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File: [cvs.NetBSD.org] / src / sys / kern / vfs_subr.c (download)

Revision 1.243.2.6, Sun Aug 26 18:40:11 2007 UTC (16 years, 7 months ago) by bouyer
Branch: netbsd-3
Changes since 1.243.2.5: +7 -4 lines

Pull up following revision(s) (requested by pooka in ticket #1809):
	sys/kern/vfs_subr.c: revision 1.289
Don't drain a vnode's lock when we are cleaning it out.  It still
might be used by upper layers in the vnode stack due to exported
lock pointers.  This introduces no difference to the normal case
and works around a problem where a lower layer vnode is cleaned
out before the upper layer due to forced unmount or revoke.  And
for cosmetics, set a vnode's lock export to NULL when it is cleaned
out.
per discussion with Bill Stouder-Studenmund on tech-kern

/*	$NetBSD: vfs_subr.c,v 1.243.2.6 2007/08/26 18:40:11 bouyer Exp $	*/

/*-
 * Copyright (c) 1997, 1998, 2004, 2005 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.
 * This code is derived from software contributed to The NetBSD Foundation
 * by Charles M. Hannum.
 *
 * 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
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_subr.c,v 1.243.2.6 2007/08/26 18:40:11 bouyer 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/time.h>
#include <sys/event.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/domain.h>
#include <sys/mbuf.h>
#include <sys/sa.h>
#include <sys/syscallargs.h>
#include <sys/device.h>
#include <sys/extattr.h>
#include <sys/dirent.h>
#include <sys/filedesc.h>

#include <miscfs/specfs/specdev.h>
#include <miscfs/genfs/genfs.h>
#include <miscfs/syncfs/syncfs.h>

#include <netinet/in.h>

#include <uvm/uvm.h>
#include <uvm/uvm_ddb.h>

#include <netinet/in.h>

#include <sys/sysctl.h>

const enum vtype iftovt_tab[16] = {
	VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
	VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
};
const int	vttoif_tab[9] = {
	0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
	S_IFSOCK, S_IFIFO, S_IFMT,
};

int doforce = 1;		/* 1 => permit forcible unmounting */
int prtactive = 0;		/* 1 => print out reclaim of active vnodes */

extern int dovfsusermount;	/* 1 => permit any user to mount filesystems */

/*
 * Insq/Remq for the vnode usage lists.
 */
#define	bufinsvn(bp, dp)	LIST_INSERT_HEAD(dp, bp, b_vnbufs)
#define	bufremvn(bp) {							\
	LIST_REMOVE(bp, b_vnbufs);					\
	(bp)->b_vnbufs.le_next = NOLIST;				\
}
/* 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 mntlist mountlist =			/* mounted filesystem list */
    CIRCLEQ_HEAD_INITIALIZER(mountlist);
struct vfs_list_head vfs_list =			/* vfs list */
    LIST_HEAD_INITIALIZER(vfs_list);

struct nfs_public nfs_pub;			/* publicly exported FS */

struct simplelock mountlist_slock = SIMPLELOCK_INITIALIZER;
static struct simplelock mntid_slock = SIMPLELOCK_INITIALIZER;
struct simplelock mntvnode_slock = SIMPLELOCK_INITIALIZER;
struct simplelock vnode_free_list_slock = SIMPLELOCK_INITIALIZER;
struct simplelock spechash_slock = SIMPLELOCK_INITIALIZER;

/* XXX - gross; single global lock to protect v_numoutput */
struct simplelock global_v_numoutput_slock = SIMPLELOCK_INITIALIZER;

/*
 * These define the root filesystem and device.
 */
struct mount *rootfs;
struct vnode *rootvnode;
struct device *root_device;			/* root device */

POOL_INIT(vnode_pool, sizeof(struct vnode), 0, 0, 0, "vnodepl",
    &pool_allocator_nointr);

MALLOC_DEFINE(M_VNODE, "vnodes", "Dynamically allocated vnodes");

/*
 * Local declarations.
 */
void insmntque(struct vnode *, struct mount *);
int getdevvp(dev_t, struct vnode **, enum vtype);

void vclean(struct vnode *, int, struct proc *);

static int vfs_hang_addrlist(struct mount *, struct netexport *,
			     struct export_args *);
static int vfs_free_netcred(struct radix_node *, void *);
static void vfs_free_addrlist(struct netexport *);
static struct vnode *getcleanvnode(struct proc *);

#ifdef DEBUG
void printlockedvnodes(void);
#endif

/*
 * Initialize the vnode management data structures.
 */
void
vntblinit()
{

	/*
	 * Initialize the filesystem syncer.
	 */
	vn_initialize_syncerd();
}

int
vfs_drainvnodes(long target, struct proc *p)
{

	simple_lock(&vnode_free_list_slock);
	while (numvnodes > target) {
		struct vnode *vp;

		vp = getcleanvnode(p);
		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(p)
	struct proc *p;
{
	struct vnode *vp;
	struct mount *mp;
	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_flag & VXLOCK) == 0 &&
		    ((vp->v_flag & VLAYER) == 0 || VOP_ISLOCKED(vp) == 0)) {
			if (vn_start_write(vp, &mp, V_NOWAIT) == 0)
				break;
		}
		mp = NULL;
		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);
	vp->v_lease = NULL;

	if (vp->v_type != VBAD)
		vgonel(vp, p);
	else
		simple_unlock(&vp->v_interlock);
	vn_finished_write(mp, 0);
#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_flag & VONWORKLST) == 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(mp, flags, interlkp)
	struct mount *mp;
	int flags;
	struct simplelock *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 == curproc)
			return (EDEADLK);
		if (interlkp)
			simple_unlock(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((caddr_t)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)
			simple_lock(interlkp);
		if (gone)
			return (ENOENT);
	}
	lkflags = LK_SHARED;
	if (interlkp)
		lkflags |= LK_INTERLOCK;
	if (lockmgr(&mp->mnt_lock, lkflags, interlkp))
		panic("vfs_busy: unexpected lock failure");
	return (0);
}

/*
 * Free a busy filesystem.
 */
void
vfs_unbusy(mp)
	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(fstypename, devname, mpp)
	char *fstypename;
	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, MFSNAMELEN))
			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);
	LIST_INIT(&mp->mnt_vnodelist);
	mp->mnt_op = vfsp;
	mp->mnt_flag = MNT_RDONLY;
	mp->mnt_vnodecovered = NULLVP;
	mp->mnt_leaf = mp;
	vfsp->vfs_refcount++;
	strncpy(mp->mnt_stat.f_fstypename, vfsp->vfs_name, MFSNAMELEN);
	mp->mnt_stat.f_mntonname[0] = '/';
	(void) copystr(devname, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 0);
	*mpp = mp;
	return (0);
}

/*
 * Lookup a mount point by filesystem identifier.
 */
struct mount *
vfs_getvfs(fsid)
	fsid_t *fsid;
{
	struct mount *mp;

	simple_lock(&mountlist_slock);
	CIRCLEQ_FOREACH(mp, &mountlist, mnt_list) {
		if (mp->mnt_stat.f_fsidx.__fsid_val[0] == fsid->__fsid_val[0] &&
		    mp->mnt_stat.f_fsidx.__fsid_val[1] == fsid->__fsid_val[1]) {
			simple_unlock(&mountlist_slock);
			return (mp);
		}
	}
	simple_unlock(&mountlist_slock);
	return ((struct mount *)0);
}

/*
 * Get a new unique fsid
 */
void
vfs_getnewfsid(mp)
	struct mount *mp;
{
	static u_short xxxfs_mntid;
	fsid_t tfsid;
	int mtype;

	simple_lock(&mntid_slock);
	mtype = makefstype(mp->mnt_op->vfs_name);
	mp->mnt_stat.f_fsidx.__fsid_val[0] = makedev(mtype, 0);
	mp->mnt_stat.f_fsidx.__fsid_val[1] = mtype;
	mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0];
	if (xxxfs_mntid == 0)
		++xxxfs_mntid;
	tfsid.__fsid_val[0] = makedev(mtype & 0xff, xxxfs_mntid);
	tfsid.__fsid_val[1] = mtype;
	if (!CIRCLEQ_EMPTY(&mountlist)) {
		while (vfs_getvfs(&tfsid)) {
			tfsid.__fsid_val[0]++;
			xxxfs_mntid++;
		}
	}
	mp->mnt_stat.f_fsidx.__fsid_val[0] = tfsid.__fsid_val[0];
	mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0];
	simple_unlock(&mntid_slock);
}

/*
 * Make a 'unique' number from a mount type name.
 */
long
makefstype(type)
	const char *type;
{
	long rv;

	for (rv = 0; *type; type++) {
		rv <<= 2;
		rv ^= *type;
	}
	return rv;
}


/*
 * Set vnode attributes to VNOVAL
 */
void
vattr_null(vap)
	struct vattr *vap;
{

	vap->va_type = VNON;

	/*
	 * Assign individually so that it is safe even if size and
	 * sign of each member are varied.
	 */
	vap->va_mode = VNOVAL;
	vap->va_nlink = VNOVAL;
	vap->va_uid = VNOVAL;
	vap->va_gid = VNOVAL;
	vap->va_fsid = VNOVAL;
	vap->va_fileid = VNOVAL;
	vap->va_size = VNOVAL;
	vap->va_blocksize = VNOVAL;
	vap->va_atime.tv_sec =
	    vap->va_mtime.tv_sec =
	    vap->va_ctime.tv_sec =
	    vap->va_birthtime.tv_sec = VNOVAL;
	vap->va_atime.tv_nsec =
	    vap->va_mtime.tv_nsec =
	    vap->va_ctime.tv_nsec =
	    vap->va_birthtime.tv_nsec = VNOVAL;
	vap->va_gen = VNOVAL;
	vap->va_flags = VNOVAL;
	vap->va_rdev = VNOVAL;
	vap->va_bytes = VNOVAL;
	vap->va_vaflags = 0;
}

/*
 * Routines having to do with the management of the vnode table.
 */
extern int (**dead_vnodeop_p)(void *);
long numvnodes;

/*
 * Return the next vnode from the free list.
 */
int
getnewvnode(tag, mp, vops, vpp)
	enum vtagtype tag;
	struct mount *mp;
	int (**vops)(void *);
	struct vnode **vpp;
{
	extern struct uvm_pagerops uvm_vnodeops;
	struct uvm_object *uobj;
	struct proc *p = curproc;	/* 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));
		simple_lock_init(&vp->v_interlock);
		uobj = &vp->v_uobj;
		uobj->pgops = &uvm_vnodeops;
		TAILQ_INIT(&uobj->memq);
		/*
		 * done by memset() above.
		 *	uobj->uo_npages = 0;
		 *	LIST_INIT(&vp->v_nclist);
		 *	LIST_INIT(&vp->v_dnclist);
		 */
	} else {
		vp = getcleanvnode(p);
		/*
		 * 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_flag = 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_usecount = 1;
	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 = 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(vp)
	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.
 */
void
insmntque(vp, mp)
	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)
		LIST_REMOVE(vp, v_mntvnodes);
	/*
	 * Insert into list of vnodes for the new mount point, if available.
	 */
	if ((vp->v_mount = mp) != NULL)
		LIST_INSERT_HEAD(&mp->mnt_vnodelist, vp, v_mntvnodes);
	simple_unlock(&mntvnode_slock);
}

/*
 * Update outstanding I/O count and do wakeup if requested.
 */
void
vwakeup(bp)
	struct buf *bp;
{
	struct vnode *vp;

	if ((vp = bp->b_vp) != NULL) {
		/* XXX global lock hack
		 * can't use v_interlock here since this is called
		 * in interrupt context from biodone().
		 */
		simple_lock(&global_v_numoutput_slock);
		if (--vp->v_numoutput < 0)
			panic("vwakeup: neg numoutput, vp %p", vp);
		if ((vp->v_flag & VBWAIT) && vp->v_numoutput <= 0) {
			vp->v_flag &= ~VBWAIT;
			wakeup((caddr_t)&vp->v_numoutput);
		}
		simple_unlock(&global_v_numoutput_slock);
	}
}

/*
 * Flush out and invalidate all buffers associated with a vnode.
 * Called with the underlying vnode locked, which should prevent new dirty
 * buffers from being queued.
 */
int
vinvalbuf(vp, flags, cred, p, slpflag, slptimeo)
	struct vnode *vp;
	int flags;
	struct ucred *cred;
	struct proc *p;
	int slpflag, slptimeo;
{
	struct buf *bp, *nbp;
	int s, error;
	int flushflags = PGO_ALLPAGES | PGO_FREE | PGO_SYNCIO |
		(flags & V_SAVE ? PGO_CLEANIT : 0);

	/* XXXUBC this doesn't look at flags or slp* */
	simple_lock(&vp->v_interlock);
	error = VOP_PUTPAGES(vp, 0, 0, flushflags);
	if (error) {
		return error;
	}

	if (flags & V_SAVE) {
		error = VOP_FSYNC(vp, cred, FSYNC_WAIT|FSYNC_RECLAIM, 0, 0, p);
		if (error)
		        return (error);
#ifdef DIAGNOSTIC
		s = splbio();
		if (vp->v_numoutput > 0 || !LIST_EMPTY(&vp->v_dirtyblkhd))
		        panic("vinvalbuf: dirty bufs, vp %p", vp);
		splx(s);
#endif
	}

	s = splbio();

restart:
	for (bp = LIST_FIRST(&vp->v_cleanblkhd); bp; bp = nbp) {
		nbp = LIST_NEXT(bp, b_vnbufs);
		simple_lock(&bp->b_interlock);
		if (bp->b_flags & B_BUSY) {
			bp->b_flags |= B_WANTED;
			error = ltsleep((caddr_t)bp,
				    slpflag | (PRIBIO + 1) | PNORELOCK,
				    "vinvalbuf", slptimeo, &bp->b_interlock);
			if (error) {
				splx(s);
				return (error);
			}
			goto restart;
		}
		bp->b_flags |= B_BUSY | B_INVAL | B_VFLUSH;
		simple_unlock(&bp->b_interlock);
		brelse(bp);
	}

	for (bp = LIST_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
		nbp = LIST_NEXT(bp, b_vnbufs);
		simple_lock(&bp->b_interlock);
		if (bp->b_flags & B_BUSY) {
			bp->b_flags |= B_WANTED;
			error = ltsleep((caddr_t)bp,
				    slpflag | (PRIBIO + 1) | PNORELOCK,
				    "vinvalbuf", slptimeo, &bp->b_interlock);
			if (error) {
				splx(s);
				return (error);
			}
			goto restart;
		}
		/*
		 * XXX Since there are no node locks for NFS, I believe
		 * there is a slight chance that a delayed write will
		 * occur while sleeping just above, so check for it.
		 */
		if ((bp->b_flags & B_DELWRI) && (flags & V_SAVE)) {
#ifdef DEBUG
			printf("buffer still DELWRI\n");
#endif
			bp->b_flags |= B_BUSY | B_VFLUSH;
			simple_unlock(&bp->b_interlock);
			VOP_BWRITE(bp);
			goto restart;
		}
		bp->b_flags |= B_BUSY | B_INVAL | B_VFLUSH;
		simple_unlock(&bp->b_interlock);
		brelse(bp);
	}

#ifdef DIAGNOSTIC
	if (!LIST_EMPTY(&vp->v_cleanblkhd) || !LIST_EMPTY(&vp->v_dirtyblkhd))
		panic("vinvalbuf: flush failed, vp %p", vp);
#endif

	splx(s);

	return (0);
}

/*
 * Destroy any in core blocks past the truncation length.
 * Called with the underlying vnode locked, which should prevent new dirty
 * buffers from being queued.
 */
int
vtruncbuf(vp, lbn, slpflag, slptimeo)
	struct vnode *vp;
	daddr_t lbn;
	int slpflag, slptimeo;
{
	struct buf *bp, *nbp;
	int s, error;
	voff_t off;

	off = round_page((voff_t)lbn << vp->v_mount->mnt_fs_bshift);
	simple_lock(&vp->v_interlock);
	error = VOP_PUTPAGES(vp, off, 0, PGO_FREE | PGO_SYNCIO);
	if (error) {
		return error;
	}

	s = splbio();

restart:
	for (bp = LIST_FIRST(&vp->v_cleanblkhd); bp; bp = nbp) {
		nbp = LIST_NEXT(bp, b_vnbufs);
		if (bp->b_lblkno < lbn)
			continue;
		simple_lock(&bp->b_interlock);
		if (bp->b_flags & B_BUSY) {
			bp->b_flags |= B_WANTED;
			error = ltsleep(bp, slpflag | (PRIBIO + 1) | PNORELOCK,
			    "vtruncbuf", slptimeo, &bp->b_interlock);
			if (error) {
				splx(s);
				return (error);
			}
			goto restart;
		}
		bp->b_flags |= B_BUSY | B_INVAL | B_VFLUSH;
		simple_unlock(&bp->b_interlock);
		brelse(bp);
	}

	for (bp = LIST_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
		nbp = LIST_NEXT(bp, b_vnbufs);
		if (bp->b_lblkno < lbn)
			continue;
		simple_lock(&bp->b_interlock);
		if (bp->b_flags & B_BUSY) {
			bp->b_flags |= B_WANTED;
			error = ltsleep(bp, slpflag | (PRIBIO + 1) | PNORELOCK,
			    "vtruncbuf", slptimeo, &bp->b_interlock);
			if (error) {
				splx(s);
				return (error);
			}
			goto restart;
		}
		bp->b_flags |= B_BUSY | B_INVAL | B_VFLUSH;
		simple_unlock(&bp->b_interlock);
		brelse(bp);
	}

	splx(s);

	return (0);
}

void
vflushbuf(vp, sync)
	struct vnode *vp;
	int sync;
{
	struct buf *bp, *nbp;
	int flags = PGO_CLEANIT | PGO_ALLPAGES | (sync ? PGO_SYNCIO : 0);
	int s;

	simple_lock(&vp->v_interlock);
	(void) VOP_PUTPAGES(vp, 0, 0, flags);

loop:
	s = splbio();
	for (bp = LIST_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
		nbp = LIST_NEXT(bp, b_vnbufs);
		simple_lock(&bp->b_interlock);
		if ((bp->b_flags & B_BUSY)) {
			simple_unlock(&bp->b_interlock);
			continue;
		}
		if ((bp->b_flags & B_DELWRI) == 0)
			panic("vflushbuf: not dirty, bp %p", bp);
		bp->b_flags |= B_BUSY | B_VFLUSH;
		simple_unlock(&bp->b_interlock);
		splx(s);
		/*
		 * Wait for I/O associated with indirect blocks to complete,
		 * since there is no way to quickly wait for them below.
		 */
		if (bp->b_vp == vp || sync == 0)
			(void) bawrite(bp);
		else
			(void) bwrite(bp);
		goto loop;
	}
	if (sync == 0) {
		splx(s);
		return;
	}
	simple_lock(&global_v_numoutput_slock);
	while (vp->v_numoutput) {
		vp->v_flag |= VBWAIT;
		ltsleep((caddr_t)&vp->v_numoutput, PRIBIO + 1, "vflushbuf", 0,
			&global_v_numoutput_slock);
	}
	simple_unlock(&global_v_numoutput_slock);
	splx(s);
	if (!LIST_EMPTY(&vp->v_dirtyblkhd)) {
		vprint("vflushbuf: dirty", vp);
		goto loop;
	}
}

/*
 * Associate a buffer with a vnode.
 */
void
bgetvp(vp, bp)
	struct vnode *vp;
	struct buf *bp;
{
	int s;

	if (bp->b_vp)
		panic("bgetvp: not free, bp %p", bp);
	VHOLD(vp);
	s = splbio();
	bp->b_vp = vp;
	if (vp->v_type == VBLK || vp->v_type == VCHR)
		bp->b_dev = vp->v_rdev;
	else
		bp->b_dev = NODEV;
	/*
	 * Insert onto list for new vnode.
	 */
	bufinsvn(bp, &vp->v_cleanblkhd);
	splx(s);
}

/*
 * Disassociate a buffer from a vnode.
 */
void
brelvp(bp)
	struct buf *bp;
{
	struct vnode *vp;
	int s;

	if (bp->b_vp == NULL)
		panic("brelvp: vp NULL, bp %p", bp);

	s = splbio();
	vp = bp->b_vp;
	/*
	 * Delete from old vnode list, if on one.
	 */
	if (LIST_NEXT(bp, b_vnbufs) != NOLIST)
		bufremvn(bp);

	if (TAILQ_EMPTY(&vp->v_uobj.memq) && (vp->v_flag & VONWORKLST) &&
	    LIST_FIRST(&vp->v_dirtyblkhd) == NULL) {
		vp->v_flag &= ~(VWRITEMAPDIRTY|VONWORKLST);
		LIST_REMOVE(vp, v_synclist);
	}

	bp->b_vp = NULL;
	HOLDRELE(vp);
	splx(s);
}

/*
 * Reassign a buffer from one vnode to another.
 * Used to assign file specific control information
 * (indirect blocks) to the vnode to which they belong.
 *
 * This function must be called at splbio().
 */
void
reassignbuf(bp, newvp)
	struct buf *bp;
	struct vnode *newvp;
{
	struct buflists *listheadp;
	int delay;

	/*
	 * Delete from old vnode list, if on one.
	 */
	if (LIST_NEXT(bp, b_vnbufs) != NOLIST)
		bufremvn(bp);
	/*
	 * If dirty, put on list of dirty buffers;
	 * otherwise insert onto list of clean buffers.
	 */
	if ((bp->b_flags & B_DELWRI) == 0) {
		listheadp = &newvp->v_cleanblkhd;
		if (TAILQ_EMPTY(&newvp->v_uobj.memq) &&
		    (newvp->v_flag & VONWORKLST) &&
		    LIST_FIRST(&newvp->v_dirtyblkhd) == NULL) {
			newvp->v_flag &= ~(VWRITEMAPDIRTY|VONWORKLST);
			LIST_REMOVE(newvp, v_synclist);
		}
	} else {
		listheadp = &newvp->v_dirtyblkhd;
		if ((newvp->v_flag & VONWORKLST) == 0) {
			switch (newvp->v_type) {
			case VDIR:
				delay = dirdelay;
				break;
			case VBLK:
				if (newvp->v_specmountpoint != NULL) {
					delay = metadelay;
					break;
				}
				/* fall through */
			default:
				delay = filedelay;
				break;
			}
			if (!newvp->v_mount ||
			    (newvp->v_mount->mnt_flag & MNT_ASYNC) == 0)
				vn_syncer_add_to_worklist(newvp, delay);
		}
	}
	bufinsvn(bp, listheadp);
}

/*
 * 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, vpp)
	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, vpp)
	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.
 */
int
getdevvp(dev, vpp, type)
	dev_t dev;
	struct vnode **vpp;
	enum vtype type;
{
	struct vnode *vp;
	struct vnode *nvp;
	int error;

	if (dev == NODEV) {
		*vpp = NULLVP;
		return (0);
	}
	error = getnewvnode(VT_NON, NULL, spec_vnodeop_p, &nvp);
	if (error) {
		*vpp = NULLVP;
		return (error);
	}
	vp = nvp;
	vp->v_type = type;
	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(nvp, nvp_rdev, mp)
	struct vnode *nvp;
	dev_t nvp_rdev;
	struct mount *mp;
{
	struct proc *p = curproc;       /* 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, p);
			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.  Therefore, we use
		 * LK_SLEEPFAIL and retry.
		 */
		if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK | LK_SLEEPFAIL))
			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;
		simple_lock_init(&nvp->v_spec_cow_slock);
		SLIST_INIT(&nvp->v_spec_cow_head);
		nvp->v_spec_cow_req = 0;
		nvp->v_spec_cow_count = 0;

		*vpp = nvp;
		if (vp != NULLVP) {
			nvp->v_flag |= VALIASED;
			vp->v_flag |= VALIASED;
			vput(vp);
		}
		return (NULLVP);
	}
	simple_unlock(&spechash_slock);
	VOP_UNLOCK(vp, 0);
	simple_lock(&vp->v_interlock);
	vclean(vp, 0, p);
	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(vp, flags)
	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 VXLOCK flag is set.
	 */

	if ((flags & LK_INTERLOCK) == 0)
		simple_lock(&vp->v_interlock);
	if (vp->v_flag & VXLOCK) {
		if (flags & LK_NOWAIT) {
			simple_unlock(&vp->v_interlock);
			return EBUSY;
		}
		vp->v_flag |= VXWANT;
		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))) {
			/*
			 * must expand vrele here because we do not want
			 * to call VOP_INACTIVE if the reference count
			 * drops back to zero since it was never really
			 * active. We must remove it from the free list
			 * before sleeping so that multiple processes do
			 * not try to recycle it.
			 */
			simple_lock(&vp->v_interlock);
			vp->v_usecount--;
			if (vp->v_usecount > 0) {
				simple_unlock(&vp->v_interlock);
				return (error);
			}
			/*
			 * 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);
			simple_unlock(&vp->v_interlock);
		}
		return (error);
	}
	simple_unlock(&vp->v_interlock);
	return (0);
}

/*
 * vput(), just unlock and vrele()
 */
void
vput(vp)
	struct vnode *vp;
{
	struct proc *p = curproc;	/* 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_flag & VEXECMAP) {
		uvmexp.execpages -= vp->v_uobj.uo_npages;
		uvmexp.filepages += vp->v_uobj.uo_npages;
	}
	vp->v_flag &= ~(VTEXT|VEXECMAP|VWRITEMAP);
	simple_unlock(&vp->v_interlock);
	VOP_INACTIVE(vp, p);
}

/*
 * Vnode release.
 * If count drops to zero, call inactive routine and return to freelist.
 */
void
vrele(vp)
	struct vnode *vp;
{
	struct proc *p = curproc;	/* 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
		TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
	simple_unlock(&vnode_free_list_slock);
	if (vp->v_flag & VEXECMAP) {
		uvmexp.execpages -= vp->v_uobj.uo_npages;
		uvmexp.filepages += vp->v_uobj.uo_npages;
	}
	vp->v_flag &= ~(VTEXT|VEXECMAP|VWRITEMAP);
	if (vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK) == 0)
		VOP_INACTIVE(vp, p);
}

#ifdef DIAGNOSTIC
/*
 * Page or buffer structure gets a reference.
 */
void
vholdl(vp)
	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.
 */
void
holdrelel(vp)
	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(vp)
	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);
}
#endif /* DIAGNOSTIC */

/*
 * 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(mp, skipvp, flags)
	struct mount *mp;
	struct vnode *skipvp;
	int flags;
{
	struct proc *p = curproc;	/* XXX */
	struct vnode *vp, *nvp;
	int busy = 0;

	simple_lock(&mntvnode_slock);
loop:
	for (vp = LIST_FIRST(&mp->mnt_vnodelist); vp; vp = nvp) {
		if (vp->v_mount != mp)
			goto loop;
		nvp = LIST_NEXT(vp, v_mntvnodes);
		/*
		 * Skip over a selected vnode.
		 */
		if (vp == skipvp)
			continue;
		simple_lock(&vp->v_interlock);
		/*
		 * Skip over a vnodes marked VSYSTEM.
		 */
		if ((flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM)) {
			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, p);
			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, p);
			} else {
				vclean(vp, 0, p);
				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.
 */
void
vclean(vp, flags, p)
	struct vnode *vp;
	int flags;
	struct proc *p;
{
	struct mount *mp;
	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_flag & VXLOCK)
		panic("vclean: deadlock, vp %p", vp);
	vp->v_flag |= VXLOCK;
	if (vp->v_flag & VEXECMAP) {
		uvmexp.execpages -= vp->v_uobj.uo_npages;
		uvmexp.filepages += vp->v_uobj.uo_npages;
	}
	vp->v_flag &= ~(VTEXT|VEXECMAP);

	/*
	 * 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 don't drain the lock because it might have been exported
	 * to upper layers by this vnode and could still be in use.
	 */
	VOP_LOCK(vp, LK_EXCLUSIVE | 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;

		vn_start_write(vp, &mp, V_WAIT | V_LOWER);
		error = vinvalbuf(vp, V_SAVE, NOCRED, p, 0, 0);
		vn_finished_write(mp, V_LOWER);
		if (error)
			error = vinvalbuf(vp, 0, NOCRED, p, 0, 0);
		KASSERT(error == 0);
		KASSERT((vp->v_flag & VONWORKLST) == 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_flag & VALIASED) {
					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_flag &= ~VALIASED;
					vp->v_flag &= ~VALIASED;
				}
			}
			simple_unlock(&spechash_slock);
			FREE(vp->v_specinfo, M_VNODE);
			vp->v_specinfo = NULL;
		}
	}
	LOCK_ASSERT(!simple_lock_held(&vp->v_interlock));

	/*
	 * 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, p);
	} else {
		/*
		 * Any other processes trying to obtain this lock must first
		 * wait for VXLOCK to clear, then call the new lock operation.
		 */
		VOP_UNLOCK(vp, 0);
	}
	/*
	 * Reclaim the vnode.
	 */
	if (VOP_RECLAIM(vp, p))
		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);
	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_flag &= ~(VXLOCK|VLOCKSWORK);
	if (vp->v_flag & VXWANT) {
		vp->v_flag &= ~VXWANT;
		simple_unlock(&vp->v_interlock);
		wakeup((caddr_t)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(vp, inter_lkp, p)
	struct vnode *vp;
	struct simplelock *inter_lkp;
	struct proc *p;
{

	simple_lock(&vp->v_interlock);
	if (vp->v_usecount == 0) {
		if (inter_lkp)
			simple_unlock(inter_lkp);
		vgonel(vp, p);
		return (1);
	}
	simple_unlock(&vp->v_interlock);
	return (0);
}

/*
 * Eliminate all activity associated with a vnode
 * in preparation for reuse.
 */
void
vgone(vp)
	struct vnode *vp;
{
	struct proc *p = curproc;	/* XXX */

	simple_lock(&vp->v_interlock);
	vgonel(vp, p);
}

/*
 * vgone, with the vp interlock held.
 */
void
vgonel(vp, p)
	struct vnode *vp;
	struct proc *p;
{

	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_flag & VXLOCK) {
		vp->v_flag |= VXWANT;
		ltsleep(vp, PINOD | PNORELOCK, "vgone", 0, &vp->v_interlock);
		return;
	}

	/*
	 * Clean out the filesystem specific data.
	 */

	vclean(vp, DOCLOSE, p);
	KASSERT((vp->v_flag & VONWORKLST) == 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) {
		boolean_t 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, type, vpp)
	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(maj, minl, minh, type)
	int maj, minl, minh;
	enum vtype type;
{
	struct vnode *vp;
	int mn;

	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(vp)
	struct vnode *vp;
{
	struct vnode *vq, *vnext;
	int count;

loop:
	if ((vp->v_flag & VALIASED) == 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_flag & VXLOCK) == 0) {
			simple_unlock(&spechash_slock);
			vgone(vq);
			goto loop;
		}
		count += vq->v_usecount;
	}
	simple_unlock(&spechash_slock);
	return (count);
}

#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
#define ARRAY_PRINT(idx, arr) \
    ((idx) > 0 && (idx) < ARRAY_SIZE(arr) ? (arr)[(idx)] : "UNKNOWN")

const char * const vnode_tags[] = { VNODE_TAGS };
const char * const vnode_types[] = { VNODE_TYPES };
const char vnode_flagbits[] = VNODE_FLAGBITS;

/*
 * Print out a description of a vnode.
 */
void
vprint(label, vp)
	char *label;
	struct vnode *vp;
{
	char buf[96];

	if (label != NULL)
		printf("%s: ", label);
	printf("tag %s(%d) type %s(%d), usecount %d, writecount %ld, "
	    "refcount %ld,", ARRAY_PRINT(vp->v_tag, vnode_tags), vp->v_tag,
	    ARRAY_PRINT(vp->v_type, vnode_types), vp->v_type,
	    vp->v_usecount, vp->v_writecount, vp->v_holdcnt);
	bitmask_snprintf(vp->v_flag, vnode_flagbits, buf, sizeof(buf));
	if (buf[0] != '\0')
		printf(" flags (%s)", &buf[1]);
	if (vp->v_data == NULL) {
		printf("\n");
	} else {
		printf("\n\t");
		VOP_PRINT(vp);
	}
}

#ifdef DEBUG
/*
 * List all of the locked vnodes in the system.
 * Called when debugging the kernel.
 */
void
printlockedvnodes()
{
	struct mount *mp, *nmp;
	struct vnode *vp;

	printf("Locked vnodes\n");
	simple_lock(&mountlist_slock);
	for (mp = CIRCLEQ_FIRST(&mountlist); mp != (void *)&mountlist;
	     mp = nmp) {
		if (vfs_busy(mp, LK_NOWAIT, &mountlist_slock)) {
			nmp = CIRCLEQ_NEXT(mp, mnt_list);
			continue;
		}
		LIST_FOREACH(vp, &mp->mnt_vnodelist, v_mntvnodes) {
			if (VOP_ISLOCKED(vp))
				vprint(NULL, vp);
		}
		simple_lock(&mountlist_slock);
		nmp = CIRCLEQ_NEXT(mp, mnt_list);
		vfs_unbusy(mp);
	}
	simple_unlock(&mountlist_slock);
}
#endif

/*
 * sysctl helper routine for vfs.generic.conf lookups.
 */
#if defined(COMPAT_09) || defined(COMPAT_43) || defined(COMPAT_44)
static int
sysctl_vfs_generic_conf(SYSCTLFN_ARGS)
{
        struct vfsconf vfc;
        extern const char * const mountcompatnames[];
        extern int nmountcompatnames;
	struct sysctlnode node;
	struct vfsops *vfsp;
	u_int vfsnum;

	if (namelen != 1)
		return (ENOTDIR);
	vfsnum = name[0];
	if (vfsnum >= nmountcompatnames ||
	    mountcompatnames[vfsnum] == NULL)
		return (EOPNOTSUPP);
	vfsp = vfs_getopsbyname(mountcompatnames[vfsnum]);
	if (vfsp == NULL)
		return (EOPNOTSUPP);

	vfc.vfc_vfsops = vfsp;
	strncpy(vfc.vfc_name, vfsp->vfs_name, MFSNAMELEN);
	vfc.vfc_typenum = vfsnum;
	vfc.vfc_refcount = vfsp->vfs_refcount;
	vfc.vfc_flags = 0;
	vfc.vfc_mountroot = vfsp->vfs_mountroot;
	vfc.vfc_next = NULL;

	node = *rnode;
	node.sysctl_data = &vfc;
	return (sysctl_lookup(SYSCTLFN_CALL(&node)));
}
#endif

/*
 * sysctl helper routine to return list of supported fstypes
 */
static int
sysctl_vfs_generic_fstypes(SYSCTLFN_ARGS)
{
	char buf[MFSNAMELEN];
	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;

	LIST_FOREACH(v, &vfs_list, vfs_list) {
		if (where == NULL)
			needed += strlen(v->vfs_name) + 1;
		else {
			memset(buf, 0, sizeof(buf));
			if (first) {
				strncpy(buf, v->vfs_name, sizeof(buf));
				first = 0;
			} else {
				buf[0] = ' ';
				strncpy(buf + 1, v->vfs_name, sizeof(buf) - 1);
			}
			buf[sizeof(buf)-1] = '\0';
			slen = strlen(buf);
			if (left < slen + 1)
				break;
			/* +1 to copy out the trailing NUL byte */
			error = copyout(buf, where, slen + 1);
			if (error)
				break;
			where += slen;
			needed += slen;
			left -= slen;
		}
	}
	*oldlenp = needed;
	return (error);
}

/*
 * Top level filesystem related information gathering.
 */
SYSCTL_SETUP(sysctl_vfs_setup, "sysctl vfs subtree setup")
{
#if defined(COMPAT_09) || defined(COMPAT_43) || defined(COMPAT_44)
	extern int nmountcompatnames;
#endif

	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);

#if defined(COMPAT_09) || defined(COMPAT_43) || defined(COMPAT_44)
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_IMMEDIATE,
		       CTLTYPE_INT, "maxtypenum",
		       SYSCTL_DESCR("Highest valid filesystem type number"),
		       NULL, nmountcompatnames, NULL, 0,
		       CTL_VFS, VFS_GENERIC, VFS_MAXTYPENUM, CTL_EOL);
#endif
	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);
#if defined(COMPAT_09) || defined(COMPAT_43) || defined(COMPAT_44)
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT,
		       CTLTYPE_STRUCT, "conf",
		       SYSCTL_DESCR("Filesystem configuration information"),
		       sysctl_vfs_generic_conf, 0, NULL,
		       sizeof(struct vfsconf),
		       CTL_VFS, VFS_GENERIC, VFS_CONF, CTL_EOL);
#endif
}


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 *nvp, *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;

	simple_lock(&mountlist_slock);
	for (mp = CIRCLEQ_FIRST(&mountlist); mp != (void *)&mountlist;
	     mp = nmp) {
		if (vfs_busy(mp, LK_NOWAIT, &mountlist_slock)) {
			nmp = CIRCLEQ_NEXT(mp, mnt_list);
			continue;
		}
		savebp = bp;
again:
		simple_lock(&mntvnode_slock);
		for (vp = LIST_FIRST(&mp->mnt_vnodelist);
		     vp != NULL;
		     vp = nvp) {
			/*
			 * 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;
			}
			nvp = LIST_NEXT(vp, v_mntvnodes);
			if (bp + VPTRSZ + VNODESZ > ewhere) {
				simple_unlock(&mntvnode_slock);
				*sizep = bp - where;
				return (ENOMEM);
			}
			simple_unlock(&mntvnode_slock);
			if ((error = copyout((caddr_t)&vp, bp, VPTRSZ)) ||
			   (error = copyout((caddr_t)vp, bp + VPTRSZ, VNODESZ)))
				return (error);
			bp += VPTRSZ + VNODESZ;
			simple_lock(&mntvnode_slock);
		}
		simple_unlock(&mntvnode_slock);
		simple_lock(&mountlist_slock);
		nmp = CIRCLEQ_NEXT(mp, mnt_list);
		vfs_unbusy(mp);
	}
	simple_unlock(&mountlist_slock);

	*sizep = bp - where;
	return (0);
}

/*
 * Check to see if a filesystem is mounted on a block device.
 */
int
vfs_mountedon(vp)
	struct vnode *vp;
{
	struct vnode *vq;
	int error = 0;

	if (vp->v_specmountpoint != NULL)
		return (EBUSY);
	if (vp->v_flag & VALIASED) {
		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);
}

static int
sacheck(struct sockaddr *sa)
{
	switch (sa->sa_family) {
#ifdef INET
	case AF_INET: {
		struct sockaddr_in *sin = (struct sockaddr_in *)sa;
		char *p = (char *)sin->sin_zero;
		size_t i;

		if (sin->sin_len != sizeof(*sin))
			return -1;
		if (sin->sin_port != 0)
			return -1;
		for (i = 0; i < sizeof(sin->sin_zero); i++)
			if (*p++ != '\0')
				return -1;
		return 0;
	}
#endif
#ifdef INET6
	case AF_INET6: {
		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa;

		if (sin6->sin6_len != sizeof(*sin6))
			return -1;
		if (sin6->sin6_port != 0)
			return -1;
		return 0;
	}
#endif
	default:
		return -1;
	}
}

/*
 * Build hash lists of net addresses and hang them off the mount point.
 * Called by ufs_mount() to set up the lists of export addresses.
 */
static int
vfs_hang_addrlist(mp, nep, argp)
	struct mount *mp;
	struct netexport *nep;
	struct export_args *argp;
{
	struct netcred *np, *enp;
	struct radix_node_head *rnh;
	int i;
	struct sockaddr *saddr, *smask = 0;
	struct domain *dom;
	int error;

	if (argp->ex_addrlen == 0) {
		if (mp->mnt_flag & MNT_DEFEXPORTED)
			return (EPERM);
		np = &nep->ne_defexported;
		np->netc_exflags = argp->ex_flags;
		crcvt(&np->netc_anon, &argp->ex_anon);
		np->netc_anon.cr_ref = 1;
		mp->mnt_flag |= MNT_DEFEXPORTED;
		return (0);
	}

	if (argp->ex_addrlen > MLEN || argp->ex_masklen > MLEN)
		return (EINVAL);

	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
	np = (struct netcred *)malloc(i, M_NETADDR, M_WAITOK);
	memset((caddr_t)np, 0, i);
	saddr = (struct sockaddr *)(np + 1);
	error = copyin(argp->ex_addr, (caddr_t)saddr, argp->ex_addrlen);
	if (error)
		goto out;
	if (saddr->sa_len > argp->ex_addrlen)
		saddr->sa_len = argp->ex_addrlen;
	if (sacheck(saddr) == -1)
		return EINVAL;
	if (argp->ex_masklen) {
		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
		error = copyin(argp->ex_mask, (caddr_t)smask, argp->ex_masklen);
		if (error)
			goto out;
		if (smask->sa_len > argp->ex_masklen)
			smask->sa_len = argp->ex_masklen;
		if (smask->sa_family != saddr->sa_family)
			return EINVAL;
		if (sacheck(smask) == -1)
			return EINVAL;
	}
	i = saddr->sa_family;
	if ((rnh = nep->ne_rtable[i]) == 0) {
		/*
		 * Seems silly to initialize every AF when most are not
		 * used, do so on demand here
		 */
		DOMAIN_FOREACH(dom) {
			if (dom->dom_family == i && dom->dom_rtattach) {
				dom->dom_rtattach((void **)&nep->ne_rtable[i],
					dom->dom_rtoffset);
				break;
			}
		}
		if ((rnh = nep->ne_rtable[i]) == 0) {
			error = ENOBUFS;
			goto out;
		}
	}

	enp = (struct netcred *)(*rnh->rnh_addaddr)(saddr, smask, rnh,
	    np->netc_rnodes);
	if (enp != np) {
		if (enp == NULL) {
			enp = (struct netcred *)(*rnh->rnh_lookup)(saddr,
			    smask, rnh);
			if (enp == NULL) {
				error = EPERM;
				goto out;
			}
		} else
			enp->netc_refcnt++;

		goto check;
	} else
		enp->netc_refcnt = 1;

	np->netc_exflags = argp->ex_flags;
	crcvt(&np->netc_anon, &argp->ex_anon);
	np->netc_anon.cr_ref = 1;
	return 0;
check:
	if (enp->netc_exflags != argp->ex_flags ||
	    crcmp(&enp->netc_anon, &argp->ex_anon) != 0)
		error = EPERM;
	else
		error = 0;
out:
	free(np, M_NETADDR);
	return error;
}

/* ARGSUSED */
static int
vfs_free_netcred(rn, w)
	struct radix_node *rn;
	void *w;
{
	struct radix_node_head *rnh = (struct radix_node_head *)w;
	struct netcred *np = (struct netcred *)(void *)rn;

	(*rnh->rnh_deladdr)(rn->rn_key, rn->rn_mask, rnh);
	if (--(np->netc_refcnt) <= 0)
		free(np, M_NETADDR);
	return (0);
}

/*
 * Free the net address hash lists that are hanging off the mount points.
 */
static void
vfs_free_addrlist(nep)
	struct netexport *nep;
{
	int i;
	struct radix_node_head *rnh;

	for (i = 0; i <= AF_MAX; i++)
		if ((rnh = nep->ne_rtable[i]) != NULL) {
			(*rnh->rnh_walktree)(rnh, vfs_free_netcred, rnh);
			free((caddr_t)rnh, M_RTABLE);
			nep->ne_rtable[i] = 0;
		}
}

int
vfs_export(mp, nep, argp)
	struct mount *mp;
	struct netexport *nep;
	struct export_args *argp;
{
	int error;

	if (argp->ex_flags & MNT_DELEXPORT) {
		if (mp->mnt_flag & MNT_EXPUBLIC) {
			vfs_setpublicfs(NULL, NULL, NULL);
			mp->mnt_flag &= ~MNT_EXPUBLIC;
		}
		vfs_free_addrlist(nep);
		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
	}
	if (argp->ex_flags & MNT_EXPORTED) {
		if (argp->ex_flags & MNT_EXPUBLIC) {
			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
				return (error);
			mp->mnt_flag |= MNT_EXPUBLIC;
		}
		if ((error = vfs_hang_addrlist(mp, nep, argp)) != 0)
			return (error);
		mp->mnt_flag |= MNT_EXPORTED;
	}
	return (0);
}

/*
 * Set the publicly exported filesystem (WebNFS). Currently, only
 * one public filesystem is possible in the spec (RFC 2054 and 2055)
 */
int
vfs_setpublicfs(mp, nep, argp)
	struct mount *mp;
	struct netexport *nep;
	struct export_args *argp;
{
	int error;
	struct vnode *rvp;
	char *cp;

	/*
	 * mp == NULL -> invalidate the current info, the FS is
	 * no longer exported. May be called from either vfs_export
	 * or unmount, so check if it hasn't already been done.
	 */
	if (mp == NULL) {
		if (nfs_pub.np_valid) {
			nfs_pub.np_valid = 0;
			if (nfs_pub.np_index != NULL) {
				FREE(nfs_pub.np_index, M_TEMP);
				nfs_pub.np_index = NULL;
			}
		}
		return (0);
	}

	/*
	 * Only one allowed at a time.
	 */
	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
		return (EBUSY);

	/*
	 * Get real filehandle for root of exported FS.
	 */
	memset((caddr_t)&nfs_pub.np_handle, 0, sizeof(nfs_pub.np_handle));
	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsidx;

	if ((error = VFS_ROOT(mp, &rvp)))
		return (error);

	if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
		return (error);

	vput(rvp);

	/*
	 * If an indexfile was specified, pull it in.
	 */
	if (argp->ex_indexfile != NULL) {
		MALLOC(nfs_pub.np_index, char *, MAXNAMLEN + 1, M_TEMP,
		    M_WAITOK);
		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
		    MAXNAMLEN, (size_t *)0);
		if (!error) {
			/*
			 * Check for illegal filenames.
			 */
			for (cp = nfs_pub.np_index; *cp; cp++) {
				if (*cp == '/') {
					error = EINVAL;
					break;
				}
			}
		}
		if (error) {
			FREE(nfs_pub.np_index, M_TEMP);
			return (error);
		}
	}

	nfs_pub.np_mount = mp;
	nfs_pub.np_valid = 1;
	return (0);
}

struct netcred *
vfs_export_lookup(mp, nep, nam)
	struct mount *mp;
	struct netexport *nep;
	struct mbuf *nam;
{
	struct netcred *np;
	struct radix_node_head *rnh;
	struct sockaddr *saddr;

	np = NULL;
	if (mp->mnt_flag & MNT_EXPORTED) {
		/*
		 * Lookup in the export list first.
		 */
		if (nam != NULL) {
			saddr = mtod(nam, struct sockaddr *);
			rnh = nep->ne_rtable[saddr->sa_family];
			if (rnh != NULL) {
				np = (struct netcred *)
					(*rnh->rnh_matchaddr)((caddr_t)saddr,
							      rnh);
				if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
					np = NULL;
			}
		}
		/*
		 * If no address match, use the default if it exists.
		 */
		if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
			np = &nep->ne_defexported;
	}
	return (np);
}

/*
 * Do the usual access checking.
 * file_mode, uid and gid are from the vnode in question,
 * while acc_mode and cred are from the VOP_ACCESS parameter list
 */
int
vaccess(type, file_mode, uid, gid, acc_mode, cred)
	enum vtype type;
	mode_t file_mode;
	uid_t uid;
	gid_t gid;
	mode_t acc_mode;
	struct ucred *cred;
{
	mode_t mask;

	/*
	 * Super-user always gets read/write access, but execute access depends
	 * on at least one execute bit being set.
	 */
	if (cred->cr_uid == 0) {
		if ((acc_mode & VEXEC) && type != VDIR &&
		    (file_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)
			return (EACCES);
		return (0);
	}

	mask = 0;

	/* Otherwise, check the owner. */
	if (cred->cr_uid == uid) {
		if (acc_mode & VEXEC)
			mask |= S_IXUSR;
		if (acc_mode & VREAD)
			mask |= S_IRUSR;
		if (acc_mode & VWRITE)
			mask |= S_IWUSR;
		return ((file_mode & mask) == mask ? 0 : EACCES);
	}

	/* Otherwise, check the groups. */
	if (cred->cr_gid == gid || groupmember(gid, cred)) {
		if (acc_mode & VEXEC)
			mask |= S_IXGRP;
		if (acc_mode & VREAD)
			mask |= S_IRGRP;
		if (acc_mode & VWRITE)
			mask |= S_IWGRP;
		return ((file_mode & mask) == mask ? 0 : EACCES);
	}

	/* Otherwise, check everyone else. */
	if (acc_mode & VEXEC)
		mask |= S_IXOTH;
	if (acc_mode & VREAD)
		mask |= S_IROTH;
	if (acc_mode & VWRITE)
		mask |= S_IWOTH;
	return ((file_mode & mask) == mask ? 0 : EACCES);
}

/*
 * 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(p)
	struct proc *p;
{
	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.
		 */
		lockmgr(&syncer_lock, LK_EXCLUSIVE, NULL);
		if (vfs_busy(mp, 0, 0)) {
			lockmgr(&syncer_lock, LK_RELEASE, NULL);
			continue;
		}
		if ((error = dounmount(mp, MNT_FORCE, p)) != 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()
{
	struct lwp *l = curlwp;
	struct proc *p;

	/* XXX we're certainly not running in proc0's context! */
	if (l == NULL || (p = l->l_proc) == NULL)
		p = &proc0;

	printf("syncing disks... ");

	/* remove user process 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(p);
}

/*
 * 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()
{
	struct vfsops *v;
	int error = ENODEV;

	if (root_device == NULL)
		panic("vfs_mountroot: root device unknown");

	switch (root_device->dv_class) {
	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, curproc);
		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.
	 */
	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
		error = (*v->vfs_mountroot)();
		if (!error) {
			aprint_normal("root file system type: %s\n",
			    v->vfs_name);
			break;
		}
	}

	if (v == NULL) {
		printf("no file system for %s", root_device->dv_xname);
		if (root_device->dv_class == DV_DISK)
			printf(" (dev 0x%x)", rootdev);
		printf("\n");
		error = EFTYPE;
	}

done:
	if (error && root_device->dv_class == DV_DISK) {
		VOP_CLOSE(rootvp, FREAD, FSCRED, curproc);
		vrele(rootvp);
	}
	return (error);
}

/*
 * Given a file system name, look up the vfsops for that
 * file system, or return NULL if file system isn't present
 * in the kernel.
 */
struct vfsops *
vfs_getopsbyname(name)
	const char *name;
{
	struct vfsops *v;

	LIST_FOREACH(v, &vfs_list, vfs_list) {
		if (strcmp(v->vfs_name, name) == 0)
			break;
	}

	return (v);
}

/*
 * Establish a file system and initialize it.
 */
int
vfs_attach(vfs)
	struct vfsops *vfs;
{
	struct vfsops *v;
	int error = 0;


	/*
	 * Make sure this file system doesn't already exist.
	 */
	LIST_FOREACH(v, &vfs_list, vfs_list) {
		if (strcmp(vfs->vfs_name, v->vfs_name) == 0) {
			error = EEXIST;
			goto out;
		}
	}

	/*
	 * Initialize the vnode operations for this file system.
	 */
	vfs_opv_init(vfs->vfs_opv_descs);

	/*
	 * Now initialize the file system itself.
	 */
	(*vfs->vfs_init)();

	/*
	 * ...and link it into the kernel's list.
	 */
	LIST_INSERT_HEAD(&vfs_list, vfs, vfs_list);

	/*
	 * Sanity: make sure the reference count is 0.
	 */
	vfs->vfs_refcount = 0;

 out:
	return (error);
}

/*
 * Remove a file system from the kernel.
 */
int
vfs_detach(vfs)
	struct vfsops *vfs;
{
	struct vfsops *v;

	/*
	 * Make sure no one is using the filesystem.
	 */
	if (vfs->vfs_refcount != 0)
		return (EBUSY);

	/*
	 * ...and remove it from the kernel's list.
	 */
	LIST_FOREACH(v, &vfs_list, vfs_list) {
		if (v == vfs) {
			LIST_REMOVE(v, vfs_list);
			break;
		}
	}

	if (v == NULL)
		return (ESRCH);

	/*
	 * Now run the file system-specific cleanups.
	 */
	(*vfs->vfs_done)();

	/*
	 * Free the vnode operations vector.
	 */
	vfs_opv_free(vfs->vfs_opv_descs);
	return (0);
}

void
vfs_reinit(void)
{
	struct vfsops *vfs;

	LIST_FOREACH(vfs, &vfs_list, vfs_list) {
		if (vfs->vfs_reinit) {
			(*vfs->vfs_reinit)();
		}
	}
}

/*
 * Request a filesystem to suspend write operations.
 */
int
vfs_write_suspend(struct mount *mp, int slpflag, int slptimeo)
{
	struct proc *p = curproc;	/* XXX */
	int error;

	while ((mp->mnt_iflag & IMNT_SUSPEND)) {
		if (slptimeo < 0)
			return EWOULDBLOCK;
		error = tsleep(&mp->mnt_flag, slpflag, "suspwt1", slptimeo);
		if (error)
			return error;
	}
	mp->mnt_iflag |= IMNT_SUSPEND;

	simple_lock(&mp->mnt_slock);
	if (mp->mnt_writeopcountupper > 0)
		ltsleep(&mp->mnt_writeopcountupper, PUSER - 1, "suspwt",
			0, &mp->mnt_slock);
	simple_unlock(&mp->mnt_slock);

	error = VFS_SYNC(mp, MNT_WAIT, p->p_ucred, p);
	if (error) {
		vfs_write_resume(mp);
		return error;
	}
	mp->mnt_iflag |= IMNT_SUSPENDLOW;

	simple_lock(&mp->mnt_slock);
	if (mp->mnt_writeopcountlower > 0)
		ltsleep(&mp->mnt_writeopcountlower, PUSER - 1, "suspwt",
			0, &mp->mnt_slock);
	mp->mnt_iflag |= IMNT_SUSPENDED;
	simple_unlock(&mp->mnt_slock);

	return 0;
}

/*
 * Request a filesystem to resume write operations.
 */
void
vfs_write_resume(struct mount *mp)
{

	if ((mp->mnt_iflag & IMNT_SUSPEND) == 0)
		return;
	mp->mnt_iflag &= ~(IMNT_SUSPEND | IMNT_SUSPENDLOW | IMNT_SUSPENDED);
	wakeup(&mp->mnt_flag);
}

void
copy_statvfs_info(struct statvfs *sbp, const struct mount *mp)
{
	const struct statvfs *mbp;

	if (sbp == (mbp = &mp->mnt_stat))
		return;

	(void)memcpy(&sbp->f_fsidx, &mbp->f_fsidx, sizeof(sbp->f_fsidx));
	sbp->f_fsid = mbp->f_fsid;
	sbp->f_owner = mbp->f_owner;
	sbp->f_flag = mbp->f_flag;
	sbp->f_syncwrites = mbp->f_syncwrites;
	sbp->f_asyncwrites = mbp->f_asyncwrites;
	sbp->f_syncreads = mbp->f_syncreads;
	sbp->f_asyncreads = mbp->f_asyncreads;
	(void)memcpy(sbp->f_spare, mbp->f_spare, sizeof(mbp->f_spare));
	(void)memcpy(sbp->f_fstypename, mbp->f_fstypename,
	    sizeof(sbp->f_fstypename));
	(void)memcpy(sbp->f_mntonname, mbp->f_mntonname,
	    sizeof(sbp->f_mntonname));
	(void)memcpy(sbp->f_mntfromname, mp->mnt_stat.f_mntfromname,
	    sizeof(sbp->f_mntfromname));
	sbp->f_namemax = mbp->f_namemax;
}

int
set_statvfs_info(const char *onp, int ukon, const char *fromp, int ukfrom,
    struct mount *mp, struct proc *p)
{
	int error;
	size_t size;
	struct statvfs *sfs = &mp->mnt_stat;
	int (*fun)(const void *, void *, size_t, size_t *);

	(void)strncpy(mp->mnt_stat.f_fstypename, mp->mnt_op->vfs_name,
	    sizeof(mp->mnt_stat.f_fstypename));

	if (onp) {
		struct cwdinfo *cwdi = p->p_cwdi;
		fun = (ukon == UIO_SYSSPACE) ? copystr : copyinstr;
		if (cwdi->cwdi_rdir != NULL) {
			size_t len;
			char *bp;
			char *path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);

			if (!path) /* XXX can't happen with M_WAITOK */
				return ENOMEM;

			bp = path + MAXPATHLEN;
			*--bp = '\0';
			error = getcwd_common(cwdi->cwdi_rdir, rootvnode, &bp,
			    path, MAXPATHLEN / 2, 0, p);
			if (error) {
				free(path, M_TEMP);
				return error;
			}

			len = strlen(bp);
			if (len > sizeof(sfs->f_mntonname) - 1)
				len = sizeof(sfs->f_mntonname) - 1;
			(void)strncpy(sfs->f_mntonname, bp, len);
			free(path, M_TEMP);

			if (len < sizeof(sfs->f_mntonname) - 1) {
				error = (*fun)(onp, &sfs->f_mntonname[len],
				    sizeof(sfs->f_mntonname) - len - 1, &size);
				if (error)
					return error;
				size += len;
			} else {
				size = len;
			}
		} else {
			error = (*fun)(onp, &sfs->f_mntonname,
			    sizeof(sfs->f_mntonname) - 1, &size);
			if (error)
				return error;
		}
		(void)memset(sfs->f_mntonname + size, 0,
		    sizeof(sfs->f_mntonname) - size);
	}

	if (fromp) {
		fun = (ukfrom == UIO_SYSSPACE) ? copystr : copyinstr;
		error = (*fun)(fromp, sfs->f_mntfromname,
		    sizeof(sfs->f_mntfromname) - 1, &size);
		if (error)
			return error;
		(void)memset(sfs->f_mntfromname + size, 0,
		    sizeof(sfs->f_mntfromname) - size);
	}
	return 0;
}

/*
 * Default vfs_extattrctl routine for file systems that do not support
 * it.
 */
/*ARGSUSED*/
int
vfs_stdextattrctl(struct mount *mp, int cmt, struct vnode *vp,
    int attrnamespace, const char *attrname, struct proc *p)
{

	if (vp != NULL)
		VOP_UNLOCK(vp, 0);
	return (EOPNOTSUPP);
}

/*
 * Credential check based on process requesting service, and per-attribute
 * permissions.
 *
 * NOTE: Vnode must be locked.
 */
int
extattr_check_cred(struct vnode *vp, int attrnamespace,
    struct ucred *cred, struct proc *p, int access)
{

	if (cred == NOCRED)
		return (0);

	switch (attrnamespace) {
	case EXTATTR_NAMESPACE_SYSTEM:
		/*
		 * Do we really want to allow this, or just require that
		 * these requests come from kernel code (NOCRED case above)?
		 */
		return (suser(cred, &p->p_acflag));

	case EXTATTR_NAMESPACE_USER:
		return (VOP_ACCESS(vp, access, cred, p));

	default:
		return (EPERM);
	}
}

#ifdef DDB
const char buf_flagbits[] = BUF_FLAGBITS;

void
vfs_buf_print(bp, full, pr)
	struct buf *bp;
	int full;
	void (*pr)(const char *, ...);
{
	char buf[1024];

	(*pr)("  vp %p lblkno 0x%"PRIx64" blkno 0x%"PRIx64" dev 0x%x\n",
		  bp->b_vp, bp->b_lblkno, bp->b_blkno, bp->b_dev);

	bitmask_snprintf(bp->b_flags, buf_flagbits, buf, sizeof(buf));
	(*pr)("  error %d flags 0x%s\n", bp->b_error, buf);

	(*pr)("  bufsize 0x%lx bcount 0x%lx resid 0x%lx\n",
		  bp->b_bufsize, bp->b_bcount, bp->b_resid);
	(*pr)("  data %p saveaddr %p dep %p\n",
		  bp->b_data, bp->b_saveaddr, LIST_FIRST(&bp->b_dep));
	(*pr)("  iodone %p\n", bp->b_iodone);
}


void
vfs_vnode_print(vp, full, pr)
	struct vnode *vp;
	int full;
	void (*pr)(const char *, ...);
{
	char buf[256];

	uvm_object_printit(&vp->v_uobj, full, pr);
	bitmask_snprintf(vp->v_flag, vnode_flagbits, buf, sizeof(buf));
	(*pr)("\nVNODE flags %s\n", buf);
	(*pr)("mp %p numoutput %d size 0x%llx\n",
	      vp->v_mount, vp->v_numoutput, vp->v_size);

	(*pr)("data %p usecount %d writecount %ld holdcnt %ld numoutput %d\n",
	      vp->v_data, vp->v_usecount, vp->v_writecount,
	      vp->v_holdcnt, vp->v_numoutput);

	(*pr)("tag %s(%d) type %s(%d) mount %p typedata %p\n",
	      ARRAY_PRINT(vp->v_tag, vnode_tags), vp->v_tag,
	      ARRAY_PRINT(vp->v_type, vnode_types), vp->v_type,
	      vp->v_mount, vp->v_mountedhere);

	if (full) {
		struct buf *bp;

		(*pr)("clean bufs:\n");
		LIST_FOREACH(bp, &vp->v_cleanblkhd, b_vnbufs) {
			(*pr)(" bp %p\n", bp);
			vfs_buf_print(bp, full, pr);
		}

		(*pr)("dirty bufs:\n");
		LIST_FOREACH(bp, &vp->v_dirtyblkhd, b_vnbufs) {
			(*pr)(" bp %p\n", bp);
			vfs_buf_print(bp, full, pr);
		}
	}
}

void
vfs_mount_print(mp, full, pr)
	struct mount *mp;
	int full;
	void (*pr)(const char *, ...);
{
	char sbuf[256];

	(*pr)("vnodecovered = %p syncer = %p data = %p\n",
			mp->mnt_vnodecovered,mp->mnt_syncer,mp->mnt_data);

	(*pr)("fs_bshift %d dev_bshift = %d\n",
			mp->mnt_fs_bshift,mp->mnt_dev_bshift);

	bitmask_snprintf(mp->mnt_flag, __MNT_FLAG_BITS, sbuf, sizeof(sbuf));
	(*pr)("flag = %s\n", sbuf);

	bitmask_snprintf(mp->mnt_iflag, __IMNT_FLAG_BITS, sbuf, sizeof(sbuf));
	(*pr)("iflag = %s\n", sbuf);

	/* XXX use lockmgr_printinfo */
	if (mp->mnt_lock.lk_sharecount)
		(*pr)(" lock type %s: SHARED (count %d)", mp->mnt_lock.lk_wmesg,
		    mp->mnt_lock.lk_sharecount);
	else if (mp->mnt_lock.lk_flags & LK_HAVE_EXCL) {
		(*pr)(" lock type %s: EXCL (count %d) by ",
		    mp->mnt_lock.lk_wmesg, mp->mnt_lock.lk_exclusivecount);
		if (mp->mnt_lock.lk_flags & LK_SPIN)
			(*pr)("processor %lu", mp->mnt_lock.lk_cpu);
		else
			(*pr)("pid %d.%d", mp->mnt_lock.lk_lockholder,
			    mp->mnt_lock.lk_locklwp);
	} else
		(*pr)(" not locked");
	if ((mp->mnt_lock.lk_flags & LK_SPIN) == 0 && mp->mnt_lock.lk_waitcount > 0)
		(*pr)(" with %d pending", mp->mnt_lock.lk_waitcount);

	(*pr)("\n");

	if (mp->mnt_unmounter) {
		(*pr)("unmounter pid = %d ",mp->mnt_unmounter->p_pid);
	}
	(*pr)("wcnt = %d, writeopcountupper = %d, writeopcountupper = %d\n",
		mp->mnt_wcnt,mp->mnt_writeopcountupper,mp->mnt_writeopcountlower);

	(*pr)("statvfs cache:\n");
	(*pr)("\tbsize = %lu\n",mp->mnt_stat.f_bsize);
	(*pr)("\tfrsize = %lu\n",mp->mnt_stat.f_frsize);
	(*pr)("\tiosize = %lu\n",mp->mnt_stat.f_iosize);

	(*pr)("\tblocks = %"PRIu64"\n",mp->mnt_stat.f_blocks);
	(*pr)("\tbfree = %"PRIu64"\n",mp->mnt_stat.f_bfree);
	(*pr)("\tbavail = %"PRIu64"\n",mp->mnt_stat.f_bavail);
	(*pr)("\tbresvd = %"PRIu64"\n",mp->mnt_stat.f_bresvd);

	(*pr)("\tfiles = %"PRIu64"\n",mp->mnt_stat.f_files);
	(*pr)("\tffree = %"PRIu64"\n",mp->mnt_stat.f_ffree);
	(*pr)("\tfavail = %"PRIu64"\n",mp->mnt_stat.f_favail);
	(*pr)("\tfresvd = %"PRIu64"\n",mp->mnt_stat.f_fresvd);

	(*pr)("\tf_fsidx = { 0x%"PRIx32", 0x%"PRIx32" }\n",
			mp->mnt_stat.f_fsidx.__fsid_val[0],
			mp->mnt_stat.f_fsidx.__fsid_val[1]);

	(*pr)("\towner = %"PRIu32"\n",mp->mnt_stat.f_owner);
	(*pr)("\tnamemax = %lu\n",mp->mnt_stat.f_namemax);

	bitmask_snprintf(mp->mnt_stat.f_flag, __MNT_FLAG_BITS, sbuf,
	    sizeof(sbuf));
	(*pr)("\tflag = %s\n",sbuf);
	(*pr)("\tsyncwrites = %" PRIu64 "\n",mp->mnt_stat.f_syncwrites);
	(*pr)("\tasyncwrites = %" PRIu64 "\n",mp->mnt_stat.f_asyncwrites);
	(*pr)("\tsyncreads = %" PRIu64 "\n",mp->mnt_stat.f_syncreads);
	(*pr)("\tasyncreads = %" PRIu64 "\n",mp->mnt_stat.f_asyncreads);
	(*pr)("\tfstypename = %s\n",mp->mnt_stat.f_fstypename);
	(*pr)("\tmntonname = %s\n",mp->mnt_stat.f_mntonname);
	(*pr)("\tmntfromname = %s\n",mp->mnt_stat.f_mntfromname);

	{
		int cnt = 0;
		struct vnode *vp;
		(*pr)("locked vnodes =");
		/* XXX would take mountlist lock, except ddb may not have context */
		LIST_FOREACH(vp, &mp->mnt_vnodelist, v_mntvnodes) {
			if (VOP_ISLOCKED(vp)) {
				if ((++cnt % 6) == 0) {
					(*pr)(" %p,\n\t", vp);
				} else {
					(*pr)(" %p,", vp);
				}
			}
		}
		(*pr)("\n");
	}

	if (full) {
		int cnt = 0;
		struct vnode *vp;
		(*pr)("all vnodes =");
		/* XXX would take mountlist lock, except ddb may not have context */
		LIST_FOREACH(vp, &mp->mnt_vnodelist, v_mntvnodes) {
			if (!LIST_NEXT(vp, v_mntvnodes)) {
				(*pr)(" %p", vp);
			} else if ((++cnt % 6) == 0) {
				(*pr)(" %p,\n\t", vp);
			} else {
				(*pr)(" %p,", vp);
			}
		}
		(*pr)("\n", vp);
	}
}

#endif