &dovfsusermount, 0,
CTL_VFS, VFS_GENERIC, VFS_USERMOUNT, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_STRING, "fstypes",
SYSCTL_DESCR("List of file systems present"),
sysctl_vfs_generic_fstypes, 0, NULL, 0,
CTL_VFS, VFS_GENERIC, CTL_CREATE, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "magiclinks",
SYSCTL_DESCR("Whether \"magic\" symlinks are expanded"),
NULL, 0, &vfs_magiclinks, 0,
CTL_VFS, VFS_GENERIC, VFS_MAGICLINKS, CTL_EOL);
}
int kinfo_vdebug = 1;
int kinfo_vgetfailed;
#define KINFO_VNODESLOP 10
/*
* Dump vnode list (via sysctl).
* Copyout address of vnode followed by vnode.
*/
/* ARGSUSED */
int
sysctl_kern_vnode(SYSCTLFN_ARGS)
{
char *where = oldp;
size_t *sizep = oldlenp;
struct mount *mp, *nmp;
struct vnode *vp;
char *bp = where, *savebp;
char *ewhere;
int error;
if (namelen != 0)
return (EOPNOTSUPP);
if (newp != NULL)
return (EPERM);
#define VPTRSZ sizeof(struct vnode *)
#define VNODESZ sizeof(struct vnode)
if (where == NULL) {
*sizep = (numvnodes + KINFO_VNODESLOP) * (VPTRSZ + VNODESZ);
return (0);
}
ewhere = where + *sizep;
mutex_enter(&mountlist_lock);
for (mp = CIRCLEQ_FIRST(&mountlist); mp != (void *)&mountlist;
mp = nmp) {
if (vfs_busy(mp, LK_NOWAIT, &mountlist_lock)) {
nmp = CIRCLEQ_NEXT(mp, mnt_list);
continue;
}
savebp = bp;
again:
simple_lock(&mntvnode_slock);
TAILQ_FOREACH(vp, &mp->mnt_vnodelist, v_mntvnodes) {
/*
* Check that the vp is still associated with
* this filesystem. RACE: could have been
* recycled onto the same filesystem.
*/
if (vp->v_mount != mp) {
simple_unlock(&mntvnode_slock);
if (kinfo_vdebug)
printf("kinfo: vp changed\n");
bp = savebp;
goto again;
}
if (bp + VPTRSZ + VNODESZ > ewhere) {
simple_unlock(&mntvnode_slock);
*sizep = bp - where;
return (ENOMEM);
}
simple_unlock(&mntvnode_slock);
if ((error = copyout((void *)&vp, bp, VPTRSZ)) ||
(error = copyout((void *)vp, bp + VPTRSZ, VNODESZ)))
return (error);
bp += VPTRSZ + VNODESZ;
simple_lock(&mntvnode_slock);
}
simple_unlock(&mntvnode_slock);
mutex_enter(&mountlist_lock);
nmp = CIRCLEQ_NEXT(mp, mnt_list);
vfs_unbusy(mp);
}
mutex_exit(&mountlist_lock);
*sizep = bp - where;
return (0);
}
/*
* Check to see if a filesystem is mounted on a block device.
*/
int
vfs_mountedon(struct vnode *vp)
{
struct vnode *vq;
int error = 0;
if (vp->v_type != VBLK)
return ENOTBLK;
if (vp->v_specmountpoint != NULL)
return (EBUSY);
if (vp->v_iflag & VI_ALIASED) {
simple_lock(&spechash_slock);
for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
if (vq->v_rdev != vp->v_rdev ||
vq->v_type != vp->v_type)
continue;
if (vq->v_specmountpoint != NULL) {
error = EBUSY;
break;
}
}
simple_unlock(&spechash_slock);
}
return (error);
}
/*
* Unmount all file systems.
* We traverse the list in reverse order under the assumption that doing so
* will avoid needing to worry about dependencies.
*/
void
vfs_unmountall(struct lwp *l)
{
struct mount *mp, *nmp;
int allerror, error;
printf("unmounting file systems...");
for (allerror = 0,
mp = mountlist.cqh_last; mp != (void *)&mountlist; mp = nmp) {
nmp = mp->mnt_list.cqe_prev;
#ifdef DEBUG
printf("\nunmounting %s (%s)...",
mp->mnt_stat.f_mntonname, mp->mnt_stat.f_mntfromname);
#endif
/*
* XXX Freeze syncer. Must do this before locking the
* mount point. See dounmount() for details.
*/
mutex_enter(&syncer_mutex);
if (vfs_busy(mp, 0, 0)) {
mutex_exit(&syncer_mutex);
continue;
}
if ((error = dounmount(mp, MNT_FORCE, l)) != 0) {
printf("unmount of %s failed with error %d\n",
mp->mnt_stat.f_mntonname, error);
allerror = 1;
}
}
printf(" done\n");
if (allerror)
printf("WARNING: some file systems would not unmount\n");
}
extern struct simplelock bqueue_slock; /* XXX */
/*
* Sync and unmount file systems before shutting down.
*/
void
vfs_shutdown(void)
{
struct lwp *l;
/* XXX we're certainly not running in lwp0's context! */
l = curlwp;
if (l == NULL)
l = &lwp0;
printf("syncing disks... ");
/* remove user processes from run queue */
suspendsched();
(void) spl0();
/* avoid coming back this way again if we panic. */
doing_shutdown = 1;
sys_sync(l, NULL, NULL);
/* Wait for sync to finish. */
if (buf_syncwait() != 0) {
#if defined(DDB) && defined(DEBUG_HALT_BUSY)
Debugger();
#endif
printf("giving up\n");
return;
} else
printf("done\n");
/*
* If we've panic'd, don't make the situation potentially
* worse by unmounting the file systems.
*/
if (panicstr != NULL)
return;
/* Release inodes held by texts before update. */
#ifdef notdef
vnshutdown();
#endif
/* Unmount file systems. */
vfs_unmountall(l);
}
/*
* Mount the root file system. If the operator didn't specify a
* file system to use, try all possible file systems until one
* succeeds.
*/
int
vfs_mountroot(void)
{
struct vfsops *v;
int error = ENODEV;
if (root_device == NULL)
panic("vfs_mountroot: root device unknown");
switch (device_class(root_device)) {
case DV_IFNET:
if (rootdev != NODEV)
panic("vfs_mountroot: rootdev set for DV_IFNET "
"(0x%08x -> %d,%d)", rootdev,
major(rootdev), minor(rootdev));
break;
case DV_DISK:
if (rootdev == NODEV)
panic("vfs_mountroot: rootdev not set for DV_DISK");
if (bdevvp(rootdev, &rootvp))
panic("vfs_mountroot: can't get vnode for rootdev");
error = VOP_OPEN(rootvp, FREAD, FSCRED, curlwp);
if (error) {
printf("vfs_mountroot: can't open root device\n");
return (error);
}
break;
default:
printf("%s: inappropriate for root file system\n",
root_device->dv_xname);
return (ENODEV);
}
/*
* If user specified a file system, use it.
*/
if (mountroot != NULL) {
error = (*mountroot)();
goto done;
}
/*
* Try each file system currently configured into the kernel.
*/
mutex_enter(&vfs_list_lock);
LIST_FOREACH(v, &vfs_list, vfs_list) {
if (v->vfs_mountroot == NULL)
continue;
#ifdef DEBUG
aprint_normal("mountroot: trying %s...\n", v->vfs_name);
#endif
v->vfs_refcount++;
mutex_exit(&vfs_list_lock);
error = (*v->vfs_mountroot)();
mutex_enter(&vfs_list_lock);
v->vfs_refcount--;
if (!error) {
aprint_normal("root file system type: %s\n",
v->vfs_name);
break;
}
}
mutex_exit(&vfs_list_lock);
if (v == NULL) {
printf("no file system for %s", root_device->dv_xname);
if (device_class(root_device) == DV_DISK)
printf(" (dev 0x%x)", rootdev);
printf("\n");
error = EFTYPE;
}
done:
if (error && device_class(root_device) == DV_DISK) {
VOP_CLOSE(rootvp, FREAD, FSCRED, curlwp);
vrele(rootvp);
}
return (error);
}
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