xref: /xnu-11215/bsd/vfs/vfs_subr.c (revision 4f1223e8)

/*
 *
 * Copyright (c) 2000-2024 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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	8.31 (Berkeley) 5/26/95
 */
/*
 * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
 * support for mandatory and extensible security protections.  This notice
 * is included in support of clause 2.2 (b) of the Apple Public License,
 * Version 2.0.
 */

/*
 * External virtual filesystem routines
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc_internal.h>
#include <sys/kauth.h>
#include <sys/mount_internal.h>
#include <sys/time.h>
#include <sys/lock.h>
#include <sys/vnode.h>
#include <sys/vnode_internal.h>
#include <sys/stat.h>
#include <sys/namei.h>
#include <sys/ucred.h>
#include <sys/buf_internal.h>
#include <sys/errno.h>
#include <kern/kalloc.h>
#include <sys/uio_internal.h>
#include <sys/uio.h>
#include <sys/domain.h>
#include <sys/mbuf.h>
#include <sys/syslog.h>
#include <sys/ubc_internal.h>
#include <sys/vm.h>
#include <sys/sysctl.h>
#include <sys/filedesc.h>
#include <sys/fcntl.h>
#include <sys/event.h>
#include <sys/kdebug.h>
#include <sys/kauth.h>
#include <sys/user.h>
#include <sys/systm.h>
#include <sys/kern_memorystatus.h>
#include <sys/lockf.h>
#include <sys/reboot.h>
#include <miscfs/fifofs/fifo.h>

#include <nfs/nfs.h>

#include <string.h>
#include <machine/machine_routines.h>

#include <kern/assert.h>
#include <mach/kern_return.h>
#include <kern/thread.h>
#include <kern/sched_prim.h>
#include <kern/smr.h>

#include <miscfs/specfs/specdev.h>

#include <mach/mach_types.h>
#include <mach/memory_object_types.h>
#include <mach/memory_object_control.h>

#include <kern/kalloc.h>        /* kalloc()/kfree() */
#include <kern/clock.h>         /* delay_for_interval() */
#include <libkern/coreanalytics/coreanalytics.h>
#include <libkern/OSAtomic.h>   /* OSAddAtomic() */
#include <os/atomic_private.h>
#if defined(XNU_TARGET_OS_OSX)
#include <console/video_console.h>
#endif

#ifdef CONFIG_IOCOUNT_TRACE
#include <libkern/OSDebug.h>
#endif

#include <vm/vm_protos.h>       /* vnode_pager_vrele() */
#include <vm/vm_ubc.h>
#include <vm/memory_object_xnu.h>

#if CONFIG_MACF
#include <security/mac_framework.h>
#endif

#include <vfs/vfs_disk_conditioner.h>
#include <libkern/section_keywords.h>

static LCK_GRP_DECLARE(vnode_lck_grp, "vnode");
static LCK_ATTR_DECLARE(vnode_lck_attr, 0, 0);

#if CONFIG_TRIGGERS
static LCK_GRP_DECLARE(trigger_vnode_lck_grp, "trigger_vnode");
static LCK_ATTR_DECLARE(trigger_vnode_lck_attr, 0, 0);
#endif

extern lck_mtx_t mnt_list_mtx_lock;

static KALLOC_TYPE_DEFINE(specinfo_zone, struct specinfo, KT_DEFAULT);

ZONE_DEFINE(vnode_zone, "vnodes",
    sizeof(struct vnode), ZC_NOGC | ZC_ZFREE_CLEARMEM);

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

extern int paniclog_append_noflush(const char *format, ...);

/* XXX next prototytype should be from libsa/stdlib.h> but conflicts libkern */
__private_extern__ void qsort(
	void * array,
	size_t nmembers,
	size_t member_size,
	int (*)(const void *, const void *));

__private_extern__ void vntblinit(void);
__private_extern__ int unlink1(vfs_context_t, vnode_t, user_addr_t,
    enum uio_seg, int);

static void vnode_list_add(vnode_t);
static void vnode_async_list_add(vnode_t);
static void vnode_list_remove(vnode_t);
static void vnode_list_remove_locked(vnode_t);

static void vnode_abort_advlocks(vnode_t);
static errno_t vnode_drain(vnode_t);
static void vgone(vnode_t, int flags);
static void vclean(vnode_t vp, int flag);
static void vnode_reclaim_internal(vnode_t, int, int, int);

static void vnode_dropiocount(vnode_t);

static vnode_t checkalias(vnode_t vp, dev_t nvp_rdev);
static int  vnode_reload(vnode_t);

static int unmount_callback(mount_t, __unused void *);

static void insmntque(vnode_t vp, mount_t mp);
static int mount_getvfscnt(void);
static int mount_fillfsids(fsid_t *, int );
static void vnode_iterate_setup(mount_t);
int vnode_umount_preflight(mount_t, vnode_t, int);
static int vnode_iterate_prepare(mount_t);
static int vnode_iterate_reloadq(mount_t);
static void vnode_iterate_clear(mount_t);
static mount_t vfs_getvfs_locked(fsid_t *);
static int vn_create_reg(vnode_t dvp, vnode_t *vpp, struct nameidata *ndp,
    struct vnode_attr *vap, uint32_t flags, int fmode, uint32_t *statusp, vfs_context_t ctx);
static int vnode_authattr_new_internal(vnode_t dvp, struct vnode_attr *vap, int noauth, uint32_t *defaulted_fieldsp, vfs_context_t ctx);

errno_t rmdir_remove_orphaned_appleDouble(vnode_t, vfs_context_t, int *);

#ifdef CONFIG_IOCOUNT_TRACE
static void record_vp(vnode_t vp, int count);
static TUNABLE(int, bootarg_vnode_iocount_trace, "vnode_iocount_trace", 0);
static TUNABLE(int, bootarg_uthread_iocount_trace, "uthread_iocount_trace", 0);
#endif /* CONFIG_IOCOUNT_TRACE */

#if CONFIG_JETSAM && (DEVELOPMENT || DEBUG)
static TUNABLE(bool, bootarg_no_vnode_jetsam, "-no_vnode_jetsam", false);
#endif /* CONFIG_JETSAM && (DEVELOPMENT || DEBUG) */

static TUNABLE(bool, bootarg_no_vnode_drain, "-no_vnode_drain", false);

__options_decl(freeable_vnode_level_t, uint32_t, {
	DEALLOC_VNODE_NONE = 0,
	DEALLOC_VNODE_ONLY_OVERFLOW = 1,
	DEALLOC_VNODE_ALL = 2
});

#if XNU_TARGET_OS_OSX
static TUNABLE(freeable_vnode_level_t, bootarg_vn_dealloc_level, "vn_dealloc_level", DEALLOC_VNODE_NONE);
#else
static TUNABLE(freeable_vnode_level_t, bootarg_vn_dealloc_level, "vn_dealloc_level", DEALLOC_VNODE_ONLY_OVERFLOW);
#endif /* CONFIG_VNDEALLOC */

static freeable_vnode_level_t vn_dealloc_level = DEALLOC_VNODE_NONE;

boolean_t root_is_CF_drive = FALSE;

#if CONFIG_TRIGGERS
static int vnode_resolver_create(mount_t, vnode_t, struct vnode_trigger_param *, boolean_t external);
static void vnode_resolver_detach(vnode_t);
#endif

TAILQ_HEAD(freelst, vnode) vnode_free_list;     /* vnode free list */
TAILQ_HEAD(deadlst, vnode) vnode_dead_list;     /* vnode dead list */
TAILQ_HEAD(async_work_lst, vnode) vnode_async_work_list;


TAILQ_HEAD(ragelst, vnode) vnode_rage_list;     /* vnode rapid age list */
struct timeval rage_tv;
int     rage_limit = 0;
int     ragevnodes = 0;

long  reusablevnodes_max = LONG_MAX;
long  reusablevnodes = 0;
int   deadvnodes_low = 0;
int   deadvnodes_high = 0;
int   numvnodes_min = 0;
int   numvnodes_max = 0;

uint64_t newvnode = 0;
unsigned long newvnode_nodead = 0;

static  int vfs_unmountall_started = 0;
static  int vfs_unmountall_finished = 0;
static  uint64_t vfs_shutdown_last_completion_time;

#define RAGE_LIMIT_MIN  100
#define RAGE_TIME_LIMIT 5

VFS_SMR_DECLARE;
extern uint32_t nc_smr_enabled;

/*
 * ROSV definitions
 * NOTE: These are shadowed from PlatformSupport definitions, but XNU
 * builds standalone.
 */
#define PLATFORM_DATA_VOLUME_MOUNT_POINT "/System/Volumes/Data"

/*
 * These could be in PlatformSupport but aren't yet
 */
#define PLATFORM_PREBOOT_VOLUME_MOUNT_POINT "/System/Volumes/Preboot"
#define PLATFORM_RECOVERY_VOLUME_MOUNT_POINT "/System/Volumes/Recovery"

#if CONFIG_MOUNT_VM
#define PLATFORM_VM_VOLUME_MOUNT_POINT "/System/Volumes/VM"
#endif

struct mntlist mountlist;                       /* mounted filesystem list */
static int nummounts = 0;

static int print_busy_vnodes = 0;                               /* print out busy vnodes */

#if DIAGNOSTIC
#define VLISTCHECK(fun, vp, list)       \
	if ((vp)->v_freelist.tqe_prev == (struct vnode **)0xdeadb) \
	        panic("%s: %s vnode not on %slist", (fun), (list), (list));
#else
#define VLISTCHECK(fun, vp, list)
#endif /* DIAGNOSTIC */

#define VLISTNONE(vp)   \
	do {    \
	        (vp)->v_freelist.tqe_next = (struct vnode *)0;  \
	        (vp)->v_freelist.tqe_prev = (struct vnode **)0xdeadb;   \
	} while(0)

#define VONLIST(vp)     \
	((vp)->v_freelist.tqe_prev != (struct vnode **)0xdeadb)

/* remove a vnode from free vnode list */
#define VREMFREE(fun, vp)       \
	do {    \
	        VLISTCHECK((fun), (vp), "free");        \
	        TAILQ_REMOVE(&vnode_free_list, (vp), v_freelist);       \
	        VLISTNONE((vp));        \
	        freevnodes--;   \
	        reusablevnodes--;    \
	} while(0)


/* remove a vnode from dead vnode list */
#define VREMDEAD(fun, vp)       \
	do {    \
	        VLISTCHECK((fun), (vp), "dead");        \
	        TAILQ_REMOVE(&vnode_dead_list, (vp), v_freelist);       \
	        VLISTNONE((vp));        \
	        vp->v_listflag &= ~VLIST_DEAD;  \
	        deadvnodes--;   \
	        if (vp->v_listflag & VLIST_NO_REUSE) {        \
	                deadvnodes_noreuse--;        \
	        }        \
	} while(0)


/* remove a vnode from async work vnode list */
#define VREMASYNC_WORK(fun, vp) \
	do {    \
	        VLISTCHECK((fun), (vp), "async_work");  \
	        TAILQ_REMOVE(&vnode_async_work_list, (vp), v_freelist); \
	        VLISTNONE((vp));        \
	        vp->v_listflag &= ~VLIST_ASYNC_WORK;    \
	        async_work_vnodes--;    \
	        if (!(vp->v_listflag & VLIST_NO_REUSE)) {        \
	                reusablevnodes--;    \
	        }        \
	} while(0)


/* remove a vnode from rage vnode list */
#define VREMRAGE(fun, vp)       \
	do {    \
	        if ( !(vp->v_listflag & VLIST_RAGE))                    \
	                panic("VREMRAGE: vp not on rage list");         \
	        VLISTCHECK((fun), (vp), "rage");                        \
	        TAILQ_REMOVE(&vnode_rage_list, (vp), v_freelist);       \
	        VLISTNONE((vp));                \
	        vp->v_listflag &= ~VLIST_RAGE;  \
	        ragevnodes--;                   \
	        reusablevnodes--;    \
	} while(0)

static void async_work_continue(void);
static void vn_laundry_continue(void);
static void wakeup_laundry_thread(void);
static void vnode_smr_free(void *, size_t);

CA_EVENT(freeable_vnodes,
    CA_INT, numvnodes_min,
    CA_INT, numvnodes_max,
    CA_INT, desiredvnodes,
    CA_INT, numvnodes,
    CA_INT, freevnodes,
    CA_INT, deadvnodes,
    CA_INT, freeablevnodes,
    CA_INT, busyvnodes,
    CA_BOOL, threshold_crossed);
static CA_EVENT_TYPE(freeable_vnodes) freeable_vnodes_telemetry;

static bool freeablevnodes_threshold_crossed = false;

/*
 * Initialize the vnode management data structures.
 */
__private_extern__ void
vntblinit(void)
{
	thread_t        thread = THREAD_NULL;
	int desiredvnodes_one_percent = desiredvnodes / 100;

	TAILQ_INIT(&vnode_free_list);
	TAILQ_INIT(&vnode_rage_list);
	TAILQ_INIT(&vnode_dead_list);
	TAILQ_INIT(&vnode_async_work_list);
	TAILQ_INIT(&mountlist);

	microuptime(&rage_tv);
	rage_limit = desiredvnodes_one_percent;
	if (rage_limit < RAGE_LIMIT_MIN) {
		rage_limit = RAGE_LIMIT_MIN;
	}

	deadvnodes_low = desiredvnodes_one_percent;
	if (deadvnodes_low > 300) {
		deadvnodes_low = 300;
	}
	deadvnodes_high = deadvnodes_low * 2;

	numvnodes_min = numvnodes_max = desiredvnodes;
	if (bootarg_vn_dealloc_level == DEALLOC_VNODE_ONLY_OVERFLOW) {
		numvnodes_max = desiredvnodes * 2;
		vn_dealloc_level = bootarg_vn_dealloc_level;
	} else if (bootarg_vn_dealloc_level == DEALLOC_VNODE_ALL) {
		numvnodes_min = desiredvnodes_one_percent * 40;
		numvnodes_max = desiredvnodes * 2;
		reusablevnodes_max = (desiredvnodes_one_percent * 20) - deadvnodes_low;
		vn_dealloc_level = bootarg_vn_dealloc_level;
	}

	bzero(&freeable_vnodes_telemetry, sizeof(CA_EVENT_TYPE(freeable_vnodes)));
	freeable_vnodes_telemetry.numvnodes_min = numvnodes_min;
	freeable_vnodes_telemetry.numvnodes_max = numvnodes_max;
	freeable_vnodes_telemetry.desiredvnodes = desiredvnodes;

	if (nc_smr_enabled) {
		zone_enable_smr(vnode_zone, VFS_SMR(), &vnode_smr_free);
	}

	/*
	 * create worker threads
	 */
	kernel_thread_start((thread_continue_t)async_work_continue, NULL, &thread);
	thread_deallocate(thread);
	kernel_thread_start((thread_continue_t)vn_laundry_continue, NULL, &thread);
	thread_deallocate(thread);
}

/* the timeout is in 10 msecs */
int
vnode_waitforwrites(vnode_t vp, int output_target, int slpflag, int slptimeout, const char *msg)
{
	int error = 0;
	struct timespec ts;

	if (output_target < 0) {
		return EINVAL;
	}

	KERNEL_DEBUG(0x3010280 | DBG_FUNC_START, (int)vp, output_target, vp->v_numoutput, 0, 0);

	if (vp->v_numoutput > output_target) {
		slpflag |= PDROP;

		vnode_lock_spin(vp);

		while ((vp->v_numoutput > output_target) && error == 0) {
			if (output_target) {
				vp->v_flag |= VTHROTTLED;
			} else {
				vp->v_flag |= VBWAIT;
			}

			ts.tv_sec = (slptimeout / 100);
			ts.tv_nsec = (slptimeout % 1000)  * 10 * NSEC_PER_USEC * 1000;
			error = msleep((caddr_t)&vp->v_numoutput, &vp->v_lock, (slpflag | (PRIBIO + 1)), msg, &ts);

			vnode_lock_spin(vp);
		}
		vnode_unlock(vp);
	}
	KERNEL_DEBUG(0x3010280 | DBG_FUNC_END, (int)vp, output_target, vp->v_numoutput, error, 0);

	return error;
}


void
vnode_startwrite(vnode_t vp)
{
	OSAddAtomic(1, &vp->v_numoutput);
}


void
vnode_writedone(vnode_t vp)
{
	if (vp) {
		int need_wakeup = 0;

		OSAddAtomic(-1, &vp->v_numoutput);

		vnode_lock_spin(vp);

		if (vp->v_numoutput < 0) {
			panic("vnode_writedone: numoutput < 0");
		}

		if ((vp->v_flag & VTHROTTLED)) {
			vp->v_flag &= ~VTHROTTLED;
			need_wakeup = 1;
		}
		if ((vp->v_flag & VBWAIT) && (vp->v_numoutput == 0)) {
			vp->v_flag &= ~VBWAIT;
			need_wakeup = 1;
		}
		vnode_unlock(vp);

		if (need_wakeup) {
			wakeup((caddr_t)&vp->v_numoutput);
		}
	}
}



int
vnode_hasdirtyblks(vnode_t vp)
{
	struct cl_writebehind *wbp;

	/*
	 * Not taking the buf_mtx as there is little
	 * point doing it. Even if the lock is taken the
	 * state can change right after that. If their
	 * needs to be a synchronization, it must be driven
	 * by the caller
	 */
	if (vp->v_dirtyblkhd.lh_first) {
		return 1;
	}

	if (!UBCINFOEXISTS(vp)) {
		return 0;
	}

	wbp = vp->v_ubcinfo->cl_wbehind;

	if (wbp && (wbp->cl_number || wbp->cl_scmap)) {
		return 1;
	}

	return 0;
}

int
vnode_hascleanblks(vnode_t vp)
{
	/*
	 * Not taking the buf_mtx as there is little
	 * point doing it. Even if the lock is taken the
	 * state can change right after that. If their
	 * needs to be a synchronization, it must be driven
	 * by the caller
	 */
	if (vp->v_cleanblkhd.lh_first) {
		return 1;
	}
	return 0;
}

void
vnode_iterate_setup(mount_t mp)
{
	mp->mnt_lflag |= MNT_LITER;
}

int
vnode_umount_preflight(mount_t mp, vnode_t skipvp, int flags)
{
	vnode_t vp;
	int ret = 0;

	TAILQ_FOREACH(vp, &mp->mnt_vnodelist, v_mntvnodes) {
		if (vp->v_type == VDIR) {
			continue;
		}
		if (vp == skipvp) {
			continue;
		}
		if ((flags & SKIPSYSTEM) && ((vp->v_flag & VSYSTEM) || (vp->v_flag & VNOFLUSH))) {
			continue;
		}
		if ((flags & SKIPSWAP) && (vp->v_flag & VSWAP)) {
			continue;
		}
		if ((flags & WRITECLOSE) && (vp->v_writecount == 0 || vp->v_type != VREG)) {
			continue;
		}

		/* Look for busy vnode */
		if ((vp->v_usecount != 0) && ((vp->v_usecount - vp->v_kusecount) != 0)) {
			ret = 1;
			if (print_busy_vnodes && ((flags & FORCECLOSE) == 0)) {
				vprint("vnode_umount_preflight - busy vnode", vp);
			} else {
				return ret;
			}
		} else if (vp->v_iocount > 0) {
			/* Busy if iocount is > 0 for more than 3 seconds */
			tsleep(&vp->v_iocount, PVFS, "vnode_drain_network", 3 * hz);
			if (vp->v_iocount > 0) {
				ret = 1;
				if (print_busy_vnodes && ((flags & FORCECLOSE) == 0)) {
					vprint("vnode_umount_preflight - busy vnode", vp);
				} else {
					return ret;
				}
			}
			continue;
		}
	}

	return ret;
}

/*
 * This routine prepares iteration by moving all the vnodes to worker queue
 * called with mount lock held
 */
int
vnode_iterate_prepare(mount_t mp)
{
	vnode_t vp;

	if (TAILQ_EMPTY(&mp->mnt_vnodelist)) {
		/* nothing to do */
		return 0;
	}

	vp = TAILQ_FIRST(&mp->mnt_vnodelist);
	vp->v_mntvnodes.tqe_prev = &(mp->mnt_workerqueue.tqh_first);
	mp->mnt_workerqueue.tqh_first = mp->mnt_vnodelist.tqh_first;
	mp->mnt_workerqueue.tqh_last = mp->mnt_vnodelist.tqh_last;

	TAILQ_INIT(&mp->mnt_vnodelist);
	if (mp->mnt_newvnodes.tqh_first != NULL) {
		panic("vnode_iterate_prepare: newvnode when entering vnode");
	}
	TAILQ_INIT(&mp->mnt_newvnodes);

	return 1;
}


/* called with mount lock held */
int
vnode_iterate_reloadq(mount_t mp)
{
	int moved = 0;

	/* add the remaining entries in workerq to the end of mount vnode list */
	if (!TAILQ_EMPTY(&mp->mnt_workerqueue)) {
		struct vnode * mvp;
		mvp = TAILQ_LAST(&mp->mnt_vnodelist, vnodelst);

		/* Joining the workerque entities to mount vnode list */
		if (mvp) {
			mvp->v_mntvnodes.tqe_next = mp->mnt_workerqueue.tqh_first;
		} else {
			mp->mnt_vnodelist.tqh_first = mp->mnt_workerqueue.tqh_first;
		}
		mp->mnt_workerqueue.tqh_first->v_mntvnodes.tqe_prev = mp->mnt_vnodelist.tqh_last;
		mp->mnt_vnodelist.tqh_last = mp->mnt_workerqueue.tqh_last;
		TAILQ_INIT(&mp->mnt_workerqueue);
	}

	/* add the newvnodes to the head of mount vnode list */
	if (!TAILQ_EMPTY(&mp->mnt_newvnodes)) {
		struct vnode * nlvp;
		nlvp = TAILQ_LAST(&mp->mnt_newvnodes, vnodelst);

		mp->mnt_newvnodes.tqh_first->v_mntvnodes.tqe_prev = &mp->mnt_vnodelist.tqh_first;
		nlvp->v_mntvnodes.tqe_next = mp->mnt_vnodelist.tqh_first;
		if (mp->mnt_vnodelist.tqh_first) {
			mp->mnt_vnodelist.tqh_first->v_mntvnodes.tqe_prev = &nlvp->v_mntvnodes.tqe_next;
		} else {
			mp->mnt_vnodelist.tqh_last = mp->mnt_newvnodes.tqh_last;
		}
		mp->mnt_vnodelist.tqh_first = mp->mnt_newvnodes.tqh_first;
		TAILQ_INIT(&mp->mnt_newvnodes);
		moved = 1;
	}

	return moved;
}


void
vnode_iterate_clear(mount_t mp)
{
	mp->mnt_lflag &= ~MNT_LITER;
}

#if defined(__x86_64__)

#include <i386/panic_hooks.h>

struct vnode_iterate_panic_hook {
	panic_hook_t hook;
	mount_t mp;
	struct vnode *vp;
};

static void
vnode_iterate_panic_hook(panic_hook_t *hook_)
{
	struct vnode_iterate_panic_hook *hook = (struct vnode_iterate_panic_hook *)hook_;
	panic_phys_range_t range;
	uint64_t phys;

	if (panic_phys_range_before(hook->mp, &phys, &range)) {
		paniclog_append_noflush("mp = %p, phys = %p, prev (%p: %p-%p)\n",
		    hook->mp, phys, range.type, range.phys_start,
		    range.phys_start + range.len);
	} else {
		paniclog_append_noflush("mp = %p, phys = %p, prev (!)\n", hook->mp, phys);
	}

	if (panic_phys_range_before(hook->vp, &phys, &range)) {
		paniclog_append_noflush("vp = %p, phys = %p, prev (%p: %p-%p)\n",
		    hook->vp, phys, range.type, range.phys_start,
		    range.phys_start + range.len);
	} else {
		paniclog_append_noflush("vp = %p, phys = %p, prev (!)\n", hook->vp, phys);
	}
	panic_dump_mem((void *)(((vm_offset_t)hook->mp - 4096) & ~4095), 12288);
}
#endif /* defined(__x86_64__) */

int
vnode_iterate(mount_t mp, int flags, int (*callout)(struct vnode *, void *),
    void *arg)
{
	struct vnode *vp;
	int vid, retval;
	int ret = 0;

	/*
	 * The mount iterate mutex is held for the duration of the iteration.
	 * This can be done by a state flag on the mount structure but we can
	 * run into priority inversion issues sometimes.
	 * Using a mutex allows us to benefit from the priority donation
	 * mechanisms in the kernel for locks. This mutex should never be
	 * acquired in spin mode and it should be acquired before attempting to
	 * acquire the mount lock.
	 */
	mount_iterate_lock(mp);

	mount_lock(mp);

	vnode_iterate_setup(mp);

	/* If it returns 0 then there is nothing to do */
	retval = vnode_iterate_prepare(mp);

	if (retval == 0) {
		vnode_iterate_clear(mp);
		mount_unlock(mp);
		mount_iterate_unlock(mp);
		return ret;
	}

#if defined(__x86_64__)
	struct vnode_iterate_panic_hook hook;
	hook.mp = mp;
	hook.vp = NULL;
	panic_hook(&hook.hook, vnode_iterate_panic_hook);
#endif
	/* iterate over all the vnodes */
	while (!TAILQ_EMPTY(&mp->mnt_workerqueue)) {
		vp = TAILQ_FIRST(&mp->mnt_workerqueue);
#if defined(__x86_64__)
		hook.vp = vp;
#endif
		TAILQ_REMOVE(&mp->mnt_workerqueue, vp, v_mntvnodes);
		TAILQ_INSERT_TAIL(&mp->mnt_vnodelist, vp, v_mntvnodes);
		vid = vp->v_id;
		if ((vp->v_data == NULL) || (vp->v_type == VNON) || (vp->v_mount != mp)) {
			continue;
		}
		vnode_hold(vp);
		mount_unlock(mp);

		if (vget_internal(vp, vid, (flags | VNODE_NODEAD | VNODE_WITHID | VNODE_NOSUSPEND))) {
			mount_lock(mp);
			vnode_drop(vp);
			continue;
		}
		vnode_drop(vp);
		if (flags & VNODE_RELOAD) {
			/*
			 * we're reloading the filesystem
			 * cast out any inactive vnodes...
			 */
			if (vnode_reload(vp)) {
				/* vnode will be recycled on the refcount drop */
				vnode_put(vp);
				mount_lock(mp);
				continue;
			}
		}

		retval = callout(vp, arg);

		switch (retval) {
		case VNODE_RETURNED:
		case VNODE_RETURNED_DONE:
			vnode_put(vp);
			if (retval == VNODE_RETURNED_DONE) {
				mount_lock(mp);
				ret = 0;
				goto out;
			}
			break;

		case VNODE_CLAIMED_DONE:
			mount_lock(mp);
			ret = 0;
			goto out;
		case VNODE_CLAIMED:
		default:
			break;
		}
		mount_lock(mp);
	}

out:
#if defined(__x86_64__)
	panic_unhook(&hook.hook);
#endif
	(void)vnode_iterate_reloadq(mp);
	vnode_iterate_clear(mp);
	mount_unlock(mp);
	mount_iterate_unlock(mp);
	return ret;
}

void
mount_lock_renames(mount_t mp)
{
	lck_mtx_lock(&mp->mnt_renamelock);
}

void
mount_unlock_renames(mount_t mp)
{
	lck_mtx_unlock(&mp->mnt_renamelock);
}

void
mount_iterate_lock(mount_t mp)
{
	lck_mtx_lock(&mp->mnt_iter_lock);
}

void
mount_iterate_unlock(mount_t mp)
{
	lck_mtx_unlock(&mp->mnt_iter_lock);
}

void
mount_lock(mount_t mp)
{
	lck_mtx_lock(&mp->mnt_mlock);
}

void
mount_lock_spin(mount_t mp)
{
	lck_mtx_lock_spin(&mp->mnt_mlock);
}

void
mount_unlock(mount_t mp)
{
	lck_mtx_unlock(&mp->mnt_mlock);
}


void
mount_ref(mount_t mp, int locked)
{
	if (!locked) {
		mount_lock_spin(mp);
	}

	mp->mnt_count++;

	if (!locked) {
		mount_unlock(mp);
	}
}


void
mount_drop(mount_t mp, int locked)
{
	if (!locked) {
		mount_lock_spin(mp);
	}

	mp->mnt_count--;

	if (mp->mnt_count == 0 && (mp->mnt_lflag & MNT_LDRAIN)) {
		wakeup(&mp->mnt_lflag);
	}

	if (!locked) {
		mount_unlock(mp);
	}
}


int
mount_iterref(mount_t mp, int locked)
{
	int retval = 0;

	if (!locked) {
		mount_list_lock();
	}
	if (mp->mnt_iterref < 0) {
		retval = 1;
	} else {
		mp->mnt_iterref++;
	}
	if (!locked) {
		mount_list_unlock();
	}
	return retval;
}

int
mount_isdrained(mount_t mp, int locked)
{
	int retval;

	if (!locked) {
		mount_list_lock();
	}
	if (mp->mnt_iterref < 0) {
		retval = 1;
	} else {
		retval = 0;
	}
	if (!locked) {
		mount_list_unlock();
	}
	return retval;
}

void
mount_iterdrop(mount_t mp)
{
	mount_list_lock();
	mp->mnt_iterref--;
	wakeup(&mp->mnt_iterref);
	mount_list_unlock();
}

void
mount_iterdrain(mount_t mp)
{
	mount_list_lock();
	while (mp->mnt_iterref) {
		msleep((caddr_t)&mp->mnt_iterref, &mnt_list_mtx_lock, PVFS, "mount_iterdrain", NULL);
	}
	/* mount iterations drained */
	mp->mnt_iterref = -1;
	mount_list_unlock();
}
void
mount_iterreset(mount_t mp)
{
	mount_list_lock();
	if (mp->mnt_iterref == -1) {
		mp->mnt_iterref = 0;
	}
	mount_list_unlock();
}

/* always called with  mount lock held */
int
mount_refdrain(mount_t mp)
{
	if (mp->mnt_lflag & MNT_LDRAIN) {
		panic("already in drain");
	}
	mp->mnt_lflag |= MNT_LDRAIN;

	while (mp->mnt_count) {
		msleep((caddr_t)&mp->mnt_lflag, &mp->mnt_mlock, PVFS, "mount_drain", NULL);
	}

	if (mp->mnt_vnodelist.tqh_first != NULL) {
		panic("mount_refdrain: dangling vnode");
	}

	mp->mnt_lflag &= ~MNT_LDRAIN;

	return 0;
}

/* Tags the mount point as not supportine extended readdir for NFS exports */
void
mount_set_noreaddirext(mount_t mp)
{
	mount_lock(mp);
	mp->mnt_kern_flag |= MNTK_DENY_READDIREXT;
	mount_unlock(mp);
}

/*
 * Mark a mount point as busy. Used to synchronize access and to delay
 * unmounting.
 */
int
vfs_busy(mount_t mp, int flags)
{
restart:
	if (mp->mnt_lflag & MNT_LDEAD) {
		return ENOENT;
	}

	mount_lock(mp);

	if (mp->mnt_lflag & MNT_LUNMOUNT) {
		if (flags & LK_NOWAIT || mp->mnt_lflag & MNT_LDEAD) {
			mount_unlock(mp);
			return ENOENT;
		}

		/*
		 * 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.
		 */
		mp->mnt_lflag |= MNT_LWAIT;
		msleep((caddr_t)mp, &mp->mnt_mlock, (PVFS | PDROP), "vfsbusy", NULL);
		return ENOENT;
	}

	mount_unlock(mp);

	lck_rw_lock_shared(&mp->mnt_rwlock);

	/*
	 * Until we are granted the rwlock, it's possible for the mount point to
	 * change state, so re-evaluate before granting the vfs_busy.
	 */
	if (mp->mnt_lflag & (MNT_LDEAD | MNT_LUNMOUNT)) {
		lck_rw_done(&mp->mnt_rwlock);
		goto restart;
	}
	return 0;
}

/*
 * Free a busy filesystem.
 */
void
vfs_unbusy(mount_t mp)
{
	lck_rw_done(&mp->mnt_rwlock);
}



static void
vfs_rootmountfailed(mount_t mp)
{
	mount_list_lock();
	mp->mnt_vtable->vfc_refcount--;
	mount_list_unlock();

	vfs_unbusy(mp);

	if (nc_smr_enabled) {
		vfs_smr_synchronize();
	}

	mount_lock_destroy(mp);

#if CONFIG_MACF
	mac_mount_label_destroy(mp);
#endif

	zfree(mount_zone, mp);
}

/*
 * Lookup a filesystem type, and if found allocate and initialize
 * a mount structure for it.
 *
 * Devname is usually updated by mount(8) after booting.
 */
static mount_t
vfs_rootmountalloc_internal(struct vfstable *vfsp, const char *devname)
{
	mount_t mp;

	mp = zalloc_flags(mount_zone, Z_WAITOK | Z_ZERO);
	/* Initialize the default IO constraints */
	mp->mnt_maxreadcnt = mp->mnt_maxwritecnt = MAXPHYS;
	mp->mnt_segreadcnt = mp->mnt_segwritecnt = 32;
	mp->mnt_maxsegreadsize = mp->mnt_maxreadcnt;
	mp->mnt_maxsegwritesize = mp->mnt_maxwritecnt;
	mp->mnt_devblocksize = DEV_BSIZE;
	mp->mnt_alignmentmask = PAGE_MASK;
	mp->mnt_ioqueue_depth = MNT_DEFAULT_IOQUEUE_DEPTH;
	mp->mnt_ioscale = 1;
	mp->mnt_ioflags = 0;
	mp->mnt_realrootvp = NULLVP;
	mp->mnt_authcache_ttl = CACHED_LOOKUP_RIGHT_TTL;
	mp->mnt_throttle_mask = LOWPRI_MAX_NUM_DEV - 1;
	mp->mnt_devbsdunit = 0;

	mount_lock_init(mp);
	(void)vfs_busy(mp, LK_NOWAIT);

	TAILQ_INIT(&mp->mnt_vnodelist);
	TAILQ_INIT(&mp->mnt_workerqueue);
	TAILQ_INIT(&mp->mnt_newvnodes);

	mp->mnt_vtable = vfsp;
	mp->mnt_op = vfsp->vfc_vfsops;
	mp->mnt_flag = MNT_RDONLY | MNT_ROOTFS;
	mp->mnt_vnodecovered = NULLVP;
	//mp->mnt_stat.f_type = vfsp->vfc_typenum;
	mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;

	mount_list_lock();
	vfsp->vfc_refcount++;
	mount_list_unlock();

	strlcpy(mp->mnt_vfsstat.f_fstypename, vfsp->vfc_name, MFSTYPENAMELEN);
	mp->mnt_vfsstat.f_mntonname[0] = '/';
	/* XXX const poisoning layering violation */
	(void) copystr((const void *)devname, mp->mnt_vfsstat.f_mntfromname, MAXPATHLEN - 1, NULL);

#if CONFIG_MACF
	mac_mount_label_init(mp);
	mac_mount_label_associate(vfs_context_kernel(), mp);
#endif
	return mp;
}

errno_t
vfs_rootmountalloc(const char *fstypename, const char *devname, mount_t *mpp)
{
	struct vfstable *vfsp;

	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
		if (!strncmp(vfsp->vfc_name, fstypename,
		    sizeof(vfsp->vfc_name))) {
			break;
		}
	}
	if (vfsp == NULL) {
		return ENODEV;
	}

	*mpp = vfs_rootmountalloc_internal(vfsp, devname);

	if (*mpp) {
		return 0;
	}

	return ENOMEM;
}

#define DBG_MOUNTROOT (FSDBG_CODE(DBG_MOUNT, 0))

/*
 * Find an appropriate filesystem to use for the root. If a filesystem
 * has not been preselected, walk through the list of known filesystems
 * trying those that have mountroot routines, and try them until one
 * works or we have tried them all.
 */
extern int (*mountroot)(void);

int
vfs_mountroot(void)
{
#if CONFIG_MACF
	struct vnode *vp;
#endif
	struct vfstable *vfsp;
	vfs_context_t ctx = vfs_context_kernel();
	struct vfs_attr vfsattr;
	int     error;
	mount_t mp;
	vnode_t bdevvp_rootvp;

	/*
	 * Reset any prior "unmounting everything" state.  This handles the
	 * situation where mount root and then unmountall and re-mountroot
	 * a new image (see bsd/kern/imageboot.c).
	 */
	vfs_unmountall_started = vfs_unmountall_finished = 0;
	OSMemoryBarrier();

	KDBG_RELEASE(DBG_MOUNTROOT | DBG_FUNC_START);
	if (mountroot != NULL) {
		/*
		 * used for netboot which follows a different set of rules
		 */
		error = (*mountroot)();

		KDBG_RELEASE(DBG_MOUNTROOT | DBG_FUNC_END, error, 0);
		return error;
	}
	if ((error = bdevvp(rootdev, &rootvp))) {
		printf("vfs_mountroot: can't setup bdevvp\n");

		KDBG_RELEASE(DBG_MOUNTROOT | DBG_FUNC_END, error, 1);
		return error;
	}
	/*
	 * 4951998 - code we call in vfc_mountroot may replace rootvp
	 * so keep a local copy for some house keeping.
	 */
	bdevvp_rootvp = rootvp;

	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
		if (vfsp->vfc_mountroot == NULL
		    && !ISSET(vfsp->vfc_vfsflags, VFC_VFSCANMOUNTROOT)) {
			continue;
		}

		mp = vfs_rootmountalloc_internal(vfsp, "root_device");
		mp->mnt_devvp = rootvp;

		if (vfsp->vfc_mountroot) {
			error = (*vfsp->vfc_mountroot)(mp, rootvp, ctx);
		} else {
			error = VFS_MOUNT(mp, rootvp, 0, ctx);
		}

		if (!error) {
			if (bdevvp_rootvp != rootvp) {
				/*
				 * rootvp changed...
				 *   bump the iocount and fix up mnt_devvp for the
				 *   new rootvp (it will already have a usecount taken)...
				 *   drop the iocount and the usecount on the orignal
				 *   since we are no longer going to use it...
				 */
				vnode_getwithref(rootvp);
				mp->mnt_devvp = rootvp;

				vnode_rele(bdevvp_rootvp);
				vnode_put(bdevvp_rootvp);
			}
			mp->mnt_devvp->v_specflags |= SI_MOUNTEDON;

			vfs_unbusy(mp);

			mount_list_add(mp);

			/*
			 *   cache the IO attributes for the underlying physical media...
			 *   an error return indicates the underlying driver doesn't
			 *   support all the queries necessary... however, reasonable
			 *   defaults will have been set, so no reason to bail or care
			 */
			vfs_init_io_attributes(rootvp, mp);

			if (mp->mnt_ioflags & MNT_IOFLAGS_FUSION_DRIVE) {
				root_is_CF_drive = TRUE;
			}

			/*
			 * Shadow the VFC_VFSNATIVEXATTR flag to MNTK_EXTENDED_ATTRS.
			 */
			if (mp->mnt_vtable->vfc_vfsflags & VFC_VFSNATIVEXATTR) {
				mp->mnt_kern_flag |= MNTK_EXTENDED_ATTRS;
			}
			if (mp->mnt_vtable->vfc_vfsflags & VFC_VFSPREFLIGHT) {
				mp->mnt_kern_flag |= MNTK_UNMOUNT_PREFLIGHT;
			}

#if defined(XNU_TARGET_OS_OSX)
			uint32_t speed;

			if (MNTK_VIRTUALDEV & mp->mnt_kern_flag) {
				speed = 128;
			} else if (disk_conditioner_mount_is_ssd(mp)) {
				speed = 7 * 256;
			} else {
				speed = 256;
			}
			vc_progress_setdiskspeed(speed);
#endif /* XNU_TARGET_OS_OSX */
			/*
			 * Probe root file system for additional features.
			 */
			(void)VFS_START(mp, 0, ctx);

			VFSATTR_INIT(&vfsattr);
			VFSATTR_WANTED(&vfsattr, f_capabilities);
			if (vfs_getattr(mp, &vfsattr, ctx) == 0 &&
			    VFSATTR_IS_SUPPORTED(&vfsattr, f_capabilities)) {
				if ((vfsattr.f_capabilities.capabilities[VOL_CAPABILITIES_INTERFACES] & VOL_CAP_INT_EXTENDED_ATTR) &&
				    (vfsattr.f_capabilities.valid[VOL_CAPABILITIES_INTERFACES] & VOL_CAP_INT_EXTENDED_ATTR)) {
					mp->mnt_kern_flag |= MNTK_EXTENDED_ATTRS;
				}
#if NAMEDSTREAMS
				if ((vfsattr.f_capabilities.capabilities[VOL_CAPABILITIES_INTERFACES] & VOL_CAP_INT_NAMEDSTREAMS) &&
				    (vfsattr.f_capabilities.valid[VOL_CAPABILITIES_INTERFACES] & VOL_CAP_INT_NAMEDSTREAMS)) {
					mp->mnt_kern_flag |= MNTK_NAMED_STREAMS;
				}
#endif
				if ((vfsattr.f_capabilities.capabilities[VOL_CAPABILITIES_FORMAT] & VOL_CAP_FMT_PATH_FROM_ID) &&
				    (vfsattr.f_capabilities.valid[VOL_CAPABILITIES_FORMAT] & VOL_CAP_FMT_PATH_FROM_ID)) {
					mp->mnt_kern_flag |= MNTK_PATH_FROM_ID;
				}

				if ((vfsattr.f_capabilities.capabilities[VOL_CAPABILITIES_FORMAT] & VOL_CAP_FMT_DIR_HARDLINKS) &&
				    (vfsattr.f_capabilities.valid[VOL_CAPABILITIES_FORMAT] & VOL_CAP_FMT_DIR_HARDLINKS)) {
					mp->mnt_kern_flag |= MNTK_DIR_HARDLINKS;
				}
			}

			/*
			 * get rid of iocount reference returned
			 * by bdevvp (or picked up by us on the substitued
			 * rootvp)... it (or we) will have also taken
			 * a usecount reference which we want to keep
			 */
			vnode_put(rootvp);

#if CONFIG_MACF
			if ((vfs_flags(mp) & MNT_MULTILABEL) == 0) {
				KDBG_RELEASE(DBG_MOUNTROOT | DBG_FUNC_END, 0, 2);
				return 0;
			}

			error = VFS_ROOT(mp, &vp, ctx);
			if (error) {
				printf("%s() VFS_ROOT() returned %d\n",
				    __func__, error);
				dounmount(mp, MNT_FORCE, 0, ctx);
				goto fail;
			}
			error = vnode_label(mp, NULL, vp, NULL, 0, ctx);
			/*
			 * get rid of reference provided by VFS_ROOT
			 */
			vnode_put(vp);

			if (error) {
				printf("%s() vnode_label() returned %d\n",
				    __func__, error);
				dounmount(mp, MNT_FORCE, 0, ctx);
				goto fail;
			}
#endif
			KDBG_RELEASE(DBG_MOUNTROOT | DBG_FUNC_END, 0, 3);
			return 0;
		}
		vfs_rootmountfailed(mp);
#if CONFIG_MACF
fail:
#endif
		if (error != EINVAL) {
			printf("%s_mountroot failed: %d\n", vfsp->vfc_name, error);
		}
	}
	KDBG_RELEASE(DBG_MOUNTROOT | DBG_FUNC_END, error ? error : ENODEV, 4);
	return ENODEV;
}

static int
cache_purge_callback(mount_t mp, __unused void * arg)
{
	cache_purgevfs(mp);
	return VFS_RETURNED;
}

extern lck_rw_t rootvnode_rw_lock;
extern void set_rootvnode(vnode_t);


static int
mntonname_fixup_callback(mount_t mp, __unused void *arg)
{
	int error = 0;

	if ((strncmp(&mp->mnt_vfsstat.f_mntonname[0], "/", sizeof("/")) == 0) ||
	    (strncmp(&mp->mnt_vfsstat.f_mntonname[0], "/dev", sizeof("/dev")) == 0)) {
		return 0;
	}

	if ((error = vfs_busy(mp, LK_NOWAIT))) {
		printf("vfs_busy failed with %d for %s\n", error, mp->mnt_vfsstat.f_mntonname);
		return -1;
	}

	size_t pathlen = MAXPATHLEN;
	if ((error = vn_getpath_ext(mp->mnt_vnodecovered, NULL, mp->mnt_vfsstat.f_mntonname, &pathlen, VN_GETPATH_FSENTER))) {
		printf("vn_getpath_ext failed with %d for mnt_vnodecovered of %s\n", error, mp->mnt_vfsstat.f_mntonname);
	}

	vfs_unbusy(mp);

	return error;
}

static int
clear_mntk_backs_root_callback(mount_t mp, __unused void *arg)
{
	lck_rw_lock_exclusive(&mp->mnt_rwlock);
	mp->mnt_kern_flag &= ~MNTK_BACKS_ROOT;
	lck_rw_done(&mp->mnt_rwlock);
	return VFS_RETURNED;
}

static int
verify_incoming_rootfs(vnode_t *incoming_rootvnodep, vfs_context_t ctx,
    vfs_switch_root_flags_t flags)
{
	mount_t mp;
	vnode_t tdp;
	vnode_t incoming_rootvnode_with_iocount = *incoming_rootvnodep;
	vnode_t incoming_rootvnode_with_usecount = NULLVP;
	int error = 0;

	if (vnode_vtype(incoming_rootvnode_with_iocount) != VDIR) {
		printf("Incoming rootfs path not a directory\n");
		error = ENOTDIR;
		goto done;
	}

	/*
	 * Before we call VFS_ROOT, we have to let go of the iocount already
	 * acquired, but before doing that get a usecount.
	 */
	vnode_ref_ext(incoming_rootvnode_with_iocount, 0, VNODE_REF_FORCE);
	incoming_rootvnode_with_usecount = incoming_rootvnode_with_iocount;
	vnode_lock_spin(incoming_rootvnode_with_usecount);
	if ((mp = incoming_rootvnode_with_usecount->v_mount)) {
		mp->mnt_crossref++;
		vnode_unlock(incoming_rootvnode_with_usecount);
	} else {
		vnode_unlock(incoming_rootvnode_with_usecount);
		printf("Incoming rootfs root vnode does not have associated mount\n");
		error = ENOTDIR;
		goto done;
	}

	if (vfs_busy(mp, LK_NOWAIT)) {
		printf("Incoming rootfs root vnode mount is busy\n");
		error = ENOENT;
		goto out;
	}

	vnode_put(incoming_rootvnode_with_iocount);
	incoming_rootvnode_with_iocount = NULLVP;

	error = VFS_ROOT(mp, &tdp, ctx);

	if (error) {
		printf("Could not get rootvnode of incoming rootfs\n");
	} else if (tdp != incoming_rootvnode_with_usecount) {
		vnode_put(tdp);
		tdp = NULLVP;
		printf("Incoming rootfs root vnode mount is is not a mountpoint\n");
		error = EINVAL;
		goto out_busy;
	} else {
		incoming_rootvnode_with_iocount = tdp;
		tdp = NULLVP;
	}

	if ((flags & VFSSR_VIRTUALDEV_PROHIBITED) != 0) {
		if (mp->mnt_kern_flag & MNTK_VIRTUALDEV) {
			error = ENODEV;
		}
		if (error) {
			printf("Incoming rootfs is backed by a virtual device; cannot switch to it");
			goto out_busy;
		}
	}

out_busy:
	vfs_unbusy(mp);

out:
	vnode_lock(incoming_rootvnode_with_usecount);
	mp->mnt_crossref--;
	if (mp->mnt_crossref < 0) {
		panic("mount cross refs -ve");
	}
	vnode_unlock(incoming_rootvnode_with_usecount);

done:
	if (incoming_rootvnode_with_usecount) {
		vnode_rele(incoming_rootvnode_with_usecount);
		incoming_rootvnode_with_usecount = NULLVP;
	}

	if (error && incoming_rootvnode_with_iocount) {
		vnode_put(incoming_rootvnode_with_iocount);
		incoming_rootvnode_with_iocount = NULLVP;
	}

	*incoming_rootvnodep = incoming_rootvnode_with_iocount;
	return error;
}

/*
 * vfs_switch_root()
 *
 * Move the current root volume, and put a different volume at the root.
 *
 * incoming_vol_old_path: This is the path where the incoming root volume
 *	is mounted when this function begins.
 * outgoing_vol_new_path: This is the path where the outgoing root volume
 *	will be mounted when this function (successfully) ends.
 *	Note: Do not use a leading slash.
 *
 * Volumes mounted at several fixed points (including /dev) will be preserved
 * at the same absolute path. That means they will move within the folder
 * hierarchy during the pivot operation. For example, /dev before the pivot
 * will be at /dev after the pivot.
 *
 * If any filesystem has MNTK_BACKS_ROOT set, it will be cleared. If the
 * incoming root volume is actually a disk image backed by some other
 * filesystem, it is the caller's responsibility to re-set MNTK_BACKS_ROOT
 * as appropriate.
 */
int
vfs_switch_root(const char *incoming_vol_old_path,
    const char *outgoing_vol_new_path,
    vfs_switch_root_flags_t flags)
{
	// grumble grumble
#define countof(x) (sizeof(x) / sizeof(x[0]))

	struct preserved_mount {
		vnode_t pm_rootvnode;
		mount_t pm_mount;
		vnode_t pm_new_covered_vp;
		vnode_t pm_old_covered_vp;
		const char *pm_path;
	};

	vfs_context_t ctx = vfs_context_kernel();
	vnode_t incoming_rootvnode = NULLVP;
	vnode_t outgoing_vol_new_covered_vp = NULLVP;
	vnode_t incoming_vol_old_covered_vp = NULLVP;
	mount_t outgoing = NULL;
	mount_t incoming = NULL;

	struct preserved_mount devfs = { NULLVP, NULL, NULLVP, NULLVP, "dev" };
	struct preserved_mount preboot = { NULLVP, NULL, NULLVP, NULLVP, "System/Volumes/Preboot" };
	struct preserved_mount recovery = { NULLVP, NULL, NULLVP, NULLVP, "System/Volumes/Recovery" };
	struct preserved_mount vm = { NULLVP, NULL, NULLVP, NULLVP, "System/Volumes/VM" };
	struct preserved_mount update = { NULLVP, NULL, NULLVP, NULLVP, "System/Volumes/Update" };
	struct preserved_mount iscPreboot = { NULLVP, NULL, NULLVP, NULLVP, "System/Volumes/iSCPreboot" };
	struct preserved_mount hardware = { NULLVP, NULL, NULLVP, NULLVP, "System/Volumes/Hardware" };
	struct preserved_mount xarts = { NULLVP, NULL, NULLVP, NULLVP, "System/Volumes/xarts" };
	struct preserved_mount factorylogs = { NULLVP, NULL, NULLVP, NULLVP, "FactoryLogs" };
	struct preserved_mount idiags = { NULLVP, NULL, NULLVP, NULLVP, "System/Volumes/Diags" };

	struct preserved_mount *preserved[10];
	preserved[0] = &devfs;
	preserved[1] = &preboot;
	preserved[2] = &recovery;
	preserved[3] = &vm;
	preserved[4] = &update;
	preserved[5] = &iscPreboot;
	preserved[6] = &hardware;
	preserved[7] = &xarts;
	preserved[8] = &factorylogs;
	preserved[9] = &idiags;

	int error;

	printf("%s : shuffling mount points : %s <-> / <-> %s\n", __FUNCTION__, incoming_vol_old_path, outgoing_vol_new_path);

	if (outgoing_vol_new_path[0] == '/') {
		// I should have written this to be more helpful and just advance the pointer forward past the slash
		printf("Do not use a leading slash in outgoing_vol_new_path\n");
		return EINVAL;
	}

	// Set incoming_rootvnode.
	// Find the vnode representing the mountpoint of the new root
	// filesystem. That will be the new root directory.
	error = vnode_lookup(incoming_vol_old_path, 0, &incoming_rootvnode, ctx);
	if (error) {
		printf("Incoming rootfs root vnode not found\n");
		error = ENOENT;
		goto done;
	}

	/*
	 * This function drops the icoount and sets the vnode to NULL on error.
	 */
	error = verify_incoming_rootfs(&incoming_rootvnode, ctx, flags);
	if (error) {
		goto done;
	}

	/*
	 * Set outgoing_vol_new_covered_vp.
	 * Find the vnode representing the future mountpoint of the old
	 * root filesystem, inside the directory incoming_rootvnode.
	 * Right now it's at "/incoming_vol_old_path/outgoing_vol_new_path".
	 * soon it will become "/oldrootfs_path_after", which will be covered.
	 */
	error = vnode_lookupat(outgoing_vol_new_path, 0, &outgoing_vol_new_covered_vp, ctx, incoming_rootvnode);
	if (error) {
		printf("Outgoing rootfs path not found, abandoning / switch, error = %d\n", error);
		error = ENOENT;
		goto done;
	}
	if (vnode_vtype(outgoing_vol_new_covered_vp) != VDIR) {
		printf("Outgoing rootfs path is not a directory, abandoning / switch\n");
		error = ENOTDIR;
		goto done;
	}

	/*
	 * Find the preserved mounts - see if they are mounted. Get their root
	 * vnode if they are. If they aren't, leave rootvnode NULL which will
	 * be the signal to ignore this mount later on.
	 *
	 * Also get preserved mounts' new_covered_vp.
	 * Find the node representing the folder "dev" inside the directory newrootvnode.
	 * Right now it's at "/incoming_vol_old_path/dev".
	 * Soon it will become /dev, which will be covered by the devfs mountpoint.
	 */
	for (size_t i = 0; i < countof(preserved); i++) {
		struct preserved_mount *pmi = preserved[i];

		error = vnode_lookupat(pmi->pm_path, 0, &pmi->pm_rootvnode, ctx, rootvnode);
		if (error) {
			printf("skipping preserved mountpoint because not found or error: %d: %s\n", error, pmi->pm_path);
			// not fatal. try the next one in the list.
			continue;
		}
		bool is_mountpoint = false;
		vnode_lock_spin(pmi->pm_rootvnode);
		if ((pmi->pm_rootvnode->v_flag & VROOT) != 0) {
			is_mountpoint = true;
		}
		vnode_unlock(pmi->pm_rootvnode);
		if (!is_mountpoint) {
			printf("skipping preserved mountpoint because not a mountpoint: %s\n", pmi->pm_path);
			vnode_put(pmi->pm_rootvnode);
			pmi->pm_rootvnode = NULLVP;
			// not fatal. try the next one in the list.
			continue;
		}

		error = vnode_lookupat(pmi->pm_path, 0, &pmi->pm_new_covered_vp, ctx, incoming_rootvnode);
		if (error) {
			printf("preserved new mount directory not found or error: %d: %s\n", error, pmi->pm_path);
			error = ENOENT;
			goto done;
		}
		if (vnode_vtype(pmi->pm_new_covered_vp) != VDIR) {
			printf("preserved new mount directory not directory: %s\n", pmi->pm_path);
			error = ENOTDIR;
			goto done;
		}

		printf("will preserve mountpoint across pivot: /%s\n", pmi->pm_path);
	}

	/*
	 * --
	 * At this point, everything has been prepared and all error conditions
	 * have been checked. We check everything we can before this point;
	 * from now on we start making destructive changes, and we can't stop
	 * until we reach the end.
	 * ----
	 */

	/* this usecount is transferred to the mnt_vnodecovered */
	vnode_ref_ext(outgoing_vol_new_covered_vp, 0, VNODE_REF_FORCE);
	/* this usecount is transferred to set_rootvnode */
	vnode_ref_ext(incoming_rootvnode, 0, VNODE_REF_FORCE);


	for (size_t i = 0; i < countof(preserved); i++) {
		struct preserved_mount *pmi = preserved[i];
		if (pmi->pm_rootvnode == NULLVP) {
			continue;
		}

		/* this usecount is transferred to the mnt_vnodecovered */
		vnode_ref_ext(pmi->pm_new_covered_vp, 0, VNODE_REF_FORCE);

		/* The new_covered_vp is a mountpoint from now on. */
		vnode_lock_spin(pmi->pm_new_covered_vp);
		pmi->pm_new_covered_vp->v_flag |= VMOUNTEDHERE;
		vnode_unlock(pmi->pm_new_covered_vp);
	}

	/* The outgoing_vol_new_covered_vp is a mountpoint from now on. */
	vnode_lock_spin(outgoing_vol_new_covered_vp);
	outgoing_vol_new_covered_vp->v_flag |= VMOUNTEDHERE;
	vnode_unlock(outgoing_vol_new_covered_vp);


	/*
	 * Identify the mount_ts of the mounted filesystems that are being
	 * manipulated: outgoing rootfs, incoming rootfs, and the preserved
	 * mounts.
	 */
	outgoing = rootvnode->v_mount;
	incoming = incoming_rootvnode->v_mount;
	for (size_t i = 0; i < countof(preserved); i++) {
		struct preserved_mount *pmi = preserved[i];
		if (pmi->pm_rootvnode == NULLVP) {
			continue;
		}

		pmi->pm_mount = pmi->pm_rootvnode->v_mount;
	}

	lck_rw_lock_exclusive(&rootvnode_rw_lock);

	/* Setup incoming as the new rootfs */
	lck_rw_lock_exclusive(&incoming->mnt_rwlock);
	incoming_vol_old_covered_vp = incoming->mnt_vnodecovered;
	incoming->mnt_vnodecovered = NULLVP;
	strlcpy(incoming->mnt_vfsstat.f_mntonname, "/", MAXPATHLEN);
	incoming->mnt_flag |= MNT_ROOTFS;
	lck_rw_done(&incoming->mnt_rwlock);

	/*
	 * The preserved mountpoints will now be moved to
	 * incoming_rootnode/pm_path, and then by the end of the function,
	 * since incoming_rootnode is going to /, the preserved mounts
	 * will be end up back at /pm_path
	 */
	for (size_t i = 0; i < countof(preserved); i++) {
		struct preserved_mount *pmi = preserved[i];
		if (pmi->pm_rootvnode == NULLVP) {
			continue;
		}

		lck_rw_lock_exclusive(&pmi->pm_mount->mnt_rwlock);
		pmi->pm_old_covered_vp = pmi->pm_mount->mnt_vnodecovered;
		pmi->pm_mount->mnt_vnodecovered = pmi->pm_new_covered_vp;
		vnode_lock_spin(pmi->pm_new_covered_vp);
		pmi->pm_new_covered_vp->v_mountedhere = pmi->pm_mount;
		SET(pmi->pm_new_covered_vp->v_flag, VMOUNTEDHERE);
		vnode_unlock(pmi->pm_new_covered_vp);
		lck_rw_done(&pmi->pm_mount->mnt_rwlock);
	}

	/*
	 * The old root volume now covers outgoing_vol_new_covered_vp
	 * on the new root volume. Remove the ROOTFS marker.
	 * Now it is to be found at outgoing_vol_new_path
	 */
	lck_rw_lock_exclusive(&outgoing->mnt_rwlock);
	outgoing->mnt_vnodecovered = outgoing_vol_new_covered_vp;
	strlcpy(outgoing->mnt_vfsstat.f_mntonname, "/", MAXPATHLEN);
	strlcat(outgoing->mnt_vfsstat.f_mntonname, outgoing_vol_new_path, MAXPATHLEN);
	outgoing->mnt_flag &= ~MNT_ROOTFS;
	vnode_lock_spin(outgoing_vol_new_covered_vp);
	outgoing_vol_new_covered_vp->v_mountedhere = outgoing;
	vnode_unlock(outgoing_vol_new_covered_vp);
	lck_rw_done(&outgoing->mnt_rwlock);

	if (!(outgoing->mnt_kern_flag & MNTK_VIRTUALDEV) &&
	    (TAILQ_FIRST(&mountlist) == outgoing)) {
		vfs_setmntsystem(outgoing);
	}

	/*
	 * Finally, remove the mount_t linkage from the previously covered
	 * vnodes on the old root volume. These were incoming_vol_old_path,
	 * and each preserved mounts's "/pm_path". The filesystems previously
	 * mounted there have already been moved away.
	 */
	vnode_lock_spin(incoming_vol_old_covered_vp);
	incoming_vol_old_covered_vp->v_flag &= ~VMOUNT;
	incoming_vol_old_covered_vp->v_mountedhere = NULL;
	vnode_unlock(incoming_vol_old_covered_vp);

	for (size_t i = 0; i < countof(preserved); i++) {
		struct preserved_mount *pmi = preserved[i];
		if (pmi->pm_rootvnode == NULLVP) {
			continue;
		}

		vnode_lock_spin(pmi->pm_old_covered_vp);
		CLR(pmi->pm_old_covered_vp->v_flag, VMOUNTEDHERE);
		pmi->pm_old_covered_vp->v_mountedhere = NULL;
		vnode_unlock(pmi->pm_old_covered_vp);
	}

	/*
	 * Clear the name cache since many cached names are now invalid.
	 */
	vfs_iterate(0 /* flags */, cache_purge_callback, NULL);

	/*
	 * Actually change the rootvnode! And finally drop the lock that
	 * prevents concurrent vnode_lookups.
	 */
	set_rootvnode(incoming_rootvnode);
	lck_rw_unlock_exclusive(&rootvnode_rw_lock);

	if (!(incoming->mnt_kern_flag & MNTK_VIRTUALDEV) &&
	    !(outgoing->mnt_kern_flag & MNTK_VIRTUALDEV)) {
		/*
		 * Switch the order of mount structures in the mountlist, new root
		 * mount moves to the head of the list followed by /dev and the other
		 * preserved mounts then all the preexisting mounts (old rootfs + any
		 * others)
		 */
		mount_list_lock();
		for (size_t i = 0; i < countof(preserved); i++) {
			struct preserved_mount *pmi = preserved[i];
			if (pmi->pm_rootvnode == NULLVP) {
				continue;
			}

			TAILQ_REMOVE(&mountlist, pmi->pm_mount, mnt_list);
			TAILQ_INSERT_HEAD(&mountlist, pmi->pm_mount, mnt_list);
		}
		TAILQ_REMOVE(&mountlist, incoming, mnt_list);
		TAILQ_INSERT_HEAD(&mountlist, incoming, mnt_list);
		mount_list_unlock();
	}

	/*
	 * Fixups across all volumes
	 */
	vfs_iterate(0 /* flags */, mntonname_fixup_callback, NULL);
	vfs_iterate(0 /* flags */, clear_mntk_backs_root_callback, NULL);

	error = 0;

done:
	for (size_t i = 0; i < countof(preserved); i++) {
		struct preserved_mount *pmi = preserved[i];

		if (pmi->pm_rootvnode) {
			vnode_put(pmi->pm_rootvnode);
		}
		if (pmi->pm_new_covered_vp) {
			vnode_put(pmi->pm_new_covered_vp);
		}
		if (pmi->pm_old_covered_vp) {
			vnode_rele(pmi->pm_old_covered_vp);
		}
	}

	if (outgoing_vol_new_covered_vp) {
		vnode_put(outgoing_vol_new_covered_vp);
	}

	if (incoming_vol_old_covered_vp) {
		vnode_rele(incoming_vol_old_covered_vp);
	}

	if (incoming_rootvnode) {
		vnode_put(incoming_rootvnode);
	}

	printf("%s : done shuffling mount points with error: %d\n", __FUNCTION__, error);
	return error;
}

/*
 * Mount the Recovery volume of a container
 */
int
vfs_mount_recovery(void)
{
#if CONFIG_MOUNT_PREBOOTRECOVERY
	int error = 0;

	error = vnode_get(rootvnode);
	if (error) {
		/* root must be mounted first */
		printf("vnode_get(rootvnode) failed with error %d\n", error);
		return error;
	}

	char recoverypath[] = PLATFORM_RECOVERY_VOLUME_MOUNT_POINT; /* !const because of internal casting */

	/* Mount the recovery volume */
	printf("attempting kernel mount for recovery volume... \n");
	error = kernel_mount(rootvnode->v_mount->mnt_vfsstat.f_fstypename, NULLVP, NULLVP,
	    recoverypath, (rootvnode->v_mount), 0, 0, (KERNEL_MOUNT_RECOVERYVOL), vfs_context_kernel());

	if (error) {
		printf("Failed to mount recovery volume (%d)\n", error);
	} else {
		printf("mounted recovery volume\n");
	}

	vnode_put(rootvnode);
	return error;
#else
	return 0;
#endif
}

/*
 * Lookup a mount point by filesystem identifier.
 */

struct mount *
vfs_getvfs(fsid_t *fsid)
{
	return mount_list_lookupby_fsid(fsid, 0, 0);
}

static struct mount *
vfs_getvfs_locked(fsid_t *fsid)
{
	return mount_list_lookupby_fsid(fsid, 1, 0);
}

struct mount *
vfs_getvfs_with_vfsops(fsid_t *fsid, const struct vfsops * const ops)
{
	mount_t mp = mount_list_lookupby_fsid(fsid, 0, 0);

	if (mp != NULL && mp->mnt_op != ops) {
		mp = NULL;
	}
	return mp;
}

struct mount *
vfs_getvfs_by_mntonname(char *path)
{
	mount_t retmp = (mount_t)0;
	mount_t mp;

	mount_list_lock();
	TAILQ_FOREACH(mp, &mountlist, mnt_list) {
		if (!strncmp(mp->mnt_vfsstat.f_mntonname, path,
		    sizeof(mp->mnt_vfsstat.f_mntonname))) {
			retmp = mp;
			if (mount_iterref(retmp, 1)) {
				retmp = NULL;
			}
			goto out;
		}
	}
out:
	mount_list_unlock();
	return retmp;
}

/* generation number for creation of new fsids */
u_short mntid_gen = 0;
/*
 * Get a new unique fsid
 */
void
vfs_getnewfsid(struct mount *mp)
{
	fsid_t tfsid;
	int mtype;

	mount_list_lock();

	/* generate a new fsid */
	mtype = mp->mnt_vtable->vfc_typenum;
	if (++mntid_gen == 0) {
		mntid_gen++;
	}
	tfsid.val[0] = makedev(nblkdev + mtype, mntid_gen);
	tfsid.val[1] = mtype;

	while (vfs_getvfs_locked(&tfsid)) {
		if (++mntid_gen == 0) {
			mntid_gen++;
		}
		tfsid.val[0] = makedev(nblkdev + mtype, mntid_gen);
	}

	mp->mnt_vfsstat.f_fsid.val[0] = tfsid.val[0];
	mp->mnt_vfsstat.f_fsid.val[1] = tfsid.val[1];
	mount_list_unlock();
}

/*
 * Routines having to do with the management of the vnode table.
 */
extern int(**dead_vnodeop_p)(void *);
long numvnodes, freevnodes, deadvnodes, async_work_vnodes;
long busyvnodes = 0;
long deadvnodes_noreuse = 0;
int32_t freeablevnodes = 0;
uint64_t allocedvnodes = 0;
uint64_t deallocedvnodes = 0;


int async_work_timed_out = 0;
int async_work_handled = 0;
int dead_vnode_wanted = 0;
int dead_vnode_waited = 0;

/*
 * Move a vnode from one mount queue to another.
 */
static void
insmntque(vnode_t vp, mount_t mp)
{
	mount_t lmp;
	/*
	 * Delete from old mount point vnode list, if on one.
	 */
	if ((lmp = vp->v_mount) != NULL && lmp != dead_mountp) {
		if ((vp->v_lflag & VNAMED_MOUNT) == 0) {
			panic("insmntque: vp not in mount vnode list");
		}
		vp->v_lflag &= ~VNAMED_MOUNT;

		mount_lock_spin(lmp);

		mount_drop(lmp, 1);

		if (vp->v_mntvnodes.tqe_next == NULL) {
			if (TAILQ_LAST(&lmp->mnt_vnodelist, vnodelst) == vp) {
				TAILQ_REMOVE(&lmp->mnt_vnodelist, vp, v_mntvnodes);
			} else if (TAILQ_LAST(&lmp->mnt_newvnodes, vnodelst) == vp) {
				TAILQ_REMOVE(&lmp->mnt_newvnodes, vp, v_mntvnodes);
			} else if (TAILQ_LAST(&lmp->mnt_workerqueue, vnodelst) == vp) {
				TAILQ_REMOVE(&lmp->mnt_workerqueue, vp, v_mntvnodes);
			}
		} else {
			vp->v_mntvnodes.tqe_next->v_mntvnodes.tqe_prev = vp->v_mntvnodes.tqe_prev;
			*vp->v_mntvnodes.tqe_prev = vp->v_mntvnodes.tqe_next;
		}
		vp->v_mntvnodes.tqe_next = NULL;
		vp->v_mntvnodes.tqe_prev = NULL;
		mount_unlock(lmp);
		vnode_drop(vp);
		return;
	}

	/*
	 * Insert into list of vnodes for the new mount point, if available.
	 */
	if ((vp->v_mount = mp) != NULL) {
		mount_lock_spin(mp);
		if ((vp->v_mntvnodes.tqe_next != 0) && (vp->v_mntvnodes.tqe_prev != 0)) {
			panic("vp already in mount list");
		}
		if (mp->mnt_lflag & MNT_LITER) {
			TAILQ_INSERT_HEAD(&mp->mnt_newvnodes, vp, v_mntvnodes);
		} else {
			TAILQ_INSERT_HEAD(&mp->mnt_vnodelist, vp, v_mntvnodes);
		}
		if (vp->v_lflag & VNAMED_MOUNT) {
			panic("insmntque: vp already in mount vnode list");
		}
		vnode_hold(vp);
		vp->v_lflag |= VNAMED_MOUNT;
		mount_ref(mp, 1);
		mount_unlock(mp);
	}
}


/*
 * Create a vnode for a block device.
 * Used for root filesystem, argdev, and swap areas.
 * Also used for memory file system special devices.
 */
int
bdevvp(dev_t dev, vnode_t *vpp)
{
	vnode_t nvp;
	int     error;
	struct vnode_fsparam vfsp;
	struct vfs_context context;

	if (dev == NODEV) {
		*vpp = NULLVP;
		return ENODEV;
	}

	context.vc_thread = current_thread();
	context.vc_ucred = FSCRED;

	vfsp.vnfs_mp = (struct mount *)0;
	vfsp.vnfs_vtype = VBLK;
	vfsp.vnfs_str = "bdevvp";
	vfsp.vnfs_dvp = NULL;
	vfsp.vnfs_fsnode = NULL;
	vfsp.vnfs_cnp = NULL;
	vfsp.vnfs_vops = spec_vnodeop_p;
	vfsp.vnfs_rdev = dev;
	vfsp.vnfs_filesize = 0;

	vfsp.vnfs_flags = VNFS_NOCACHE | VNFS_CANTCACHE;

	vfsp.vnfs_marksystem = 0;
	vfsp.vnfs_markroot = 0;

	if ((error = vnode_create(VNCREATE_FLAVOR, VCREATESIZE, &vfsp, &nvp))) {
		*vpp = NULLVP;
		return error;
	}
	vnode_lock_spin(nvp);
	nvp->v_flag |= VBDEVVP;
	nvp->v_tag = VT_NON;    /* set this to VT_NON so during aliasing it can be replaced */
	vnode_unlock(nvp);
	if ((error = vnode_ref(nvp))) {
		panic("bdevvp failed: vnode_ref");
		return error;
	}
	if ((error = VNOP_FSYNC(nvp, MNT_WAIT, &context))) {
		panic("bdevvp failed: fsync");
		return error;
	}
	if ((error = buf_invalidateblks(nvp, BUF_WRITE_DATA, 0, 0))) {
		panic("bdevvp failed: invalidateblks");
		return error;
	}

#if CONFIG_MACF
	/*
	 * XXXMAC: We can't put a MAC check here, the system will
	 * panic without this vnode.
	 */
#endif /* MAC */

	if ((error = VNOP_OPEN(nvp, FREAD, &context))) {
		panic("bdevvp failed: open");
		return error;
	}
	*vpp = nvp;

	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.
 */
static vnode_t
checkalias(struct vnode *nvp, dev_t nvp_rdev)
{
	struct vnode *vp;
	struct vnode **vpp;
	struct specinfo *sin = NULL;
	int vid = 0;

	vpp = &speclisth[SPECHASH(nvp_rdev)];
loop:
	SPECHASH_LOCK();

	for (vp = *vpp; vp; vp = vp->v_specnext) {
		if (nvp_rdev == vp->v_rdev && nvp->v_type == vp->v_type) {
			vid = vp->v_id;
			vnode_hold(vp);
			break;
		}
	}
	SPECHASH_UNLOCK();

	if (vp) {
found_alias:
		if (vnode_getwithvid(vp, vid)) {
			vnode_drop(vp);
			goto loop;
		}
		vnode_drop(vp);
		/*
		 * Termination state is checked in vnode_getwithvid
		 */
		vnode_lock(vp);

		/*
		 * Alias, but not in use, so flush it out.
		 */
		if ((vp->v_iocount == 1) && (vp->v_usecount == 0)) {
			vnode_hold(vp);
			vnode_reclaim_internal(vp, 1, 1, 0);
			vnode_put_locked(vp);
			vnode_drop_and_unlock(vp);
			goto loop;
		}
	}
	if (vp == NULL || vp->v_tag != VT_NON) {
		if (sin == NULL) {
			sin = zalloc_flags(specinfo_zone, Z_WAITOK | Z_ZERO);
		} else {
			bzero(sin, sizeof(struct specinfo));
		}

		nvp->v_specinfo = sin;
		nvp->v_rdev = nvp_rdev;
		nvp->v_specflags = 0;
		nvp->v_speclastr = -1;
		nvp->v_specinfo->si_opencount = 0;
		nvp->v_specinfo->si_initted = 0;
		nvp->v_specinfo->si_throttleable = 0;
		nvp->v_specinfo->si_devbsdunit = LOWPRI_MAX_NUM_DEV;

		SPECHASH_LOCK();

		/* We dropped the lock, someone could have added */
		if (vp == NULLVP) {
			for (vp = *vpp; vp; vp = vp->v_specnext) {
				if (nvp_rdev == vp->v_rdev && nvp->v_type == vp->v_type) {
					vid = vp->v_id;
					vnode_hold(vp);
					SPECHASH_UNLOCK();
					goto found_alias;
				}
			}
		}

		nvp->v_hashchain = vpp;
		nvp->v_specnext = *vpp;
		*vpp = nvp;

		if (vp != NULLVP) {
			nvp->v_specflags |= SI_ALIASED;
			vp->v_specflags |= SI_ALIASED;
			SPECHASH_UNLOCK();
			vnode_put_locked(vp);
			vnode_unlock(vp);
		} else {
			SPECHASH_UNLOCK();
		}

		return NULLVP;
	}

	if (sin) {
		zfree(specinfo_zone, sin);
	}

	if ((vp->v_flag & (VBDEVVP | VDEVFLUSH)) != 0) {
		return vp;
	}

	panic("checkalias with VT_NON vp that shouldn't: %p", vp);

	return vp;
}


/*
 * Get a reference on a particular vnode and lock it if requested.
 * If the vnode was on the inactive list, remove it from the list.
 * If the vnode was on the free list, remove it from the list and
 * move it to inactive list as needed.
 * The vnode lock bit is set if the vnode is being eliminated in
 * vgone. 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_internal(vnode_t vp, int vid, int vflags)
{
	int error = 0;

	vnode_lock_spin(vp);

	if ((vflags & VNODE_WRITEABLE) && (vp->v_writecount == 0)) {
		/*
		 * vnode to be returned only if it has writers opened
		 */
		error = EINVAL;
	} else {
		error = vnode_getiocount(vp, vid, vflags);
	}

	vnode_unlock(vp);

	return error;
}

/*
 * Returns:	0			Success
 *		ENOENT			No such file or directory [terminating]
 */
int
vnode_ref(vnode_t vp)
{
	return vnode_ref_ext(vp, 0, 0);
}

/*
 * Returns:	0			Success
 *		ENOENT			No such file or directory [terminating]
 */
int
vnode_ref_ext(vnode_t vp, int fmode, int flags)
{
	int     error = 0;

	vnode_lock_spin(vp);

	/*
	 * once all the current call sites have been fixed to insure they have
	 * taken an iocount, we can toughen this assert up and insist that the
	 * iocount is non-zero... a non-zero usecount doesn't insure correctness
	 */
	if (vp->v_iocount <= 0 && vp->v_usecount <= 0) {
		panic("vnode_ref_ext: vp %p has no valid reference %d, %d", vp, vp->v_iocount, vp->v_usecount);
	}

	/*
	 * if you are the owner of drain/termination, can acquire usecount
	 */
	if ((flags & VNODE_REF_FORCE) == 0) {
		if ((vp->v_lflag & (VL_DRAIN | VL_TERMINATE | VL_DEAD))) {
			if (vp->v_owner != current_thread()) {
				error = ENOENT;
				goto out;
			}
		}
	}

	/* Enable atomic ops on v_usecount without the vnode lock */
	os_atomic_inc(&vp->v_usecount, relaxed);

	if (fmode & FWRITE) {
		if (++vp->v_writecount <= 0) {
			panic("vnode_ref_ext: v_writecount");
		}
	}
	if (fmode & O_EVTONLY) {
		if (++vp->v_kusecount <= 0) {
			panic("vnode_ref_ext: v_kusecount");
		}
	}
	if (vp->v_flag & VRAGE) {
		struct  uthread *ut;

		ut = current_uthread();

		if (!(current_proc()->p_lflag & P_LRAGE_VNODES) &&
		    !(ut->uu_flag & UT_RAGE_VNODES)) {
			/*
			 * a 'normal' process accessed this vnode
			 * so make sure its no longer marked
			 * for rapid aging...  also, make sure
			 * it gets removed from the rage list...
			 * when v_usecount drops back to 0, it
			 * will be put back on the real free list
			 */
			vp->v_flag &= ~VRAGE;
			vp->v_references = 0;
			vnode_list_remove(vp);
		}
	}
	if (vp->v_usecount == 1 && vp->v_type == VREG && !(vp->v_flag & VSYSTEM)) {
		if (vp->v_ubcinfo) {
			vnode_lock_convert(vp);
			memory_object_mark_used(vp->v_ubcinfo->ui_control);
		}
	}
out:
	vnode_unlock(vp);

	return error;
}


boolean_t
vnode_on_reliable_media(vnode_t vp)
{
	mount_t mp = vp->v_mount;

	/*
	 * A NULL mountpoint would imply it's not attached to a any filesystem.
	 * This can only happen with a vnode created by bdevvp(). We'll consider
	 * those as not unreliable as the primary use of this function is determine
	 * which vnodes are to be handed off to the async cleaner thread for
	 * reclaim.
	 */
	if (!mp || (!(mp->mnt_kern_flag & MNTK_VIRTUALDEV) && (mp->mnt_flag & MNT_LOCAL))) {
		return TRUE;
	}

	return FALSE;
}

static void
vnode_async_list_add_locked(vnode_t vp)
{
	if (VONLIST(vp) || (vp->v_lflag & (VL_TERMINATE | VL_DEAD))) {
		panic("vnode_async_list_add: %p is in wrong state", vp);
	}

	TAILQ_INSERT_HEAD(&vnode_async_work_list, vp, v_freelist);
	vp->v_listflag |= VLIST_ASYNC_WORK;

	async_work_vnodes++;
	if (!(vp->v_listflag & VLIST_NO_REUSE)) {
		reusablevnodes++;
	}
	if (vp->v_flag & VCANDEALLOC) {
		os_atomic_dec(&busyvnodes, relaxed);
	}
}

static void
vnode_async_list_add(vnode_t vp)
{
	vnode_list_lock();

	if (VONLIST(vp)) {
		if (!(vp->v_listflag & VLIST_ASYNC_WORK)) {
			vnode_list_remove_locked(vp);
			vnode_async_list_add_locked(vp);
		}
	} else {
		vnode_async_list_add_locked(vp);
	}

	vnode_list_unlock();

	wakeup(&vnode_async_work_list);
}


/*
 * put the vnode on appropriate free list.
 * called with vnode LOCKED
 */
static void
vnode_list_add(vnode_t vp)
{
	boolean_t need_dead_wakeup = FALSE;
	bool no_busy_decrement = false;

#if DIAGNOSTIC
	lck_mtx_assert(&vp->v_lock, LCK_MTX_ASSERT_OWNED);
#endif

again:

	/*
	 * if it is already on a list or non zero references return
	 */
	if (VONLIST(vp) || (vp->v_usecount != 0) || (vp->v_iocount != 0) || (vp->v_lflag & VL_TERMINATE)) {
		return;
	}

	/*
	 * In vclean, we might have deferred ditching locked buffers
	 * because something was still referencing them (indicated by
	 * usecount).  We can ditch them now.
	 */
	if (ISSET(vp->v_lflag, VL_DEAD)
	    && (!LIST_EMPTY(&vp->v_cleanblkhd) || !LIST_EMPTY(&vp->v_dirtyblkhd))) {
		++vp->v_iocount;        // Probably not necessary, but harmless
#ifdef CONFIG_IOCOUNT_TRACE
		record_vp(vp, 1);
#endif
		vnode_unlock(vp);
		buf_invalidateblks(vp, BUF_INVALIDATE_LOCKED, 0, 0);
		vnode_lock(vp);
		vnode_dropiocount(vp);
		goto again;
	}

	vnode_list_lock();

	if (!(vp->v_lflag & VL_DEAD) && (vp->v_listflag & VLIST_NO_REUSE)) {
		if (!(vp->v_listflag & VLIST_ASYNC_WORK)) {
			vnode_async_list_add_locked(vp);
		}
		no_busy_decrement = true;
	} else if ((vp->v_flag & VRAGE) && !(vp->v_lflag & VL_DEAD)) {
		/*
		 * add the new guy to the appropriate end of the RAGE list
		 */
		if ((vp->v_flag & VAGE)) {
			TAILQ_INSERT_HEAD(&vnode_rage_list, vp, v_freelist);
		} else {
			TAILQ_INSERT_TAIL(&vnode_rage_list, vp, v_freelist);
		}

		vp->v_listflag |= VLIST_RAGE;
		ragevnodes++;
		reusablevnodes++;
		wakeup_laundry_thread();

		/*
		 * reset the timestamp for the last inserted vp on the RAGE
		 * queue to let new_vnode know that its not ok to start stealing
		 * from this list... as long as we're actively adding to this list
		 * we'll push out the vnodes we want to donate to the real free list
		 * once we stop pushing, we'll let some time elapse before we start
		 * stealing them in the new_vnode routine
		 */
		microuptime(&rage_tv);
	} else {
		/*
		 * if VL_DEAD, insert it at head of the dead list
		 * else insert at tail of LRU list or at head if VAGE is set
		 */
		if ((vp->v_lflag & VL_DEAD)) {
			if (vp->v_flag & VCANDEALLOC) {
				TAILQ_INSERT_TAIL(&vnode_dead_list, vp, v_freelist);
				if (vp->v_listflag & VLIST_NO_REUSE) {
					deadvnodes_noreuse++;
				}
			} else {
				TAILQ_INSERT_HEAD(&vnode_dead_list, vp, v_freelist);
			}
			vp->v_listflag |= VLIST_DEAD;
			deadvnodes++;

			if (dead_vnode_wanted) {
				dead_vnode_wanted--;
				need_dead_wakeup = TRUE;
			}
		} else if ((vp->v_flag & VAGE)) {
			TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
			vp->v_flag &= ~VAGE;
			freevnodes++;
			reusablevnodes++;
			wakeup_laundry_thread();
		} else {
			TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
			freevnodes++;
			reusablevnodes++;
			wakeup_laundry_thread();
		}
	}
	if ((vp->v_flag & VCANDEALLOC) && !no_busy_decrement) {
		os_atomic_dec(&busyvnodes, relaxed);
	}
	vnode_list_unlock();

	if (need_dead_wakeup == TRUE) {
		wakeup_one((caddr_t)&dead_vnode_wanted);
	}
}


/*
 * remove the vnode from appropriate free list.
 * called with vnode LOCKED and
 * the list lock held
 */
static void
vnode_list_remove_locked(vnode_t vp)
{
	if (VONLIST(vp)) {
		/*
		 * the v_listflag field is
		 * protected by the vnode_list_lock
		 */
		if (vp->v_listflag & VLIST_RAGE) {
			VREMRAGE("vnode_list_remove", vp);
		} else if (vp->v_listflag & VLIST_DEAD) {
			VREMDEAD("vnode_list_remove", vp);
			wakeup_laundry_thread();
		} else if (vp->v_listflag & VLIST_ASYNC_WORK) {
			VREMASYNC_WORK("vnode_list_remove", vp);
		} else {
			VREMFREE("vnode_list_remove", vp);
		}
		if (vp->v_flag & VCANDEALLOC) {
			os_atomic_inc(&busyvnodes, relaxed);
		}
	}
}


/*
 * remove the vnode from appropriate free list.
 * called with vnode LOCKED
 */
static void
vnode_list_remove(vnode_t vp)
{
#if DIAGNOSTIC
	lck_mtx_assert(&vp->v_lock, LCK_MTX_ASSERT_OWNED);
#endif
	/*
	 * we want to avoid taking the list lock
	 * in the case where we're not on the free
	 * list... this will be true for most
	 * directories and any currently in use files
	 *
	 * we're guaranteed that we can't go from
	 * the not-on-list state to the on-list
	 * state since we hold the vnode lock...
	 * all calls to vnode_list_add are done
	 * under the vnode lock... so we can
	 * check for that condition (the prevelant one)
	 * without taking the list lock
	 */
	if (VONLIST(vp)) {
		vnode_list_lock();
		/*
		 * however, we're not guaranteed that
		 * we won't go from the on-list state
		 * to the not-on-list state until we
		 * hold the vnode_list_lock... this
		 * is due to "new_vnode" removing vnodes
		 * from the free list uder the list_lock
		 * w/o the vnode lock... so we need to
		 * check again whether we're currently
		 * on the free list
		 */
		vnode_list_remove_locked(vp);

		vnode_list_unlock();
	}
}


void
vnode_rele(vnode_t vp)
{
	vnode_rele_internal(vp, 0, 0, 0);
}


void
vnode_rele_ext(vnode_t vp, int fmode, int dont_reenter)
{
	vnode_rele_internal(vp, fmode, dont_reenter, 0);
}


void
vnode_rele_internal(vnode_t vp, int fmode, int dont_reenter, int locked)
{
	int32_t old_usecount;

	if (!locked) {
		vnode_hold(vp);
		vnode_lock_spin(vp);
	}
#if DIAGNOSTIC
	else {
		lck_mtx_assert(&vp->v_lock, LCK_MTX_ASSERT_OWNED);
	}
#endif
	/* Enable atomic ops on v_usecount without the vnode lock */
	old_usecount = os_atomic_dec_orig(&vp->v_usecount, relaxed);
	if (old_usecount < 1) {
		/*
		 * Because we allow atomic ops on usecount (in lookup only, under
		 * specific conditions of already having a usecount) it is
		 * possible that when the vnode is examined, its usecount is
		 * different than what will be printed in this panic message.
		 */
		panic("vnode_rele_ext: vp %p usecount -ve : %d.  v_tag = %d, v_type = %d, v_flag = %x.",
		    vp, old_usecount - 1, vp->v_tag, vp->v_type, vp->v_flag);
	}

	if (fmode & FWRITE) {
		if (--vp->v_writecount < 0) {
			panic("vnode_rele_ext: vp %p writecount -ve : %d.  v_tag = %d, v_type = %d, v_flag = %x.", vp, vp->v_writecount, vp->v_tag, vp->v_type, vp->v_flag);
		}
	}
	if (fmode & O_EVTONLY) {
		if (--vp->v_kusecount < 0) {
			panic("vnode_rele_ext: vp %p kusecount -ve : %d.  v_tag = %d, v_type = %d, v_flag = %x.", vp, vp->v_kusecount, vp->v_tag, vp->v_type, vp->v_flag);
		}
	}
	if (vp->v_kusecount > vp->v_usecount) {
		panic("vnode_rele_ext: vp %p kusecount(%d) out of balance with usecount(%d).  v_tag = %d, v_type = %d, v_flag = %x.", vp, vp->v_kusecount, vp->v_usecount, vp->v_tag, vp->v_type, vp->v_flag);
	}

	if ((vp->v_iocount > 0) || (vp->v_usecount > 0)) {
		/*
		 * vnode is still busy... if we're the last
		 * usecount, mark for a future call to VNOP_INACTIVE
		 * when the iocount finally drops to 0
		 */
		if (vp->v_usecount == 0) {
			vp->v_lflag |= VL_NEEDINACTIVE;
			vp->v_flag  &= ~(VNOCACHE_DATA | VRAOFF | VOPENEVT);
		}
		goto done;
	}
	vp->v_flag  &= ~(VNOCACHE_DATA | VRAOFF | VOPENEVT);

	if (ISSET(vp->v_lflag, VL_TERMINATE | VL_DEAD) || dont_reenter) {
		/*
		 * vnode is being cleaned, or
		 * we've requested that we don't reenter
		 * the filesystem on this release...in
		 * the latter case, we'll mark the vnode aged
		 */
		if (dont_reenter) {
			if (!(vp->v_lflag & (VL_TERMINATE | VL_DEAD | VL_MARKTERM))) {
				vp->v_lflag |= VL_NEEDINACTIVE;

				if (vnode_on_reliable_media(vp) == FALSE || vp->v_flag & VISDIRTY) {
					vnode_async_list_add(vp);
					goto done;
				}
			}
			vp->v_flag |= VAGE;
		}
		vnode_list_add(vp);

		goto done;
	}
	/*
	 * at this point both the iocount and usecount
	 * are zero
	 * pick up an iocount so that we can call
	 * VNOP_INACTIVE with the vnode lock unheld
	 */
	vp->v_iocount++;
#ifdef CONFIG_IOCOUNT_TRACE
	record_vp(vp, 1);
#endif
	vp->v_lflag &= ~VL_NEEDINACTIVE;

	if (UBCINFOEXISTS(vp)) {
		ubc_cs_free_and_vnode_unlock(vp);
	} else {
		vnode_unlock(vp);
	}

	VNOP_INACTIVE(vp, vfs_context_current());

	vnode_lock_spin(vp);

	/*
	 * because we dropped the vnode lock to call VNOP_INACTIVE
	 * the state of the vnode may have changed... we may have
	 * picked up an iocount, usecount or the MARKTERM may have
	 * been set... we need to reevaluate the reference counts
	 * to determine if we can call vnode_reclaim_internal at
	 * this point... if the reference counts are up, we'll pick
	 * up the MARKTERM state when they get subsequently dropped
	 */
	if ((vp->v_iocount == 1) && (vp->v_usecount == 0) &&
	    ((vp->v_lflag & (VL_MARKTERM | VL_TERMINATE | VL_DEAD)) == VL_MARKTERM)) {
		struct  uthread *ut;

		ut = current_uthread();

		if (ut->uu_defer_reclaims) {
			vp->v_defer_reclaimlist = ut->uu_vreclaims;
			ut->uu_vreclaims = vp;
			goto done;
		}
		vnode_lock_convert(vp);
		vnode_reclaim_internal(vp, 1, 1, 0);
	}
	vnode_dropiocount(vp);
	vnode_list_add(vp);
done:
	if (vp->v_usecount == 0 && vp->v_type == VREG && !(vp->v_flag & VSYSTEM)) {
		if (vp->v_ubcinfo) {
			vnode_lock_convert(vp);
			memory_object_mark_unused(vp->v_ubcinfo->ui_control, (vp->v_flag & VRAGE) == VRAGE);
		}
	}
	if (!locked) {
		vnode_drop_and_unlock(vp);
	}
	return;
}

/*
 * Remove any vnodes in the vnode table belonging to mount point mp.
 *
 * If MNT_NOFORCE is 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 MNT_FORCE is specified, detach any active vnodes
 * that are found.
 */

int
vflush(struct mount *mp, struct vnode *skipvp, int flags)
{
	struct vnode *vp;
	int busy = 0;
	int reclaimed = 0;
	int retval;
	unsigned int vid;
	bool first_try = true;

	/*
	 * See comments in vnode_iterate() for the rationale for this lock
	 */
	mount_iterate_lock(mp);

	mount_lock(mp);
	vnode_iterate_setup(mp);
	/*
	 * On regular unmounts(not forced) do a
	 * quick check for vnodes to be in use. This
	 * preserves the caching of vnodes. automounter
	 * tries unmounting every so often to see whether
	 * it is still busy or not.
	 */
	if (((flags & FORCECLOSE) == 0) && ((mp->mnt_kern_flag & MNTK_UNMOUNT_PREFLIGHT) != 0)) {
		if (vnode_umount_preflight(mp, skipvp, flags)) {
			vnode_iterate_clear(mp);
			mount_unlock(mp);
			mount_iterate_unlock(mp);
			return EBUSY;
		}
	}
loop:
	/* If it returns 0 then there is nothing to do */
	retval = vnode_iterate_prepare(mp);

	if (retval == 0) {
		vnode_iterate_clear(mp);
		mount_unlock(mp);
		mount_iterate_unlock(mp);
		return retval;
	}

	/* iterate over all the vnodes */
	while (!TAILQ_EMPTY(&mp->mnt_workerqueue)) {
		vp = TAILQ_FIRST(&mp->mnt_workerqueue);
		TAILQ_REMOVE(&mp->mnt_workerqueue, vp, v_mntvnodes);
		TAILQ_INSERT_TAIL(&mp->mnt_vnodelist, vp, v_mntvnodes);

		if ((vp->v_mount != mp) || (vp == skipvp)) {
			continue;
		}
		vid = vp->v_id;
		mount_unlock(mp);

		vnode_lock_spin(vp);

		// If vnode is already terminating, wait for it...
		while (vp->v_id == vid && ISSET(vp->v_lflag, VL_TERMINATE)) {
			vp->v_lflag |= VL_TERMWANT;
			msleep(&vp->v_lflag, &vp->v_lock, PVFS, "vflush", NULL);
		}

		if ((vp->v_id != vid) || ISSET(vp->v_lflag, VL_DEAD)) {
			vnode_unlock(vp);
			mount_lock(mp);
			continue;
		}

		/*
		 * If requested, skip over vnodes marked VSYSTEM.
		 * Skip over all vnodes marked VNOFLUSH.
		 */
		if ((flags & SKIPSYSTEM) && ((vp->v_flag & VSYSTEM) ||
		    (vp->v_flag & VNOFLUSH))) {
			vnode_unlock(vp);
			mount_lock(mp);
			continue;
		}
		/*
		 * If requested, skip over vnodes marked VSWAP.
		 */
		if ((flags & SKIPSWAP) && (vp->v_flag & VSWAP)) {
			vnode_unlock(vp);
			mount_lock(mp);
			continue;
		}
		/*
		 * If requested, skip over vnodes marked VROOT.
		 */
		if ((flags & SKIPROOT) && (vp->v_flag & VROOT)) {
			vnode_unlock(vp);
			mount_lock(mp);
			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)) {
			vnode_unlock(vp);
			mount_lock(mp);
			continue;
		}
		/*
		 * If the real usecount is 0, all we need to do is clear
		 * out the vnode data structures and we are done.
		 */
		if (((vp->v_usecount == 0) ||
		    ((vp->v_usecount - vp->v_kusecount) == 0))) {
			vnode_lock_convert(vp);
			vnode_hold(vp);
			vp->v_iocount++;        /* so that drain waits for * other iocounts */
#ifdef CONFIG_IOCOUNT_TRACE
			record_vp(vp, 1);
#endif
			vnode_reclaim_internal(vp, 1, 1, 0);
			vnode_dropiocount(vp);
			vnode_list_add(vp);
			vnode_drop_and_unlock(vp);

			reclaimed++;
			mount_lock(mp);
			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) {
			vnode_lock_convert(vp);

			if (vp->v_type != VBLK && vp->v_type != VCHR) {
				vp->v_iocount++;        /* so that drain waits * for other iocounts */
				vnode_hold(vp);
#ifdef CONFIG_IOCOUNT_TRACE
				record_vp(vp, 1);
#endif
				vnode_abort_advlocks(vp);
				vnode_reclaim_internal(vp, 1, 1, 0);
				vnode_dropiocount(vp);
				vnode_list_add(vp);
				vnode_drop_and_unlock(vp);
			} else {
				vnode_hold(vp);
				vp->v_lflag |= VL_OPSCHANGE;
				vclean(vp, 0);
				vp->v_lflag &= ~VL_DEAD;
				vp->v_op = spec_vnodeop_p;
				vp->v_flag |= VDEVFLUSH;
				vnode_drop_and_unlock(vp);
				wakeup(&vp->v_lflag); /* chkvnlock is waitng for VL_DEAD to get unset */
			}
			mount_lock(mp);
			continue;
		}

		/* log vnodes blocking unforced unmounts */
		if (print_busy_vnodes && first_try && ((flags & FORCECLOSE) == 0)) {
			vprint("vflush - busy vnode", vp);
		}

		vnode_unlock(vp);
		mount_lock(mp);
		busy++;
	}

	/* At this point the worker queue is completed */
	if (busy && ((flags & FORCECLOSE) == 0) && reclaimed) {
		busy = 0;
		reclaimed = 0;
		(void)vnode_iterate_reloadq(mp);
		first_try = false;
		/* returned with mount lock held */
		goto loop;
	}

	/* if new vnodes were created in between retry the reclaim */
	if (vnode_iterate_reloadq(mp) != 0) {
		if (!(busy && ((flags & FORCECLOSE) == 0))) {
			first_try = false;
			goto loop;
		}
	}
	vnode_iterate_clear(mp);
	mount_unlock(mp);
	mount_iterate_unlock(mp);

	if (busy && ((flags & FORCECLOSE) == 0)) {
		return EBUSY;
	}
	return 0;
}

long num_recycledvnodes = 0;
/*
 * Disassociate the underlying file system from a vnode.
 * The vnode lock is held on entry.
 */
static void
vclean(vnode_t vp, int flags)
{
	vfs_context_t ctx = vfs_context_current();
	int active;
	int need_inactive;
	int already_terminating;
	int clflags = 0;
#if NAMEDSTREAMS
	int is_namedstream;
#endif

	/*
	 * 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.
	 */
	active = vp->v_usecount;

	/*
	 * just in case we missed sending a needed
	 * VNOP_INACTIVE, we'll do it now
	 */
	need_inactive = (vp->v_lflag & VL_NEEDINACTIVE);

	vp->v_lflag &= ~VL_NEEDINACTIVE;

	/*
	 * Prevent the vnode from being recycled or
	 * brought into use while we clean it out.
	 */
	already_terminating = (vp->v_lflag & VL_TERMINATE);

	vp->v_lflag |= VL_TERMINATE;

#if NAMEDSTREAMS
	is_namedstream = vnode_isnamedstream(vp);
#endif

	vnode_unlock(vp);

	OSAddAtomicLong(1, &num_recycledvnodes);

	if (flags & DOCLOSE) {
		clflags |= IO_NDELAY;
	}
	if (flags & REVOKEALL) {
		clflags |= IO_REVOKE;
	}

#if CONFIG_MACF
	if (vp->v_mount) {
		/*
		 * It is possible for bdevvp vnodes to not have a mount
		 * pointer. It's fine to let it get reclaimed without
		 * notifying.
		 */
		mac_vnode_notify_reclaim(vp);
	}
#endif

	if (active && (flags & DOCLOSE)) {
		VNOP_CLOSE(vp, clflags, ctx);
	}

	/*
	 * Clean out any buffers associated with the vnode.
	 */
	if (flags & DOCLOSE) {
		if (vp->v_tag == VT_NFS) {
			nfs_vinvalbuf(vp, V_SAVE, ctx, 0);
		} else {
			VNOP_FSYNC(vp, MNT_WAIT, ctx);

			/*
			 * If the vnode is still in use (by the journal for
			 * example) we don't want to invalidate locked buffers
			 * here.  In that case, either the journal will tidy them
			 * up, or we will deal with it when the usecount is
			 * finally released in vnode_rele_internal.
			 */
			buf_invalidateblks(vp, BUF_WRITE_DATA | (active ? 0 : BUF_INVALIDATE_LOCKED), 0, 0);
		}
		if (UBCINFOEXISTS(vp)) {
			/*
			 * Clean the pages in VM.
			 */
			(void)ubc_msync(vp, (off_t)0, ubc_getsize(vp), NULL, UBC_PUSHALL | UBC_INVALIDATE | UBC_SYNC);
		}
	}
	if (active || need_inactive) {
		VNOP_INACTIVE(vp, ctx);
	}

#if NAMEDSTREAMS
	if ((is_namedstream != 0) && (vp->v_parent != NULLVP)) {
		vnode_t pvp = vp->v_parent;

		/* Delete the shadow stream file before we reclaim its vnode */
		if (vnode_isshadow(vp)) {
			vnode_relenamedstream(pvp, vp);
		}

		/*
		 * No more streams associated with the parent.  We
		 * have a ref on it, so its identity is stable.
		 * If the parent is on an opaque volume, then we need to know
		 * whether it has associated named streams.
		 */
		if (vfs_authopaque(pvp->v_mount)) {
			vnode_lock_spin(pvp);
			pvp->v_lflag &= ~VL_HASSTREAMS;
			vnode_unlock(pvp);
		}
	}
#endif

	vm_object_destroy_reason_t reason = VM_OBJECT_DESTROY_RECLAIM;
	bool forced_unmount = vnode_mount(vp) != NULL && (vnode_mount(vp)->mnt_lflag & MNT_LFORCE) != 0;
	bool ungraft_heuristic = flags & REVOKEALL;
	bool unmount = vnode_mount(vp) != NULL && (vnode_mount(vp)->mnt_lflag & MNT_LUNMOUNT) != 0;
	if (forced_unmount) {
		reason = VM_OBJECT_DESTROY_FORCED_UNMOUNT;
	} else if (ungraft_heuristic) {
		reason = VM_OBJECT_DESTROY_UNGRAFT;
	} else if (unmount) {
		reason = VM_OBJECT_DESTROY_UNMOUNT;
	}

	/*
	 * Destroy ubc named reference
	 * cluster_release is done on this path
	 * along with dropping the reference on the ucred
	 * (and in the case of forced unmount of an mmap-ed file,
	 * the ubc reference on the vnode is dropped here too).
	 */
	ubc_destroy_named(vp, reason);

#if CONFIG_TRIGGERS
	/*
	 * cleanup trigger info from vnode (if any)
	 */
	if (vp->v_resolve) {
		vnode_resolver_detach(vp);
	}
#endif

#if CONFIG_IO_COMPRESSION_STATS
	if ((vp->io_compression_stats)) {
		vnode_iocs_record_and_free(vp);
	}
#endif /* CONFIG_IO_COMPRESSION_STATS */

	/*
	 * Reclaim the vnode.
	 */
	if (VNOP_RECLAIM(vp, ctx)) {
		panic("vclean: cannot reclaim");
	}

	// make sure the name & parent ptrs get cleaned out!
	vnode_update_identity(vp, NULLVP, NULL, 0, 0, VNODE_UPDATE_PARENT | VNODE_UPDATE_NAME | VNODE_UPDATE_PURGE | VNODE_UPDATE_PURGEFIRMLINK);

	vnode_lock(vp);

	/*
	 * Remove the vnode from any mount list it might be on.  It is not
	 * safe to do this any earlier because unmount needs to wait for
	 * any vnodes to terminate and it cannot do that if it cannot find
	 * them.
	 */
	insmntque(vp, (struct mount *)0);

	vp->v_lflag |= VL_DEAD;
	vp->v_mount = dead_mountp;
	vp->v_op = dead_vnodeop_p;
	vp->v_tag = VT_NON;
	vp->v_data = NULL;

	vp->v_flag &= ~VISDIRTY;

	if (already_terminating == 0) {
		vp->v_lflag &= ~VL_TERMINATE;
		/*
		 * Done with purge, notify sleepers of the grim news.
		 */
		if (vp->v_lflag & VL_TERMWANT) {
			vp->v_lflag &= ~VL_TERMWANT;
			wakeup(&vp->v_lflag);
		}
	}
}

/*
 * Eliminate all activity associated with  the requested vnode
 * and with all vnodes aliased to the requested vnode.
 */
int
#if DIAGNOSTIC
vn_revoke(vnode_t vp, int flags, __unused vfs_context_t a_context)
#else
vn_revoke(vnode_t vp, __unused int flags, __unused vfs_context_t a_context)
#endif
{
	struct vnode *vq;
	int vid;

#if DIAGNOSTIC
	if ((flags & REVOKEALL) == 0) {
		panic("vnop_revoke");
	}
#endif

	if (vnode_isaliased(vp)) {
		/*
		 * If a vgone (or vclean) is already in progress,
		 * return an immediate error
		 */
		if (vp->v_lflag & VL_TERMINATE) {
			return ENOENT;
		}

		/*
		 * Ensure that vp will not be vgone'd while we
		 * are eliminating its aliases.
		 */
		SPECHASH_LOCK();
		while ((vp->v_specflags & SI_ALIASED)) {
			for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
				if (vq->v_rdev != vp->v_rdev ||
				    vq->v_type != vp->v_type || vp == vq) {
					continue;
				}
				vid = vq->v_id;
				vnode_hold(vq);
				SPECHASH_UNLOCK();
				if (vnode_getwithvid(vq, vid)) {
					vq = vnode_drop(vq);
					SPECHASH_LOCK();
					break;
				}
				vnode_lock(vq);
				if (!(vq->v_lflag & VL_TERMINATE)) {
					vnode_reclaim_internal(vq, 1, 1, 0);
				}
				vnode_put_locked(vq);
				vq = vnode_drop_and_unlock(vq);
				SPECHASH_LOCK();
				break;
			}
		}
		SPECHASH_UNLOCK();
	}
	vnode_lock(vp);
	if (vp->v_lflag & VL_TERMINATE) {
		vnode_unlock(vp);
		return ENOENT;
	}
	vnode_reclaim_internal(vp, 1, 0, REVOKEALL);
	vnode_unlock(vp);

	return 0;
}

/*
 * Recycle an unused vnode to the front of the free list.
 * Release the passed interlock if the vnode will be recycled.
 */
int
vnode_recycle(struct vnode *vp)
{
	vnode_lock_spin(vp);

	if (vp->v_iocount || vp->v_usecount) {
		vp->v_lflag |= VL_MARKTERM;
		vnode_unlock(vp);
		return 0;
	}
	vnode_lock_convert(vp);
	vnode_hold(vp);
	vnode_reclaim_internal(vp, 1, 0, 0);

	vnode_drop_and_unlock(vp);

	return 1;
}

static int
vnode_reload(vnode_t vp)
{
	vnode_lock_spin(vp);

	if ((vp->v_iocount > 1) || vp->v_usecount) {
		vnode_unlock(vp);
		return 0;
	}
	if (vp->v_iocount <= 0) {
		panic("vnode_reload with no iocount %d", vp->v_iocount);
	}

	/* mark for release when iocount is dopped */
	vp->v_lflag |= VL_MARKTERM;
	vnode_unlock(vp);

	return 1;
}


static void
vgone(vnode_t vp, int flags)
{
	struct vnode *vq;
	struct vnode *vx;

	/*
	 * Clean out the filesystem specific data.
	 * vclean also takes care of removing the
	 * vnode from any mount list it might be on
	 */
	vclean(vp, flags | DOCLOSE);

	/*
	 * If special device, remove it from special device alias list
	 * if it is on one.
	 */
	if ((vp->v_type == VBLK || vp->v_type == VCHR) && vp->v_specinfo != 0) {
		SPECHASH_LOCK();
		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_specflags & SI_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_specflags &= ~SI_ALIASED;
			}
			vp->v_specflags &= ~SI_ALIASED;
		}
		SPECHASH_UNLOCK();
		{
			struct specinfo *tmp = vp->v_specinfo;
			vp->v_specinfo = NULL;
			zfree(specinfo_zone, tmp);
		}
	}
}

/*
 * internal helper function only!
 * vend an _iocounted_ vnode via output argument, or return an error if unable.
 */
static int
get_vp_from_dev(dev_t dev, enum vtype type, vnode_t *outvp)
{
	vnode_t vp;
	int vid;

loop:
	SPECHASH_LOCK();
	for (vp = speclisth[SPECHASH(dev)]; vp; vp = vp->v_specnext) {
		if (dev != vp->v_rdev || type != vp->v_type) {
			continue;
		}
		vid = vp->v_id;
		vnode_hold(vp);
		SPECHASH_UNLOCK();

		/* acquire iocount */
		if (vnode_getwithvid(vp, vid)) {
			vnode_drop(vp);
			goto loop;
		}
		vnode_drop(vp);

		/* Vend iocounted vnode */
		*outvp = vp;
		return 0;
	}

	/* vnode not found, error out */
	SPECHASH_UNLOCK();
	return ENOENT;
}



/*
 * Lookup a vnode by device number.
 */
int
check_mountedon(dev_t dev, enum vtype type, int *errorp)
{
	vnode_t vp = NULLVP;
	int rc = 0;

	rc = get_vp_from_dev(dev, type, &vp);
	if (rc) {
		/* if no vnode found, it cannot be mounted on */
		return 0;
	}

	/* otherwise, examine it */
	vnode_lock_spin(vp);
	/* note: exclude the iocount we JUST got (e.g. >1, not >0) */
	if ((vp->v_usecount > 0) || (vp->v_iocount > 1)) {
		vnode_unlock(vp);
		if ((*errorp = vfs_mountedon(vp)) != 0) {
			rc = 1;
		}
	} else {
		vnode_unlock(vp);
	}
	/* release iocount! */
	vnode_put(vp);

	return rc;
}

extern dev_t chrtoblk(dev_t d);

/*
 * Examine the supplied vnode's dev_t and find its counterpart
 * (e.g.  VCHR => VDEV) to compare against.
 */
static int
vnode_cmp_paired_dev(vnode_t vp, vnode_t bdev_vp, enum vtype in_type,
    enum vtype out_type)
{
	if (!vp || !bdev_vp) {
		return EINVAL;
	}
	/* Verify iocounts */
	if (vnode_iocount(vp) <= 0 ||
	    vnode_iocount(bdev_vp) <= 0) {
		return EINVAL;
	}

	/* check for basic matches */
	if (vnode_vtype(vp) != in_type) {
		return EINVAL;
	}
	if (vnode_vtype(bdev_vp) != out_type) {
		return EINVAL;
	}

	dev_t dev = vnode_specrdev(vp);
	dev_t blk_devt = vnode_specrdev(bdev_vp);

	if (in_type == VCHR) {
		if (out_type != VBLK) {
			return EINVAL;
		}
		dev_t bdev = chrtoblk(dev);
		if (bdev == NODEV) {
			return EINVAL;
		} else if (bdev == blk_devt) {
			return 0;
		}
		//fall through
	}
	/*
	 * else case:
	 *
	 * in_type == VBLK? => VCHR?
	 * not implemented...
	 * exercise to the reader: this can be built by
	 * taking the device's major, and iterating the `chrtoblktab`
	 * array to look for a value that matches.
	 */
	return EINVAL;
}
/*
 * Vnode compare: does the supplied vnode's CHR device, match the dev_t
 * of the accompanying `blk_vp` ?
 * NOTE: vnodes MUST be iocounted BEFORE calling this!
 */

int
vnode_cmp_chrtoblk(vnode_t vp, vnode_t blk_vp)
{
	return vnode_cmp_paired_dev(vp, blk_vp, VCHR, VBLK);
}



/*
 * Calculate the total number of references to a special device.
 */
int
vcount(vnode_t vp)
{
	vnode_t vq, vnext;
	int count;
	int vid;

	if (!vnode_isspec(vp)) {
		return vp->v_usecount - vp->v_kusecount;
	}

loop:
	if (!vnode_isaliased(vp)) {
		return vp->v_specinfo->si_opencount;
	}
	count = 0;

	SPECHASH_LOCK();
	/*
	 * Grab first vnode and its vid.
	 */
	vq = *vp->v_hashchain;
	if (vq) {
		vid = vq->v_id;
		vnode_hold(vq);
	} else {
		vid = 0;
	}
	SPECHASH_UNLOCK();

	while (vq) {
		/*
		 * Attempt to get the vnode outside the SPECHASH lock.
		 * Don't take iocount on 'vp' as iocount is already held by the caller.
		 */
		if ((vq != vp) && vnode_getwithvid(vq, vid)) {
			vnode_drop(vq);
			goto loop;
		}
		vnode_drop(vq);
		vnode_lock(vq);

		if (vq->v_rdev == vp->v_rdev && vq->v_type == vp->v_type) {
			if ((vq->v_usecount == 0) && (vq->v_iocount == 1) && vq != vp) {
				/*
				 * Alias, but not in use, so flush it out.
				 */
				vnode_hold(vq);
				vnode_reclaim_internal(vq, 1, 1, 0);
				vnode_put_locked(vq);
				vnode_drop_and_unlock(vq);
				goto loop;
			}
			count += vq->v_specinfo->si_opencount;
		}
		vnode_unlock(vq);

		SPECHASH_LOCK();
		/*
		 * must do this with the reference still held on 'vq'
		 * so that it can't be destroyed while we're poking
		 * through v_specnext
		 */
		vnext = vq->v_specnext;
		if (vnext) {
			vid = vnext->v_id;
			vnode_hold(vnext);
		} else {
			vid = 0;
		}
		SPECHASH_UNLOCK();

		if (vq != vp) {
			vnode_put(vq);
		}

		vq = vnext;
	}

	return count;
}

int     prtactive = 0;          /* 1 => print out reclaim of active vnodes */

/*
 * Print out a description of a vnode.
 */
static const char *typename[] =
{ "VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD" };

void
vprint(const char *label, struct vnode *vp)
{
	char sbuf[64];

	if (label != NULL) {
		printf("%s: ", label);
	}
	printf("name %s type %s, usecount %d, writecount %d\n",
	    vp->v_name, typename[vp->v_type],
	    vp->v_usecount, vp->v_writecount);
	sbuf[0] = '\0';
	if (vp->v_flag & VROOT) {
		strlcat(sbuf, "|VROOT", sizeof(sbuf));
	}
	if (vp->v_flag & VTEXT) {
		strlcat(sbuf, "|VTEXT", sizeof(sbuf));
	}
	if (vp->v_flag & VSYSTEM) {
		strlcat(sbuf, "|VSYSTEM", sizeof(sbuf));
	}
	if (vp->v_flag & VNOFLUSH) {
		strlcat(sbuf, "|VNOFLUSH", sizeof(sbuf));
	}
	if (vp->v_flag & VBWAIT) {
		strlcat(sbuf, "|VBWAIT", sizeof(sbuf));
	}
	if (vnode_isaliased(vp)) {
		strlcat(sbuf, "|VALIASED", sizeof(sbuf));
	}
	if (sbuf[0] != '\0') {
		printf("vnode flags (%s\n", &sbuf[1]);
	}
}

static int
vn_getpath_flags_to_buildpath_flags(int flags)
{
	int bpflags = (flags & VN_GETPATH_FSENTER) ? 0 : BUILDPATH_NO_FS_ENTER;

	if (flags && (flags != VN_GETPATH_FSENTER)) {
		if (flags & VN_GETPATH_NO_FIRMLINK) {
			bpflags |= BUILDPATH_NO_FIRMLINK;
		}
		if (flags & VN_GETPATH_VOLUME_RELATIVE) {
			bpflags |= (BUILDPATH_VOLUME_RELATIVE |
			    BUILDPATH_NO_FIRMLINK);
		}
		if (flags & VN_GETPATH_NO_PROCROOT) {
			bpflags |= BUILDPATH_NO_PROCROOT;
		}
		if (flags & VN_GETPATH_CHECK_MOVED) {
			bpflags |= BUILDPATH_CHECK_MOVED;
		}
	}

	return bpflags;
}

int
vn_getpath_ext_with_mntlen(struct vnode *vp, struct vnode *dvp, char *pathbuf,
    size_t *len, size_t *mntlen, int flags)
{
	int bpflags = vn_getpath_flags_to_buildpath_flags(flags);
	int local_len;
	int error;

	if (*len > INT_MAX) {
		return EINVAL;
	}

	local_len = *len;

	error = build_path_with_parent(vp, dvp, pathbuf, local_len, &local_len,
	    mntlen, bpflags, vfs_context_current());

	if (local_len >= 0 && local_len <= (int)*len) {
		*len = (size_t)local_len;
	}

	return error;
}

int
vn_getpath_ext(struct vnode *vp, struct vnode *dvp, char *pathbuf, size_t *len,
    int flags)
{
	return vn_getpath_ext_with_mntlen(vp, dvp, pathbuf, len, NULL, flags);
}

/*
 * Wrapper around vn_getpath_ext() that takes care of the int * <-> size_t *
 * conversion for the legacy KPIs.
 */
static int
vn_getpath_ext_int(struct vnode *vp, struct vnode *dvp, char *pathbuf,
    int *len, int flags)
{
	size_t slen = *len;
	int error;

	if (*len < 0) {
		return EINVAL;
	}

	error = vn_getpath_ext(vp, dvp, pathbuf, &slen, flags);

	if (slen <= INT_MAX) {
		*len = (int)slen;
	}

	return error;
}

int
vn_getpath(struct vnode *vp, char *pathbuf, int *len)
{
	return vn_getpath_ext_int(vp, NULL, pathbuf, len, 0);
}

int
vn_getpath_fsenter(struct vnode *vp, char *pathbuf, int *len)
{
	return vn_getpath_ext_int(vp, NULL, pathbuf, len, VN_GETPATH_FSENTER);
}

/*
 * vn_getpath_fsenter_with_parent will reenter the file system to fine the path of the
 * vnode.  It requires that there are IO counts on both the vnode and the directory vnode.
 *
 * vn_getpath_fsenter is called by MAC hooks to authorize operations for every thing, but
 * unlink, rmdir and rename. For these operation the MAC hook  calls vn_getpath. This presents
 * problems where if the path can not be found from the name cache, those operations can
 * erroneously fail with EPERM even though the call should succeed. When removing or moving
 * file system objects with operations such as unlink or rename, those operations need to
 * take IO counts on the target and containing directory. Calling vn_getpath_fsenter from a
 * MAC hook from these operations during forced unmount operations can lead to dead
 * lock. This happens when the operation starts, IO counts are taken on the containing
 * directories and targets. Before the MAC hook is called a forced unmount from another
 * thread takes place and blocks on the on going operation's directory vnode in vdrain.
 * After which, the MAC hook gets called and calls vn_getpath_fsenter.  vn_getpath_fsenter
 * is called with the understanding that there is an IO count on the target. If in
 * build_path the directory vnode is no longer in the cache, then the parent object id via
 * vnode_getattr from the target is obtain and used to call VFS_VGET to get the parent
 * vnode. The file system's VFS_VGET then looks up by inode in its hash and tries to get
 * an IO count. But VFS_VGET "sees" the directory vnode is in vdrain and can block
 * depending on which version and how it calls the vnode_get family of interfaces.
 *
 * N.B.  A reasonable interface to use is vnode_getwithvid. This interface was modified to
 * call vnode_getiocount with VNODE_DRAINO, so it will happily get an IO count and not
 * cause issues, but there is no guarantee that all or any file systems are doing that.
 *
 * vn_getpath_fsenter_with_parent can enter the file system safely since there is a known
 * IO count on the directory vnode by calling build_path_with_parent.
 */

int
vn_getpath_fsenter_with_parent(struct vnode *dvp, struct vnode *vp, char *pathbuf, int *len)
{
	return build_path_with_parent(vp, dvp, pathbuf, *len, len, NULL, 0, vfs_context_current());
}

int
vn_getpath_no_firmlink(struct vnode *vp, char *pathbuf, int *len)
{
	return vn_getpath_ext_int(vp, NULLVP, pathbuf, len,
	           VN_GETPATH_NO_FIRMLINK);
}

int
vn_getcdhash(struct vnode *vp, off_t offset, unsigned char *cdhash)
{
	return ubc_cs_getcdhash(vp, offset, cdhash);
}


static char *extension_table = NULL;
static int   nexts;
static int   max_ext_width;

static int
extension_cmp(const void *a, const void *b)
{
	return (int)(strlen((const char *)a) - strlen((const char *)b));
}


//
// This is the api LaunchServices uses to inform the kernel
// the list of package extensions to ignore.
//
// Internally we keep the list sorted by the length of the
// the extension (from longest to shortest).  We sort the
// list of extensions so that we can speed up our searches
// when comparing file names -- we only compare extensions
// that could possibly fit into the file name, not all of
// them (i.e. a short 8 character name can't have an 8
// character extension).
//
extern lck_mtx_t pkg_extensions_lck;

__private_extern__ int
set_package_extensions_table(user_addr_t data, int nentries, int maxwidth)
{
	char *new_exts, *old_exts;
	int old_nentries = 0, old_maxwidth = 0;
	int error;

	if (nentries <= 0 || nentries > 1024 || maxwidth <= 0 || maxwidth > 255) {
		return EINVAL;
	}


	// allocate one byte extra so we can guarantee null termination
	new_exts = kalloc_data((nentries * maxwidth) + 1, Z_WAITOK);
	if (new_exts == NULL) {
		return ENOMEM;
	}

	error = copyin(data, new_exts, nentries * maxwidth);
	if (error) {
		kfree_data(new_exts, (nentries * maxwidth) + 1);
		return error;
	}

	new_exts[(nentries * maxwidth)] = '\0'; // guarantee null termination of the block

	qsort(new_exts, nentries, maxwidth, extension_cmp);

	lck_mtx_lock(&pkg_extensions_lck);

	old_exts        = extension_table;
	old_nentries    = nexts;
	old_maxwidth    = max_ext_width;
	extension_table = new_exts;
	nexts           = nentries;
	max_ext_width   = maxwidth;

	lck_mtx_unlock(&pkg_extensions_lck);

	kfree_data(old_exts, (old_nentries * old_maxwidth) + 1);

	return 0;
}


int
is_package_name(const char *name, int len)
{
	int i;
	size_t extlen;
	const char *ptr, *name_ext;

	// if the name is less than 3 bytes it can't be of the
	// form A.B and if it begins with a "." then it is also
	// not a package.
	if (len <= 3 || name[0] == '.') {
		return 0;
	}

	name_ext = NULL;
	for (ptr = name; *ptr != '\0'; ptr++) {
		if (*ptr == '.') {
			name_ext = ptr;
		}
	}

	// if there is no "." extension, it can't match
	if (name_ext == NULL) {
		return 0;
	}

	// advance over the "."
	name_ext++;

	lck_mtx_lock(&pkg_extensions_lck);

	// now iterate over all the extensions to see if any match
	ptr = &extension_table[0];
	for (i = 0; i < nexts; i++, ptr += max_ext_width) {
		extlen = strlen(ptr);
		if (strncasecmp(name_ext, ptr, extlen) == 0 && name_ext[extlen] == '\0') {
			// aha, a match!
			lck_mtx_unlock(&pkg_extensions_lck);
			return 1;
		}
	}

	lck_mtx_unlock(&pkg_extensions_lck);

	// if we get here, no extension matched
	return 0;
}

int
vn_path_package_check(__unused vnode_t vp, char *path, int pathlen, int *component)
{
	char *ptr, *end;
	int comp = 0;

	if (pathlen < 0) {
		return EINVAL;
	}

	*component = -1;
	if (*path != '/') {
		return EINVAL;
	}

	end = path + 1;
	while (end < path + pathlen && *end != '\0') {
		while (end < path + pathlen && *end == '/' && *end != '\0') {
			end++;
		}

		ptr = end;

		while (end < path + pathlen && *end != '/' && *end != '\0') {
			end++;
		}

		if (end > path + pathlen) {
			// hmm, string wasn't null terminated
			return EINVAL;
		}

		*end = '\0';
		if (is_package_name(ptr, (int)(end - ptr))) {
			*component = comp;
			break;
		}

		end++;
		comp++;
	}

	return 0;
}

/*
 * Determine if a name is inappropriate for a searchfs query.
 * This list consists of /System currently.
 */

int
vn_searchfs_inappropriate_name(const char *name, int len)
{
	const char *bad_names[] = { "System" };
	int   bad_len[]   = { 6 };
	int  i;

	if (len < 0) {
		return EINVAL;
	}

	for (i = 0; i < (int) (sizeof(bad_names) / sizeof(bad_names[0])); i++) {
		if (len == bad_len[i] && strncmp(name, bad_names[i], strlen(bad_names[i]) + 1) == 0) {
			return 1;
		}
	}

	// if we get here, no name matched
	return 0;
}

/*
 * Top level filesystem related information gathering.
 */
extern unsigned int vfs_nummntops;

/*
 * The VFS_NUMMNTOPS shouldn't be at name[1] since
 * is a VFS generic variable. Since we no longer support
 * VT_UFS, we reserve its value to support this sysctl node.
 *
 * It should have been:
 *    name[0]:  VFS_GENERIC
 *    name[1]:  VFS_NUMMNTOPS
 */
SYSCTL_INT(_vfs, VFS_NUMMNTOPS, nummntops,
    CTLFLAG_RD | CTLFLAG_KERN | CTLFLAG_LOCKED,
    &vfs_nummntops, 0, "");

int
vfs_sysctl(int *name __unused, u_int namelen __unused,
    user_addr_t oldp __unused, size_t *oldlenp __unused,
    user_addr_t newp __unused, size_t newlen __unused, proc_t p __unused);

int
vfs_sysctl(int *name __unused, u_int namelen __unused,
    user_addr_t oldp __unused, size_t *oldlenp __unused,
    user_addr_t newp __unused, size_t newlen __unused, proc_t p __unused)
{
	return EINVAL;
}


//
// The following code disallows specific sysctl's that came through
// the direct sysctl interface (vfs_sysctl_node) instead of the newer
// sysctl_vfs_ctlbyfsid() interface.  We can not allow these selectors
// through vfs_sysctl_node() because it passes the user's oldp pointer
// directly to the file system which (for these selectors) casts it
// back to a struct sysctl_req and then proceed to use SYSCTL_IN()
// which jumps through an arbitrary function pointer.  When called
// through the sysctl_vfs_ctlbyfsid() interface this does not happen
// and so it's safe.
//
// Unfortunately we have to pull in definitions from AFP and SMB and
// perform explicit name checks on the file system to determine if
// these selectors are being used.
//

#define AFPFS_VFS_CTL_GETID            0x00020001
#define AFPFS_VFS_CTL_NETCHANGE        0x00020002
#define AFPFS_VFS_CTL_VOLCHANGE        0x00020003

#define SMBFS_SYSCTL_REMOUNT           1
#define SMBFS_SYSCTL_REMOUNT_INFO      2
#define SMBFS_SYSCTL_GET_SERVER_SHARE  3


static int
is_bad_sysctl_name(struct vfstable *vfsp, int selector_name)
{
	switch (selector_name) {
	case VFS_CTL_QUERY:
	case VFS_CTL_TIMEO:
	case VFS_CTL_NOLOCKS:
	case VFS_CTL_NSTATUS:
	case VFS_CTL_SADDR:
	case VFS_CTL_DISC:
	case VFS_CTL_SERVERINFO:
		return 1;

	default:
		break;
	}

	// the more complicated check for some of SMB's special values
	if (strcmp(vfsp->vfc_name, "smbfs") == 0) {
		switch (selector_name) {
		case SMBFS_SYSCTL_REMOUNT:
		case SMBFS_SYSCTL_REMOUNT_INFO:
		case SMBFS_SYSCTL_GET_SERVER_SHARE:
			return 1;
		}
	} else if (strcmp(vfsp->vfc_name, "afpfs") == 0) {
		switch (selector_name) {
		case AFPFS_VFS_CTL_GETID:
		case AFPFS_VFS_CTL_NETCHANGE:
		case AFPFS_VFS_CTL_VOLCHANGE:
			return 1;
		}
	}

	//
	// If we get here we passed all the checks so the selector is ok
	//
	return 0;
}


int vfs_sysctl_node SYSCTL_HANDLER_ARGS
{
	int *name, namelen;
	struct vfstable *vfsp;
	int error;
	int fstypenum;

	fstypenum = oidp->oid_number;
	name = arg1;
	namelen = arg2;

	/* all sysctl names at this level should have at least one name slot for the FS */
	if (namelen < 1) {
		return EISDIR; /* overloaded */
	}
	mount_list_lock();
	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
		if (vfsp->vfc_typenum == fstypenum) {
			vfsp->vfc_refcount++;
			break;
		}
	}
	mount_list_unlock();

	if (vfsp == NULL) {
		return ENOTSUP;
	}

	if (is_bad_sysctl_name(vfsp, name[0])) {
		printf("vfs: bad selector 0x%.8x for old-style sysctl().  use the sysctl-by-fsid interface instead\n", name[0]);
		error = EPERM;
	} else {
		error = (vfsp->vfc_vfsops->vfs_sysctl)(name, namelen,
		    req->oldptr, &req->oldlen, req->newptr, req->newlen,
		    vfs_context_current());
	}

	mount_list_lock();
	vfsp->vfc_refcount--;
	mount_list_unlock();

	return error;
}

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

restart:
	SPECHASH_LOCK();
	if (vp->v_specflags & SI_MOUNTING && (vp->v_specinfo->si_mountingowner != current_thread())) {
		msleep((caddr_t)&vp->v_specflags, SPECHASH_LOCK_ADDR(), PVFS | PDROP, "vnode_waitformounting", NULL);
		goto restart;
	}
	if (vp->v_specflags & SI_MOUNTEDON) {
		error = EBUSY;
		goto out;
	}
	if (vp->v_specflags & SI_ALIASED) {
		for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
			if (vq->v_rdev != vp->v_rdev ||
			    vq->v_type != vp->v_type || vq == vp) {
				continue;
			}
			if (vq->v_specflags & SI_MOUNTING) {
				msleep((caddr_t)&vq->v_specflags, SPECHASH_LOCK_ADDR(), PVFS | PDROP, "vnode_waitformounting", NULL);
				goto restart;
			}
			if (vq->v_specflags & SI_MOUNTEDON) {
				error = EBUSY;
				break;
			}
		}
	}
out:
	SPECHASH_UNLOCK();
	return error;
}

void
vfs_setmountedon(vnode_t vp)
{
	vnode_lock(vp);
	SPECHASH_LOCK();
	vp->v_specflags |= SI_MOUNTEDON;
	vp->v_specflags &= ~SI_MOUNTING;
	vp->v_specinfo->si_mountingowner = NULL;
	SPECHASH_UNLOCK();
	vnode_unlock(vp);
	wakeup(&vp->v_specflags);
}

void
vfs_clearmounting(vnode_t vp)
{
	vnode_lock(vp);
	SPECHASH_LOCK();
	vp->v_specflags &= ~SI_MOUNTING;
	vp->v_specinfo->si_mountingowner = NULL;
	SPECHASH_UNLOCK();
	vnode_unlock(vp);
	wakeup(&vp->v_specflags);
}

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

	vnode_lock(vp);
	while (vp->v_specflags & SI_MOUNTING) {
		msleep((caddr_t)&vp->v_specflags, &vp->v_lock, PVFS, "vnode_waitformounting", NULL);
	}
	if (vp->v_specflags & SI_MOUNTEDON) {
		vnode_unlock(vp);
		return EBUSY;
	}
	SPECHASH_LOCK();
	vp->v_specflags |= SI_MOUNTING;
	vp->v_specinfo->si_mountingowner = current_thread();
	vnode_unlock(vp);
restart:
	if (vp->v_specflags & SI_ALIASED) {
		for (vq = *vp->v_hashchain; vq; vq = vq->v_specnext) {
			if (vq->v_rdev != vp->v_rdev ||
			    vq->v_type != vp->v_type || vq == vp) {
				continue;
			}
			if (vq->v_specflags & SI_MOUNTING) {
				msleep((caddr_t)&vq->v_specflags, SPECHASH_LOCK_ADDR(), PVFS | PDROP, "vnode_waitformounting", NULL);
				SPECHASH_LOCK();
				goto restart;
			}
			if (vq->v_specflags & SI_MOUNTEDON) {
				error = EBUSY;
				break;
			}
		}
	}
	SPECHASH_UNLOCK();
	if (error) {
		vnode_lock(vp);
		SPECHASH_LOCK();
		vp->v_specflags &= ~SI_MOUNTING;
		SPECHASH_UNLOCK();
		vnode_unlock(vp);
		wakeup(&vp->v_specflags);
	}
	return error;
}

struct unmount_info {
	int     u_errs; // Total failed unmounts
	int     u_busy; // EBUSY failed unmounts
	int     u_count; // Total volumes iterated
	int     u_only_non_system;
};

static int
unmount_callback(mount_t mp, void *arg)
{
	int error;
	char *mntname;
	struct unmount_info *uip = arg;

	uip->u_count++;

	mntname = zalloc_flags(ZV_NAMEI, Z_WAITOK | Z_NOFAIL);
	strlcpy(mntname, mp->mnt_vfsstat.f_mntonname, MAXPATHLEN);

	if (uip->u_only_non_system
	    && ((mp->mnt_flag & MNT_ROOTFS) || (mp->mnt_kern_flag & MNTK_SYSTEM))) { //MNTK_BACKS_ROOT
		printf("unmount(%d) %s skipped\n", uip->u_only_non_system, mntname);
		mount_iterdrop(mp);     // VFS_ITERATE_CB_DROPREF
	} else {
		printf("unmount(%d) %s\n", uip->u_only_non_system, mntname);

		mount_ref(mp, 0);
		mount_iterdrop(mp);     // VFS_ITERATE_CB_DROPREF
		error = dounmount(mp, MNT_FORCE, 1, vfs_context_current());
		if (error) {
			uip->u_errs++;
			printf("Unmount of %s failed (%d)\n", mntname ? mntname:"?", error);
			if (error == EBUSY) {
				uip->u_busy++;
			}
		}
	}
	zfree(ZV_NAMEI, mntname);

	return VFS_RETURNED;
}

/*
 * Unmount all filesystems. The list is traversed in reverse order
 * of mounting to avoid dependencies.
 * Busy mounts are retried.
 */
__private_extern__ void
vfs_unmountall(int only_non_system)
{
	int mounts, sec = 1;
	struct unmount_info ui;

	/*
	 * Ensure last-completion-time is valid before anyone can see that
	 * VFS shutdown has started.
	 */
	vfs_shutdown_last_completion_time = mach_absolute_time();
	OSMemoryBarrier();
	vfs_unmountall_started = 1;
	printf("vfs_unmountall(%ssystem) start\n", only_non_system ? "non" : "");

retry:
	ui.u_errs = ui.u_busy = ui.u_count = 0;
	ui.u_only_non_system = only_non_system;
	// avoid vfs_iterate deadlock in dounmount(), use VFS_ITERATE_CB_DROPREF
	vfs_iterate(VFS_ITERATE_CB_DROPREF | VFS_ITERATE_TAIL_FIRST, unmount_callback, &ui);
	mounts = mount_getvfscnt();
	if (mounts == 0) {
		goto out;
	}
	if (ui.u_busy > 0) {            // Busy mounts - wait & retry
		tsleep(&nummounts, PVFS, "busy mount", sec * hz);
		sec *= 2;
		if (sec <= 32) {
			goto retry;
		}
		printf("Unmounting timed out\n");
	} else if (ui.u_count < mounts) {
		// If the vfs_iterate missed mounts in progress - wait a bit
		tsleep(&nummounts, PVFS, "missed mount", 2 * hz);
	}

out:
	printf("vfs_unmountall(%ssystem) end\n", only_non_system ? "non" : "");

	/*
	 * reboot_kernel() calls us twice; once to deal with non-system
	 * mounts, and again to sweep up anything left after terminating
	 * DEXTs.  We're only finished once we've completed the second pass.
	 */
	if (!only_non_system) {
		vfs_unmountall_finished = 1;
	}
}

/*
 * vfs_shutdown_in_progress --
 *
 * Returns whether or not the VFS is shutting down the file systems.
 */
boolean_t
vfs_shutdown_in_progress(void)
{
	return vfs_unmountall_started && !vfs_unmountall_finished;
}

/*
 * vfs_shutdown_finished --
 *
 * Returns whether or not the VFS shutdown has completed.
 */
boolean_t
vfs_shutdown_finished(void)
{
	return !!vfs_unmountall_finished;
}

/*
 * vfs_update_last_completion_time --
 *
 * Updates the "last I/O completion time" timestamp used by the watchdog
 * to monitor VFS shutdown progress.  Called by various I/O stack layers
 * as operations complete and progress moves forward.
 */
void
vfs_update_last_completion_time(void)
{
	if (vfs_unmountall_started) {
		vfs_shutdown_last_completion_time = mach_absolute_time();
	}
}

/*
 * vfs_last_completion_time --
 *
 * Returns the "last I/O completion time" timestamp.  Return
 * value is a mach_absolute_time() value, and is not meaningful
 * unless vfs_is_shutting_down() also returns true.
 */
uint64_t
vfs_last_completion_time(void)
{
	return vfs_unmountall_started ? vfs_shutdown_last_completion_time : 0;
}

/*
 * This routine is called from vnode_pager_deallocate out of the VM
 * The path to vnode_pager_deallocate can only be initiated by ubc_destroy_named
 * on a vnode that has a UBCINFO
 */
__private_extern__ void
vnode_pager_vrele(vnode_t vp)
{
	struct ubc_info *uip;

	vnode_lock_spin(vp);

	vp->v_lflag &= ~VNAMED_UBC;
	if (vp->v_usecount != 0) {
		/*
		 * At the eleventh hour, just before the ubcinfo is
		 * destroyed, ensure the ubc-specific v_usecount
		 * reference has gone.  We use v_usecount != 0 as a hint;
		 * ubc_unmap() does nothing if there's no mapping.
		 *
		 * This case is caused by coming here via forced unmount,
		 * versus the usual vm_object_deallocate() path.
		 * In the forced unmount case, ubc_destroy_named()
		 * releases the pager before memory_object_last_unmap()
		 * can be called.
		 */
		vnode_unlock(vp);
		ubc_unmap(vp);
		vnode_lock_spin(vp);
	}

	uip = vp->v_ubcinfo;
	vp->v_ubcinfo = UBC_INFO_NULL;

	vnode_unlock(vp);

	ubc_info_deallocate(uip);
}


#include <sys/disk.h>

u_int32_t rootunit = (u_int32_t)-1;

#if CONFIG_IOSCHED
extern int lowpri_throttle_enabled;
extern int iosched_enabled;
#endif

errno_t
vfs_init_io_attributes(vnode_t devvp, mount_t mp)
{
	int     error;
	off_t   readblockcnt = 0;
	off_t   writeblockcnt = 0;
	off_t   readmaxcnt = 0;
	off_t   writemaxcnt = 0;
	off_t   readsegcnt = 0;
	off_t   writesegcnt = 0;
	off_t   readsegsize = 0;
	off_t   writesegsize = 0;
	off_t   alignment = 0;
	u_int32_t minsaturationbytecount = 0;
	u_int32_t ioqueue_depth = 0;
	u_int32_t blksize;
	u_int64_t temp;
	u_int32_t features;
	u_int64_t location = 0;
	vfs_context_t ctx = vfs_context_current();
	dk_corestorage_info_t cs_info;
	boolean_t cs_present = FALSE;
	int isssd = 0;
	int isvirtual = 0;


	VNOP_IOCTL(devvp, DKIOCGETTHROTTLEMASK, (caddr_t)&mp->mnt_throttle_mask, 0, NULL);
	/*
	 * as a reasonable approximation, only use the lowest bit of the mask
	 * to generate a disk unit number
	 */
	mp->mnt_devbsdunit = mp->mnt_throttle_mask ?
	    num_trailing_0(mp->mnt_throttle_mask) : (LOWPRI_MAX_NUM_DEV - 1);

	if (devvp == rootvp) {
		rootunit = mp->mnt_devbsdunit;
	}

	if (mp->mnt_devbsdunit == rootunit) {
		/*
		 * this mount point exists on the same device as the root
		 * partition, so it comes under the hard throttle control...
		 * this is true even for the root mount point itself
		 */
		mp->mnt_kern_flag |= MNTK_ROOTDEV;
	}
	/*
	 * force the spec device to re-cache
	 * the underlying block size in case
	 * the filesystem overrode the initial value
	 */
	set_fsblocksize(devvp);


	if ((error = VNOP_IOCTL(devvp, DKIOCGETBLOCKSIZE,
	    (caddr_t)&blksize, 0, ctx))) {
		return error;
	}

	mp->mnt_devblocksize = blksize;

	/*
	 * set the maximum possible I/O size
	 * this may get clipped to a smaller value
	 * based on which constraints are being advertised
	 * and if those advertised constraints result in a smaller
	 * limit for a given I/O
	 */
	mp->mnt_maxreadcnt = MAX_UPL_SIZE_BYTES;
	mp->mnt_maxwritecnt = MAX_UPL_SIZE_BYTES;

	if (VNOP_IOCTL(devvp, DKIOCISVIRTUAL, (caddr_t)&isvirtual, 0, ctx) == 0) {
		if (isvirtual) {
			mp->mnt_kern_flag |= MNTK_VIRTUALDEV;
			mp->mnt_flag |= MNT_REMOVABLE;
		}
	}
	if (VNOP_IOCTL(devvp, DKIOCISSOLIDSTATE, (caddr_t)&isssd, 0, ctx) == 0) {
		if (isssd) {
			mp->mnt_kern_flag |= MNTK_SSD;
		}
	}
	if ((error = VNOP_IOCTL(devvp, DKIOCGETFEATURES,
	    (caddr_t)&features, 0, ctx))) {
		return error;
	}

	if ((error = VNOP_IOCTL(devvp, DKIOCGETMAXBLOCKCOUNTREAD,
	    (caddr_t)&readblockcnt, 0, ctx))) {
		return error;
	}

	if ((error = VNOP_IOCTL(devvp, DKIOCGETMAXBLOCKCOUNTWRITE,
	    (caddr_t)&writeblockcnt, 0, ctx))) {
		return error;
	}

	if ((error = VNOP_IOCTL(devvp, DKIOCGETMAXBYTECOUNTREAD,
	    (caddr_t)&readmaxcnt, 0, ctx))) {
		return error;
	}

	if ((error = VNOP_IOCTL(devvp, DKIOCGETMAXBYTECOUNTWRITE,
	    (caddr_t)&writemaxcnt, 0, ctx))) {
		return error;
	}

	if ((error = VNOP_IOCTL(devvp, DKIOCGETMAXSEGMENTCOUNTREAD,
	    (caddr_t)&readsegcnt, 0, ctx))) {
		return error;
	}

	if ((error = VNOP_IOCTL(devvp, DKIOCGETMAXSEGMENTCOUNTWRITE,
	    (caddr_t)&writesegcnt, 0, ctx))) {
		return error;
	}

	if ((error = VNOP_IOCTL(devvp, DKIOCGETMAXSEGMENTBYTECOUNTREAD,
	    (caddr_t)&readsegsize, 0, ctx))) {
		return error;
	}

	if ((error = VNOP_IOCTL(devvp, DKIOCGETMAXSEGMENTBYTECOUNTWRITE,
	    (caddr_t)&writesegsize, 0, ctx))) {
		return error;
	}

	if ((error = VNOP_IOCTL(devvp, DKIOCGETMINSEGMENTALIGNMENTBYTECOUNT,
	    (caddr_t)&alignment, 0, ctx))) {
		return error;
	}

	if ((error = VNOP_IOCTL(devvp, DKIOCGETCOMMANDPOOLSIZE,
	    (caddr_t)&ioqueue_depth, 0, ctx))) {
		return error;
	}

	if (readmaxcnt) {
		mp->mnt_maxreadcnt = (readmaxcnt > UINT32_MAX) ? UINT32_MAX :(uint32_t) readmaxcnt;
	}

	if (readblockcnt) {
		temp = readblockcnt * blksize;
		temp = (temp > UINT32_MAX) ? UINT32_MAX : temp;

		if (temp < mp->mnt_maxreadcnt) {
			mp->mnt_maxreadcnt = (u_int32_t)temp;
		}
	}

	if (writemaxcnt) {
		mp->mnt_maxwritecnt = (writemaxcnt > UINT32_MAX) ? UINT32_MAX : (uint32_t)writemaxcnt;
	}

	if (writeblockcnt) {
		temp = writeblockcnt * blksize;
		temp = (temp > UINT32_MAX) ? UINT32_MAX : temp;

		if (temp < mp->mnt_maxwritecnt) {
			mp->mnt_maxwritecnt = (u_int32_t)temp;
		}
	}

	if (readsegcnt) {
		temp = (readsegcnt > UINT16_MAX) ? UINT16_MAX : readsegcnt;
	} else {
		temp = mp->mnt_maxreadcnt / PAGE_SIZE;

		if (temp > UINT16_MAX) {
			temp = UINT16_MAX;
		}
	}
	mp->mnt_segreadcnt = (u_int16_t)temp;

	if (writesegcnt) {
		temp = (writesegcnt > UINT16_MAX) ? UINT16_MAX : writesegcnt;
	} else {
		temp = mp->mnt_maxwritecnt / PAGE_SIZE;

		if (temp > UINT16_MAX) {
			temp = UINT16_MAX;
		}
	}
	mp->mnt_segwritecnt = (u_int16_t)temp;

	if (readsegsize) {
		temp = (readsegsize > UINT32_MAX) ? UINT32_MAX : readsegsize;
	} else {
		temp = mp->mnt_maxreadcnt;
	}
	mp->mnt_maxsegreadsize = (u_int32_t)temp;

	if (writesegsize) {
		temp = (writesegsize > UINT32_MAX) ? UINT32_MAX : writesegsize;
	} else {
		temp = mp->mnt_maxwritecnt;
	}
	mp->mnt_maxsegwritesize = (u_int32_t)temp;

	if (alignment) {
		temp = (alignment > PAGE_SIZE) ? PAGE_MASK : alignment - 1;
	} else {
		temp = 0;
	}
	mp->mnt_alignmentmask = (uint32_t)temp;


	if (ioqueue_depth > MNT_DEFAULT_IOQUEUE_DEPTH) {
		temp = ioqueue_depth;
	} else {
		temp = MNT_DEFAULT_IOQUEUE_DEPTH;
	}

	mp->mnt_ioqueue_depth = (uint32_t)temp;
	mp->mnt_ioscale = MNT_IOSCALE(mp->mnt_ioqueue_depth);

	if (mp->mnt_ioscale > 1) {
		printf("ioqueue_depth = %d,   ioscale = %d\n", (int)mp->mnt_ioqueue_depth, (int)mp->mnt_ioscale);
	}

	if (features & DK_FEATURE_FORCE_UNIT_ACCESS) {
		mp->mnt_ioflags |= MNT_IOFLAGS_FUA_SUPPORTED;
	}

	if (VNOP_IOCTL(devvp, DKIOCGETIOMINSATURATIONBYTECOUNT, (caddr_t)&minsaturationbytecount, 0, ctx) == 0) {
		mp->mnt_minsaturationbytecount = minsaturationbytecount;
	} else {
		mp->mnt_minsaturationbytecount = 0;
	}

	if (VNOP_IOCTL(devvp, DKIOCCORESTORAGE, (caddr_t)&cs_info, 0, ctx) == 0) {
		cs_present = TRUE;
	}

	if (features & DK_FEATURE_UNMAP) {
		mp->mnt_ioflags |= MNT_IOFLAGS_UNMAP_SUPPORTED;

		if (cs_present == TRUE) {
			mp->mnt_ioflags |= MNT_IOFLAGS_CSUNMAP_SUPPORTED;
		}
	}
	if (cs_present == TRUE) {
		/*
		 * for now we'll use the following test as a proxy for
		 * the underlying drive being FUSION in nature
		 */
		if ((cs_info.flags & DK_CORESTORAGE_PIN_YOUR_METADATA)) {
			mp->mnt_ioflags |= MNT_IOFLAGS_FUSION_DRIVE;
		}
	} else {
		/* Check for APFS Fusion */
		dk_apfs_flavour_t flavour;
		if ((VNOP_IOCTL(devvp, DKIOCGETAPFSFLAVOUR, (caddr_t)&flavour, 0, ctx) == 0) &&
		    (flavour == DK_APFS_FUSION)) {
			mp->mnt_ioflags |= MNT_IOFLAGS_FUSION_DRIVE;
		}
	}

	if (VNOP_IOCTL(devvp, DKIOCGETLOCATION, (caddr_t)&location, 0, ctx) == 0) {
		if (location & DK_LOCATION_EXTERNAL) {
			mp->mnt_ioflags |= MNT_IOFLAGS_PERIPHERAL_DRIVE;
			mp->mnt_flag |= MNT_REMOVABLE;
		}
	}

#if CONFIG_IOSCHED
	if (iosched_enabled && (features & DK_FEATURE_PRIORITY)) {
		mp->mnt_ioflags |= MNT_IOFLAGS_IOSCHED_SUPPORTED;
		throttle_info_disable_throttle(mp->mnt_devbsdunit, (mp->mnt_ioflags & MNT_IOFLAGS_FUSION_DRIVE) != 0);
	}
#endif /* CONFIG_IOSCHED */
	return error;
}

static struct klist fs_klist;
static LCK_GRP_DECLARE(fs_klist_lck_grp, "fs_klist");
static LCK_MTX_DECLARE(fs_klist_lock, &fs_klist_lck_grp);

void
vfs_event_init(void)
{
	klist_init(&fs_klist);
}

void
vfs_event_signal(fsid_t *fsid, u_int32_t event, intptr_t data)
{
	if (event == VQ_DEAD || event == VQ_NOTRESP) {
		struct mount *mp = vfs_getvfs(fsid);
		if (mp) {
			mount_lock_spin(mp);
			if (data) {
				mp->mnt_lflag &= ~MNT_LNOTRESP;     // Now responding
			} else {
				mp->mnt_lflag |= MNT_LNOTRESP;      // Not responding
			}
			mount_unlock(mp);
		}
	}

	lck_mtx_lock(&fs_klist_lock);
	KNOTE(&fs_klist, event);
	lck_mtx_unlock(&fs_klist_lock);
}

/*
 * return the number of mounted filesystems.
 */
static int
sysctl_vfs_getvfscnt(void)
{
	return mount_getvfscnt();
}


static int
mount_getvfscnt(void)
{
	int ret;

	mount_list_lock();
	ret = nummounts;
	mount_list_unlock();
	return ret;
}



static int
mount_fillfsids(fsid_t *fsidlst, int count)
{
	struct mount *mp;
	int actual = 0;

	actual = 0;
	mount_list_lock();
	TAILQ_FOREACH(mp, &mountlist, mnt_list) {
		if (actual < count) {
			fsidlst[actual] = mp->mnt_vfsstat.f_fsid;
			actual++;
		}
	}
	mount_list_unlock();
	return actual;
}

/*
 * fill in the array of fsid_t's up to a max of 'count', the actual
 * number filled in will be set in '*actual'.  If there are more fsid_t's
 * than room in fsidlst then ENOMEM will be returned and '*actual' will
 * have the actual count.
 * having *actual filled out even in the error case is depended upon.
 */
static int
sysctl_vfs_getvfslist(fsid_t *fsidlst, unsigned long count, unsigned long *actual)
{
	struct mount *mp;

	*actual = 0;
	mount_list_lock();
	TAILQ_FOREACH(mp, &mountlist, mnt_list) {
		(*actual)++;
		if (*actual <= count) {
			fsidlst[(*actual) - 1] = mp->mnt_vfsstat.f_fsid;
		}
	}
	mount_list_unlock();
	return *actual <= count ? 0 : ENOMEM;
}

static int
sysctl_vfs_vfslist(__unused struct sysctl_oid *oidp, __unused void *arg1,
    __unused int arg2, struct sysctl_req *req)
{
	unsigned long actual;
	int error;
	size_t space;
	fsid_t *fsidlst;

	/* This is a readonly node. */
	if (req->newptr != USER_ADDR_NULL) {
		return EPERM;
	}

	/* they are querying us so just return the space required. */
	if (req->oldptr == USER_ADDR_NULL) {
		req->oldidx = sysctl_vfs_getvfscnt() * sizeof(fsid_t);
		return 0;
	}
again:
	/*
	 * Retrieve an accurate count of the amount of space required to copy
	 * out all the fsids in the system.
	 */
	space = req->oldlen;
	req->oldlen = sysctl_vfs_getvfscnt() * sizeof(fsid_t);

	/* they didn't give us enough space. */
	if (space < req->oldlen) {
		return ENOMEM;
	}

	fsidlst = kalloc_data(req->oldlen, Z_WAITOK | Z_ZERO);
	if (fsidlst == NULL) {
		return ENOMEM;
	}

	error = sysctl_vfs_getvfslist(fsidlst, req->oldlen / sizeof(fsid_t),
	    &actual);
	/*
	 * If we get back ENOMEM, then another mount has been added while we
	 * slept in malloc above.  If this is the case then try again.
	 */
	if (error == ENOMEM) {
		kfree_data(fsidlst, req->oldlen);
		req->oldlen = space;
		goto again;
	}
	if (error == 0) {
		error = SYSCTL_OUT(req, fsidlst, actual * sizeof(fsid_t));
	}
	kfree_data(fsidlst, req->oldlen);
	return error;
}

/*
 * Do a sysctl by fsid.
 */
static int
sysctl_vfs_ctlbyfsid(__unused struct sysctl_oid *oidp, void *arg1, int arg2,
    struct sysctl_req *req)
{
	union union_vfsidctl vc;
	struct mount *mp = NULL;
	struct vfsstatfs *sp;
	int *name, namelen;
	int flags = 0;
	int error = 0, gotref = 0;
	vfs_context_t ctx = vfs_context_current();
	proc_t p = req->p;      /* XXX req->p != current_proc()? */
	boolean_t is_64_bit;
	union {
		struct statfs64 sfs64;
		struct user64_statfs osfs64;
		struct user32_statfs osfs32;
	} *sfsbuf;

	if (req->newptr == USER_ADDR_NULL) {
		error = EINVAL;
		goto out;
	}

	name = arg1;
	namelen = arg2;
	is_64_bit = proc_is64bit(p);

	error = SYSCTL_IN(req, &vc, is_64_bit? sizeof(vc.vc64):sizeof(vc.vc32));
	if (error) {
		goto out;
	}
	if (vc.vc32.vc_vers != VFS_CTL_VERS1) { /* works for 32 and 64 */
		error = EINVAL;
		goto out;
	}
	mp = mount_list_lookupby_fsid(&vc.vc32.vc_fsid, 0, 1); /* works for 32 and 64 */
	if (mp == NULL) {
		error = ENOENT;
		goto out;
	}
	gotref = 1;
	/* reset so that the fs specific code can fetch it. */
	req->newidx = 0;
	/*
	 * Note if this is a VFS_CTL then we pass the actual sysctl req
	 * in for "oldp" so that the lower layer can DTRT and use the
	 * SYSCTL_IN/OUT routines.
	 */
	if (mp->mnt_op->vfs_sysctl != NULL) {
		if (is_64_bit) {
			if (vfs_64bitready(mp)) {
				error = mp->mnt_op->vfs_sysctl(name, namelen,
				    CAST_USER_ADDR_T(req),
				    NULL, USER_ADDR_NULL, 0,
				    ctx);
			} else {
				error = ENOTSUP;
			}
		} else {
			error = mp->mnt_op->vfs_sysctl(name, namelen,
			    CAST_USER_ADDR_T(req),
			    NULL, USER_ADDR_NULL, 0,
			    ctx);
		}
		if (error != ENOTSUP) {
			goto out;
		}
	}
	switch (name[0]) {
	case VFS_CTL_UMOUNT:
#if CONFIG_MACF
		error = mac_mount_check_umount(ctx, mp);
		if (error != 0) {
			goto out;
		}
#endif
		req->newidx = 0;
		if (is_64_bit) {
			req->newptr = vc.vc64.vc_ptr;
			req->newlen = (size_t)vc.vc64.vc_len;
		} else {
			req->newptr = CAST_USER_ADDR_T(vc.vc32.vc_ptr);
			req->newlen = vc.vc32.vc_len;
		}
		error = SYSCTL_IN(req, &flags, sizeof(flags));
		if (error) {
			break;
		}

		mount_ref(mp, 0);
		mount_iterdrop(mp);
		gotref = 0;
		/* safedounmount consumes a ref */
		error = safedounmount(mp, flags, ctx);
		break;
	case VFS_CTL_OSTATFS:
	case VFS_CTL_STATFS64:
#if CONFIG_MACF
		error = mac_mount_check_stat(ctx, mp);
		if (error != 0) {
			break;
		}
#endif
		req->newidx = 0;
		if (is_64_bit) {
			req->newptr = vc.vc64.vc_ptr;
			req->newlen = (size_t)vc.vc64.vc_len;
		} else {
			req->newptr = CAST_USER_ADDR_T(vc.vc32.vc_ptr);
			req->newlen = vc.vc32.vc_len;
		}
		error = SYSCTL_IN(req, &flags, sizeof(flags));
		if (error) {
			break;
		}
		sp = &mp->mnt_vfsstat;
		if (((flags & MNT_NOWAIT) == 0 || (flags & (MNT_WAIT | MNT_DWAIT))) &&
		    (error = vfs_update_vfsstat(mp, ctx, VFS_USER_EVENT))) {
			goto out;
		}

		sfsbuf = kalloc_type(typeof(*sfsbuf), Z_WAITOK);

		if (name[0] == VFS_CTL_STATFS64) {
			struct statfs64 *sfs = &sfsbuf->sfs64;

			vfs_get_statfs64(mp, sfs);
			error = SYSCTL_OUT(req, sfs, sizeof(*sfs));
		} else if (is_64_bit) {
			struct user64_statfs *sfs = &sfsbuf->osfs64;

			bzero(sfs, sizeof(*sfs));
			sfs->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
			sfs->f_type = (short)mp->mnt_vtable->vfc_typenum;
			sfs->f_bsize = (user64_long_t)sp->f_bsize;
			sfs->f_iosize = (user64_long_t)sp->f_iosize;
			sfs->f_blocks = (user64_long_t)sp->f_blocks;
			sfs->f_bfree = (user64_long_t)sp->f_bfree;
			sfs->f_bavail = (user64_long_t)sp->f_bavail;
			sfs->f_files = (user64_long_t)sp->f_files;
			sfs->f_ffree = (user64_long_t)sp->f_ffree;
			sfs->f_fsid = sp->f_fsid;
			sfs->f_owner = sp->f_owner;
			vfs_getfstypename(mp, sfs->f_fstypename, MFSNAMELEN);
			strlcpy(sfs->f_mntonname, sp->f_mntonname, MNAMELEN);
			strlcpy(sfs->f_mntfromname, sp->f_mntfromname, MNAMELEN);

			error = SYSCTL_OUT(req, sfs, sizeof(*sfs));
		} else {
			struct user32_statfs *sfs = &sfsbuf->osfs32;
			long temp;

			bzero(sfs, sizeof(*sfs));
			sfs->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
			sfs->f_type = (short)mp->mnt_vtable->vfc_typenum;

			/*
			 * It's possible for there to be more than 2^^31 blocks in the filesystem, so we
			 * have to fudge the numbers here in that case.   We inflate the blocksize in order
			 * to reflect the filesystem size as best we can.
			 */
			if (sp->f_blocks > INT_MAX) {
				int             shift;

				/*
				 * Work out how far we have to shift the block count down to make it fit.
				 * Note that it's possible to have to shift so far that the resulting
				 * blocksize would be unreportably large.  At that point, we will clip
				 * any values that don't fit.
				 *
				 * For safety's sake, we also ensure that f_iosize is never reported as
				 * being smaller than f_bsize.
				 */
				for (shift = 0; shift < 32; shift++) {
					if ((sp->f_blocks >> shift) <= INT_MAX) {
						break;
					}
					if ((((long long)sp->f_bsize) << (shift + 1)) > INT_MAX) {
						break;
					}
				}
#define __SHIFT_OR_CLIP(x, s)   ((((x) >> (s)) > INT_MAX) ? INT_MAX : ((x) >> (s)))
				sfs->f_blocks = (user32_long_t)__SHIFT_OR_CLIP(sp->f_blocks, shift);
				sfs->f_bfree = (user32_long_t)__SHIFT_OR_CLIP(sp->f_bfree, shift);
				sfs->f_bavail = (user32_long_t)__SHIFT_OR_CLIP(sp->f_bavail, shift);
#undef __SHIFT_OR_CLIP
				sfs->f_bsize = (user32_long_t)(sp->f_bsize << shift);
				temp = lmax(sp->f_iosize, sp->f_bsize);
				if (temp > INT32_MAX) {
					error = EINVAL;
					kfree_type(typeof(*sfsbuf), sfsbuf);
					goto out;
				}
				sfs->f_iosize = (user32_long_t)temp;
			} else {
				sfs->f_bsize = (user32_long_t)sp->f_bsize;
				sfs->f_iosize = (user32_long_t)sp->f_iosize;
				sfs->f_blocks = (user32_long_t)sp->f_blocks;
				sfs->f_bfree = (user32_long_t)sp->f_bfree;
				sfs->f_bavail = (user32_long_t)sp->f_bavail;
			}
			sfs->f_files = (user32_long_t)sp->f_files;
			sfs->f_ffree = (user32_long_t)sp->f_ffree;
			sfs->f_fsid = sp->f_fsid;
			sfs->f_owner = sp->f_owner;

			vfs_getfstypename(mp, sfs->f_fstypename, MFSNAMELEN);
			strlcpy(sfs->f_mntonname, sp->f_mntonname, MNAMELEN);
			strlcpy(sfs->f_mntfromname, sp->f_mntfromname, MNAMELEN);

			error = SYSCTL_OUT(req, sfs, sizeof(*sfs));
		}
		kfree_type(typeof(*sfsbuf), sfsbuf);
		break;
	default:
		error = ENOTSUP;
		goto out;
	}
out:
	if (gotref != 0) {
		mount_iterdrop(mp);
	}
	return error;
}

static int      filt_fsattach(struct knote *kn, struct kevent_qos_s *kev);
static void     filt_fsdetach(struct knote *kn);
static int      filt_fsevent(struct knote *kn, long hint);
static int      filt_fstouch(struct knote *kn, struct kevent_qos_s *kev);
static int      filt_fsprocess(struct knote *kn, struct kevent_qos_s *kev);
SECURITY_READ_ONLY_EARLY(struct filterops) fs_filtops = {
	.f_attach = filt_fsattach,
	.f_detach = filt_fsdetach,
	.f_event = filt_fsevent,
	.f_touch = filt_fstouch,
	.f_process = filt_fsprocess,
};

static int
filt_fsattach(struct knote *kn, __unused struct kevent_qos_s *kev)
{
	kn->kn_flags |= EV_CLEAR; /* automatic */
	kn->kn_sdata = 0;         /* incoming data is ignored */

	lck_mtx_lock(&fs_klist_lock);
	KNOTE_ATTACH(&fs_klist, kn);
	lck_mtx_unlock(&fs_klist_lock);

	/*
	 * filter only sees future events,
	 * so it can't be fired already.
	 */
	return 0;
}

static void
filt_fsdetach(struct knote *kn)
{
	lck_mtx_lock(&fs_klist_lock);
	KNOTE_DETACH(&fs_klist, kn);
	lck_mtx_unlock(&fs_klist_lock);
}

static int
filt_fsevent(struct knote *kn, long hint)
{
	/*
	 * Backwards compatibility:
	 * Other filters would do nothing if kn->kn_sfflags == 0
	 */

	if ((kn->kn_sfflags == 0) || (kn->kn_sfflags & hint)) {
		kn->kn_fflags |= hint;
	}

	return kn->kn_fflags != 0;
}

static int
filt_fstouch(struct knote *kn, struct kevent_qos_s *kev)
{
	int res;

	lck_mtx_lock(&fs_klist_lock);

	kn->kn_sfflags = kev->fflags;

	/*
	 * the above filter function sets bits even if nobody is looking for them.
	 * Just preserve those bits even in the new mask is more selective
	 * than before.
	 *
	 * For compatibility with previous implementations, we leave kn_fflags
	 * as they were before.
	 */
	//if (kn->kn_sfflags)
	//	kn->kn_fflags &= kn->kn_sfflags;
	res = (kn->kn_fflags != 0);

	lck_mtx_unlock(&fs_klist_lock);

	return res;
}

static int
filt_fsprocess(struct knote *kn, struct kevent_qos_s *kev)
{
	int res = 0;

	lck_mtx_lock(&fs_klist_lock);
	if (kn->kn_fflags) {
		knote_fill_kevent(kn, kev, 0);
		res = 1;
	}
	lck_mtx_unlock(&fs_klist_lock);
	return res;
}

static int
sysctl_vfs_noremotehang(__unused struct sysctl_oid *oidp,
    __unused void *arg1, __unused int arg2, struct sysctl_req *req)
{
	int out, error;
	pid_t pid;
	proc_t p;

	/* We need a pid. */
	if (req->newptr == USER_ADDR_NULL) {
		return EINVAL;
	}

	error = SYSCTL_IN(req, &pid, sizeof(pid));
	if (error) {
		return error;
	}

	p = proc_find(pid < 0 ? -pid : pid);
	if (p == NULL) {
		return ESRCH;
	}

	/*
	 * Fetching the value is ok, but we only fetch if the old
	 * pointer is given.
	 */
	if (req->oldptr != USER_ADDR_NULL) {
		out = !((p->p_flag & P_NOREMOTEHANG) == 0);
		proc_rele(p);
		error = SYSCTL_OUT(req, &out, sizeof(out));
		return error;
	}

	/* cansignal offers us enough security. */
	if (p != req->p && proc_suser(req->p) != 0) {
		proc_rele(p);
		return EPERM;
	}

	if (pid < 0) {
		OSBitAndAtomic(~((uint32_t)P_NOREMOTEHANG), &p->p_flag);
	} else {
		OSBitOrAtomic(P_NOREMOTEHANG, &p->p_flag);
	}
	proc_rele(p);

	return 0;
}

static int
sysctl_vfs_generic_conf SYSCTL_HANDLER_ARGS
{
	int *name, namelen;
	struct vfstable *vfsp;
	struct vfsconf vfsc = {};

	(void)oidp;
	name = arg1;
	namelen = arg2;

	if (namelen < 1) {
		return EISDIR;
	} else if (namelen > 1) {
		return ENOTDIR;
	}

	mount_list_lock();
	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
		if (vfsp->vfc_typenum == name[0]) {
			break;
		}
	}

	if (vfsp == NULL) {
		mount_list_unlock();
		return ENOTSUP;
	}

	vfsc.vfc_reserved1 = 0;
	bcopy(vfsp->vfc_name, vfsc.vfc_name, sizeof(vfsc.vfc_name));
	vfsc.vfc_typenum = vfsp->vfc_typenum;
	vfsc.vfc_refcount = vfsp->vfc_refcount;
	vfsc.vfc_flags = vfsp->vfc_flags;
	vfsc.vfc_reserved2 = 0;
	vfsc.vfc_reserved3 = 0;

	mount_list_unlock();
	return SYSCTL_OUT(req, &vfsc, sizeof(struct vfsconf));
}

/* the vfs.generic. branch. */
SYSCTL_EXTENSIBLE_NODE(_vfs, VFS_GENERIC, generic,
    CTLFLAG_RW | CTLFLAG_LOCKED, NULL, "vfs generic hinge");
/* retreive a list of mounted filesystem fsid_t */
SYSCTL_PROC(_vfs_generic, OID_AUTO, vfsidlist,
    CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED,
    NULL, 0, sysctl_vfs_vfslist, "S,fsid", "List of mounted filesystem ids");
/* perform operations on filesystem via fsid_t */
SYSCTL_NODE(_vfs_generic, OID_AUTO, ctlbyfsid, CTLFLAG_RW | CTLFLAG_LOCKED,
    sysctl_vfs_ctlbyfsid, "ctlbyfsid");
SYSCTL_PROC(_vfs_generic, OID_AUTO, noremotehang, CTLFLAG_RW | CTLFLAG_ANYBODY,
    NULL, 0, sysctl_vfs_noremotehang, "I", "noremotehang");
SYSCTL_INT(_vfs_generic, VFS_MAXTYPENUM, maxtypenum,
    CTLFLAG_RD | CTLFLAG_KERN | CTLFLAG_LOCKED,
    &maxvfstypenum, 0, "");
SYSCTL_INT(_vfs_generic, OID_AUTO, sync_timeout, CTLFLAG_RW | CTLFLAG_LOCKED, &sync_timeout_seconds, 0, "");
SYSCTL_NODE(_vfs_generic, VFS_CONF, conf,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    sysctl_vfs_generic_conf, "");
#if DEVELOPMENT || DEBUG
SYSCTL_INT(_vfs_generic, OID_AUTO, print_busy_vnodes,
    CTLTYPE_INT | CTLFLAG_RW,
    &print_busy_vnodes, 0,
    "VFS log busy vnodes blocking unmount");
#endif

/* Indicate that the root file system unmounted cleanly */
static int vfs_root_unmounted_cleanly = 0;
SYSCTL_INT(_vfs_generic, OID_AUTO, root_unmounted_cleanly, CTLFLAG_RD, &vfs_root_unmounted_cleanly, 0, "Root filesystem was unmounted cleanly");

void
vfs_set_root_unmounted_cleanly(void)
{
	vfs_root_unmounted_cleanly = 1;
}

/*
 * Print vnode state.
 */
void
vn_print_state(struct vnode *vp, const char *fmt, ...)
{
	va_list ap;
	char perm_str[] = "(VM_KERNEL_ADDRPERM pointer)";
	char fs_name[MFSNAMELEN];

	va_start(ap, fmt);
	vprintf(fmt, ap);
	va_end(ap);
	printf("vp 0x%0llx %s: ", (uint64_t)VM_KERNEL_ADDRPERM(vp), perm_str);
	printf("tag %d, type %d\n", vp->v_tag, vp->v_type);
	/* Counts .. */
	printf("    iocount %d, usecount %d, kusecount %d references %d\n",
	    vp->v_iocount, vp->v_usecount, vp->v_kusecount, vp->v_references);
	printf("    writecount %d, numoutput %d\n", vp->v_writecount,
	    vp->v_numoutput);
	/* Flags */
	printf("    flag 0x%x, lflag 0x%x, listflag 0x%x\n", vp->v_flag,
	    vp->v_lflag, vp->v_listflag);

	if (vp->v_mount == NULL || vp->v_mount == dead_mountp) {
		strlcpy(fs_name, "deadfs", MFSNAMELEN);
	} else {
		vfs_name(vp->v_mount, fs_name);
	}

	printf("    v_data 0x%0llx %s\n",
	    (vp->v_data ? (uint64_t)VM_KERNEL_ADDRPERM(vp->v_data) : 0),
	    perm_str);
	printf("    v_mount 0x%0llx %s vfs_name %s\n",
	    (vp->v_mount ? (uint64_t)VM_KERNEL_ADDRPERM(vp->v_mount) : 0),
	    perm_str, fs_name);
}

long num_reusedvnodes = 0;


static vnode_t
process_vp(vnode_t vp, int want_vp, bool can_defer, int *deferred)
{
	unsigned int  vpid;

	*deferred = 0;

	vpid = vp->v_id;

	vnode_list_remove_locked(vp);

	vnode_hold(vp);
	vnode_list_unlock();

	vnode_lock_spin(vp);

	/*
	 * We could wait for the vnode_lock after removing the vp from the freelist
	 * and the vid is bumped only at the very end of reclaim. So it is  possible
	 * that we are looking at a vnode that is being terminated. If so skip it.
	 */
	if ((vpid != vp->v_id) || (vp->v_usecount != 0) || (vp->v_iocount != 0) ||
	    VONLIST(vp) || (vp->v_lflag & VL_TERMINATE)) {
		/*
		 * we lost the race between dropping the list lock
		 * and picking up the vnode_lock... someone else
		 * used this vnode and it is now in a new state
		 */
		vnode_drop_and_unlock(vp);

		return NULLVP;
	}
	if ((vp->v_lflag & (VL_NEEDINACTIVE | VL_MARKTERM)) == VL_NEEDINACTIVE) {
		/*
		 * we did a vnode_rele_ext that asked for
		 * us not to reenter the filesystem during
		 * the release even though VL_NEEDINACTIVE was
		 * set... we'll do it here by doing a
		 * vnode_get/vnode_put
		 *
		 * pick up an iocount so that we can call
		 * vnode_put and drive the VNOP_INACTIVE...
		 * vnode_put will either leave us off
		 * the freelist if a new ref comes in,
		 * or put us back on the end of the freelist
		 * or recycle us if we were marked for termination...
		 * so we'll just go grab a new candidate
		 */
		vp->v_iocount++;
#ifdef CONFIG_IOCOUNT_TRACE
		record_vp(vp, 1);
#endif
		vnode_put_locked(vp);
		vnode_drop_and_unlock(vp);

		return NULLVP;
	}
	/*
	 * Checks for anyone racing us for recycle
	 */
	if (vp->v_type != VBAD) {
		if ((want_vp || can_defer) && (vnode_on_reliable_media(vp) == FALSE || (vp->v_flag & VISDIRTY))) {
			vnode_async_list_add(vp);
			vnode_drop_and_unlock(vp);

			*deferred = 1;

			return NULLVP;
		}
		if (vp->v_lflag & VL_DEAD) {
			panic("new_vnode(%p): the vnode is VL_DEAD but not VBAD", vp);
		}

		vnode_lock_convert(vp);
		(void)vnode_reclaim_internal(vp, 1, want_vp, 0);

		if (want_vp) {
			if ((VONLIST(vp))) {
				panic("new_vnode(%p): vp on list", vp);
			}
			if (vp->v_usecount || vp->v_iocount || vp->v_kusecount ||
			    (vp->v_lflag & (VNAMED_UBC | VNAMED_MOUNT | VNAMED_FSHASH))) {
				panic("new_vnode(%p): free vnode still referenced", vp);
			}
			if ((vp->v_mntvnodes.tqe_prev != 0) && (vp->v_mntvnodes.tqe_next != 0)) {
				panic("new_vnode(%p): vnode seems to be on mount list", vp);
			}
			if (!LIST_EMPTY(&vp->v_nclinks) || !TAILQ_EMPTY(&vp->v_ncchildren)) {
				panic("new_vnode(%p): vnode still hooked into the name cache", vp);
			}
		} else {
			vnode_drop_and_unlock(vp);
			vp = NULLVP;
		}
	}
	return vp;
}

__attribute__((noreturn))
static void
async_work_continue(void)
{
	struct async_work_lst *q;
	int     deferred;
	vnode_t vp;

	q = &vnode_async_work_list;

	for (;;) {
		vnode_list_lock();

		if (TAILQ_EMPTY(q)) {
			assert_wait(q, (THREAD_UNINT));

			vnode_list_unlock();

			thread_block((thread_continue_t)async_work_continue);

			continue;
		}
		async_work_handled++;

		vp = TAILQ_FIRST(q);

		vp = process_vp(vp, 0, false, &deferred);

		if (vp != NULLVP) {
			panic("found VBAD vp (%p) on async queue", vp);
		}
	}
}

#if CONFIG_JETSAM
bool do_async_jetsam = false;
#endif

__attribute__((noreturn))
static void
vn_laundry_continue(void)
{
	struct freelst *free_q;
	struct ragelst *rage_q;
	vnode_t vp;
	int deferred;
	bool rage_q_empty;
	bool free_q_empty;


	free_q = &vnode_free_list;
	rage_q = &vnode_rage_list;

	for (;;) {
		vnode_list_lock();

#if CONFIG_JETSAM
		if (do_async_jetsam) {
			do_async_jetsam = false;
			if (deadvnodes <= deadvnodes_low) {
				vnode_list_unlock();

				log(LOG_EMERG, "Initiating vnode jetsam : %d desired, %ld numvnodes, "
				    "%ld free, %ld dead, %ld async, %d rage\n",
				    desiredvnodes, numvnodes, freevnodes, deadvnodes, async_work_vnodes, ragevnodes);

				memorystatus_kill_on_vnode_limit();

				continue;
			}
		}
#endif

		if (!TAILQ_EMPTY(&vnode_async_work_list)) {
			vp = TAILQ_FIRST(&vnode_async_work_list);
			async_work_handled++;

			vp = process_vp(vp, 0, false, &deferred);

			if (vp != NULLVP) {
				panic("found VBAD vp (%p) on async queue", vp);
			}
			continue;
		}

		free_q_empty = TAILQ_EMPTY(free_q);
		rage_q_empty = TAILQ_EMPTY(rage_q);

		if (!rage_q_empty && !free_q_empty) {
			struct timeval current_tv;

			microuptime(&current_tv);
			if (ragevnodes < rage_limit &&
			    ((current_tv.tv_sec - rage_tv.tv_sec) < RAGE_TIME_LIMIT)) {
				rage_q_empty = true;
			}
		}

		if (numvnodes < numvnodes_min || (rage_q_empty && free_q_empty) ||
		    (reusablevnodes <= reusablevnodes_max && deadvnodes >= deadvnodes_high)) {
			assert_wait(free_q, (THREAD_UNINT));

			vnode_list_unlock();

			thread_block((thread_continue_t)vn_laundry_continue);

			continue;
		}

		if (!rage_q_empty) {
			vp = TAILQ_FIRST(rage_q);
		} else {
			vp = TAILQ_FIRST(free_q);
		}

		vp = process_vp(vp, 0, false, &deferred);

		if (vp != NULLVP) {
			/* If process_vp returns a vnode, it is locked and has a holdcount */
			vnode_drop_and_unlock(vp);
			vp = NULLVP;
		}
	}
}

static inline void
wakeup_laundry_thread()
{
	if (deadvnodes_noreuse || (numvnodes >= numvnodes_min && deadvnodes < deadvnodes_low &&
	    (reusablevnodes > reusablevnodes_max || numvnodes >= desiredvnodes))) {
		wakeup(&vnode_free_list);
	}
}

/*
 * This must be called under vnode_list_lock() to prevent race when accessing
 * various vnode stats.
 */
static void
send_freeable_vnodes_telemetry(void)
{
	bool send_event = false;

	/*
	 * Log an event when the 'numvnodes' is above the freeable vnodes threshold
	 * or when it falls back within the threshold.
	 * When the 'numvnodes' is above the threshold, log an event when it has
	 * been incrementally growing by 25%.
	 */
	if ((numvnodes > desiredvnodes) && (freevnodes + deadvnodes) == 0) {
		long last_numvnodes = freeable_vnodes_telemetry.numvnodes;

		if (numvnodes > (last_numvnodes + ((last_numvnodes * 25) / 100)) ||
		    numvnodes >= numvnodes_max) {
			send_event = true;
		}
		freeablevnodes_threshold_crossed = true;
	} else if (freeablevnodes_threshold_crossed &&
	    (freevnodes + deadvnodes) > busyvnodes) {
		freeablevnodes_threshold_crossed = false;
		send_event = true;
	}

	if (__improbable(send_event)) {
		ca_event_t event = CA_EVENT_ALLOCATE_FLAGS(freeable_vnodes, Z_NOWAIT);

		if (event) {
			/*
			 * Update the stats except the 'numvnodes_max' and 'desiredvnodes'
			 * as they are immutable after init.
			 */
			freeable_vnodes_telemetry.numvnodes_min = numvnodes_min;
			freeable_vnodes_telemetry.numvnodes = numvnodes;
			freeable_vnodes_telemetry.freevnodes = freevnodes;
			freeable_vnodes_telemetry.deadvnodes = deadvnodes;
			freeable_vnodes_telemetry.freeablevnodes = freeablevnodes;
			freeable_vnodes_telemetry.busyvnodes = busyvnodes;
			freeable_vnodes_telemetry.threshold_crossed =
			    freeablevnodes_threshold_crossed;

			memcpy(event->data, &freeable_vnodes_telemetry,
			    sizeof(CA_EVENT_TYPE(freeable_vnodes)));

			if (!freeablevnodes_threshold_crossed) {
				freeable_vnodes_telemetry.numvnodes = 0;
			}
			CA_EVENT_SEND(event);
		}
	}
}

static int
new_vnode(vnode_t *vpp, bool can_free)
{
	long force_alloc_min;
	vnode_t vp;
#if CONFIG_JETSAM
	uint32_t retries = 0, max_retries = 2;                  /* retry incase of tablefull */
#else
	uint32_t retries = 0, max_retries = 100;                /* retry incase of tablefull */
#endif
	int force_alloc = 0, walk_count = 0;
	boolean_t need_reliable_vp = FALSE;
	int deferred;
	struct timeval initial_tv;
	struct timeval current_tv;
	proc_t  curproc = current_proc();
	bool force_alloc_freeable = false;

	if (vn_dealloc_level == DEALLOC_VNODE_NONE) {
		can_free = false;
	}

	initial_tv.tv_sec = 0;
retry:
	vp = NULLVP;

	vnode_list_lock();
	newvnode++;

	if (need_reliable_vp == TRUE) {
		async_work_timed_out++;
	}

	/*
	 * The vnode list lock was dropped after force_alloc_freeable was set,
	 * reevaluate.
	 */
	force_alloc_min = MAX(desiredvnodes, numvnodes_min);
	if (force_alloc_freeable &&
	    (numvnodes < force_alloc_min || numvnodes >= numvnodes_max)) {
		force_alloc_freeable = false;
	}

#if CONFIG_JETSAM
	if ((numvnodes_max > desiredvnodes) && numvnodes > (numvnodes_max - 100)
#if (DEVELOPMENT || DEBUG)
	    && !bootarg_no_vnode_jetsam
#endif
	    ) {
		do_async_jetsam = true;
		wakeup(&vnode_free_list);
	}
#endif /* CONFIG_JETSAM */

	if (((numvnodes - deadvnodes + deadvnodes_noreuse) < desiredvnodes) ||
	    force_alloc || force_alloc_freeable) {
		struct timespec ts;
		uint32_t vflag = 0;

		/*
		 * Can always reuse a dead one except if it is in the process of
		 * being freed or the FS cannot handle freeable vnodes.
		 */
		if (!TAILQ_EMPTY(&vnode_dead_list)) {
			/* Select an appropriate deadvnode */
			if (numvnodes <= numvnodes_min || !can_free) {
				/* all vnodes upto numvnodes_min are not freeable */
				vp = TAILQ_FIRST(&vnode_dead_list);
				if (numvnodes > numvnodes_min &&
				    (vp->v_flag & VCANDEALLOC)) {
					/*
					 * Freeable vnodes are added to the
					 * back of the queue, so if the first
					 * from the front is freeable, then
					 * there are none on the dead list.
					 */
					vp = NULLVP;
				}
			} else {
				/*
				 * Filesystems which opt in to freeable vnodes
				 * can get either one.
				 */
				TAILQ_FOREACH_REVERSE(vp, &vnode_dead_list,
				    deadlst, v_freelist) {
					if (!(vp->v_listflag & VLIST_NO_REUSE)) {
						break;
					}
				}
			}

			if (vp) {
				force_alloc_freeable = false;
				goto steal_this_vp;
			}
		}

		/*
		 * no dead vnodes available... if we're under
		 * the limit, we'll create a new vnode
		 */
		numvnodes++;
		if (force_alloc) {
			numvnodes_min++;
		} else if (can_free && (numvnodes > numvnodes_min)) {
			allocedvnodes++;
			freeablevnodes++;
			vflag = VCANDEALLOC;

			send_freeable_vnodes_telemetry();
		}
		vnode_list_unlock();

		if (nc_smr_enabled) {
			vp = zalloc_smr(vnode_zone, Z_WAITOK_ZERO_NOFAIL);
		} else {
			vp = zalloc_flags(vnode_zone, Z_WAITOK_ZERO_NOFAIL);
		}

		VLISTNONE(vp);          /* avoid double queue removal */
		lck_mtx_init(&vp->v_lock, &vnode_lck_grp, &vnode_lck_attr);

		TAILQ_INIT(&vp->v_ncchildren);

		klist_init(&vp->v_knotes);
		nanouptime(&ts);
		vp->v_id = (uint32_t)ts.tv_nsec;
		vp->v_flag = VSTANDARD | vflag;
		if (force_alloc_freeable) {
			/* This vnode should be recycled and freed immediately */
			vp->v_lflag = VL_MARKTERM;
			vp->v_listflag = VLIST_NO_REUSE;
		}

		if (vflag & VCANDEALLOC) {
			os_atomic_inc(&busyvnodes, relaxed);
		}

#if CONFIG_MACF
		if (mac_vnode_label_init_needed(vp)) {
			mac_vnode_label_init(vp);
		}
#endif /* MAC */

#if CONFIG_IOCOUNT_TRACE
		if (__improbable(bootarg_vnode_iocount_trace)) {
			vp->v_iocount_trace = (vnode_iocount_trace_t)zalloc_permanent(
				IOCOUNT_TRACE_MAX_TYPES * sizeof(struct vnode_iocount_trace),
				ZALIGN(struct vnode_iocount_trace));
		}
#endif /* CONFIG_IOCOUNT_TRACE */

#if CONFIG_FILE_LEASES
		LIST_INIT(&vp->v_leases);
#endif

		vp->v_iocount = 1;

		goto done;
	}

	microuptime(&current_tv);

#define MAX_WALK_COUNT 1000

	if (!TAILQ_EMPTY(&vnode_rage_list) &&
	    (ragevnodes >= rage_limit ||
	    (current_tv.tv_sec - rage_tv.tv_sec) >= RAGE_TIME_LIMIT)) {
		TAILQ_FOREACH(vp, &vnode_rage_list, v_freelist) {
			if (!(vp->v_listflag & VLIST_RAGE)) {
				panic("new_vnode: vp (%p) on RAGE list not marked VLIST_RAGE", vp);
			}

			// if we're a dependency-capable process, skip vnodes that can
			// cause recycling deadlocks. (i.e. this process is diskimages
			// helper and the vnode is in a disk image).  Querying the
			// mnt_kern_flag for the mount's virtual device status
			// is safer than checking the mnt_dependent_process, which
			// may not be updated if there are multiple devnode layers
			// in between the disk image and the final consumer.

			if (((curproc->p_flag & P_DEPENDENCY_CAPABLE) == 0 || vp->v_mount == NULL ||
			    (vp->v_mount->mnt_kern_flag & MNTK_VIRTUALDEV) == 0) &&
			    !(vp->v_listflag & VLIST_NO_REUSE) &&
			    (can_free || !(vp->v_flag & VCANDEALLOC))) {
				/*
				 * if need_reliable_vp == TRUE, then we've already sent one or more
				 * non-reliable vnodes to the async thread for processing and timed
				 * out waiting for a dead vnode to show up.  Use the MAX_WALK_COUNT
				 * mechanism to first scan for a reliable vnode before forcing
				 * a new vnode to be created
				 */
				if (need_reliable_vp == FALSE || vnode_on_reliable_media(vp) == TRUE) {
					break;
				}
			}

			// don't iterate more than MAX_WALK_COUNT vnodes to
			// avoid keeping the vnode list lock held for too long.

			if (walk_count++ > MAX_WALK_COUNT) {
				vp = NULL;
				break;
			}
		}
	}

	if (vp == NULL && !TAILQ_EMPTY(&vnode_free_list)) {
		/*
		 * Pick the first vp for possible reuse
		 */
		walk_count = 0;
		TAILQ_FOREACH(vp, &vnode_free_list, v_freelist) {
			// if we're a dependency-capable process, skip vnodes that can
			// cause recycling deadlocks. (i.e. this process is diskimages
			// helper and the vnode is in a disk image).  Querying the
			// mnt_kern_flag for the mount's virtual device status
			// is safer than checking the mnt_dependent_process, which
			// may not be updated if there are multiple devnode layers
			// in between the disk image and the final consumer.

			if (((curproc->p_flag & P_DEPENDENCY_CAPABLE) == 0 || vp->v_mount == NULL ||
			    (vp->v_mount->mnt_kern_flag & MNTK_VIRTUALDEV) == 0) &&
			    !(vp->v_listflag & VLIST_NO_REUSE) &&
			    (can_free || !(vp->v_flag & VCANDEALLOC))) {
				/*
				 * if need_reliable_vp == TRUE, then we've already sent one or more
				 * non-reliable vnodes to the async thread for processing and timed
				 * out waiting for a dead vnode to show up.  Use the MAX_WALK_COUNT
				 * mechanism to first scan for a reliable vnode before forcing
				 * a new vnode to be created
				 */
				if (need_reliable_vp == FALSE || vnode_on_reliable_media(vp) == TRUE) {
					break;
				}
			}

			// don't iterate more than MAX_WALK_COUNT vnodes to
			// avoid keeping the vnode list lock held for too long.

			if (walk_count++ > MAX_WALK_COUNT) {
				vp = NULL;
				break;
			}
		}
	}

	//
	// if we don't have a vnode and the walk_count is >= MAX_WALK_COUNT
	// then we're trying to create a vnode on behalf of a
	// process like diskimages-helper that has file systems
	// mounted on top of itself (and thus we can't reclaim
	// vnodes in the file systems on top of us).  if we can't
	// find a vnode to reclaim then we'll just have to force
	// the allocation.
	//
	if (vp == NULL && walk_count >= MAX_WALK_COUNT) {
		force_alloc = 1;
		vnode_list_unlock();
		goto retry;
	}

	if (vp == NULL) {
		if (can_free && (vn_dealloc_level > DEALLOC_VNODE_NONE) &&
		    (numvnodes >= force_alloc_min) && (numvnodes < numvnodes_max)) {
			force_alloc_freeable = true;
			vnode_list_unlock();
			goto retry;
		}
		vnode_list_unlock();

		/*
		 * we've reached the system imposed maximum number of vnodes
		 * but there isn't a single one available
		 * wait a bit and then retry... if we can't get a vnode
		 * after our target number of retries, than log a complaint
		 */
		if (++retries <= max_retries) {
			delay_for_interval(1, 1000 * 1000);
			goto retry;
		}

		tablefull("vnode");
		log(LOG_EMERG, "%d desired, %ld numvnodes, "
		    "%ld free, %ld dead, %ld async, %d rage\n",
		    desiredvnodes, numvnodes, freevnodes, deadvnodes, async_work_vnodes, ragevnodes);

#if CONFIG_JETSAM
		/*
		 * Running out of vnodes tends to make a system unusable. Start killing
		 * processes that jetsam knows are killable.
		 */
		if (memorystatus_kill_on_vnode_limit() == FALSE
#if DEVELOPMENT || DEBUG
		    || bootarg_no_vnode_jetsam
#endif
		    ) {
			/*
			 * If jetsam can't find any more processes to kill and there
			 * still aren't any free vnodes, panic. Hopefully we'll get a
			 * panic log to tell us why we ran out.
			 */
			panic("vnode table is full");
		}

		/*
		 * Now that we've killed someone, wait a bit and continue looking
		 */
		delay_for_interval(3, 1000 * 1000);
		retries = 0;
		goto retry;
#endif

		*vpp = NULL;
		return ENFILE;
	}
	newvnode_nodead++;
steal_this_vp:
	if ((vp = process_vp(vp, 1, true, &deferred)) == NULLVP) {
		if (deferred) {
			int     elapsed_msecs;
			struct timeval elapsed_tv;

			if (initial_tv.tv_sec == 0) {
				microuptime(&initial_tv);
			}

			vnode_list_lock();

			dead_vnode_waited++;
			dead_vnode_wanted++;

			/*
			 * note that we're only going to explicitly wait 10ms
			 * for a dead vnode to become available, since even if one
			 * isn't available, a reliable vnode might now be available
			 * at the head of the VRAGE or free lists... if so, we
			 * can satisfy the new_vnode request with less latency then waiting
			 * for the full 100ms duration we're ultimately willing to tolerate
			 */
			assert_wait_timeout((caddr_t)&dead_vnode_wanted, (THREAD_INTERRUPTIBLE), 10000, NSEC_PER_USEC);

			vnode_list_unlock();

			thread_block(THREAD_CONTINUE_NULL);

			microuptime(&elapsed_tv);

			timevalsub(&elapsed_tv, &initial_tv);
			elapsed_msecs = (int)(elapsed_tv.tv_sec * 1000 + elapsed_tv.tv_usec / 1000);

			if (elapsed_msecs >= 100) {
				/*
				 * we've waited long enough... 100ms is
				 * somewhat arbitrary for this case, but the
				 * normal worst case latency used for UI
				 * interaction is 100ms, so I've chosen to
				 * go with that.
				 *
				 * setting need_reliable_vp to TRUE
				 * forces us to find a reliable vnode
				 * that we can process synchronously, or
				 * to create a new one if the scan for
				 * a reliable one hits the scan limit
				 */
				need_reliable_vp = TRUE;
			}
		}
		goto retry;
	}
	OSAddAtomicLong(1, &num_reusedvnodes);


#if CONFIG_MACF
	/*
	 * We should never see VL_LABELWAIT or VL_LABEL here.
	 * as those operations hold a reference.
	 */
	assert((vp->v_lflag & VL_LABELWAIT) != VL_LABELWAIT);
	assert((vp->v_lflag & VL_LABEL) != VL_LABEL);
	if (vp->v_lflag & VL_LABELED || mac_vnode_label(vp) != NULL) {
		vnode_lock_convert(vp);
		mac_vnode_label_recycle(vp);
	} else if (mac_vnode_label_init_needed(vp)) {
		vnode_lock_convert(vp);
		mac_vnode_label_init(vp);
	}

#endif /* MAC */

	vp->v_iocount = 1;
	vp->v_lflag = 0;
	vp->v_writecount = 0;
	vp->v_references = 0;
	vp->v_iterblkflags = 0;
	if (can_free && (vp->v_flag & VCANDEALLOC)) {
		vp->v_flag = VSTANDARD | VCANDEALLOC;
	} else {
		vp->v_flag = VSTANDARD;
	}

	/* vbad vnodes can point to dead_mountp */
	vp->v_mount = NULL;
	vp->v_defer_reclaimlist = (vnode_t)0;

	/* process_vp returns a locked vnode with a holdcount */
	vnode_drop_and_unlock(vp);

done:
	*vpp = vp;

	return 0;
}

void
vnode_lock(vnode_t vp)
{
	lck_mtx_lock(&vp->v_lock);
}

void
vnode_lock_spin(vnode_t vp)
{
	lck_mtx_lock_spin(&vp->v_lock);
}

void
vnode_unlock(vnode_t vp)
{
	lck_mtx_unlock(&vp->v_lock);
}

void
vnode_hold(vnode_t vp)
{
	int32_t old_holdcount = os_atomic_inc_orig(&vp->v_holdcount, relaxed);

	if (old_holdcount == INT32_MAX) {
		/*
		 * Because we allow atomic ops on the holdcount it is
		 * possible that when the vnode is examined, its holdcount
		 * is different than what will be printed in this
		 * panic message.
		 */
		panic("%s: vp %p holdcount overflow from : %d v_tag = %d, v_type = %d, v_flag = %x.",
		    __FUNCTION__, vp, old_holdcount, vp->v_tag, vp->v_type, vp->v_flag);
	}
}

#define VNODE_HOLD_NO_SMR    (1<<29) /* Disable vnode_hold_smr */

/*
 * To be used when smr is the only protection (cache_lookup and cache_lookup_path)
 */
bool
vnode_hold_smr(vnode_t vp)
{
	int32_t holdcount;

	/*
	 * For "high traffic" vnodes like rootvnode, the atomic
	 * cmpexcg loop below can turn into a infinite loop, no need
	 * to do it for vnodes that won't be dealloc'ed
	 */
	if (!(os_atomic_load(&vp->v_flag, relaxed) & VCANDEALLOC)) {
		vnode_hold(vp);
		return true;
	}

	for (;;) {
		holdcount = os_atomic_load(&vp->v_holdcount, relaxed);

		if (holdcount & VNODE_HOLD_NO_SMR) {
			return false;
		}

		if ((os_atomic_cmpxchg(&vp->v_holdcount, holdcount, holdcount + 1, relaxed) != 0)) {
			return true;
		}
	}
}

/*
 * free callback from smr enabled zones
 */
static void
vnode_smr_free(void *_vp, __unused size_t _size)
{
	vnode_t vp = _vp;

	bzero(vp, sizeof(*vp));
}

static vnode_t
vnode_drop_internal(vnode_t vp, bool locked)
{
	int32_t old_holdcount = os_atomic_dec_orig(&vp->v_holdcount, relaxed);

	if (old_holdcount < 1) {
		if (locked) {
			vnode_unlock(vp);
		}

		/*
		 * Because we allow atomic ops on the holdcount it is possible
		 * that when the vnode is examined, its holdcount is different
		 * than what will be printed in this panic message.
		 */
		panic("%s : vp %p holdcount -ve: %d.  v_tag = %d, v_type = %d, v_flag = %x.",
		    __FUNCTION__, vp, old_holdcount - 1, vp->v_tag, vp->v_type, vp->v_flag);
	}

	if (vn_dealloc_level == DEALLOC_VNODE_NONE || old_holdcount > 1 ||
	    !(vp->v_flag & VCANDEALLOC) || !(vp->v_lflag & VL_DEAD)) {
		if (locked) {
			vnode_unlock(vp);
		}
		return vp;
	}

	if (!locked) {
		vnode_lock(vp);
	}

	if ((os_atomic_load(&vp->v_holdcount, relaxed) != 0) || vp->v_iocount ||
	    vp->v_usecount || !(vp->v_flag & VCANDEALLOC) || !(vp->v_lflag & VL_DEAD)) {
		vnode_unlock(vp);
		return vp;
	}

	vnode_list_lock();

	/*
	 * the v_listflag field is protected by the vnode_list_lock
	 */
	if (VONLIST(vp) && (vp->v_listflag & VLIST_DEAD) &&
	    (numvnodes > desiredvnodes || (vp->v_listflag & VLIST_NO_REUSE) ||
	    vn_dealloc_level != DEALLOC_VNODE_ALL || deadvnodes >= deadvnodes_high) &&
	    (os_atomic_cmpxchg(&vp->v_holdcount, 0, VNODE_HOLD_NO_SMR, relaxed) != 0)) {
		VREMDEAD("vnode_list_remove", vp);
		numvnodes--;
		freeablevnodes--;
		deallocedvnodes++;
		vp->v_listflag = 0;

		send_freeable_vnodes_telemetry();
		vnode_list_unlock();

#if CONFIG_MACF
		struct label *tmpl = mac_vnode_label(vp);
		vp->v_label = NULL;
#endif /* CONFIG_MACF */

		vnode_unlock(vp);

#if CONFIG_MACF
		if (tmpl) {
			mac_vnode_label_free(tmpl);
		}
#endif /* CONFIG_MACF */

		if (nc_smr_enabled) {
			zfree_smr(vnode_zone, vp);
		} else {
			zfree(vnode_zone, vp);
		}

		vp = NULLVP;
	} else {
		vnode_list_unlock();
		vnode_unlock(vp);
	}

	return vp;
}

vnode_t
vnode_drop_and_unlock(vnode_t vp)
{
	return vnode_drop_internal(vp, true);
}

vnode_t
vnode_drop(vnode_t vp)
{
	return vnode_drop_internal(vp, false);
}

SYSCTL_NODE(_vfs, OID_AUTO, vnstats, CTLFLAG_RD | CTLFLAG_LOCKED, NULL, "vfs vnode stats");

SYSCTL_COMPAT_INT(_vfs_vnstats, OID_AUTO, vn_dealloc_level,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &vn_dealloc_level, 0, "");
SYSCTL_COMPAT_INT(_vfs_vnstats, OID_AUTO, desired_vnodes,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &desiredvnodes, 0, "");
SYSCTL_LONG(_vfs_vnstats, OID_AUTO, num_vnodes,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &numvnodes, "");
SYSCTL_COMPAT_INT(_vfs_vnstats, OID_AUTO, num_vnodes_min,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &numvnodes_min, 0, "");
SYSCTL_COMPAT_INT(_vfs_vnstats, OID_AUTO, num_vnodes_max,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &numvnodes_max, 0, "");
SYSCTL_COMPAT_INT(_vfs_vnstats, OID_AUTO, num_deallocable_vnodes,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &freeablevnodes, 0, "");
SYSCTL_LONG(_vfs_vnstats, OID_AUTO, num_deallocable_busy_vnodes,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &busyvnodes, "");
SYSCTL_LONG(_vfs_vnstats, OID_AUTO, num_dead_vnodes,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &deadvnodes, "");
SYSCTL_LONG(_vfs_vnstats, OID_AUTO, num_dead_vnodes_to_dealloc,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &deadvnodes_noreuse, "");
SYSCTL_LONG(_vfs_vnstats, OID_AUTO, num_async_work_vnodes,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &async_work_vnodes, "");
SYSCTL_COMPAT_INT(_vfs_vnstats, OID_AUTO, num_rapid_aging_vnodes,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &ragevnodes, 0, "");
SYSCTL_LONG(_vfs_vnstats, OID_AUTO, num_free_vnodes,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &freevnodes, "");
SYSCTL_LONG(_vfs_vnstats, OID_AUTO, num_recycledvnodes,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &num_recycledvnodes, "");
SYSCTL_QUAD(_vfs_vnstats, OID_AUTO, num_allocedvnodes,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &allocedvnodes, "");
SYSCTL_QUAD(_vfs_vnstats, OID_AUTO, num_deallocedvnodes,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &deallocedvnodes, "");
SYSCTL_QUAD(_vfs_vnstats, OID_AUTO, num_newvnode_calls,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &newvnode, "");
SYSCTL_QUAD(_vfs_vnstats, OID_AUTO, num_newvnode_calls_nodead,
    CTLFLAG_RD | CTLFLAG_LOCKED,
    &newvnode_nodead, "");

int
vnode_get(struct vnode *vp)
{
	int retval;

	vnode_lock_spin(vp);
	retval = vnode_get_locked(vp);
	vnode_unlock(vp);

	return retval;
}

int
vnode_get_locked(struct vnode *vp)
{
#if DIAGNOSTIC
	lck_mtx_assert(&vp->v_lock, LCK_MTX_ASSERT_OWNED);
#endif
	if ((vp->v_iocount == 0) && (vp->v_lflag & (VL_TERMINATE | VL_DEAD))) {
		return ENOENT;
	}

	if (os_add_overflow(vp->v_iocount, 1, &vp->v_iocount)) {
		panic("v_iocount overflow");
	}

#ifdef CONFIG_IOCOUNT_TRACE
	record_vp(vp, 1);
#endif
	return 0;
}

/*
 * vnode_getwithvid() cuts in line in front of a vnode drain (that is,
 * while the vnode is draining, but at no point after that) to prevent
 * deadlocks when getting vnodes from filesystem hashes while holding
 * resources that may prevent other iocounts from being released.
 */
int
vnode_getwithvid(vnode_t vp, uint32_t vid)
{
	return vget_internal(vp, vid, (VNODE_NODEAD | VNODE_WITHID | VNODE_DRAINO));
}

/*
 * vnode_getwithvid_drainok() is like vnode_getwithvid(), but *does* block behind a vnode
 * drain; it exists for use in the VFS name cache, where we really do want to block behind
 * vnode drain to prevent holding off an unmount.
 */
int
vnode_getwithvid_drainok(vnode_t vp, uint32_t vid)
{
	return vget_internal(vp, vid, (VNODE_NODEAD | VNODE_WITHID));
}

int
vnode_getwithref(vnode_t vp)
{
	return vget_internal(vp, 0, 0);
}

int
vnode_getwithref_noblock(vnode_t vp)
{
	return vget_internal(vp, 0, VNODE_NOBLOCK);
}

__private_extern__ int
vnode_getalways(vnode_t vp)
{
	return vget_internal(vp, 0, VNODE_ALWAYS);
}

__private_extern__ int
vnode_getalways_from_pager(vnode_t vp)
{
	return vget_internal(vp, 0, VNODE_ALWAYS | VNODE_PAGER);
}

static inline void
vn_set_dead(vnode_t vp)
{
	vp->v_mount = NULL;
	vp->v_op = dead_vnodeop_p;
	vp->v_tag = VT_NON;
	vp->v_data = NULL;
	vp->v_type = VBAD;
	vp->v_lflag |= VL_DEAD;
}

static int
vnode_put_internal_locked(vnode_t vp, bool from_pager)
{
	vfs_context_t ctx = vfs_context_current();      /* hoist outside loop */

#if DIAGNOSTIC
	lck_mtx_assert(&vp->v_lock, LCK_MTX_ASSERT_OWNED);
#endif
retry:
	if (vp->v_iocount < 1) {
		panic("vnode_put(%p): iocount < 1", vp);
	}

	if ((vp->v_usecount > 0) || (vp->v_iocount > 1)) {
		vnode_dropiocount(vp);
		return 0;
	}

	if (((vp->v_lflag & (VL_DEAD | VL_NEEDINACTIVE)) == VL_NEEDINACTIVE)) {
		vp->v_lflag &= ~VL_NEEDINACTIVE;

		if (UBCINFOEXISTS(vp)) {
			ubc_cs_free_and_vnode_unlock(vp);
		} else {
			vnode_unlock(vp);
		}

		VNOP_INACTIVE(vp, ctx);

		vnode_lock_spin(vp);
		/*
		 * because we had to drop the vnode lock before calling
		 * VNOP_INACTIVE, the state of this vnode may have changed...
		 * we may pick up both VL_MARTERM and either
		 * an iocount or a usecount while in the VNOP_INACTIVE call
		 * we don't want to call vnode_reclaim_internal on a vnode
		 * that has active references on it... so loop back around
		 * and reevaluate the state
		 */
		goto retry;
	}
	vp->v_lflag &= ~VL_NEEDINACTIVE;

	vnode_lock_convert(vp);
	if ((vp->v_lflag & (VL_MARKTERM | VL_TERMINATE | VL_DEAD)) == VL_MARKTERM) {
		if (from_pager) {
			/*
			 * We can't initiate reclaim when called from the pager
			 * because it will deadlock with itself so we hand it
			 * off to the async cleaner thread.
			 */
			vnode_async_list_add(vp);
		} else {
			vnode_reclaim_internal(vp, 1, 1, 0);
		}
	}
	vnode_dropiocount(vp);
	vnode_list_add(vp);

	return 0;
}

int
vnode_put_locked(vnode_t vp)
{
	return vnode_put_internal_locked(vp, false);
}

int
vnode_put(vnode_t vp)
{
	int retval;

	vnode_lock_spin(vp);
	vnode_hold(vp);
	retval = vnode_put_internal_locked(vp, false);
	vnode_drop_and_unlock(vp);

	return retval;
}

int
vnode_put_from_pager(vnode_t vp)
{
	int retval;

	vnode_lock_spin(vp);
	vnode_hold(vp);
	/* Cannot initiate reclaim while paging */
	retval = vnode_put_internal_locked(vp, true);
	vnode_drop_and_unlock(vp);

	return retval;
}

int
vnode_writecount(vnode_t vp)
{
	return vp->v_writecount;
}

/* is vnode_t in use by others?  */
int
vnode_isinuse(vnode_t vp, int refcnt)
{
	return vnode_isinuse_locked(vp, refcnt, 0);
}

int
vnode_usecount(vnode_t vp)
{
	return vp->v_usecount;
}

int
vnode_iocount(vnode_t vp)
{
	if (!(vp->v_ext_flag & VE_LINKCHANGE)) {
		return vp->v_iocount;
	} else {
		int iocount = 0;
		vnode_lock_spin(vp);
		if (!(vp->v_ext_flag & VE_LINKCHANGE)) {
			iocount = vp->v_iocount;
		} else {
			/* the "link lock" takes its own iocount */
			iocount = vp->v_iocount - 1;
		}
		vnode_unlock(vp);
		return iocount;
	}
}

int
vnode_isinuse_locked(vnode_t vp, int refcnt, int locked)
{
	int retval = 0;

	if (!locked) {
		vnode_lock_spin(vp);
	}
	if ((vp->v_type != VREG) && ((vp->v_usecount - vp->v_kusecount) > refcnt)) {
		retval = 1;
		goto out;
	}
	if (vp->v_type == VREG) {
		retval = ubc_isinuse_locked(vp, refcnt, 1);
	}

out:
	if (!locked) {
		vnode_unlock(vp);
	}
	return retval;
}

kauth_cred_t
vnode_cred(vnode_t vp)
{
	if (vp->v_cred) {
		return kauth_cred_require(vp->v_cred);
	}

	return NULL;
}


/* resume vnode_t */
errno_t
vnode_resume(vnode_t vp)
{
	if ((vp->v_lflag & VL_SUSPENDED) && vp->v_owner == current_thread()) {
		vnode_lock_spin(vp);
		vp->v_lflag &= ~VL_SUSPENDED;
		vp->v_owner = NULL;
		vnode_unlock(vp);

		wakeup(&vp->v_iocount);
	}
	return 0;
}

/* suspend vnode_t
 * Please do not use on more than one vnode at a time as it may
 * cause deadlocks.
 * xxx should we explicity prevent this from happening?
 */

errno_t
vnode_suspend(vnode_t vp)
{
	if (vp->v_lflag & VL_SUSPENDED) {
		return EBUSY;
	}

	vnode_lock_spin(vp);

	/*
	 * xxx is this sufficient to check if a vnode_drain is
	 * progress?
	 */

	if (vp->v_owner == NULL) {
		vp->v_lflag |= VL_SUSPENDED;
		vp->v_owner = current_thread();
	}
	vnode_unlock(vp);

	return 0;
}

/*
 * Release any blocked locking requests on the vnode.
 * Used for forced-unmounts.
 *
 * XXX	What about network filesystems?
 */
static void
vnode_abort_advlocks(vnode_t vp)
{
	if (vp->v_flag & VLOCKLOCAL) {
		lf_abort_advlocks(vp);
	}
}


static errno_t
vnode_drain(vnode_t vp)
{
	if (vp->v_lflag & VL_DRAIN) {
		panic("vnode_drain: recursive drain");
		return ENOENT;
	}
	vp->v_lflag |= VL_DRAIN;
	vp->v_owner = current_thread();

	while (vp->v_iocount > 1) {
		if (bootarg_no_vnode_drain) {
			struct timespec ts = {.tv_sec = 10, .tv_nsec = 0};
			int error;

			if (vfs_unmountall_started) {
				ts.tv_sec = 1;
			}

			error = msleep(&vp->v_iocount, &vp->v_lock, PVFS, "vnode_drain_with_timeout", &ts);

			/* Try to deal with leaked iocounts under bootarg and shutting down */
			if (vp->v_iocount > 1 && error == EWOULDBLOCK &&
			    ts.tv_sec == 1 && vp->v_numoutput == 0) {
				vp->v_iocount = 1;
				break;
			}
		} else {
			msleep(&vp->v_iocount, &vp->v_lock, PVFS, "vnode_drain", NULL);
		}
	}

	vp->v_lflag &= ~VL_DRAIN;

	return 0;
}


/*
 * if the number of recent references via vnode_getwithvid or vnode_getwithref
 * exceeds this threshold, than 'UN-AGE' the vnode by removing it from
 * the LRU list if it's currently on it... once the iocount and usecount both drop
 * to 0, it will get put back on the end of the list, effectively making it younger
 * this allows us to keep actively referenced vnodes in the list without having
 * to constantly remove and add to the list each time a vnode w/o a usecount is
 * referenced which costs us taking and dropping a global lock twice.
 * However, if the vnode is marked DIRTY, we want to pull it out much earlier
 */
#define UNAGE_THRESHHOLD        25
#define UNAGE_DIRTYTHRESHHOLD    6

errno_t
vnode_getiocount(vnode_t vp, unsigned int vid, int vflags)
{
	int nodead = vflags & VNODE_NODEAD;
	int nosusp = vflags & VNODE_NOSUSPEND;
	int always = vflags & VNODE_ALWAYS;
	int beatdrain = vflags & VNODE_DRAINO;
	int withvid = vflags & VNODE_WITHID;
	int forpager = vflags & VNODE_PAGER;
	int noblock = vflags & VNODE_NOBLOCK;

	for (;;) {
		int sleepflg = 0;

		/*
		 * if it is a dead vnode with deadfs
		 */
		if (nodead && (vp->v_lflag & VL_DEAD) && ((vp->v_type == VBAD) || (vp->v_data == 0))) {
			return ENOENT;
		}
		/*
		 * will return VL_DEAD ones
		 */
		if ((vp->v_lflag & (VL_SUSPENDED | VL_DRAIN | VL_TERMINATE)) == 0) {
			break;
		}
		/*
		 * if suspended vnodes are to be failed
		 */
		if (nosusp && (vp->v_lflag & VL_SUSPENDED)) {
			return ENOENT;
		}
		/*
		 * if you are the owner of drain/suspend/termination , can acquire iocount
		 * check for VL_TERMINATE; it does not set owner
		 */
		if ((vp->v_lflag & (VL_DRAIN | VL_SUSPENDED | VL_TERMINATE)) &&
		    (vp->v_owner == current_thread())) {
			break;
		}

		if (always != 0) {
			break;
		}

		if (noblock && (vp->v_lflag & (VL_DRAIN | VL_SUSPENDED | VL_TERMINATE))) {
			return ENOENT;
		}

		/*
		 * If this vnode is getting drained, there are some cases where
		 * we can't block or, in case of tty vnodes, want to be
		 * interruptible.
		 */
		if (vp->v_lflag & VL_DRAIN) {
			/*
			 * In some situations, we want to get an iocount
			 * even if the vnode is draining to prevent deadlock,
			 * e.g. if we're in the filesystem, potentially holding
			 * resources that could prevent other iocounts from
			 * being released.
			 */
			if (beatdrain) {
				break;
			}
			/*
			 * Don't block if the vnode's mount point is unmounting as
			 * we may be the thread the unmount is itself waiting on
			 * Only callers who pass in vids (at this point, we've already
			 * handled nosusp and nodead) are expecting error returns
			 * from this function, so only we can only return errors for
			 * those. ENODEV is intended to inform callers that the call
			 * failed because an unmount is in progress.
			 */
			if (withvid && (vp->v_mount) && vfs_isunmount(vp->v_mount)) {
				return ENODEV;
			}

			if (vnode_istty(vp)) {
				sleepflg = PCATCH;
			}
		}

		vnode_lock_convert(vp);

		if (vp->v_lflag & VL_TERMINATE) {
			int error;

			vp->v_lflag |= VL_TERMWANT;

			error = msleep(&vp->v_lflag, &vp->v_lock,
			    (PVFS | sleepflg), "vnode getiocount", NULL);
			if (error) {
				return error;
			}
		} else {
			msleep(&vp->v_iocount, &vp->v_lock, PVFS, "vnode_getiocount", NULL);
		}
	}
	if (withvid && vid != vp->v_id) {
		return ENOENT;
	}
	if (!forpager && (++vp->v_references >= UNAGE_THRESHHOLD ||
	    (vp->v_flag & VISDIRTY && vp->v_references >= UNAGE_DIRTYTHRESHHOLD))) {
		vp->v_references = 0;
		vnode_list_remove(vp);
	}
	vp->v_iocount++;
#ifdef CONFIG_IOCOUNT_TRACE
	record_vp(vp, 1);
#endif
	return 0;
}

static void
vnode_dropiocount(vnode_t vp)
{
	if (vp->v_iocount < 1) {
		panic("vnode_dropiocount(%p): v_iocount < 1", vp);
	}

	vp->v_iocount--;
#ifdef CONFIG_IOCOUNT_TRACE
	record_vp(vp, -1);
#endif
	if ((vp->v_lflag & (VL_DRAIN | VL_SUSPENDED)) && (vp->v_iocount <= 1)) {
		wakeup(&vp->v_iocount);
	}
}


void
vnode_reclaim(struct vnode * vp)
{
	vnode_reclaim_internal(vp, 0, 0, 0);
}

__private_extern__
void
vnode_reclaim_internal(struct vnode * vp, int locked, int reuse, int flags)
{
	int isfifo = 0;
	bool clear_tty_revoke = false;

	if (!locked) {
		vnode_lock(vp);
	}

	if (vp->v_lflag & VL_TERMINATE) {
		panic("vnode reclaim in progress");
	}
	vp->v_lflag |= VL_TERMINATE;

	vn_clearunionwait(vp, 1);

	/*
	 * We have to force any terminals in reads to return and give up
	 * their iocounts. It's important to do this after VL_TERMINATE
	 * has been set to ensure new reads are blocked while the
	 * revoke is in progress.
	 */
	if (vnode_istty(vp) && (flags & REVOKEALL) && (vp->v_iocount > 1)) {
		vnode_unlock(vp);
		VNOP_IOCTL(vp, TIOCREVOKE, (caddr_t)NULL, 0, vfs_context_kernel());
		clear_tty_revoke = true;
		vnode_lock(vp);
	}

	vnode_drain(vp);

	if (clear_tty_revoke) {
		vnode_unlock(vp);
		VNOP_IOCTL(vp, TIOCREVOKECLEAR, (caddr_t)NULL, 0, vfs_context_kernel());
		vnode_lock(vp);
	}

#if CONFIG_FILE_LEASES
	/*
	 * Revoke all leases in place for this vnode as it is about to be reclaimed.
	 * In normal case, there shouldn't be any leases in place by the time we
	 * get here as there shouldn't be any opens on the vnode (usecount == 0).
	 * However, in the case of force unmount or unmount of a volume that
	 * contains file that was opened with O_EVTONLY then the vnode can be
	 * reclaimed while the file is still opened.
	 */
	vnode_revokelease(vp, true);
#endif

	isfifo = (vp->v_type == VFIFO);

	if (vp->v_type != VBAD) {
		vgone(vp, flags);               /* clean and reclaim the vnode */
	}
	/*
	 * give the vnode a new identity so that vnode_getwithvid will fail
	 * on any stale cache accesses...
	 * grab the list_lock so that if we're in "new_vnode"
	 * behind the list_lock trying to steal this vnode, the v_id is stable...
	 * once new_vnode drops the list_lock, it will block trying to take
	 * the vnode lock until we release it... at that point it will evaluate
	 * whether the v_vid has changed
	 * also need to make sure that the vnode isn't on a list where "new_vnode"
	 * can find it after the v_id has been bumped until we are completely done
	 * with the vnode (i.e. putting it back on a list has to be the very last
	 * thing we do to this vnode... many of the callers of vnode_reclaim_internal
	 * are holding an io_count on the vnode... they need to drop the io_count
	 * BEFORE doing a vnode_list_add or make sure to hold the vnode lock until
	 * they are completely done with the vnode
	 */
	vnode_list_lock();

	vnode_list_remove_locked(vp);
	vp->v_id++;

	vnode_list_unlock();

	if (isfifo) {
		struct fifoinfo * fip;

		fip = vp->v_fifoinfo;
		vp->v_fifoinfo = NULL;
		kfree_type(struct fifoinfo, fip);
	}
	vp->v_type = VBAD;

	if (vp->v_data) {
		panic("vnode_reclaim_internal: cleaned vnode isn't");
	}
	if (vp->v_numoutput) {
		panic("vnode_reclaim_internal: clean vnode has pending I/O's");
	}
	if (UBCINFOEXISTS(vp)) {
		panic("vnode_reclaim_internal: ubcinfo not cleaned");
	}
	if (vp->v_parent) {
		panic("vnode_reclaim_internal: vparent not removed");
	}
	if (vp->v_name) {
		panic("vnode_reclaim_internal: vname not removed");
	}

#if CONFIG_FILE_LEASES
	if (__improbable(!LIST_EMPTY(&vp->v_leases))) {
		panic("vnode_reclaim_internal: vleases NOT empty");
	}
#endif

	vp->v_socket = NULL;

	vp->v_lflag &= ~VL_TERMINATE;
	vp->v_owner = NULL;

#if CONFIG_IOCOUNT_TRACE
	if (__improbable(bootarg_vnode_iocount_trace)) {
		bzero(vp->v_iocount_trace,
		    IOCOUNT_TRACE_MAX_TYPES * sizeof(struct vnode_iocount_trace));
	}
#endif /* CONFIG_IOCOUNT_TRACE */

	KNOTE(&vp->v_knotes, NOTE_REVOKE);

	/* Make sure that when we reuse the vnode, no knotes left over */
	klist_init(&vp->v_knotes);

	if (vp->v_lflag & VL_TERMWANT) {
		vp->v_lflag &= ~VL_TERMWANT;
		wakeup(&vp->v_lflag);
	}
	if (!reuse) {
		/*
		 * make sure we get on the
		 * dead list if appropriate
		 */
		vnode_list_add(vp);
	}
	if (!locked) {
		vnode_unlock(vp);
	}
}

static int
vnode_create_internal(uint32_t flavor, uint32_t size, void *data, vnode_t *vpp,
    vnode_create_options_t vc_options)
{
	int error;
	int insert = 1;
	vnode_t vp = NULLVP;
	vnode_t nvp;
	vnode_t dvp;
	struct  uthread *ut;
	struct componentname *cnp;
	struct vnode_fsparam *param = (struct vnode_fsparam *)data;
#if CONFIG_TRIGGERS
	struct vnode_trigger_param *tinfo = NULL;
#endif
	bool existing_vnode;
	bool init_vnode = !(vc_options & VNODE_CREATE_EMPTY);
	bool is_bdevvp = false;

	if (*vpp) {
		vp = *vpp;
		*vpp = NULLVP;
		existing_vnode = true;
	} else {
		existing_vnode = false;
	}

	if (init_vnode) {
		/* Do quick sanity check on the parameters. */
		if ((param == NULL) || (param->vnfs_vtype == VBAD)) {
			error = EINVAL;
			goto error_out;
		}

#if CONFIG_TRIGGERS
		if ((flavor == VNCREATE_TRIGGER) && (size == VNCREATE_TRIGGER_SIZE)) {
			tinfo = (struct vnode_trigger_param *)data;

			/* Validate trigger vnode input */
			if ((param->vnfs_vtype != VDIR) ||
			    (tinfo->vnt_resolve_func == NULL) ||
			    (tinfo->vnt_flags & ~VNT_VALID_MASK)) {
				error = EINVAL;
				goto error_out;
			}
			/* Fall through a normal create (params will be the same) */
			flavor = VNCREATE_FLAVOR;
			size = VCREATESIZE;
		}
#endif
		if ((flavor != VNCREATE_FLAVOR) || (size != VCREATESIZE)) {
			error = EINVAL;
			goto error_out;
		}
	}

	if (!existing_vnode) {
		if ((error = new_vnode(&vp, !(vc_options & VNODE_CREATE_NODEALLOC)))) {
			return error;
		}
		if (!init_vnode) {
			/* Make it so that it can be released by a vnode_put) */
			vnode_lock(vp);
			vn_set_dead(vp);
			vnode_unlock(vp);
			*vpp = vp;
			return 0;
		}
	} else {
		/*
		 * A vnode obtained by vnode_create_empty has been passed to
		 * vnode_initialize - Unset VL_DEAD set by vn_set_dead. After
		 * this point, it is set back on any error.
		 */
		vnode_lock(vp);
		vp->v_lflag &= ~VL_DEAD;
		vnode_unlock(vp);
	}

	dvp = param->vnfs_dvp;
	cnp = param->vnfs_cnp;

	vp->v_op = param->vnfs_vops;
	vp->v_type = (uint8_t)param->vnfs_vtype;
	vp->v_data = param->vnfs_fsnode;

	if (param->vnfs_markroot) {
		vp->v_flag |= VROOT;
	}
	if (param->vnfs_marksystem) {
		vp->v_flag |= VSYSTEM;
	}
	if (vp->v_type == VREG) {
		error = ubc_info_init_withsize(vp, param->vnfs_filesize);
		if (error) {
#ifdef CONFIG_IOCOUNT_TRACE
			record_vp(vp, 1);
#endif
			vnode_hold(vp);
			vnode_lock(vp);
			vn_set_dead(vp);

			vnode_put_locked(vp);
			vnode_drop_and_unlock(vp);
			return error;
		}
		if (param->vnfs_mp->mnt_ioflags & MNT_IOFLAGS_IOSCHED_SUPPORTED) {
			memory_object_mark_io_tracking(vp->v_ubcinfo->ui_control);
		}
	}
#ifdef CONFIG_IOCOUNT_TRACE
	record_vp(vp, 1);
#endif

#if CONFIG_FIRMLINKS
	vp->v_fmlink = NULLVP;
#endif
	vp->v_flag &= ~VFMLINKTARGET;

#if CONFIG_TRIGGERS
	/*
	 * For trigger vnodes, attach trigger info to vnode
	 */
	if ((vp->v_type == VDIR) && (tinfo != NULL)) {
		/*
		 * Note: has a side effect of incrementing trigger count on the
		 * mount if successful, which we would need to undo on a
		 * subsequent failure.
		 */
#ifdef CONFIG_IOCOUNT_TRACE
		record_vp(vp, -1);
#endif
		error = vnode_resolver_create(param->vnfs_mp, vp, tinfo, FALSE);
		if (error) {
			printf("vnode_create: vnode_resolver_create() err %d\n", error);
			vnode_hold(vp);
			vnode_lock(vp);
			vn_set_dead(vp);
#ifdef CONFIG_IOCOUNT_TRACE
			record_vp(vp, 1);
#endif
			vnode_put_locked(vp);
			vnode_drop_and_unlock(vp);
			return error;
		}
	}
#endif
	if (vp->v_type == VCHR || vp->v_type == VBLK) {
		vp->v_tag = VT_DEVFS;           /* callers will reset if needed (bdevvp) */

		if ((nvp = checkalias(vp, param->vnfs_rdev))) {
			/*
			 * if checkalias returns a vnode, it will be locked
			 *
			 * first get rid of the unneeded vnode we acquired
			 */
			vp->v_data = NULL;
			vp->v_op = spec_vnodeop_p;
			vp->v_type = VBAD;
			vp->v_lflag = VL_DEAD;
			vp->v_data = NULL;
			vp->v_tag = VT_NON;
			vnode_put(vp);

			/*
			 * switch to aliased vnode and finish
			 * preparing it
			 */
			vp = nvp;

			is_bdevvp = (vp->v_flag & VBDEVVP);

			if (is_bdevvp) {
				printf("%s: alias vnode (vid = %u) is in state of change (start) v_flags = 0x%x v_numoutput = %d\n",
				    __func__, vp->v_id, vp->v_flag, vp->v_numoutput);
			}

			vnode_hold(vp);
			vp->v_lflag |= VL_OPSCHANGE;
			vclean(vp, 0);
			vp->v_op = param->vnfs_vops;
			vp->v_type = (uint8_t)param->vnfs_vtype;
			vp->v_data = param->vnfs_fsnode;
			vp->v_lflag = VL_OPSCHANGE;
			vp->v_mount = NULL;
			insmntque(vp, param->vnfs_mp);
			insert = 0;

			if (is_bdevvp) {
				printf("%s: alias vnode (vid = %u), is in state of change (end) v_flags = 0x%x v_numoutput = %d\n",
				    __func__, vp->v_id, vp->v_flag, vp->v_numoutput);
			}

			vnode_drop_and_unlock(vp);
			wakeup(&vp->v_lflag); /* chkvnlock is waitng for VL_DEAD to get unset */
		}

		if (VCHR == vp->v_type) {
			u_int maj = major(vp->v_rdev);

			if (maj < (u_int)nchrdev && cdevsw[maj].d_type == D_TTY) {
				vp->v_flag |= VISTTY;
			}
		}
	}

	if (vp->v_type == VFIFO) {
		struct fifoinfo *fip;

		fip = kalloc_type(struct fifoinfo, Z_WAITOK | Z_ZERO);
		vp->v_fifoinfo = fip;
	}
	/* The file systems must pass the address of the location where
	 * they store the vnode pointer. When we add the vnode into the mount
	 * list and name cache they become discoverable. So the file system node
	 * must have the connection to vnode setup by then
	 */
	*vpp = vp;

	/* Add fs named reference. */
	if (param->vnfs_flags & VNFS_ADDFSREF) {
		vp->v_lflag |= VNAMED_FSHASH;
	}
	if (param->vnfs_mp) {
		if (param->vnfs_mp->mnt_kern_flag & MNTK_LOCK_LOCAL) {
			vp->v_flag |= VLOCKLOCAL;
		}
		if (insert) {
			if ((vp->v_freelist.tqe_prev != (struct vnode **)0xdeadb)) {
				panic("insmntque: vp on the free list");
			}

			/*
			 * enter in mount vnode list
			 */
			insmntque(vp, param->vnfs_mp);
		}
	}
	if (dvp && vnode_ref(dvp) == 0) {
		vp->v_parent = dvp;
	}
	if (cnp) {
		if (dvp && ((param->vnfs_flags & (VNFS_NOCACHE | VNFS_CANTCACHE)) == 0)) {
			/*
			 * enter into name cache
			 * we've got the info to enter it into the name cache now
			 * cache_enter_create will pick up an extra reference on
			 * the name entered into the string cache
			 */
			vp->v_name = cache_enter_create(dvp, vp, cnp);
		} else {
			vp->v_name = vfs_addname(cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_hash, 0);
		}

		if ((cnp->cn_flags & UNIONCREATED) == UNIONCREATED) {
			vp->v_flag |= VISUNION;
		}
	}
	if ((param->vnfs_flags & VNFS_CANTCACHE) == 0) {
		/*
		 * this vnode is being created as cacheable in the name cache
		 * this allows us to re-enter it in the cache
		 */
		vp->v_flag |= VNCACHEABLE;
	}
	ut = current_uthread();

	if ((current_proc()->p_lflag & P_LRAGE_VNODES) ||
	    (ut->uu_flag & (UT_RAGE_VNODES | UT_KERN_RAGE_VNODES))) {
		/*
		 * process has indicated that it wants any
		 * vnodes created on its behalf to be rapidly
		 * aged to reduce the impact on the cached set
		 * of vnodes
		 *
		 * if UT_KERN_RAGE_VNODES is set, then the
		 * kernel internally wants vnodes to be rapidly
		 * aged, even if the process hasn't requested
		 * this
		 */
		vp->v_flag |= VRAGE;
	}

#if CONFIG_SECLUDED_MEMORY
	switch (secluded_for_filecache) {
	case SECLUDED_FILECACHE_NONE:
		/*
		 * secluded_for_filecache == 0:
		 * + no file contents in secluded pool
		 */
		break;
	case SECLUDED_FILECACHE_APPS:
		/*
		 * secluded_for_filecache == 1:
		 * + no files from /
		 * + files from /Applications/ are OK
		 * + files from /Applications/Camera are not OK
		 * + no files that are open for write
		 */
		if (vnode_vtype(vp) == VREG &&
		    vnode_mount(vp) != NULL &&
		    (!(vfs_flags(vnode_mount(vp)) & MNT_ROOTFS))) {
			/* not from root filesystem: eligible for secluded pages */
			memory_object_mark_eligible_for_secluded(
				ubc_getobject(vp, UBC_FLAGS_NONE),
				TRUE);
		}
		break;
	case SECLUDED_FILECACHE_RDONLY:
		/*
		 * secluded_for_filecache == 2:
		 * + all read-only files OK, except:
		 *      + dyld_shared_cache_arm64*
		 *      + Camera
		 *      + mediaserverd
		 *      + cameracaptured
		 */
		if (vnode_vtype(vp) == VREG) {
			memory_object_mark_eligible_for_secluded(
				ubc_getobject(vp, UBC_FLAGS_NONE),
				TRUE);
		}
		break;
	default:
		break;
	}
#endif /* CONFIG_SECLUDED_MEMORY */

	if (is_bdevvp) {
		/*
		 * The v_flags and v_lflags felds for the vndoe above are
		 * manipulated without the vnode lock. This is fine for
		 * everything because no other use  of this vnode is occurring.
		 * However the case of the bdevvp alias vnode reuse is different
		 * and the flags end up being modified while a thread may be in
		 * vnode_waitforwrites which sets VTHROTTLED and any one of the
		 * non atomic modifications of v_flag in this function can race
		 * with the setting of that flag and cause VTHROTTLED on vflag
		 * to get "lost".
		 *
		 * This should ideally be fixed by making sure all modifications
		 * in this function to the vnode flags are done under the
		 * vnode lock but at this time, a much smaller workaround is
		 * being  employed and a the more correct (and potentially
		 * much bigger) change will follow later.
		 *
		 * The effect of "losing" the VTHROTTLED flags would be a lost
		 * wakeup so we just issue that wakeup here since this happens
		 * only once per bdevvp vnode which are only one or two for a
		 * given boot.
		 */
		wakeup(&vp->v_numoutput);

		/*
		 * now make sure the flags that we were suppossed to put aren't
		 * lost.
		 */
		vnode_lock_spin(vp);
		if (param->vnfs_flags & VNFS_ADDFSREF) {
			vp->v_lflag |= VNAMED_FSHASH;
		}
		if (param->vnfs_mp && (param->vnfs_mp->mnt_kern_flag & MNTK_LOCK_LOCAL)) {
			vp->v_flag |= VLOCKLOCAL;
		}
		if ((param->vnfs_flags & VNFS_CANTCACHE) == 0) {
			vp->v_flag |= VNCACHEABLE;
		}
		vnode_unlock(vp);
	}

	return 0;

error_out:
	if (existing_vnode) {
		vnode_put(vp);
	}
	return error;
}

int
vnode_create_ext(uint32_t flavor, uint32_t size, void *data, vnode_t *vpp, vnode_create_options_t vc_options)
{
	if (vc_options & ~(VNODE_CREATE_EMPTY | VNODE_CREATE_NODEALLOC)) {
		return EINVAL;
	}
	*vpp = NULLVP;
	return vnode_create_internal(flavor, size, data, vpp, vc_options);
}

/* USAGE:
 * The following api creates a vnode and associates all the parameter specified in vnode_fsparam
 * structure and returns a vnode handle with a reference. device aliasing is handled here so checkalias
 * is obsoleted by this.
 */
int
vnode_create(uint32_t flavor, uint32_t size, void *data, vnode_t *vpp)
{
	return vnode_create_ext(flavor, size, data, vpp, VNODE_CREATE_NODEALLOC);
}

int
vnode_create_empty(vnode_t *vpp)
{
	return vnode_create_ext(VNCREATE_FLAVOR, VCREATESIZE, NULL,
	           vpp, VNODE_CREATE_EMPTY);
}

int
vnode_initialize(uint32_t __unused flavor, uint32_t size, void *data, vnode_t *vpp)
{
	if (*vpp == NULLVP) {
		panic("NULL vnode passed to vnode_initialize");
	}
#if DEVELOPMENT || DEBUG
	/*
	 * We lock to check that vnode is fit for unlocked use in
	 * vnode_create_internal.
	 */
	vnode_lock_spin(*vpp);
	VNASSERT(((*vpp)->v_iocount == 1), *vpp,
	    ("vnode_initialize : iocount not 1, is %d", (*vpp)->v_iocount));
	VNASSERT(((*vpp)->v_usecount == 0), *vpp,
	    ("vnode_initialize : usecount not 0, is %d", (*vpp)->v_usecount));
	VNASSERT(((*vpp)->v_lflag & VL_DEAD), *vpp,
	    ("vnode_initialize : v_lflag does not have VL_DEAD, is 0x%x",
	    (*vpp)->v_lflag));
	VNASSERT(((*vpp)->v_data == NULL), *vpp,
	    ("vnode_initialize : v_data not NULL"));
	vnode_unlock(*vpp);
#endif
	return vnode_create_internal(flavor, size, data, vpp, VNODE_CREATE_DEFAULT);
}

int
vnode_addfsref(vnode_t vp)
{
	vnode_lock_spin(vp);
	if (vp->v_lflag & VNAMED_FSHASH) {
		panic("add_fsref: vp already has named reference");
	}
	if ((vp->v_freelist.tqe_prev != (struct vnode **)0xdeadb)) {
		panic("addfsref: vp on the free list");
	}
	vp->v_lflag |= VNAMED_FSHASH;
	vnode_unlock(vp);
	return 0;
}
int
vnode_removefsref(vnode_t vp)
{
	vnode_lock_spin(vp);
	if ((vp->v_lflag & VNAMED_FSHASH) == 0) {
		panic("remove_fsref: no named reference");
	}
	vp->v_lflag &= ~VNAMED_FSHASH;
	vnode_unlock(vp);
	return 0;
}

void
vnode_link_lock(vnode_t vp)
{
	vnode_lock_spin(vp);
	while (vp->v_ext_flag & VE_LINKCHANGE) {
		vp->v_ext_flag |= VE_LINKCHANGEWAIT;
		msleep(&vp->v_ext_flag, &vp->v_lock, PVFS | PSPIN,
		    "vnode_link_lock_wait", 0);
	}
	if (vp->v_iocount == 0) {
		panic("%s called without an iocount on the vnode", __FUNCTION__);
	}
	vnode_get_locked(vp);
	vp->v_ext_flag |= VE_LINKCHANGE;
	vnode_unlock(vp);
}

void
vnode_link_unlock(vnode_t vp)
{
	bool do_wakeup = false;
	bool do_vnode_put = false;

	vnode_lock_spin(vp);
	if (vp->v_ext_flag & VE_LINKCHANGEWAIT) {
		do_wakeup = true;
	}
	vp->v_ext_flag &= ~(VE_LINKCHANGE | VE_LINKCHANGEWAIT);
	if ((vp->v_usecount > 0) || (vp->v_iocount > 1)) {
		vnode_put_locked(vp);
	} else {
		do_vnode_put = true;
	}
	vnode_unlock(vp);
	if (do_wakeup) {
		wakeup(&vp->v_ext_flag);
	}
	if (do_vnode_put) {
		vnode_put(vp);
	}
}

int
vfs_iterate(int flags, int (*callout)(mount_t, void *), void *arg)
{
	mount_t mp;
	int ret = 0;
	fsid_t * fsid_list;
	int count, actualcount, i;
	void * allocmem;
	int indx_start, indx_stop, indx_incr;
	int cb_dropref = (flags & VFS_ITERATE_CB_DROPREF);
	int noskip_unmount = (flags & VFS_ITERATE_NOSKIP_UNMOUNT);

	count = mount_getvfscnt();
	count += 10;

	fsid_list = kalloc_data(count * sizeof(fsid_t), Z_WAITOK);
	allocmem = (void *)fsid_list;

	actualcount = mount_fillfsids(fsid_list, count);

	/*
	 * Establish the iteration direction
	 * VFS_ITERATE_TAIL_FIRST overrides default head first order (oldest first)
	 */
	if (flags & VFS_ITERATE_TAIL_FIRST) {
		indx_start = actualcount - 1;
		indx_stop = -1;
		indx_incr = -1;
	} else { /* Head first by default */
		indx_start = 0;
		indx_stop = actualcount;
		indx_incr = 1;
	}

	for (i = indx_start; i != indx_stop; i += indx_incr) {
		/* obtain the mount point with iteration reference */
		mp = mount_list_lookupby_fsid(&fsid_list[i], 0, 1);

		if (mp == (struct mount *)0) {
			continue;
		}
		mount_lock(mp);
		if ((mp->mnt_lflag & MNT_LDEAD) ||
		    (!noskip_unmount && (mp->mnt_lflag & MNT_LUNMOUNT))) {
			mount_unlock(mp);
			mount_iterdrop(mp);
			continue;
		}
		mount_unlock(mp);

		/* iterate over all the vnodes */
		ret = callout(mp, arg);

		/*
		 * Drop the iterref here if the callback didn't do it.
		 * Note: If cb_dropref is set the mp may no longer exist.
		 */
		if (!cb_dropref) {
			mount_iterdrop(mp);
		}

		switch (ret) {
		case VFS_RETURNED:
		case VFS_RETURNED_DONE:
			if (ret == VFS_RETURNED_DONE) {
				ret = 0;
				goto out;
			}
			break;

		case VFS_CLAIMED_DONE:
			ret = 0;
			goto out;
		case VFS_CLAIMED:
		default:
			break;
		}
		ret = 0;
	}

out:
	kfree_data(allocmem, count * sizeof(fsid_t));
	return ret;
}

/*
 * Update the vfsstatfs structure in the mountpoint.
 * MAC: Parameter eventtype added, indicating whether the event that
 * triggered this update came from user space, via a system call
 * (VFS_USER_EVENT) or an internal kernel call (VFS_KERNEL_EVENT).
 */
int
vfs_update_vfsstat(mount_t mp, vfs_context_t ctx, __unused int eventtype)
{
	struct vfs_attr va;
	int             error;

	/*
	 * Request the attributes we want to propagate into
	 * the per-mount vfsstat structure.
	 */
	VFSATTR_INIT(&va);
	VFSATTR_WANTED(&va, f_iosize);
	VFSATTR_WANTED(&va, f_blocks);
	VFSATTR_WANTED(&va, f_bfree);
	VFSATTR_WANTED(&va, f_bavail);
	VFSATTR_WANTED(&va, f_bused);
	VFSATTR_WANTED(&va, f_files);
	VFSATTR_WANTED(&va, f_ffree);
	VFSATTR_WANTED(&va, f_bsize);
	VFSATTR_WANTED(&va, f_fssubtype);

	if ((error = vfs_getattr(mp, &va, ctx)) != 0) {
		KAUTH_DEBUG("STAT - filesystem returned error %d", error);
		return error;
	}
#if CONFIG_MACF
	if (eventtype == VFS_USER_EVENT) {
		error = mac_mount_check_getattr(ctx, mp, &va);
		if (error != 0) {
			return error;
		}
	}
#endif
	/*
	 * Unpack into the per-mount structure.
	 *
	 * We only overwrite these fields, which are likely to change:
	 *	f_blocks
	 *	f_bfree
	 *	f_bavail
	 *	f_bused
	 *	f_files
	 *	f_ffree
	 *
	 * And these which are not, but which the FS has no other way
	 * of providing to us:
	 *	f_bsize
	 *	f_iosize
	 *	f_fssubtype
	 *
	 */
	if (VFSATTR_IS_SUPPORTED(&va, f_bsize)) {
		/* 4822056 - protect against malformed server mount */
		mp->mnt_vfsstat.f_bsize = (va.f_bsize > 0 ? va.f_bsize : 512);
	} else {
		mp->mnt_vfsstat.f_bsize = mp->mnt_devblocksize; /* default from the device block size */
	}
	if (VFSATTR_IS_SUPPORTED(&va, f_iosize)) {
		mp->mnt_vfsstat.f_iosize = va.f_iosize;
	} else {
		mp->mnt_vfsstat.f_iosize = 1024 * 1024;         /* 1MB sensible I/O size */
	}
	if (VFSATTR_IS_SUPPORTED(&va, f_blocks)) {
		mp->mnt_vfsstat.f_blocks = va.f_blocks;
	}
	if (VFSATTR_IS_SUPPORTED(&va, f_bfree)) {
		mp->mnt_vfsstat.f_bfree = va.f_bfree;
	}
	if (VFSATTR_IS_SUPPORTED(&va, f_bavail)) {
		mp->mnt_vfsstat.f_bavail = va.f_bavail;
	}
	if (VFSATTR_IS_SUPPORTED(&va, f_bused)) {
		mp->mnt_vfsstat.f_bused = va.f_bused;
	}
	if (VFSATTR_IS_SUPPORTED(&va, f_files)) {
		mp->mnt_vfsstat.f_files = va.f_files;
	}
	if (VFSATTR_IS_SUPPORTED(&va, f_ffree)) {
		mp->mnt_vfsstat.f_ffree = va.f_ffree;
	}

	/* this is unlikely to change, but has to be queried for */
	if (VFSATTR_IS_SUPPORTED(&va, f_fssubtype)) {
		mp->mnt_vfsstat.f_fssubtype = va.f_fssubtype;
	}

	return 0;
}

int
mount_list_add(mount_t mp)
{
	int res;

	mount_list_lock();
	if (get_system_inshutdown() != 0) {
		res = -1;
	} else {
		TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
		nummounts++;
		res = 0;
	}
	mount_list_unlock();

	return res;
}

void
mount_list_remove(mount_t mp)
{
	mount_list_lock();
	TAILQ_REMOVE(&mountlist, mp, mnt_list);
	nummounts--;
	mp->mnt_list.tqe_next = NULL;
	mp->mnt_list.tqe_prev = NULL;
	mount_list_unlock();
}

mount_t
mount_lookupby_volfsid(int volfs_id, int withref)
{
	mount_t cur_mount = (mount_t)0;
	mount_t mp;

	mount_list_lock();
	TAILQ_FOREACH(mp, &mountlist, mnt_list) {
		if (!(mp->mnt_kern_flag & MNTK_UNMOUNT) &&
		    (mp->mnt_kern_flag & MNTK_PATH_FROM_ID) &&
		    (mp->mnt_vfsstat.f_fsid.val[0] == volfs_id)) {
			cur_mount = mp;
			if (withref) {
				if (mount_iterref(cur_mount, 1)) {
					cur_mount = (mount_t)0;
					mount_list_unlock();
					goto out;
				}
			}
			break;
		}
	}
	mount_list_unlock();
	if (withref && (cur_mount != (mount_t)0)) {
		mp = cur_mount;
		if (vfs_busy(mp, LK_NOWAIT) != 0) {
			cur_mount = (mount_t)0;
		}
		mount_iterdrop(mp);
	}
out:
	return cur_mount;
}

mount_t
mount_list_lookupby_fsid(fsid_t *fsid, int locked, int withref)
{
	mount_t retmp = (mount_t)0;
	mount_t mp;

	if (!locked) {
		mount_list_lock();
	}
	TAILQ_FOREACH(mp, &mountlist, mnt_list)
	if (mp->mnt_vfsstat.f_fsid.val[0] == fsid->val[0] &&
	    mp->mnt_vfsstat.f_fsid.val[1] == fsid->val[1]) {
		retmp = mp;
		if (withref) {
			if (mount_iterref(retmp, 1)) {
				retmp = (mount_t)0;
			}
		}
		goto out;
	}
out:
	if (!locked) {
		mount_list_unlock();
	}
	return retmp;
}

errno_t
vnode_lookupat(const char *path, int flags, vnode_t *vpp, vfs_context_t ctx,
    vnode_t start_dvp)
{
	struct nameidata *ndp;
	int error = 0;
	u_int32_t ndflags = 0;

	if (ctx == NULL) {
		return EINVAL;
	}

	ndp = kalloc_type(struct nameidata, Z_WAITOK | Z_NOFAIL);

	if (flags & VNODE_LOOKUP_NOFOLLOW) {
		ndflags = NOFOLLOW;
	} else {
		ndflags = FOLLOW;
	}

	if (flags & VNODE_LOOKUP_NOCROSSMOUNT) {
		ndflags |= NOCROSSMOUNT;
	}

	if (flags & VNODE_LOOKUP_CROSSMOUNTNOWAIT) {
		ndflags |= CN_NBMOUNTLOOK;
	}

	/* XXX AUDITVNPATH1 needed ? */
	NDINIT(ndp, LOOKUP, OP_LOOKUP, ndflags, UIO_SYSSPACE,
	    CAST_USER_ADDR_T(path), ctx);

	if (flags & VNODE_LOOKUP_NOFOLLOW_ANY) {
		ndp->ni_flag |= NAMEI_NOFOLLOW_ANY;
	}

	if (start_dvp && (path[0] != '/')) {
		ndp->ni_dvp = start_dvp;
		ndp->ni_cnd.cn_flags |= USEDVP;
	}

	if ((error = namei(ndp))) {
		goto out_free;
	}

	ndp->ni_cnd.cn_flags &= ~USEDVP;

	*vpp = ndp->ni_vp;
	nameidone(ndp);

out_free:
	kfree_type(struct nameidata, ndp);
	return error;
}

errno_t
vnode_lookup(const char *path, int flags, vnode_t *vpp, vfs_context_t ctx)
{
	return vnode_lookupat(path, flags, vpp, ctx, NULLVP);
}

errno_t
vnode_open(const char *path, int fmode, int cmode, int flags, vnode_t *vpp, vfs_context_t ctx)
{
	struct nameidata *ndp = NULL;
	int error;
	u_int32_t ndflags = 0;
	int lflags = flags;

	if (ctx == NULL) {              /* XXX technically an error */
		ctx = vfs_context_current();
	}

	ndp = kalloc_type(struct nameidata, Z_WAITOK | Z_NOFAIL);

	if (fmode & O_NOFOLLOW) {
		lflags |= VNODE_LOOKUP_NOFOLLOW;
	}

	if (lflags & VNODE_LOOKUP_NOFOLLOW) {
		ndflags = NOFOLLOW;
	} else {
		ndflags = FOLLOW;
	}

	if (lflags & VNODE_LOOKUP_NOFOLLOW_ANY) {
		fmode |= O_NOFOLLOW_ANY;
	}

	if (lflags & VNODE_LOOKUP_NOCROSSMOUNT) {
		ndflags |= NOCROSSMOUNT;
	}

	if (lflags & VNODE_LOOKUP_CROSSMOUNTNOWAIT) {
		ndflags |= CN_NBMOUNTLOOK;
	}

	/* XXX AUDITVNPATH1 needed ? */
	NDINIT(ndp, LOOKUP, OP_OPEN, ndflags, UIO_SYSSPACE,
	    CAST_USER_ADDR_T(path), ctx);

	if ((error = vn_open(ndp, fmode, cmode))) {
		*vpp = NULL;
	} else {
		*vpp = ndp->ni_vp;
	}

	kfree_type(struct nameidata, ndp);
	return error;
}

errno_t
vnode_close(vnode_t vp, int flags, vfs_context_t ctx)
{
	int error;

	if (ctx == NULL) {
		ctx = vfs_context_current();
	}

	error = vn_close(vp, flags, ctx);
	vnode_put(vp);
	return error;
}

errno_t
vnode_mtime(vnode_t vp, struct timespec *mtime, vfs_context_t ctx)
{
	struct vnode_attr       va;
	int                     error;

	VATTR_INIT(&va);
	VATTR_WANTED(&va, va_modify_time);
	error = vnode_getattr(vp, &va, ctx);
	if (!error) {
		*mtime = va.va_modify_time;
	}
	return error;
}

errno_t
vnode_flags(vnode_t vp, uint32_t *flags, vfs_context_t ctx)
{
	struct vnode_attr       va;
	int                     error;

	VATTR_INIT(&va);
	VATTR_WANTED(&va, va_flags);
	error = vnode_getattr(vp, &va, ctx);
	if (!error) {
		*flags = va.va_flags;
	}
	return error;
}

/*
 * Returns:	0			Success
 *	vnode_getattr:???
 */
errno_t
vnode_size(vnode_t vp, off_t *sizep, vfs_context_t ctx)
{
	struct vnode_attr       va;
	int                     error;

	VATTR_INIT(&va);
	VATTR_WANTED(&va, va_data_size);
	error = vnode_getattr(vp, &va, ctx);
	if (!error) {
		*sizep = va.va_data_size;
	}
	return error;
}

errno_t
vnode_setsize(vnode_t vp, off_t size, int ioflag, vfs_context_t ctx)
{
	struct vnode_attr       va;

	VATTR_INIT(&va);
	VATTR_SET(&va, va_data_size, size);
	va.va_vaflags = ioflag & 0xffff;
	return vnode_setattr(vp, &va, ctx);
}

int
vnode_setdirty(vnode_t vp)
{
	vnode_lock_spin(vp);
	vp->v_flag |= VISDIRTY;
	vnode_unlock(vp);
	return 0;
}

int
vnode_cleardirty(vnode_t vp)
{
	vnode_lock_spin(vp);
	vp->v_flag &= ~VISDIRTY;
	vnode_unlock(vp);
	return 0;
}

int
vnode_isdirty(vnode_t vp)
{
	int dirty;

	vnode_lock_spin(vp);
	dirty = (vp->v_flag & VISDIRTY) ? 1 : 0;
	vnode_unlock(vp);

	return dirty;
}

static int
vn_create_reg(vnode_t dvp, vnode_t *vpp, struct nameidata *ndp, struct vnode_attr *vap, uint32_t flags, int fmode, uint32_t *statusp, vfs_context_t ctx)
{
	/* Only use compound VNOP for compound operation */
	if (vnode_compound_open_available(dvp) && ((flags & VN_CREATE_DOOPEN) != 0)) {
		*vpp = NULLVP;
		return VNOP_COMPOUND_OPEN(dvp, vpp, ndp, O_CREAT, fmode, statusp, vap, ctx);
	} else {
		return VNOP_CREATE(dvp, vpp, &ndp->ni_cnd, vap, ctx);
	}
}

/*
 * Create a filesystem object of arbitrary type with arbitrary attributes in
 * the spevied directory with the specified name.
 *
 * Parameters:	dvp			Pointer to the vnode of the directory
 *					in which to create the object.
 *		vpp			Pointer to the area into which to
 *					return the vnode of the created object.
 *		cnp			Component name pointer from the namei
 *					data structure, containing the name to
 *					use for the create object.
 *		vap			Pointer to the vnode_attr structure
 *					describing the object to be created,
 *					including the type of object.
 *		flags			VN_* flags controlling ACL inheritance
 *					and whether or not authorization is to
 *					be required for the operation.
 *
 * Returns:	0			Success
 *		!0			errno value
 *
 * Implicit:	*vpp			Contains the vnode of the object that
 *					was created, if successful.
 *		*cnp			May be modified by the underlying VFS.
 *		*vap			May be modified by the underlying VFS.
 *					modified by either ACL inheritance or
 *
 *
 *					be modified, even if the operation is
 *
 *
 * Notes:	The kauth_filesec_t in 'vap', if any, is in host byte order.
 *
 *		Modification of '*cnp' and '*vap' by the underlying VFS is
 *		strongly discouraged.
 *
 * XXX:		This function is a 'vn_*' function; it belongs in vfs_vnops.c
 *
 * XXX:		We should enummerate the possible errno values here, and where
 *		in the code they originated.
 */
errno_t
vn_create(vnode_t dvp, vnode_t *vpp, struct nameidata *ndp, struct vnode_attr *vap, uint32_t flags, int fmode, uint32_t *statusp, vfs_context_t ctx)
{
	errno_t error, old_error;
	vnode_t vp = (vnode_t)0;
	boolean_t batched;
	struct componentname *cnp;
	uint32_t defaulted;

	cnp = &ndp->ni_cnd;
	error = 0;
	batched = namei_compound_available(dvp, ndp) ? TRUE : FALSE;

	KAUTH_DEBUG("%p    CREATE - '%s'", dvp, cnp->cn_nameptr);

	if (flags & VN_CREATE_NOINHERIT) {
		vap->va_vaflags |= VA_NOINHERIT;
	}
	if (flags & VN_CREATE_NOAUTH) {
		vap->va_vaflags |= VA_NOAUTH;
	}
	/*
	 * Handle ACL inheritance, initialize vap.
	 */
	error = vn_attribute_prepare(dvp, vap, &defaulted, ctx);
	if (error) {
		return error;
	}

	if (vap->va_type != VREG && (fmode != 0 || (flags & VN_CREATE_DOOPEN) || statusp)) {
		panic("Open parameters, but not a regular file.");
	}
	if ((fmode != 0) && ((flags & VN_CREATE_DOOPEN) == 0)) {
		panic("Mode for open, but not trying to open...");
	}


	/*
	 * Create the requested node.
	 */
	switch (vap->va_type) {
	case VREG:
		error = vn_create_reg(dvp, vpp, ndp, vap, flags, fmode, statusp, ctx);
		break;
	case VDIR:
		error = vn_mkdir(dvp, vpp, ndp, vap, ctx);
		break;
	case VSOCK:
	case VFIFO:
	case VBLK:
	case VCHR:
		error = VNOP_MKNOD(dvp, vpp, cnp, vap, ctx);
		break;
	default:
		panic("vnode_create: unknown vtype %d", vap->va_type);
	}
	if (error != 0) {
		KAUTH_DEBUG("%p    CREATE - error %d returned by filesystem", dvp, error);
		goto out;
	}

	vp = *vpp;
	old_error = error;

	/*
	 * If some of the requested attributes weren't handled by the VNOP,
	 * use our fallback code.
	 */
	if ((error == 0) && !VATTR_ALL_SUPPORTED(vap) && *vpp) {
		KAUTH_DEBUG("     CREATE - doing fallback with ACL %p", vap->va_acl);
		error = vnode_setattr_fallback(*vpp, vap, ctx);
	}

#if CONFIG_MACF
	if ((error == 0) && !(flags & VN_CREATE_NOLABEL)) {
		error = vnode_label(vnode_mount(vp), dvp, vp, cnp, VNODE_LABEL_CREATE, ctx);
	}
#endif

	if ((error != 0) && (vp != (vnode_t)0)) {
		/* If we've done a compound open, close */
		if (batched && (old_error == 0) && (vap->va_type == VREG)) {
			VNOP_CLOSE(vp, fmode, ctx);
		}

		/* Need to provide notifications if a create succeeded */
		if (!batched) {
			*vpp = (vnode_t) 0;
			vnode_put(vp);
			vp = NULLVP;
		}
	}

	/*
	 * For creation VNOPs, this is the equivalent of
	 * lookup_handle_found_vnode.
	 */
	if (kdebug_enable && *vpp) {
		kdebug_lookup(*vpp, cnp);
	}

out:
	vn_attribute_cleanup(vap, defaulted);

	return error;
}

static kauth_scope_t    vnode_scope;
static int      vnode_authorize_callback(kauth_cred_t credential, void *idata, kauth_action_t action,
    uintptr_t arg0, uintptr_t arg1, uintptr_t arg2, uintptr_t arg3);
static int vnode_authorize_callback_int(kauth_action_t action, vfs_context_t ctx,
    vnode_t vp, vnode_t dvp, int *errorp);

typedef struct _vnode_authorize_context {
	vnode_t         vp;
	struct vnode_attr *vap;
	vnode_t         dvp;
	struct vnode_attr *dvap;
	vfs_context_t   ctx;
	int             flags;
	int             flags_valid;
#define _VAC_IS_OWNER           (1<<0)
#define _VAC_IN_GROUP           (1<<1)
#define _VAC_IS_DIR_OWNER       (1<<2)
#define _VAC_IN_DIR_GROUP       (1<<3)
#define _VAC_NO_VNODE_POINTERS  (1<<4)
} *vauth_ctx;

void
vnode_authorize_init(void)
{
	vnode_scope = kauth_register_scope(KAUTH_SCOPE_VNODE, vnode_authorize_callback, NULL);
}

#define VATTR_PREPARE_DEFAULTED_UID             0x1
#define VATTR_PREPARE_DEFAULTED_GID             0x2
#define VATTR_PREPARE_DEFAULTED_MODE            0x4

int
vn_attribute_prepare(vnode_t dvp, struct vnode_attr *vap, uint32_t *defaulted_fieldsp, vfs_context_t ctx)
{
	kauth_acl_t nacl = NULL, oacl = NULL;
	int error;

	/*
	 * Handle ACL inheritance.
	 */
	if (!(vap->va_vaflags & VA_NOINHERIT) && vfs_extendedsecurity(dvp->v_mount)) {
		/* save the original filesec */
		if (VATTR_IS_ACTIVE(vap, va_acl)) {
			oacl = vap->va_acl;
		}

		vap->va_acl = NULL;
		if ((error = kauth_acl_inherit(dvp,
		    oacl,
		    &nacl,
		    vap->va_type == VDIR,
		    ctx)) != 0) {
			KAUTH_DEBUG("%p    CREATE - error %d processing inheritance", dvp, error);
			return error;
		}

		/*
		 * If the generated ACL is NULL, then we can save ourselves some effort
		 * by clearing the active bit.
		 */
		if (nacl == NULL) {
			VATTR_CLEAR_ACTIVE(vap, va_acl);
		} else {
			vap->va_base_acl = oacl;
			VATTR_SET(vap, va_acl, nacl);
		}
	}

	error = vnode_authattr_new_internal(dvp, vap, (vap->va_vaflags & VA_NOAUTH), defaulted_fieldsp, ctx);
	if (error) {
		vn_attribute_cleanup(vap, *defaulted_fieldsp);
	}

	return error;
}

void
vn_attribute_cleanup(struct vnode_attr *vap, uint32_t defaulted_fields)
{
	/*
	 * If the caller supplied a filesec in vap, it has been replaced
	 * now by the post-inheritance copy.  We need to put the original back
	 * and free the inherited product.
	 */
	kauth_acl_t nacl, oacl;

	if (VATTR_IS_ACTIVE(vap, va_acl)) {
		nacl = vap->va_acl;
		oacl = vap->va_base_acl;

		if (oacl) {
			VATTR_SET(vap, va_acl, oacl);
			vap->va_base_acl = NULL;
		} else {
			VATTR_CLEAR_ACTIVE(vap, va_acl);
		}

		if (nacl != NULL) {
			/*
			 * Only free the ACL buffer if 'VA_FILESEC_ACL' is not set as it
			 * should be freed by the caller or it is a post-inheritance copy.
			 */
			if (!(vap->va_vaflags & VA_FILESEC_ACL) ||
			    (oacl != NULL && nacl != oacl)) {
				kauth_acl_free(nacl);
			}
		}
	}

	if ((defaulted_fields & VATTR_PREPARE_DEFAULTED_MODE) != 0) {
		VATTR_CLEAR_ACTIVE(vap, va_mode);
	}
	if ((defaulted_fields & VATTR_PREPARE_DEFAULTED_GID) != 0) {
		VATTR_CLEAR_ACTIVE(vap, va_gid);
	}
	if ((defaulted_fields & VATTR_PREPARE_DEFAULTED_UID) != 0) {
		VATTR_CLEAR_ACTIVE(vap, va_uid);
	}

	return;
}

#if CONFIG_APPLEDOUBLE

#define NATIVE_XATTR(VP)  \
	((VP)->v_mount ? (VP)->v_mount->mnt_kern_flag & MNTK_EXTENDED_ATTRS : 0)

static int
dot_underbar_check_paired_vnode(struct componentname *cnp, vnode_t vp,
    vnode_t dvp, vfs_context_t ctx)
{
	int error = 0;
	bool dvp_needs_put = false;

	if (!dvp) {
		if ((dvp = vnode_getparent(vp)) == NULLVP) {
			return 0;
		}
		dvp_needs_put = true;
	}

	vnode_t dupairedvp = NULLVP;
	char lastchar = cnp->cn_nameptr[cnp->cn_namelen];

	cnp->cn_nameptr[cnp->cn_namelen] = '\0';
	error = vnode_lookupat(cnp->cn_nameptr + (sizeof("._") - 1), 0,
	    &dupairedvp, ctx, dvp);
	cnp->cn_nameptr[cnp->cn_namelen] = lastchar;
	if (dvp_needs_put) {
		vnode_put(dvp);
		dvp = NULLVP;
	}
	if (!error && dupairedvp) {
		error = mac_vnode_check_deleteextattr(ctx, dupairedvp,
		    "com.apple.quarantine");
		vnode_put(dupairedvp);
		dupairedvp = NULLVP;
	} else {
		error = 0;
	}

	return error;
}
#endif /* CONFIG_APPLEDOUBLE */

int
vn_authorize_unlink(vnode_t dvp, vnode_t vp, struct componentname *cnp, vfs_context_t ctx, __unused void *reserved)
{
#if !CONFIG_MACF
#pragma unused(cnp)
#endif
	int error = 0;

	/*
	 * Normally, unlinking of directories is not supported.
	 * However, some file systems may have limited support.
	 */
	if ((vp->v_type == VDIR) &&
	    !(vp->v_mount->mnt_kern_flag & MNTK_DIR_HARDLINKS)) {
		return EPERM; /* POSIX */
	}

	/* authorize the delete operation */
#if CONFIG_MACF
	if (!error) {
		error = mac_vnode_check_unlink(ctx, dvp, vp, cnp);
#if CONFIG_APPLEDOUBLE
		if (!error && !(NATIVE_XATTR(dvp)) &&
		    (cnp->cn_namelen > (sizeof("._a") - 1)) &&
		    cnp->cn_nameptr[0] == '.' && cnp->cn_nameptr[1] == '_') {
			error = dot_underbar_check_paired_vnode(cnp, vp, dvp, ctx);
		}
#endif /* CONFIG_APPLEDOUBLE */
	}
#endif /* MAC */
	if (!error) {
		error = vnode_authorize(vp, dvp, KAUTH_VNODE_DELETE, ctx);
	}

	return error;
}

int
vn_authorize_open_existing(vnode_t vp, struct componentname *cnp, int fmode, vfs_context_t ctx, void *reserved)
{
	/* Open of existing case */
	kauth_action_t action;
	int error = 0;
	if (cnp->cn_ndp == NULL) {
		panic("NULL ndp");
	}
	if (reserved != NULL) {
		panic("reserved not NULL.");
	}

#if CONFIG_MACF
	/* XXX may do duplicate work here, but ignore that for now (idempotent) */
	if (vfs_flags(vnode_mount(vp)) & MNT_MULTILABEL) {
		error = vnode_label(vnode_mount(vp), NULL, vp, NULL, 0, ctx);
		if (error) {
			return error;
		}
	}
#endif

	if (vnode_isdir(vp)) {
		if ((fmode & (FWRITE | O_TRUNC)) || /* disallow write operations on directories */
		    ((fmode & FSEARCH) && !(fmode & O_DIRECTORY))) {
			return EISDIR;
		}
	} else {
		if (fmode & O_DIRECTORY) {
			return ENOTDIR;
		}

		if (vp->v_type == VSOCK && vp->v_tag != VT_FDESC) {
			return EOPNOTSUPP;    /* Operation not supported on socket */
		}

		if (vp->v_type == VLNK && (fmode & O_NOFOLLOW) != 0) {
			return ELOOP;         /* O_NOFOLLOW was specified and the target is a symbolic link */
		}

		if (cnp->cn_ndp->ni_flag & NAMEI_TRAILINGSLASH) {
			return ENOTDIR;
		}

		if (!vnode_isreg(vp) && (fmode & FEXEC)) {
			return EACCES;
		}
	}

#if CONFIG_MACF
	/* If a file being opened is a shadow file containing
	 * namedstream data, ignore the macf checks because it
	 * is a kernel internal file and access should always
	 * be allowed.
	 */
	if (!(vnode_isshadow(vp) && vnode_isnamedstream(vp))) {
		error = mac_vnode_check_open(ctx, vp, fmode);
		if (error) {
			return error;
		}
	}
#if CONFIG_APPLEDOUBLE
	if (fmode & (FWRITE | O_TRUNC) && !(NATIVE_XATTR(vp)) &&
	    (cnp->cn_namelen > (sizeof("._a") - 1)) &&
	    cnp->cn_nameptr[0] == '.' && cnp->cn_nameptr[1] == '_') {
		error = dot_underbar_check_paired_vnode(cnp, vp, NULLVP, ctx);
		if (error) {
			return error;
		}
	}
#endif /* CONFIG_APPLEDOUBLE */
#endif

	/* compute action to be authorized */
	action = 0;
	if (fmode & FREAD) {
		action |= KAUTH_VNODE_READ_DATA;
	}
	if (fmode & (FWRITE | O_TRUNC)) {
		/*
		 * If we are writing, appending, and not truncating,
		 * indicate that we are appending so that if the
		 * UF_APPEND or SF_APPEND bits are set, we do not deny
		 * the open.
		 */
		if ((fmode & O_APPEND) && !(fmode & O_TRUNC)) {
			action |= KAUTH_VNODE_APPEND_DATA;
		} else {
			action |= KAUTH_VNODE_WRITE_DATA;
		}
	}
	if (fmode & (FSEARCH | FEXEC)) {
		if (vnode_isdir(vp)) {
			action |= KAUTH_VNODE_SEARCH;
		} else {
			action |= KAUTH_VNODE_EXECUTE;
		}
	}
	error = vnode_authorize(vp, NULL, action, ctx);
#if NAMEDSTREAMS
	if (error == EACCES) {
		/*
		 * Shadow files may exist on-disk with a different UID/GID
		 * than that of the current context.  Verify that this file
		 * is really a shadow file.  If it was created successfully
		 * then it should be authorized.
		 */
		if (vnode_isshadow(vp) && vnode_isnamedstream(vp)) {
			error = vnode_verifynamedstream(vp);
		}
	}
#endif

	return error;
}

int
vn_authorize_create(vnode_t dvp, struct componentname *cnp, struct vnode_attr *vap, vfs_context_t ctx, void *reserved)
{
#if !CONFIG_MACF
#pragma unused(vap)
#endif
	/* Creation case */
	int error;

	if (cnp->cn_ndp == NULL) {
		panic("NULL cn_ndp");
	}
	if (reserved != NULL) {
		panic("reserved not NULL.");
	}

	/* Only validate path for creation if we didn't do a complete lookup */
	if (cnp->cn_ndp->ni_flag & NAMEI_UNFINISHED) {
		error = lookup_validate_creation_path(cnp->cn_ndp);
		if (error) {
			return error;
		}
	}

#if CONFIG_MACF
	error = mac_vnode_check_create(ctx, dvp, cnp, vap);
	if (error) {
		return error;
	}
#endif /* CONFIG_MACF */

	return vnode_authorize(dvp, NULL, KAUTH_VNODE_ADD_FILE, ctx);
}

int
vn_authorize_rename(struct vnode *fdvp, struct vnode *fvp, struct componentname *fcnp,
    struct vnode *tdvp, struct vnode *tvp, struct componentname *tcnp,
    vfs_context_t ctx, void *reserved)
{
	return vn_authorize_renamex(fdvp, fvp, fcnp, tdvp, tvp, tcnp, ctx, 0, reserved);
}

int
vn_authorize_renamex(struct vnode *fdvp, struct vnode *fvp, struct componentname *fcnp,
    struct vnode *tdvp, struct vnode *tvp, struct componentname *tcnp,
    vfs_context_t ctx, vfs_rename_flags_t flags, void *reserved)
{
	return vn_authorize_renamex_with_paths(fdvp, fvp, fcnp, NULL, tdvp, tvp, tcnp, NULL, ctx, flags, reserved);
}

int
vn_authorize_renamex_with_paths(struct vnode *fdvp, struct vnode *fvp, struct componentname *fcnp, const char *from_path,
    struct vnode *tdvp, struct vnode *tvp, struct componentname *tcnp, const char *to_path,
    vfs_context_t ctx, vfs_rename_flags_t flags, void *reserved)
{
	int error = 0;
	int moving = 0;
	bool swap = flags & VFS_RENAME_SWAP;

	if (reserved != NULL) {
		panic("Passed something other than NULL as reserved field!");
	}

	/*
	 * Avoid renaming "." and "..".
	 *
	 * XXX No need to check for this in the FS.  We should always have the leaves
	 * in VFS in this case.
	 */
	if (fvp->v_type == VDIR &&
	    ((fdvp == fvp) ||
	    (fcnp->cn_namelen == 1 && fcnp->cn_nameptr[0] == '.') ||
	    ((fcnp->cn_flags | tcnp->cn_flags) & ISDOTDOT))) {
		error = EINVAL;
		goto out;
	}

	if (tvp == NULLVP && vnode_compound_rename_available(tdvp)) {
		error = lookup_validate_creation_path(tcnp->cn_ndp);
		if (error) {
			goto out;
		}
	}

	/***** <MACF> *****/
#if CONFIG_MACF
	if (swap) {
		error = mac_vnode_check_rename_swap(ctx, fdvp, fvp, fcnp, tdvp, tvp, tcnp);
	} else {
		error = mac_vnode_check_rename(ctx, fdvp, fvp, fcnp, tdvp, tvp, tcnp);
	}
#if CONFIG_APPLEDOUBLE
	if (!error && !(NATIVE_XATTR(fdvp)) &&
	    fcnp->cn_namelen > (sizeof("._a") - 1) &&
	    fcnp->cn_nameptr[0] == '.' && fcnp->cn_nameptr[1] == '_') {
		error = dot_underbar_check_paired_vnode(fcnp, fvp, fdvp, ctx);
	}
	/* Currently no Filesystem that does not support native xattrs supports rename swap */
	if (!error && swap && !(NATIVE_XATTR(tdvp)) &&
	    (tcnp->cn_namelen > (sizeof("._a") - 1)) &&
	    (tcnp->cn_nameptr[0] == '.') && (tcnp->cn_nameptr[1] == '_')) {
		error = dot_underbar_check_paired_vnode(tcnp, tvp, tdvp, ctx);
	}
#endif /* CONFIG_APPLEDOUBLE */
	if (error) {
		goto out;
	}
#endif
	/***** </MACF> *****/

	/***** <MiscChecks> *****/
	if (tvp != NULL) {
		if (!swap) {
			if (fvp->v_type == VDIR && tvp->v_type != VDIR) {
				error = ENOTDIR;
				goto out;
			} else if (fvp->v_type != VDIR && tvp->v_type == VDIR) {
				error = EISDIR;
				goto out;
			}
		}
	} else if (swap) {
		/*
		 * Caller should have already checked this and returned
		 * ENOENT.  If we send back ENOENT here, caller will retry
		 * which isn't what we want so we send back EINVAL here
		 * instead.
		 */
		error = EINVAL;
		goto out;
	}

	if (fvp == tdvp) {
		error = EINVAL;
		goto out;
	}

	/*
	 * The following edge case is caught here:
	 * (to cannot be a descendent of from)
	 *
	 *       o fdvp
	 *      /
	 *     /
	 *    o fvp
	 *     \
	 *      \
	 *       o tdvp
	 *      /
	 *     /
	 *    o tvp
	 */
	if (tdvp->v_parent == fvp) {
		error = EINVAL;
		goto out;
	}

	if (swap && fdvp->v_parent == tvp) {
		error = EINVAL;
		goto out;
	}
	/***** </MiscChecks> *****/

	/***** <Kauth> *****/

	/*
	 * As part of the Kauth step, we call out to allow 3rd-party
	 * fileop notification of "about to rename".  This is needed
	 * in the event that 3rd-parties need to know that the DELETE
	 * authorization is actually part of a rename.  It's important
	 * that we guarantee that the DELETE call-out will always be
	 * made if the WILL_RENAME call-out is made.  Another fileop
	 * call-out will be performed once the operation is completed.
	 * We can ignore the result of kauth_authorize_fileop().
	 *
	 * N.B. We are passing the vnode and *both* paths to each
	 * call; kauth_authorize_fileop() extracts the "from" path
	 * when posting a KAUTH_FILEOP_WILL_RENAME notification.
	 * As such, we only post these notifications if all of the
	 * information we need is provided.
	 */

	if (swap) {
		kauth_action_t f = 0, t = 0;

		/*
		 * Directories changing parents need ...ADD_SUBDIR...  to
		 * permit changing ".."
		 */
		if (fdvp != tdvp) {
			if (vnode_isdir(fvp)) {
				f = KAUTH_VNODE_ADD_SUBDIRECTORY;
			}
			if (vnode_isdir(tvp)) {
				t = KAUTH_VNODE_ADD_SUBDIRECTORY;
			}
		}
		if (to_path != NULL) {
			kauth_authorize_fileop(vfs_context_ucred(ctx),
			    KAUTH_FILEOP_WILL_RENAME,
			    (uintptr_t)fvp,
			    (uintptr_t)to_path);
		}
		error = vnode_authorize(fvp, fdvp, KAUTH_VNODE_DELETE | f, ctx);
		if (error) {
			goto out;
		}
		if (from_path != NULL) {
			kauth_authorize_fileop(vfs_context_ucred(ctx),
			    KAUTH_FILEOP_WILL_RENAME,
			    (uintptr_t)tvp,
			    (uintptr_t)from_path);
		}
		error = vnode_authorize(tvp, tdvp, KAUTH_VNODE_DELETE | t, ctx);
		if (error) {
			goto out;
		}
		f = vnode_isdir(fvp) ? KAUTH_VNODE_ADD_SUBDIRECTORY : KAUTH_VNODE_ADD_FILE;
		t = vnode_isdir(tvp) ? KAUTH_VNODE_ADD_SUBDIRECTORY : KAUTH_VNODE_ADD_FILE;
		if (fdvp == tdvp) {
			error = vnode_authorize(fdvp, NULL, f | t, ctx);
		} else {
			error = vnode_authorize(fdvp, NULL, t, ctx);
			if (error) {
				goto out;
			}
			error = vnode_authorize(tdvp, NULL, f, ctx);
		}
		if (error) {
			goto out;
		}
	} else {
		error = 0;
		if ((tvp != NULL) && vnode_isdir(tvp)) {
			if (tvp != fdvp) {
				moving = 1;
			}
		} else if (tdvp != fdvp) {
			moving = 1;
		}

		/*
		 * must have delete rights to remove the old name even in
		 * the simple case of fdvp == tdvp.
		 *
		 * If fvp is a directory, and we are changing it's parent,
		 * then we also need rights to rewrite its ".." entry as well.
		 */
		if (to_path != NULL) {
			kauth_authorize_fileop(vfs_context_ucred(ctx),
			    KAUTH_FILEOP_WILL_RENAME,
			    (uintptr_t)fvp,
			    (uintptr_t)to_path);
		}
		if (vnode_isdir(fvp)) {
			if ((error = vnode_authorize(fvp, fdvp, KAUTH_VNODE_DELETE | KAUTH_VNODE_ADD_SUBDIRECTORY, ctx)) != 0) {
				goto out;
			}
		} else {
			if ((error = vnode_authorize(fvp, fdvp, KAUTH_VNODE_DELETE, ctx)) != 0) {
				goto out;
			}
		}
		if (moving) {
			/* moving into tdvp or tvp, must have rights to add */
			if ((error = vnode_authorize(((tvp != NULL) && vnode_isdir(tvp)) ? tvp : tdvp,
			    NULL,
			    vnode_isdir(fvp) ? KAUTH_VNODE_ADD_SUBDIRECTORY : KAUTH_VNODE_ADD_FILE,
			    ctx)) != 0) {
				goto out;
			}
		} else {
			/* node staying in same directory, must be allowed to add new name */
			if ((error = vnode_authorize(fdvp, NULL,
			    vnode_isdir(fvp) ? KAUTH_VNODE_ADD_SUBDIRECTORY : KAUTH_VNODE_ADD_FILE, ctx)) != 0) {
				goto out;
			}
		}
		/* overwriting tvp */
		if ((tvp != NULL) && !vnode_isdir(tvp) &&
		    ((error = vnode_authorize(tvp, tdvp, KAUTH_VNODE_DELETE, ctx)) != 0)) {
			goto out;
		}
	}

	/***** </Kauth> *****/

	/* XXX more checks? */
out:
	return error;
}

int
vn_authorize_mkdir(vnode_t dvp, struct componentname *cnp, struct vnode_attr *vap, vfs_context_t ctx, void *reserved)
{
#if !CONFIG_MACF
#pragma unused(vap)
#endif
	int error;

	if (reserved != NULL) {
		panic("reserved not NULL in vn_authorize_mkdir()");
	}

	/* XXX A hack for now, to make shadow files work */
	if (cnp->cn_ndp == NULL) {
		return 0;
	}

	if (vnode_compound_mkdir_available(dvp)) {
		error = lookup_validate_creation_path(cnp->cn_ndp);
		if (error) {
			goto out;
		}
	}

#if CONFIG_MACF
	error = mac_vnode_check_create(ctx,
	    dvp, cnp, vap);
	if (error) {
		goto out;
	}
#endif

	/* authorize addition of a directory to the parent */
	if ((error = vnode_authorize(dvp, NULL, KAUTH_VNODE_ADD_SUBDIRECTORY, ctx)) != 0) {
		goto out;
	}

out:
	return error;
}

int
vn_authorize_rmdir(vnode_t dvp, vnode_t vp, struct componentname *cnp, vfs_context_t ctx, void *reserved)
{
#if CONFIG_MACF
	int error;
#else
#pragma unused(cnp)
#endif
	if (reserved != NULL) {
		panic("Non-NULL reserved argument to vn_authorize_rmdir()");
	}

	if (vp->v_type != VDIR) {
		/*
		 * rmdir only deals with directories
		 */
		return ENOTDIR;
	}

	if (dvp == vp) {
		/*
		 * No rmdir "." please.
		 */
		return EINVAL;
	}

#if CONFIG_MACF
	error = mac_vnode_check_unlink(ctx, dvp,
	    vp, cnp);
	if (error) {
		return error;
	}
#endif

	return vnode_authorize(vp, dvp, KAUTH_VNODE_DELETE, ctx);
}

/*
 * Authorizer for directory cloning. This does not use vnodes but instead
 * uses prefilled vnode attributes from the filesystem.
 *
 * The same function is called to set up the attributes required, perform the
 * authorization and cleanup (if required)
 */
int
vnode_attr_authorize_dir_clone(struct vnode_attr *vap, kauth_action_t action,
    struct vnode_attr *dvap, __unused vnode_t sdvp, mount_t mp,
    dir_clone_authorizer_op_t vattr_op, uint32_t flags, vfs_context_t ctx,
    __unused void *reserved)
{
	int error;
	int is_suser = vfs_context_issuser(ctx);

	if (vattr_op == OP_VATTR_SETUP) {
		VATTR_INIT(vap);

		/*
		 * When ACL inheritence is implemented, both vap->va_acl and
		 * dvap->va_acl will be required (even as superuser).
		 */
		VATTR_WANTED(vap, va_type);
		VATTR_WANTED(vap, va_mode);
		VATTR_WANTED(vap, va_flags);
		VATTR_WANTED(vap, va_uid);
		VATTR_WANTED(vap, va_gid);
		if (dvap) {
			VATTR_INIT(dvap);
			VATTR_WANTED(dvap, va_flags);
		}

		if (!is_suser) {
			/*
			 * If not superuser, we have to evaluate ACLs and
			 * need the target directory gid to set the initial
			 * gid of the new object.
			 */
			VATTR_WANTED(vap, va_acl);
			if (dvap) {
				VATTR_WANTED(dvap, va_gid);
			}
		} else if (dvap && (flags & VNODE_CLONEFILE_NOOWNERCOPY)) {
			VATTR_WANTED(dvap, va_gid);
		}
		return 0;
	} else if (vattr_op == OP_VATTR_CLEANUP) {
		return 0; /* Nothing to do for now */
	}

	/* dvap isn't used for authorization */
	error = vnode_attr_authorize(vap, NULL, mp, action, ctx);

	if (error) {
		return error;
	}

	/*
	 * vn_attribute_prepare should be able to accept attributes as well as
	 * vnodes but for now we do this inline.
	 */
	if (!is_suser || (flags & VNODE_CLONEFILE_NOOWNERCOPY)) {
		/*
		 * If the filesystem is mounted IGNORE_OWNERSHIP and an explicit
		 * owner is set, that owner takes ownership of all new files.
		 */
		if ((mp->mnt_flag & MNT_IGNORE_OWNERSHIP) &&
		    (mp->mnt_fsowner != KAUTH_UID_NONE)) {
			VATTR_SET(vap, va_uid, mp->mnt_fsowner);
		} else {
			/* default owner is current user */
			VATTR_SET(vap, va_uid,
			    kauth_cred_getuid(vfs_context_ucred(ctx)));
		}

		if ((mp->mnt_flag & MNT_IGNORE_OWNERSHIP) &&
		    (mp->mnt_fsgroup != KAUTH_GID_NONE)) {
			VATTR_SET(vap, va_gid, mp->mnt_fsgroup);
		} else {
			/*
			 * default group comes from parent object,
			 * fallback to current user
			 */
			if (VATTR_IS_SUPPORTED(dvap, va_gid)) {
				VATTR_SET(vap, va_gid, dvap->va_gid);
			} else {
				VATTR_SET(vap, va_gid,
				    kauth_cred_getgid(vfs_context_ucred(ctx)));
			}
		}
	}

	/* Inherit SF_RESTRICTED bit from destination directory only */
	if (VATTR_IS_ACTIVE(vap, va_flags)) {
		VATTR_SET(vap, va_flags,
		    ((vap->va_flags & ~(UF_DATAVAULT | SF_RESTRICTED)))); /* Turn off from source */
		if (VATTR_IS_ACTIVE(dvap, va_flags)) {
			VATTR_SET(vap, va_flags,
			    vap->va_flags | (dvap->va_flags & (UF_DATAVAULT | SF_RESTRICTED)));
		}
	} else if (VATTR_IS_ACTIVE(dvap, va_flags)) {
		VATTR_SET(vap, va_flags, (dvap->va_flags & (UF_DATAVAULT | SF_RESTRICTED)));
	}

	return 0;
}


/*
 * Authorize an operation on a vnode.
 *
 * This is KPI, but here because it needs vnode_scope.
 *
 * Returns:	0			Success
 *	kauth_authorize_action:EPERM	...
 *	xlate => EACCES			Permission denied
 *	kauth_authorize_action:0	Success
 *	kauth_authorize_action:		Depends on callback return; this is
 *					usually only vnode_authorize_callback(),
 *					but may include other listerners, if any
 *					exist.
 *		EROFS
 *		EACCES
 *		EPERM
 *		???
 */
int
vnode_authorize(vnode_t vp, vnode_t dvp, kauth_action_t action, vfs_context_t ctx)
{
	int     error, result;

	/*
	 * We can't authorize against a dead vnode; allow all operations through so that
	 * the correct error can be returned.
	 */
	if (vp->v_type == VBAD) {
		return 0;
	}

	error = 0;
	result = kauth_authorize_action(vnode_scope, vfs_context_ucred(ctx), action,
	    (uintptr_t)ctx, (uintptr_t)vp, (uintptr_t)dvp, (uintptr_t)&error);
	if (result == EPERM) {          /* traditional behaviour */
		result = EACCES;
	}
	/* did the lower layers give a better error return? */
	if ((result != 0) && (error != 0)) {
		return error;
	}
	return result;
}

/*
 * Test for vnode immutability.
 *
 * The 'append' flag is set when the authorization request is constrained
 * to operations which only request the right to append to a file.
 *
 * The 'ignore' flag is set when an operation modifying the immutability flags
 * is being authorized.  We check the system securelevel to determine which
 * immutability flags we can ignore.
 */
static int
vnode_immutable(struct vnode_attr *vap, int append, int ignore)
{
	int     mask;

	/* start with all bits precluding the operation */
	mask = IMMUTABLE | APPEND;

	/* if appending only, remove the append-only bits */
	if (append) {
		mask &= ~APPEND;
	}

	/* ignore only set when authorizing flags changes */
	if (ignore) {
		if (securelevel <= 0) {
			/* in insecure state, flags do not inhibit changes */
			mask = 0;
		} else {
			/* in secure state, user flags don't inhibit */
			mask &= ~(UF_IMMUTABLE | UF_APPEND);
		}
	}
	KAUTH_DEBUG("IMMUTABLE - file flags 0x%x mask 0x%x append = %d ignore = %d", vap->va_flags, mask, append, ignore);
	if ((vap->va_flags & mask) != 0) {
		return EPERM;
	}
	return 0;
}

static int
vauth_node_owner(struct vnode_attr *vap, kauth_cred_t cred)
{
	int result;

	/* default assumption is not-owner */
	result = 0;

	/*
	 * If the filesystem has given us a UID, we treat this as authoritative.
	 */
	if (vap && VATTR_IS_SUPPORTED(vap, va_uid)) {
		result = (vap->va_uid == kauth_cred_getuid(cred)) ? 1 : 0;
	}
	/* we could test the owner UUID here if we had a policy for it */

	return result;
}

/*
 * vauth_node_group
 *
 * Description:	Ask if a cred is a member of the group owning the vnode object
 *
 * Parameters:		vap		vnode attribute
 *				vap->va_gid	group owner of vnode object
 *			cred		credential to check
 *			ismember	pointer to where to put the answer
 *			idontknow	Return this if we can't get an answer
 *
 * Returns:		0		Success
 *			idontknow	Can't get information
 *	kauth_cred_ismember_gid:?	Error from kauth subsystem
 *	kauth_cred_ismember_gid:?	Error from kauth subsystem
 */
static int
vauth_node_group(struct vnode_attr *vap, kauth_cred_t cred, int *ismember, int idontknow)
{
	int     error;
	int     result;

	error = 0;
	result = 0;

	/*
	 * The caller is expected to have asked the filesystem for a group
	 * at some point prior to calling this function.  The answer may
	 * have been that there is no group ownership supported for the
	 * vnode object, in which case we return
	 */
	if (vap && VATTR_IS_SUPPORTED(vap, va_gid)) {
		error = kauth_cred_ismember_gid(cred, vap->va_gid, &result);
		/*
		 * Credentials which are opted into external group membership
		 * resolution which are not known to the external resolver
		 * will result in an ENOENT error.  We translate this into
		 * the appropriate 'idontknow' response for our caller.
		 *
		 * XXX We do not make a distinction here between an ENOENT
		 * XXX arising from a response from the external resolver,
		 * XXX and an ENOENT which is internally generated.  This is
		 * XXX a deficiency of the published kauth_cred_ismember_gid()
		 * XXX KPI which can not be overcome without new KPI.  For
		 * XXX all currently known cases, however, this wil result
		 * XXX in correct behaviour.
		 */
		if (error == ENOENT) {
			error = idontknow;
		}
	}
	/*
	 * XXX We could test the group UUID here if we had a policy for it,
	 * XXX but this is problematic from the perspective of synchronizing
	 * XXX group UUID and POSIX GID ownership of a file and keeping the
	 * XXX values coherent over time.  The problem is that the local
	 * XXX system will vend transient group UUIDs for unknown POSIX GID
	 * XXX values, and these are not persistent, whereas storage of values
	 * XXX is persistent.  One potential solution to this is a local
	 * XXX (persistent) replica of remote directory entries and vended
	 * XXX local ids in a local directory server (think in terms of a
	 * XXX caching DNS server).
	 */

	if (!error) {
		*ismember = result;
	}
	return error;
}

static int
vauth_file_owner(vauth_ctx vcp)
{
	int result;

	if (vcp->flags_valid & _VAC_IS_OWNER) {
		result = (vcp->flags & _VAC_IS_OWNER) ? 1 : 0;
	} else {
		result = vauth_node_owner(vcp->vap, vcp->ctx->vc_ucred);

		/* cache our result */
		vcp->flags_valid |= _VAC_IS_OWNER;
		if (result) {
			vcp->flags |= _VAC_IS_OWNER;
		} else {
			vcp->flags &= ~_VAC_IS_OWNER;
		}
	}
	return result;
}


/*
 * vauth_file_ingroup
 *
 * Description:	Ask if a user is a member of the group owning the directory
 *
 * Parameters:		vcp		The vnode authorization context that
 *					contains the user and directory info
 *				vcp->flags_valid	Valid flags
 *				vcp->flags		Flags values
 *				vcp->vap		File vnode attributes
 *				vcp->ctx		VFS Context (for user)
 *			ismember	pointer to where to put the answer
 *			idontknow	Return this if we can't get an answer
 *
 * Returns:		0		Success
 *		vauth_node_group:?	Error from vauth_node_group()
 *
 * Implicit returns:	*ismember	0	The user is not a group member
 *					1	The user is a group member
 */
static int
vauth_file_ingroup(vauth_ctx vcp, int *ismember, int idontknow)
{
	int     error;

	/* Check for a cached answer first, to avoid the check if possible */
	if (vcp->flags_valid & _VAC_IN_GROUP) {
		*ismember = (vcp->flags & _VAC_IN_GROUP) ? 1 : 0;
		error = 0;
	} else {
		/* Otherwise, go look for it */
		error = vauth_node_group(vcp->vap, vcp->ctx->vc_ucred, ismember, idontknow);

		if (!error) {
			/* cache our result */
			vcp->flags_valid |= _VAC_IN_GROUP;
			if (*ismember) {
				vcp->flags |= _VAC_IN_GROUP;
			} else {
				vcp->flags &= ~_VAC_IN_GROUP;
			}
		}
	}
	return error;
}

static int
vauth_dir_owner(vauth_ctx vcp)
{
	int result;

	if (vcp->flags_valid & _VAC_IS_DIR_OWNER) {
		result = (vcp->flags & _VAC_IS_DIR_OWNER) ? 1 : 0;
	} else {
		result = vauth_node_owner(vcp->dvap, vcp->ctx->vc_ucred);

		/* cache our result */
		vcp->flags_valid |= _VAC_IS_DIR_OWNER;
		if (result) {
			vcp->flags |= _VAC_IS_DIR_OWNER;
		} else {
			vcp->flags &= ~_VAC_IS_DIR_OWNER;
		}
	}
	return result;
}

/*
 * vauth_dir_ingroup
 *
 * Description:	Ask if a user is a member of the group owning the directory
 *
 * Parameters:		vcp		The vnode authorization context that
 *					contains the user and directory info
 *				vcp->flags_valid	Valid flags
 *				vcp->flags		Flags values
 *				vcp->dvap		Dir vnode attributes
 *				vcp->ctx		VFS Context (for user)
 *			ismember	pointer to where to put the answer
 *			idontknow	Return this if we can't get an answer
 *
 * Returns:		0		Success
 *		vauth_node_group:?	Error from vauth_node_group()
 *
 * Implicit returns:	*ismember	0	The user is not a group member
 *					1	The user is a group member
 */
static int
vauth_dir_ingroup(vauth_ctx vcp, int *ismember, int idontknow)
{
	int     error;

	/* Check for a cached answer first, to avoid the check if possible */
	if (vcp->flags_valid & _VAC_IN_DIR_GROUP) {
		*ismember = (vcp->flags & _VAC_IN_DIR_GROUP) ? 1 : 0;
		error = 0;
	} else {
		/* Otherwise, go look for it */
		error = vauth_node_group(vcp->dvap, vcp->ctx->vc_ucred, ismember, idontknow);

		if (!error) {
			/* cache our result */
			vcp->flags_valid |= _VAC_IN_DIR_GROUP;
			if (*ismember) {
				vcp->flags |= _VAC_IN_DIR_GROUP;
			} else {
				vcp->flags &= ~_VAC_IN_DIR_GROUP;
			}
		}
	}
	return error;
}

/*
 * Test the posix permissions in (vap) to determine whether (credential)
 * may perform (action)
 */
static int
vnode_authorize_posix(vauth_ctx vcp, int action, int on_dir)
{
	struct vnode_attr *vap;
	int needed, error, owner_ok, group_ok, world_ok, ismember;
#ifdef KAUTH_DEBUG_ENABLE
	const char *where = "uninitialized";
# define _SETWHERE(c)   where = c;
#else
# define _SETWHERE(c)
#endif

	/* checking file or directory? */
	if (on_dir) {
		vap = vcp->dvap;
	} else {
		vap = vcp->vap;
	}

	error = 0;

	/*
	 * We want to do as little work here as possible.  So first we check
	 * which sets of permissions grant us the access we need, and avoid checking
	 * whether specific permissions grant access when more generic ones would.
	 */

	/* owner permissions */
	needed = 0;
	if (action & VREAD) {
		needed |= S_IRUSR;
	}
	if (action & VWRITE) {
		needed |= S_IWUSR;
	}
	if (action & VEXEC) {
		needed |= S_IXUSR;
	}
	owner_ok = (needed & vap->va_mode) == needed;

	/*
	 * Processes with the appropriate entitlement can marked themselves as
	 * ignoring file/directory permissions if they own it.
	 */
	if (!owner_ok && proc_ignores_node_permissions(vfs_context_proc(vcp->ctx))) {
		owner_ok = 1;
	}

	/* group permissions */
	needed = 0;
	if (action & VREAD) {
		needed |= S_IRGRP;
	}
	if (action & VWRITE) {
		needed |= S_IWGRP;
	}
	if (action & VEXEC) {
		needed |= S_IXGRP;
	}
	group_ok = (needed & vap->va_mode) == needed;

	/* world permissions */
	needed = 0;
	if (action & VREAD) {
		needed |= S_IROTH;
	}
	if (action & VWRITE) {
		needed |= S_IWOTH;
	}
	if (action & VEXEC) {
		needed |= S_IXOTH;
	}
	world_ok = (needed & vap->va_mode) == needed;

	/* If granted/denied by all three, we're done */
	if (owner_ok && group_ok && world_ok) {
		_SETWHERE("all");
		goto out;
	}

	if (!owner_ok && !group_ok && !world_ok) {
		_SETWHERE("all");
		error = EACCES;
		goto out;
	}

	/* Check ownership (relatively cheap) */
	if ((on_dir && vauth_dir_owner(vcp)) ||
	    (!on_dir && vauth_file_owner(vcp))) {
		_SETWHERE("user");
		if (!owner_ok) {
			error = EACCES;
		}
		goto out;
	}

	/* Not owner; if group and world both grant it we're done */
	if (group_ok && world_ok) {
		_SETWHERE("group/world");
		goto out;
	}
	if (!group_ok && !world_ok) {
		_SETWHERE("group/world");
		error = EACCES;
		goto out;
	}

	/* Check group membership (most expensive) */
	ismember = 0;   /* Default to allow, if the target has no group owner */

	/*
	 * In the case we can't get an answer about the user from the call to
	 * vauth_dir_ingroup() or vauth_file_ingroup(), we want to fail on
	 * the side of caution, rather than simply granting access, or we will
	 * fail to correctly implement exclusion groups, so we set the third
	 * parameter on the basis of the state of 'group_ok'.
	 */
	if (on_dir) {
		error = vauth_dir_ingroup(vcp, &ismember, (!group_ok ? EACCES : 0));
	} else {
		error = vauth_file_ingroup(vcp, &ismember, (!group_ok ? EACCES : 0));
	}
	if (error) {
		if (!group_ok) {
			ismember = 1;
		}
		error = 0;
	}
	if (ismember) {
		_SETWHERE("group");
		if (!group_ok) {
			error = EACCES;
		}
		goto out;
	}

	/* Not owner, not in group, use world result */
	_SETWHERE("world");
	if (!world_ok) {
		error = EACCES;
	}

	/* FALLTHROUGH */

out:
	KAUTH_DEBUG("%p    %s - posix %s permissions : need %s%s%s %x have %s%s%s%s%s%s%s%s%s UID = %d file = %d,%d",
	    vcp->vp, (error == 0) ? "ALLOWED" : "DENIED", where,
	    (action & VREAD)  ? "r" : "-",
	    (action & VWRITE) ? "w" : "-",
	    (action & VEXEC)  ? "x" : "-",
	    needed,
	    (vap->va_mode & S_IRUSR) ? "r" : "-",
	    (vap->va_mode & S_IWUSR) ? "w" : "-",
	    (vap->va_mode & S_IXUSR) ? "x" : "-",
	    (vap->va_mode & S_IRGRP) ? "r" : "-",
	    (vap->va_mode & S_IWGRP) ? "w" : "-",
	    (vap->va_mode & S_IXGRP) ? "x" : "-",
	    (vap->va_mode & S_IROTH) ? "r" : "-",
	    (vap->va_mode & S_IWOTH) ? "w" : "-",
	    (vap->va_mode & S_IXOTH) ? "x" : "-",
	    kauth_cred_getuid(vcp->ctx->vc_ucred),
	    on_dir ? vcp->dvap->va_uid : vcp->vap->va_uid,
	    on_dir ? vcp->dvap->va_gid : vcp->vap->va_gid);
	return error;
}

/*
 * Authorize the deletion of the node vp from the directory dvp.
 *
 * We assume that:
 * - Neither the node nor the directory are immutable.
 * - The user is not the superuser.
 *
 * The precedence of factors for authorizing or denying delete for a credential
 *
 * 1) Explicit ACE on the node. (allow or deny DELETE)
 * 2) Explicit ACE on the directory (allow or deny DELETE_CHILD).
 *
 *    If there are conflicting ACEs on the node and the directory, the node
 *    ACE wins.
 *
 * 3) Sticky bit on the directory.
 *    Deletion is not permitted if the directory is sticky and the caller is
 *    not owner of the node or directory. The sticky bit rules are like a deny
 *    delete ACE except lower in priority than ACL's either allowing or denying
 *    delete.
 *
 * 4) POSIX permisions on the directory.
 *
 * As an optimization, we cache whether or not delete child is permitted
 * on directories. This enables us to skip directory ACL and POSIX checks
 * as we already have the result from those checks. However, we always check the
 * node ACL and, if the directory has the sticky bit set, we always check its
 * ACL (even for a directory with an authorized delete child). Furthermore,
 * caching the delete child authorization is independent of the sticky bit
 * being set as it is only applicable in determining whether the node can be
 * deleted or not.
 */
static int
vnode_authorize_delete(vauth_ctx vcp, boolean_t cached_delete_child)
{
	struct vnode_attr       *vap = vcp->vap;
	struct vnode_attr       *dvap = vcp->dvap;
	kauth_cred_t            cred = vcp->ctx->vc_ucred;
	struct kauth_acl_eval   eval;
	int                     error, ismember;

	/* Check the ACL on the node first */
	if (VATTR_IS_NOT(vap, va_acl, NULL)) {
		eval.ae_requested = KAUTH_VNODE_DELETE;
		eval.ae_acl = &vap->va_acl->acl_ace[0];
		eval.ae_count = vap->va_acl->acl_entrycount;
		eval.ae_options = 0;
		if (vauth_file_owner(vcp)) {
			eval.ae_options |= KAUTH_AEVAL_IS_OWNER;
		}
		/*
		 * We use ENOENT as a marker to indicate we could not get
		 * information in order to delay evaluation until after we
		 * have the ACL evaluation answer.  Previously, we would
		 * always deny the operation at this point.
		 */
		if ((error = vauth_file_ingroup(vcp, &ismember, ENOENT)) != 0 && error != ENOENT) {
			return error;
		}
		if (error == ENOENT) {
			eval.ae_options |= KAUTH_AEVAL_IN_GROUP_UNKNOWN;
		} else if (ismember) {
			eval.ae_options |= KAUTH_AEVAL_IN_GROUP;
		}
		eval.ae_exp_gall = KAUTH_VNODE_GENERIC_ALL_BITS;
		eval.ae_exp_gread = KAUTH_VNODE_GENERIC_READ_BITS;
		eval.ae_exp_gwrite = KAUTH_VNODE_GENERIC_WRITE_BITS;
		eval.ae_exp_gexec = KAUTH_VNODE_GENERIC_EXECUTE_BITS;

		if ((error = kauth_acl_evaluate(cred, &eval)) != 0) {
			KAUTH_DEBUG("%p    ERROR during ACL processing - %d", vcp->vp, error);
			return error;
		}

		switch (eval.ae_result) {
		case KAUTH_RESULT_DENY:
			if (vauth_file_owner(vcp) && proc_ignores_node_permissions(vfs_context_proc(vcp->ctx))) {
				KAUTH_DEBUG("%p    Override DENY due to entitlement", vcp->vp);
				return 0;
			}
			KAUTH_DEBUG("%p    DENIED - denied by ACL", vcp->vp);
			return EACCES;
		case KAUTH_RESULT_ALLOW:
			KAUTH_DEBUG("%p    ALLOWED - granted by ACL", vcp->vp);
			return 0;
		case KAUTH_RESULT_DEFER:
		default:
			/* Defer to directory */
			KAUTH_DEBUG("%p    DEFERRED - by file ACL", vcp->vp);
			break;
		}
	}

	/*
	 * Without a sticky bit, a previously authorized delete child is
	 * sufficient to authorize this delete.
	 *
	 * If the sticky bit is set, a directory ACL which allows delete child
	 * overrides a (potential) sticky bit deny. The authorized delete child
	 * cannot tell us if it was authorized because of an explicit delete
	 * child allow ACE or because of POSIX permisions so we have to check
	 * the directory ACL everytime if the directory has a sticky bit.
	 */
	if (!(dvap->va_mode & S_ISTXT) && cached_delete_child) {
		KAUTH_DEBUG("%p    ALLOWED - granted by directory ACL or POSIX permissions and no sticky bit on directory", vcp->vp);
		return 0;
	}

	/* check the ACL on the directory */
	if (VATTR_IS_NOT(dvap, va_acl, NULL)) {
		eval.ae_requested = KAUTH_VNODE_DELETE_CHILD;
		eval.ae_acl = &dvap->va_acl->acl_ace[0];
		eval.ae_count = dvap->va_acl->acl_entrycount;
		eval.ae_options = 0;
		if (vauth_dir_owner(vcp)) {
			eval.ae_options |= KAUTH_AEVAL_IS_OWNER;
		}
		/*
		 * We use ENOENT as a marker to indicate we could not get
		 * information in order to delay evaluation until after we
		 * have the ACL evaluation answer.  Previously, we would
		 * always deny the operation at this point.
		 */
		if ((error = vauth_dir_ingroup(vcp, &ismember, ENOENT)) != 0 && error != ENOENT) {
			return error;
		}
		if (error == ENOENT) {
			eval.ae_options |= KAUTH_AEVAL_IN_GROUP_UNKNOWN;
		} else if (ismember) {
			eval.ae_options |= KAUTH_AEVAL_IN_GROUP;
		}
		eval.ae_exp_gall = KAUTH_VNODE_GENERIC_ALL_BITS;
		eval.ae_exp_gread = KAUTH_VNODE_GENERIC_READ_BITS;
		eval.ae_exp_gwrite = KAUTH_VNODE_GENERIC_WRITE_BITS;
		eval.ae_exp_gexec = KAUTH_VNODE_GENERIC_EXECUTE_BITS;

		/*
		 * If there is no entry, we are going to defer to other
		 * authorization mechanisms.
		 */
		error = kauth_acl_evaluate(cred, &eval);

		if (error != 0) {
			KAUTH_DEBUG("%p    ERROR during ACL processing - %d", vcp->vp, error);
			return error;
		}
		switch (eval.ae_result) {
		case KAUTH_RESULT_DENY:
			if (vauth_dir_owner(vcp) && proc_ignores_node_permissions(vfs_context_proc(vcp->ctx))) {
				KAUTH_DEBUG("%p    Override DENY due to entitlement", vcp->vp);
				return 0;
			}
			KAUTH_DEBUG("%p    DENIED - denied by directory ACL", vcp->vp);
			return EACCES;
		case KAUTH_RESULT_ALLOW:
			KAUTH_DEBUG("%p    ALLOWED - granted by directory ACL", vcp->vp);
			if (!cached_delete_child && vcp->dvp) {
				vnode_cache_authorized_action(vcp->dvp,
				    vcp->ctx, KAUTH_VNODE_DELETE_CHILD);
			}
			return 0;
		case KAUTH_RESULT_DEFER:
		default:
			/* Deferred by directory ACL */
			KAUTH_DEBUG("%p    DEFERRED - directory ACL", vcp->vp);
			break;
		}
	}

	/*
	 * From this point, we can't explicitly allow and if we reach the end
	 * of the function without a denial, then the delete is authorized.
	 */
	if (!cached_delete_child) {
		if (vnode_authorize_posix(vcp, VWRITE, 1 /* on_dir */) != 0) {
			KAUTH_DEBUG("%p    DENIED - denied by posix permisssions", vcp->vp);
			return EACCES;
		}
		/*
		 * Cache the authorized action on the vnode if allowed by the
		 * directory ACL or POSIX permissions. It is correct to cache
		 * this action even if sticky bit would deny deleting the node.
		 */
		if (vcp->dvp) {
			vnode_cache_authorized_action(vcp->dvp, vcp->ctx,
			    KAUTH_VNODE_DELETE_CHILD);
		}
	}

	/* enforce sticky bit behaviour */
	if ((dvap->va_mode & S_ISTXT) && !vauth_file_owner(vcp) && !vauth_dir_owner(vcp)) {
		KAUTH_DEBUG("%p    DENIED - sticky bit rules (user %d  file %d  dir %d)",
		    vcp->vp, cred->cr_posix.cr_uid, vap->va_uid, dvap->va_uid);
		return EACCES;
	}

	/* not denied, must be OK */
	return 0;
}


/*
 * Authorize an operation based on the node's attributes.
 */
static int
vnode_authorize_simple(vauth_ctx vcp, kauth_ace_rights_t acl_rights, kauth_ace_rights_t preauth_rights, boolean_t *found_deny)
{
	struct vnode_attr       *vap = vcp->vap;
	kauth_cred_t            cred = vcp->ctx->vc_ucred;
	struct kauth_acl_eval   eval;
	int                     error, ismember;
	mode_t                  posix_action;

	/*
	 * If we are the file owner, we automatically have some rights.
	 *
	 * Do we need to expand this to support group ownership?
	 */
	if (vauth_file_owner(vcp)) {
		acl_rights &= ~(KAUTH_VNODE_WRITE_SECURITY);
	}

	/*
	 * If we are checking both TAKE_OWNERSHIP and WRITE_SECURITY, we can
	 * mask the latter.  If TAKE_OWNERSHIP is requested the caller is about to
	 * change ownership to themselves, and WRITE_SECURITY is implicitly
	 * granted to the owner.  We need to do this because at this point
	 * WRITE_SECURITY may not be granted as the caller is not currently
	 * the owner.
	 */
	if ((acl_rights & KAUTH_VNODE_TAKE_OWNERSHIP) &&
	    (acl_rights & KAUTH_VNODE_WRITE_SECURITY)) {
		acl_rights &= ~KAUTH_VNODE_WRITE_SECURITY;
	}

	if (acl_rights == 0) {
		KAUTH_DEBUG("%p    ALLOWED - implicit or no rights required", vcp->vp);
		return 0;
	}

	/* if we have an ACL, evaluate it */
	if (VATTR_IS_NOT(vap, va_acl, NULL)) {
		eval.ae_requested = acl_rights;
		eval.ae_acl = &vap->va_acl->acl_ace[0];
		eval.ae_count = vap->va_acl->acl_entrycount;
		eval.ae_options = 0;
		if (vauth_file_owner(vcp)) {
			eval.ae_options |= KAUTH_AEVAL_IS_OWNER;
		}
		/*
		 * We use ENOENT as a marker to indicate we could not get
		 * information in order to delay evaluation until after we
		 * have the ACL evaluation answer.  Previously, we would
		 * always deny the operation at this point.
		 */
		if ((error = vauth_file_ingroup(vcp, &ismember, ENOENT)) != 0 && error != ENOENT) {
			return error;
		}
		if (error == ENOENT) {
			eval.ae_options |= KAUTH_AEVAL_IN_GROUP_UNKNOWN;
		} else if (ismember) {
			eval.ae_options |= KAUTH_AEVAL_IN_GROUP;
		}
		eval.ae_exp_gall = KAUTH_VNODE_GENERIC_ALL_BITS;
		eval.ae_exp_gread = KAUTH_VNODE_GENERIC_READ_BITS;
		eval.ae_exp_gwrite = KAUTH_VNODE_GENERIC_WRITE_BITS;
		eval.ae_exp_gexec = KAUTH_VNODE_GENERIC_EXECUTE_BITS;

		if ((error = kauth_acl_evaluate(cred, &eval)) != 0) {
			KAUTH_DEBUG("%p    ERROR during ACL processing - %d", vcp->vp, error);
			return error;
		}

		switch (eval.ae_result) {
		case KAUTH_RESULT_DENY:
			if (vauth_file_owner(vcp) && proc_ignores_node_permissions(vfs_context_proc(vcp->ctx))) {
				KAUTH_DEBUG("%p    Override DENY due to entitlement", vcp->vp);
				return 0;
			}
			KAUTH_DEBUG("%p    DENIED - by ACL", vcp->vp);
			return EACCES;         /* deny, deny, counter-allege */
		case KAUTH_RESULT_ALLOW:
			KAUTH_DEBUG("%p    ALLOWED - all rights granted by ACL", vcp->vp);
			return 0;
		case KAUTH_RESULT_DEFER:
		default:
			/* Effectively the same as !delete_child_denied */
			KAUTH_DEBUG("%p    DEFERRED - directory ACL", vcp->vp);
			break;
		}

		*found_deny = eval.ae_found_deny;

		/* fall through and evaluate residual rights */
	} else {
		/* no ACL, everything is residual */
		eval.ae_residual = acl_rights;
	}

	/*
	 * Grant residual rights that have been pre-authorized.
	 */
	eval.ae_residual &= ~preauth_rights;

	/*
	 * We grant WRITE_ATTRIBUTES to the owner if it hasn't been denied.
	 */
	if (vauth_file_owner(vcp)) {
		eval.ae_residual &= ~KAUTH_VNODE_WRITE_ATTRIBUTES;
	}

	if (eval.ae_residual == 0) {
		KAUTH_DEBUG("%p    ALLOWED - rights already authorized", vcp->vp);
		return 0;
	}

	/*
	 * Bail if we have residual rights that can't be granted by posix permissions,
	 * or aren't presumed granted at this point.
	 *
	 * XXX these can be collapsed for performance
	 */
	if (eval.ae_residual & KAUTH_VNODE_CHANGE_OWNER) {
		KAUTH_DEBUG("%p    DENIED - CHANGE_OWNER not permitted", vcp->vp);
		return EACCES;
	}
	if (eval.ae_residual & KAUTH_VNODE_WRITE_SECURITY) {
		KAUTH_DEBUG("%p    DENIED - WRITE_SECURITY not permitted", vcp->vp);
		return EACCES;
	}

#if DIAGNOSTIC
	if (eval.ae_residual & KAUTH_VNODE_DELETE) {
		panic("vnode_authorize: can't be checking delete permission here");
	}
#endif

	/*
	 * Compute the fallback posix permissions that will satisfy the remaining
	 * rights.
	 */
	posix_action = 0;
	if (eval.ae_residual & (KAUTH_VNODE_READ_DATA |
	    KAUTH_VNODE_LIST_DIRECTORY |
	    KAUTH_VNODE_READ_EXTATTRIBUTES)) {
		posix_action |= VREAD;
	}
	if (eval.ae_residual & (KAUTH_VNODE_WRITE_DATA |
	    KAUTH_VNODE_ADD_FILE |
	    KAUTH_VNODE_ADD_SUBDIRECTORY |
	    KAUTH_VNODE_DELETE_CHILD |
	    KAUTH_VNODE_WRITE_ATTRIBUTES |
	    KAUTH_VNODE_WRITE_EXTATTRIBUTES)) {
		posix_action |= VWRITE;
	}
	if (eval.ae_residual & (KAUTH_VNODE_EXECUTE |
	    KAUTH_VNODE_SEARCH)) {
		posix_action |= VEXEC;
	}

	if (posix_action != 0) {
		return vnode_authorize_posix(vcp, posix_action, 0 /* !on_dir */);
	} else {
		KAUTH_DEBUG("%p    ALLOWED - residual rights %s%s%s%s%s%s%s%s%s%s%s%s%s%s granted due to no posix mapping",
		    vcp->vp,
		    (eval.ae_residual & KAUTH_VNODE_READ_DATA)
		    ? vnode_isdir(vcp->vp) ? " LIST_DIRECTORY" : " READ_DATA" : "",
		    (eval.ae_residual & KAUTH_VNODE_WRITE_DATA)
		    ? vnode_isdir(vcp->vp) ? " ADD_FILE" : " WRITE_DATA" : "",
		    (eval.ae_residual & KAUTH_VNODE_EXECUTE)
		    ? vnode_isdir(vcp->vp) ? " SEARCH" : " EXECUTE" : "",
		    (eval.ae_residual & KAUTH_VNODE_DELETE)
		    ? " DELETE" : "",
		    (eval.ae_residual & KAUTH_VNODE_APPEND_DATA)
		    ? vnode_isdir(vcp->vp) ? " ADD_SUBDIRECTORY" : " APPEND_DATA" : "",
		    (eval.ae_residual & KAUTH_VNODE_DELETE_CHILD)
		    ? " DELETE_CHILD" : "",
		    (eval.ae_residual & KAUTH_VNODE_READ_ATTRIBUTES)
		    ? " READ_ATTRIBUTES" : "",
		    (eval.ae_residual & KAUTH_VNODE_WRITE_ATTRIBUTES)
		    ? " WRITE_ATTRIBUTES" : "",
		    (eval.ae_residual & KAUTH_VNODE_READ_EXTATTRIBUTES)
		    ? " READ_EXTATTRIBUTES" : "",
		    (eval.ae_residual & KAUTH_VNODE_WRITE_EXTATTRIBUTES)
		    ? " WRITE_EXTATTRIBUTES" : "",
		    (eval.ae_residual & KAUTH_VNODE_READ_SECURITY)
		    ? " READ_SECURITY" : "",
		    (eval.ae_residual & KAUTH_VNODE_WRITE_SECURITY)
		    ? " WRITE_SECURITY" : "",
		    (eval.ae_residual & KAUTH_VNODE_CHECKIMMUTABLE)
		    ? " CHECKIMMUTABLE" : "",
		    (eval.ae_residual & KAUTH_VNODE_CHANGE_OWNER)
		    ? " CHANGE_OWNER" : "");
	}

	/*
	 * Lack of required Posix permissions implies no reason to deny access.
	 */
	return 0;
}

/*
 * Check for file immutability.
 */
static int
vnode_authorize_checkimmutable(mount_t mp, vauth_ctx vcp,
    struct vnode_attr *vap, int rights, int ignore)
{
	int error;
	int append;

	/*
	 * Perform immutability checks for operations that change data.
	 *
	 * Sockets, fifos and devices require special handling.
	 */
	switch (vap->va_type) {
	case VSOCK:
	case VFIFO:
	case VBLK:
	case VCHR:
		/*
		 * Writing to these nodes does not change the filesystem data,
		 * so forget that it's being tried.
		 */
		rights &= ~KAUTH_VNODE_WRITE_DATA;
		break;
	default:
		break;
	}

	error = 0;
	if (rights & KAUTH_VNODE_WRITE_RIGHTS) {
		/* check per-filesystem options if possible */
		if (mp != NULL) {
			/* check for no-EA filesystems */
			if ((rights & KAUTH_VNODE_WRITE_EXTATTRIBUTES) &&
			    (vfs_flags(mp) & MNT_NOUSERXATTR)) {
				KAUTH_DEBUG("%p    DENIED - filesystem disallowed extended attributes", vap);
				error = EACCES;  /* User attributes disabled */
				goto out;
			}
		}

		/*
		 * check for file immutability. first, check if the requested rights are
		 * allowable for a UF_APPEND file.
		 */
		append = 0;
		if (vap->va_type == VDIR) {
			if ((rights & (KAUTH_VNODE_ADD_FILE | KAUTH_VNODE_ADD_SUBDIRECTORY | KAUTH_VNODE_WRITE_EXTATTRIBUTES | ~KAUTH_VNODE_WRITE_RIGHTS)) == rights) {
				append = 1;
			}
		} else {
			if ((rights & (KAUTH_VNODE_APPEND_DATA | KAUTH_VNODE_WRITE_EXTATTRIBUTES | ~KAUTH_VNODE_WRITE_RIGHTS)) == rights) {
				append = 1;
			}
		}
		if ((error = vnode_immutable(vap, append, ignore)) != 0) {
			if (error && !ignore) {
				/*
				 * In case of a rename, we want to check ownership for dvp as well.
				 */
				int owner = 0;
				if (rights & KAUTH_VNODE_DELETE_CHILD && vcp->dvp != NULL) {
					owner = vauth_file_owner(vcp) && vauth_dir_owner(vcp);
				} else {
					owner = vauth_file_owner(vcp);
				}
				if (owner && proc_ignores_node_permissions(vfs_context_proc(vcp->ctx))) {
					error = vnode_immutable(vap, append, 1);
				}
			}
		}
		if (error) {
			KAUTH_DEBUG("%p    DENIED - file is immutable", vap);
			goto out;
		}
	}
out:
	return error;
}

/*
 * Handle authorization actions for filesystems that advertise that the
 * server will be enforcing.
 *
 * Returns:	0			Authorization should be handled locally
 *		1			Authorization was handled by the FS
 *
 * Note:	Imputed returns will only occur if the authorization request
 *		was handled by the FS.
 *
 * Imputed:	*resultp, modified	Return code from FS when the request is
 *					handled by the FS.
 *		VNOP_ACCESS:???
 *		VNOP_OPEN:???
 */
static int
vnode_authorize_opaque(vnode_t vp, int *resultp, kauth_action_t action, vfs_context_t ctx)
{
	int     error;

	/*
	 * If the vp is a device node, socket or FIFO it actually represents a local
	 * endpoint, so we need to handle it locally.
	 */
	switch (vp->v_type) {
	case VBLK:
	case VCHR:
	case VSOCK:
	case VFIFO:
		return 0;
	default:
		break;
	}

	/*
	 * In the advisory request case, if the filesystem doesn't think it's reliable
	 * we will attempt to formulate a result ourselves based on VNOP_GETATTR data.
	 */
	if ((action & KAUTH_VNODE_ACCESS) && !vfs_authopaqueaccess(vp->v_mount)) {
		return 0;
	}

	/*
	 * Let the filesystem have a say in the matter.  It's OK for it to not implemnent
	 * VNOP_ACCESS, as most will authorise inline with the actual request.
	 */
	if ((error = VNOP_ACCESS(vp, action, ctx)) != ENOTSUP) {
		*resultp = error;
		KAUTH_DEBUG("%p    DENIED - opaque filesystem VNOP_ACCESS denied access", vp);
		return 1;
	}

	/*
	 * Typically opaque filesystems do authorisation in-line, but exec is a special case.  In
	 * order to be reasonably sure that exec will be permitted, we try a bit harder here.
	 */
	if ((action & KAUTH_VNODE_EXECUTE) && (vp->v_type == VREG)) {
		/* try a VNOP_OPEN for readonly access */
		if ((error = VNOP_OPEN(vp, FREAD, ctx)) != 0) {
			*resultp = error;
			KAUTH_DEBUG("%p    DENIED - EXECUTE denied because file could not be opened readonly", vp);
			return 1;
		}
		VNOP_CLOSE(vp, FREAD, ctx);
	}

	/*
	 * We don't have any reason to believe that the request has to be denied at this point,
	 * so go ahead and allow it.
	 */
	*resultp = 0;
	KAUTH_DEBUG("%p    ALLOWED - bypassing access check for non-local filesystem", vp);
	return 1;
}




/*
 * Returns:	KAUTH_RESULT_ALLOW
 *		KAUTH_RESULT_DENY
 *
 * Imputed:	*arg3, modified		Error code in the deny case
 *		EROFS			Read-only file system
 *		EACCES			Permission denied
 *		EPERM			Operation not permitted [no execute]
 *	vnode_getattr:ENOMEM		Not enough space [only if has filesec]
 *	vnode_getattr:???
 *	vnode_authorize_opaque:*arg2	???
 *	vnode_authorize_checkimmutable:???
 *	vnode_authorize_delete:???
 *	vnode_authorize_simple:???
 */


static int
vnode_authorize_callback(__unused kauth_cred_t cred, __unused void *idata,
    kauth_action_t action, uintptr_t arg0, uintptr_t arg1, uintptr_t arg2,
    uintptr_t arg3)
{
	vfs_context_t   ctx;
	vnode_t         cvp = NULLVP;
	vnode_t         vp, dvp;
	int             result = KAUTH_RESULT_DENY;
	int             parent_iocount = 0;
	int             parent_action = 0; /* In case we need to use namedstream's data fork for cached rights*/

	ctx = (vfs_context_t)arg0;
	vp = (vnode_t)arg1;
	dvp = (vnode_t)arg2;

	/*
	 * if there are 2 vnodes passed in, we don't know at
	 * this point which rights to look at based on the
	 * combined action being passed in... defer until later...
	 * otherwise check the kauth 'rights' cache hung
	 * off of the vnode we're interested in... if we've already
	 * been granted the right we're currently interested in,
	 * we can just return success... otherwise we'll go through
	 * the process of authorizing the requested right(s)... if that
	 * succeeds, we'll add the right(s) to the cache.
	 * VNOP_SETATTR and VNOP_SETXATTR will invalidate this cache
	 */
	if (dvp && vp) {
		goto defer;
	}
	if (dvp) {
		cvp = dvp;
	} else {
		/*
		 * For named streams on local-authorization volumes, rights are cached on the parent;
		 * authorization is determined by looking at the parent's properties anyway, so storing
		 * on the parent means that we don't recompute for the named stream and that if
		 * we need to flush rights (e.g. on VNOP_SETATTR()) we don't need to track down the
		 * stream to flush its cache separately.  If we miss in the cache, then we authorize
		 * as if there were no cached rights (passing the named stream vnode and desired rights to
		 * vnode_authorize_callback_int()).
		 *
		 * On an opaquely authorized volume, we don't know the relationship between the
		 * data fork's properties and the rights granted on a stream.  Thus, named stream vnodes
		 * on such a volume are authorized directly (rather than using the parent) and have their
		 * own caches.  When a named stream vnode is created, we mark the parent as having a named
		 * stream. On a VNOP_SETATTR() for the parent that may invalidate cached authorization, we
		 * find the stream and flush its cache.
		 */
		if (vnode_isnamedstream(vp) && (!vfs_authopaque(vp->v_mount))) {
			cvp = vnode_getparent(vp);
			if (cvp != NULLVP) {
				parent_iocount = 1;
			} else {
				cvp = NULL;
				goto defer; /* If we can't use the parent, take the slow path */
			}

			/* Have to translate some actions */
			parent_action = action;
			if (parent_action & KAUTH_VNODE_READ_DATA) {
				parent_action &= ~KAUTH_VNODE_READ_DATA;
				parent_action |= KAUTH_VNODE_READ_EXTATTRIBUTES;
			}
			if (parent_action & KAUTH_VNODE_WRITE_DATA) {
				parent_action &= ~KAUTH_VNODE_WRITE_DATA;
				parent_action |= KAUTH_VNODE_WRITE_EXTATTRIBUTES;
			}
		} else {
			cvp = vp;
		}
	}

	if (vnode_cache_is_authorized(cvp, ctx, parent_iocount ? parent_action : action) == TRUE) {
		result = KAUTH_RESULT_ALLOW;
		goto out;
	}
defer:
	result = vnode_authorize_callback_int(action, ctx, vp, dvp, (int *)arg3);

	if (result == KAUTH_RESULT_ALLOW && cvp != NULLVP) {
		KAUTH_DEBUG("%p - caching action = %x", cvp, action);
		vnode_cache_authorized_action(cvp, ctx, action);
	}

out:
	if (parent_iocount) {
		vnode_put(cvp);
	}

	return result;
}

static int
vnode_attr_authorize_internal(vauth_ctx vcp, mount_t mp,
    kauth_ace_rights_t rights, int is_suser, boolean_t *found_deny,
    int noimmutable, int parent_authorized_for_delete_child)
{
	int result;

	/*
	 * Check for immutability.
	 *
	 * In the deletion case, parent directory immutability vetoes specific
	 * file rights.
	 */
	if ((result = vnode_authorize_checkimmutable(mp, vcp, vcp->vap, rights,
	    noimmutable)) != 0) {
		goto out;
	}

	if ((rights & KAUTH_VNODE_DELETE) &&
	    !parent_authorized_for_delete_child) {
		result = vnode_authorize_checkimmutable(mp, vcp, vcp->dvap,
		    KAUTH_VNODE_DELETE_CHILD, 0);
		if (result) {
			goto out;
		}
	}

	/*
	 * Clear rights that have been authorized by reaching this point, bail if nothing left to
	 * check.
	 */
	rights &= ~(KAUTH_VNODE_LINKTARGET | KAUTH_VNODE_CHECKIMMUTABLE);
	if (rights == 0) {
		goto out;
	}

	/*
	 * If we're not the superuser, authorize based on file properties;
	 * note that even if parent_authorized_for_delete_child is TRUE, we
	 * need to check on the node itself.
	 */
	if (!is_suser) {
		/* process delete rights */
		if ((rights & KAUTH_VNODE_DELETE) &&
		    ((result = vnode_authorize_delete(vcp, parent_authorized_for_delete_child)) != 0)) {
			goto out;
		}

		/* process remaining rights */
		if ((rights & ~KAUTH_VNODE_DELETE) &&
		    (result = vnode_authorize_simple(vcp, rights, rights & KAUTH_VNODE_DELETE, found_deny)) != 0) {
			goto out;
		}
	} else {
		/*
		 * Execute is only granted to root if one of the x bits is set.  This check only
		 * makes sense if the posix mode bits are actually supported.
		 */
		if ((rights & KAUTH_VNODE_EXECUTE) &&
		    (vcp->vap->va_type == VREG) &&
		    VATTR_IS_SUPPORTED(vcp->vap, va_mode) &&
		    !(vcp->vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH))) {
			result = EPERM;
			KAUTH_DEBUG("%p    DENIED - root execute requires at least one x bit in 0x%x", vcp, vcp->vap->va_mode);
			goto out;
		}

		/* Assume that there were DENYs so we don't wrongly cache KAUTH_VNODE_SEARCHBYANYONE */
		*found_deny = TRUE;

		KAUTH_DEBUG("%p    ALLOWED - caller is superuser", vcp);
	}
out:
	return result;
}

static int
vnode_authorize_callback_int(kauth_action_t action, vfs_context_t ctx,
    vnode_t vp, vnode_t dvp, int *errorp)
{
	struct _vnode_authorize_context auth_context;
	vauth_ctx               vcp;
	kauth_cred_t            cred;
	kauth_ace_rights_t      rights;
	struct vnode_attr       va, dva;
	int                     result;
	int                     noimmutable;
	boolean_t               parent_authorized_for_delete_child = FALSE;
	boolean_t               found_deny = FALSE;
	boolean_t               parent_ref = FALSE;
	boolean_t               is_suser = FALSE;

	vcp = &auth_context;
	vcp->ctx = ctx;
	vcp->vp = vp;
	vcp->dvp = dvp;
	/*
	 * Note that we authorize against the context, not the passed cred
	 * (the same thing anyway)
	 */
	cred = ctx->vc_ucred;

	VATTR_INIT(&va);
	vcp->vap = &va;
	VATTR_INIT(&dva);
	vcp->dvap = &dva;

	vcp->flags = vcp->flags_valid = 0;

#if DIAGNOSTIC
	if ((ctx == NULL) || (vp == NULL) || (cred == NULL)) {
		panic("vnode_authorize: bad arguments (context %p  vp %p  cred %p)", ctx, vp, cred);
	}
#endif

	KAUTH_DEBUG("%p  AUTH - %s %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s on %s '%s' (0x%x:%p/%p)",
	    vp, vfs_context_proc(ctx)->p_comm,
	    (action & KAUTH_VNODE_ACCESS)               ? "access" : "auth",
	    (action & KAUTH_VNODE_READ_DATA)            ? vnode_isdir(vp) ? " LIST_DIRECTORY" : " READ_DATA" : "",
	    (action & KAUTH_VNODE_WRITE_DATA)           ? vnode_isdir(vp) ? " ADD_FILE" : " WRITE_DATA" : "",
	    (action & KAUTH_VNODE_EXECUTE)              ? vnode_isdir(vp) ? " SEARCH" : " EXECUTE" : "",
	    (action & KAUTH_VNODE_DELETE)               ? " DELETE" : "",
	    (action & KAUTH_VNODE_APPEND_DATA)          ? vnode_isdir(vp) ? " ADD_SUBDIRECTORY" : " APPEND_DATA" : "",
	    (action & KAUTH_VNODE_DELETE_CHILD)         ? " DELETE_CHILD" : "",
	    (action & KAUTH_VNODE_READ_ATTRIBUTES)      ? " READ_ATTRIBUTES" : "",
	    (action & KAUTH_VNODE_WRITE_ATTRIBUTES)     ? " WRITE_ATTRIBUTES" : "",
	    (action & KAUTH_VNODE_READ_EXTATTRIBUTES)   ? " READ_EXTATTRIBUTES" : "",
	    (action & KAUTH_VNODE_WRITE_EXTATTRIBUTES)  ? " WRITE_EXTATTRIBUTES" : "",
	    (action & KAUTH_VNODE_READ_SECURITY)        ? " READ_SECURITY" : "",
	    (action & KAUTH_VNODE_WRITE_SECURITY)       ? " WRITE_SECURITY" : "",
	    (action & KAUTH_VNODE_CHANGE_OWNER)         ? " CHANGE_OWNER" : "",
	    (action & KAUTH_VNODE_NOIMMUTABLE)          ? " (noimmutable)" : "",
	    vnode_isdir(vp) ? "directory" : "file",
	    vp->v_name ? vp->v_name : "<NULL>", action, vp, dvp);

	/*
	 * Extract the control bits from the action, everything else is
	 * requested rights.
	 */
	noimmutable = (action & KAUTH_VNODE_NOIMMUTABLE) ? 1 : 0;
	rights = action & ~(KAUTH_VNODE_ACCESS | KAUTH_VNODE_NOIMMUTABLE);

	if (rights & KAUTH_VNODE_DELETE) {
#if DIAGNOSTIC
		if (dvp == NULL) {
			panic("vnode_authorize: KAUTH_VNODE_DELETE test requires a directory");
		}
#endif
		/*
		 * check to see if we've already authorized the parent
		 * directory for deletion of its children... if so, we
		 * can skip a whole bunch of work... we will still have to
		 * authorize that this specific child can be removed
		 */
		if (vnode_cache_is_authorized(dvp, ctx, KAUTH_VNODE_DELETE_CHILD) == TRUE) {
			parent_authorized_for_delete_child = TRUE;
		}
	} else {
		vcp->dvp = NULLVP;
		vcp->dvap = NULL;
	}

	/*
	 * Check for read-only filesystems.
	 */
	if ((rights & KAUTH_VNODE_WRITE_RIGHTS) &&
	    (vp->v_mount->mnt_flag & MNT_RDONLY) &&
	    ((vp->v_type == VREG) || (vp->v_type == VDIR) ||
	    (vp->v_type == VLNK) || (vp->v_type == VCPLX) ||
	    (rights & KAUTH_VNODE_DELETE) || (rights & KAUTH_VNODE_DELETE_CHILD))) {
		result = EROFS;
		goto out;
	}

	/*
	 * Check for noexec filesystems.
	 */
	if ((rights & KAUTH_VNODE_EXECUTE) && (vp->v_type == VREG) && (vp->v_mount->mnt_flag & MNT_NOEXEC)) {
		result = EACCES;
		goto out;
	}

	/*
	 * Handle cases related to filesystems with non-local enforcement.
	 * This call can return 0, in which case we will fall through to perform a
	 * check based on VNOP_GETATTR data.  Otherwise it returns 1 and sets
	 * an appropriate result, at which point we can return immediately.
	 */
	if ((vp->v_mount->mnt_kern_flag & MNTK_AUTH_OPAQUE) && vnode_authorize_opaque(vp, &result, action, ctx)) {
		goto out;
	}

	/*
	 * If the vnode is a namedstream (extended attribute) data vnode (eg.
	 * a resource fork), *_DATA becomes *_EXTATTRIBUTES.
	 */
	if (vnode_isnamedstream(vp)) {
		if (rights & KAUTH_VNODE_READ_DATA) {
			rights &= ~KAUTH_VNODE_READ_DATA;
			rights |= KAUTH_VNODE_READ_EXTATTRIBUTES;
		}
		if (rights & KAUTH_VNODE_WRITE_DATA) {
			rights &= ~KAUTH_VNODE_WRITE_DATA;
			rights |= KAUTH_VNODE_WRITE_EXTATTRIBUTES;
		}

		/*
		 * Point 'vp' to the namedstream's parent for ACL checking
		 */
		if ((vp->v_parent != NULL) &&
		    (vget_internal(vp->v_parent, 0, VNODE_NODEAD | VNODE_DRAINO) == 0)) {
			parent_ref = TRUE;
			vcp->vp = vp = vp->v_parent;
		}
	}

	if (vfs_context_issuser(ctx)) {
		/*
		 * if we're not asking for execute permissions or modifications,
		 * then we're done, this action is authorized.
		 */
		if (!(rights & (KAUTH_VNODE_EXECUTE | KAUTH_VNODE_WRITE_RIGHTS))) {
			goto success;
		}

		is_suser = TRUE;
	}

	/*
	 * Get vnode attributes and extended security information for the vnode
	 * and directory if required.
	 *
	 * If we're root we only want mode bits and flags for checking
	 * execute and immutability.
	 */
	VATTR_WANTED(&va, va_mode);
	VATTR_WANTED(&va, va_flags);
	if (!is_suser) {
		VATTR_WANTED(&va, va_uid);
		VATTR_WANTED(&va, va_gid);
		VATTR_WANTED(&va, va_acl);
	}
	if ((result = vnode_getattr(vp, &va, ctx)) != 0) {
		KAUTH_DEBUG("%p    ERROR - failed to get vnode attributes - %d", vp, result);
		goto out;
	}
	VATTR_WANTED(&va, va_type);
	VATTR_RETURN(&va, va_type, vnode_vtype(vp));

	if (vcp->dvp) {
		VATTR_WANTED(&dva, va_mode);
		VATTR_WANTED(&dva, va_flags);
		if (!is_suser) {
			VATTR_WANTED(&dva, va_uid);
			VATTR_WANTED(&dva, va_gid);
			VATTR_WANTED(&dva, va_acl);
		}
		if ((result = vnode_getattr(vcp->dvp, &dva, ctx)) != 0) {
			KAUTH_DEBUG("%p    ERROR - failed to get directory vnode attributes - %d", vp, result);
			goto out;
		}
		VATTR_WANTED(&dva, va_type);
		VATTR_RETURN(&dva, va_type, vnode_vtype(vcp->dvp));
	}

	result = vnode_attr_authorize_internal(vcp, vp->v_mount, rights, is_suser,
	    &found_deny, noimmutable, parent_authorized_for_delete_child);
out:
	if (VATTR_IS_SUPPORTED(&va, va_acl) && (va.va_acl != NULL)) {
		kauth_acl_free(va.va_acl);
	}
	if (VATTR_IS_SUPPORTED(&dva, va_acl) && (dva.va_acl != NULL)) {
		kauth_acl_free(dva.va_acl);
	}

	if (result) {
		if (parent_ref) {
			vnode_put(vp);
		}
		*errorp = result;
		KAUTH_DEBUG("%p    DENIED - auth denied", vp);
		return KAUTH_RESULT_DENY;
	}
	if ((rights & KAUTH_VNODE_SEARCH) && found_deny == FALSE && vp->v_type == VDIR) {
		/*
		 * if we were successfully granted the right to search this directory
		 * and there were NO ACL DENYs for search and the posix permissions also don't
		 * deny execute, we can synthesize a global right that allows anyone to
		 * traverse this directory during a pathname lookup without having to
		 * match the credential associated with this cache of rights.
		 *
		 * Note that we can correctly cache KAUTH_VNODE_SEARCHBYANYONE
		 * only if we actually check ACLs which we don't for root. As
		 * a workaround, the lookup fast path checks for root.
		 */
		if (!VATTR_IS_SUPPORTED(&va, va_mode) ||
		    ((va.va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) ==
		    (S_IXUSR | S_IXGRP | S_IXOTH))) {
			vnode_cache_authorized_action(vp, ctx, KAUTH_VNODE_SEARCHBYANYONE);
		}
	}
success:
	if (parent_ref) {
		vnode_put(vp);
	}

	/*
	 * Note that this implies that we will allow requests for no rights, as well as
	 * for rights that we do not recognise.  There should be none of these.
	 */
	KAUTH_DEBUG("%p    ALLOWED - auth granted", vp);
	return KAUTH_RESULT_ALLOW;
}

int
vnode_attr_authorize_init(struct vnode_attr *vap, struct vnode_attr *dvap,
    kauth_action_t action, vfs_context_t ctx)
{
	VATTR_INIT(vap);
	VATTR_WANTED(vap, va_type);
	VATTR_WANTED(vap, va_mode);
	VATTR_WANTED(vap, va_flags);
	if (dvap) {
		VATTR_INIT(dvap);
		if (action & KAUTH_VNODE_DELETE) {
			VATTR_WANTED(dvap, va_type);
			VATTR_WANTED(dvap, va_mode);
			VATTR_WANTED(dvap, va_flags);
		}
	} else if (action & KAUTH_VNODE_DELETE) {
		return EINVAL;
	}

	if (!vfs_context_issuser(ctx)) {
		VATTR_WANTED(vap, va_uid);
		VATTR_WANTED(vap, va_gid);
		VATTR_WANTED(vap, va_acl);
		if (dvap && (action & KAUTH_VNODE_DELETE)) {
			VATTR_WANTED(dvap, va_uid);
			VATTR_WANTED(dvap, va_gid);
			VATTR_WANTED(dvap, va_acl);
		}
	}

	return 0;
}

#define VNODE_SEC_ATTRS_NO_ACL (VNODE_ATTR_va_uid | VNODE_ATTR_va_gid | VNODE_ATTR_va_mode | VNODE_ATTR_va_flags | VNODE_ATTR_va_type)

int
vnode_attr_authorize(struct vnode_attr *vap, struct vnode_attr *dvap, mount_t mp,
    kauth_action_t action, vfs_context_t ctx)
{
	struct _vnode_authorize_context auth_context;
	vauth_ctx vcp;
	kauth_ace_rights_t rights;
	int noimmutable;
	boolean_t found_deny;
	boolean_t is_suser = FALSE;
	int result = 0;
	uid_t ouid = vap->va_uid;
	gid_t ogid = vap->va_gid;

	vcp = &auth_context;
	vcp->ctx = ctx;
	vcp->vp = NULLVP;
	vcp->vap = vap;
	vcp->dvp = NULLVP;
	vcp->dvap = dvap;
	vcp->flags = vcp->flags_valid = 0;

	noimmutable = (action & KAUTH_VNODE_NOIMMUTABLE) ? 1 : 0;
	rights = action & ~(KAUTH_VNODE_ACCESS | KAUTH_VNODE_NOIMMUTABLE);

	/*
	 * Check for read-only filesystems.
	 */
	if ((rights & KAUTH_VNODE_WRITE_RIGHTS) &&
	    mp && (mp->mnt_flag & MNT_RDONLY) &&
	    ((vap->va_type == VREG) || (vap->va_type == VDIR) ||
	    (vap->va_type == VLNK) || (rights & KAUTH_VNODE_DELETE) ||
	    (rights & KAUTH_VNODE_DELETE_CHILD))) {
		result = EROFS;
		goto out;
	}

	/*
	 * Check for noexec filesystems.
	 */
	if ((rights & KAUTH_VNODE_EXECUTE) &&
	    (vap->va_type == VREG) && mp && (mp->mnt_flag & MNT_NOEXEC)) {
		result = EACCES;
		goto out;
	}

	if (vfs_context_issuser(ctx)) {
		/*
		 * if we're not asking for execute permissions or modifications,
		 * then we're done, this action is authorized.
		 */
		if (!(rights & (KAUTH_VNODE_EXECUTE | KAUTH_VNODE_WRITE_RIGHTS))) {
			goto out;
		}
		is_suser = TRUE;
	}

	if (mp) {
		if (vfs_extendedsecurity(mp) && VATTR_IS_ACTIVE(vap, va_acl) && !VATTR_IS_SUPPORTED(vap, va_acl)) {
			panic("(1) vnode attrs not complete for vnode_attr_authorize");
		}
		vnode_attr_handle_uid_and_gid(vap, mp, ctx);
	}

	if ((vap->va_active & VNODE_SEC_ATTRS_NO_ACL) != (vap->va_supported & VNODE_SEC_ATTRS_NO_ACL)) {
		panic("(2) vnode attrs not complete for vnode_attr_authorize (2) vap->va_active = 0x%llx , vap->va_supported = 0x%llx",
		    vap->va_active, vap->va_supported);
	}

	result = vnode_attr_authorize_internal(vcp, mp, rights, is_suser,
	    &found_deny, noimmutable, FALSE);

	if (mp) {
		vap->va_uid = ouid;
		vap->va_gid = ogid;
	}

	if (result == EPERM) {
		result = EACCES;
	}
out:
	return result;
}


int
vnode_authattr_new(vnode_t dvp, struct vnode_attr *vap, int noauth, vfs_context_t ctx)
{
	return vnode_authattr_new_internal(dvp, vap, noauth, NULL, ctx);
}

/*
 * Check that the attribute information in vattr can be legally applied to
 * a new file by the context.
 */
static int
vnode_authattr_new_internal(vnode_t dvp, struct vnode_attr *vap, int noauth, uint32_t *defaulted_fieldsp, vfs_context_t ctx)
{
	int             error;
	int             has_priv_suser, ismember, defaulted_owner, defaulted_group, defaulted_mode;
	uint32_t        inherit_flags;
	kauth_cred_t    cred;
	guid_t          changer;
	mount_t         dmp;
	struct vnode_attr dva;

	error = 0;

	if (defaulted_fieldsp) {
		*defaulted_fieldsp = 0;
	}

	defaulted_owner = defaulted_group = defaulted_mode = 0;

	inherit_flags = 0;

	/*
	 * Require that the filesystem support extended security to apply any.
	 */
	if (!vfs_extendedsecurity(dvp->v_mount) &&
	    (VATTR_IS_ACTIVE(vap, va_acl) || VATTR_IS_ACTIVE(vap, va_uuuid) || VATTR_IS_ACTIVE(vap, va_guuid))) {
		error = EINVAL;
		goto out;
	}

	/*
	 * Default some fields.
	 */
	dmp = dvp->v_mount;

	/*
	 * If the filesystem is mounted IGNORE_OWNERSHIP and an explicit owner is set, that
	 * owner takes ownership of all new files.
	 */
	if ((dmp->mnt_flag & MNT_IGNORE_OWNERSHIP) && (dmp->mnt_fsowner != KAUTH_UID_NONE)) {
		VATTR_SET(vap, va_uid, dmp->mnt_fsowner);
		defaulted_owner = 1;
	} else {
		if (!VATTR_IS_ACTIVE(vap, va_uid)) {
			/* default owner is current user */
			VATTR_SET(vap, va_uid, kauth_cred_getuid(vfs_context_ucred(ctx)));
			defaulted_owner = 1;
		}
	}

	/*
	 * We need the dvp's va_flags and *may* need the gid of the directory,
	 * we ask for both here.
	 */
	VATTR_INIT(&dva);
	VATTR_WANTED(&dva, va_gid);
	VATTR_WANTED(&dva, va_flags);
	if ((error = vnode_getattr(dvp, &dva, ctx)) != 0) {
		goto out;
	}

	/*
	 * If the filesystem is mounted IGNORE_OWNERSHIP and an explicit grouo is set, that
	 * group takes ownership of all new files.
	 */
	if ((dmp->mnt_flag & MNT_IGNORE_OWNERSHIP) && (dmp->mnt_fsgroup != KAUTH_GID_NONE)) {
		VATTR_SET(vap, va_gid, dmp->mnt_fsgroup);
		defaulted_group = 1;
	} else {
		if (!VATTR_IS_ACTIVE(vap, va_gid)) {
			/* default group comes from parent object, fallback to current user */
			if (VATTR_IS_SUPPORTED(&dva, va_gid)) {
				VATTR_SET(vap, va_gid, dva.va_gid);
			} else {
				VATTR_SET(vap, va_gid, kauth_cred_getgid(vfs_context_ucred(ctx)));
			}
			defaulted_group = 1;
		}
	}

	if (!VATTR_IS_ACTIVE(vap, va_flags)) {
		VATTR_SET(vap, va_flags, 0);
	}

	/* Determine if SF_RESTRICTED should be inherited from the parent
	 * directory. */
	if (VATTR_IS_SUPPORTED(&dva, va_flags)) {
		inherit_flags = dva.va_flags & (UF_DATAVAULT | SF_RESTRICTED);
	}

	/* default mode is everything, masked with current umask */
	if (!VATTR_IS_ACTIVE(vap, va_mode)) {
		VATTR_SET(vap, va_mode, ACCESSPERMS & ~vfs_context_proc(ctx)->p_fd.fd_cmask);
		KAUTH_DEBUG("ATTR - defaulting new file mode to %o from umask %o",
		    vap->va_mode, vfs_context_proc(ctx)->p_fd.fd_cmask);
		defaulted_mode = 1;
	}
	/* set timestamps to now */
	if (!VATTR_IS_ACTIVE(vap, va_create_time)) {
		nanotime(&vap->va_create_time);
		VATTR_SET_ACTIVE(vap, va_create_time);
	}

	/*
	 * Check for attempts to set nonsensical fields.
	 */
	if (vap->va_active & ~VNODE_ATTR_NEWOBJ) {
		error = EINVAL;
		KAUTH_DEBUG("ATTR - ERROR - attempt to set unsupported new-file attributes %llx",
		    vap->va_active & ~VNODE_ATTR_NEWOBJ);
		goto out;
	}

	/*
	 * Quickly check for the applicability of any enforcement here.
	 * Tests below maintain the integrity of the local security model.
	 */
	if (vfs_authopaque(dvp->v_mount)) {
		goto out;
	}

	/*
	 * We need to know if the caller is the superuser, or if the work is
	 * otherwise already authorised.
	 */
	cred = vfs_context_ucred(ctx);
	if (noauth) {
		/* doing work for the kernel */
		has_priv_suser = 1;
	} else {
		has_priv_suser = vfs_context_issuser(ctx);
	}


	if (VATTR_IS_ACTIVE(vap, va_flags)) {
		vap->va_flags &= ~SF_SYNTHETIC;
		if (has_priv_suser) {
			if ((vap->va_flags & (UF_SETTABLE | SF_SETTABLE)) != vap->va_flags) {
				error = EPERM;
				KAUTH_DEBUG("  DENIED - superuser attempt to set illegal flag(s)");
				goto out;
			}
		} else {
			if ((vap->va_flags & UF_SETTABLE) != vap->va_flags) {
				error = EPERM;
				KAUTH_DEBUG("  DENIED - user attempt to set illegal flag(s)");
				goto out;
			}
		}
	}

	/* if not superuser, validate legality of new-item attributes */
	if (!has_priv_suser) {
		if (!defaulted_mode && VATTR_IS_ACTIVE(vap, va_mode)) {
			/* setgid? */
			if (vap->va_mode & S_ISGID) {
				if ((error = kauth_cred_ismember_gid(cred, vap->va_gid, &ismember)) != 0) {
					KAUTH_DEBUG("ATTR - ERROR: got %d checking for membership in %d", error, vap->va_gid);
					goto out;
				}
				if (!ismember) {
					KAUTH_DEBUG("  DENIED - can't set SGID bit, not a member of %d", vap->va_gid);
					error = EPERM;
					goto out;
				}
			}

			/* setuid? */
			if ((vap->va_mode & S_ISUID) && (vap->va_uid != kauth_cred_getuid(cred))) {
				KAUTH_DEBUG("ATTR - ERROR: illegal attempt to set the setuid bit");
				error = EPERM;
				goto out;
			}
		}
		if (!defaulted_owner && (vap->va_uid != kauth_cred_getuid(cred))) {
			KAUTH_DEBUG("  DENIED - cannot create new item owned by %d", vap->va_uid);
			error = EPERM;
			goto out;
		}
		if (!defaulted_group) {
			if ((error = kauth_cred_ismember_gid(cred, vap->va_gid, &ismember)) != 0) {
				KAUTH_DEBUG("  ERROR - got %d checking for membership in %d", error, vap->va_gid);
				goto out;
			}
			if (!ismember) {
				KAUTH_DEBUG("  DENIED - cannot create new item with group %d - not a member", vap->va_gid);
				error = EPERM;
				goto out;
			}
		}

		/* initialising owner/group UUID */
		if (VATTR_IS_ACTIVE(vap, va_uuuid)) {
			if ((error = kauth_cred_getguid(cred, &changer)) != 0) {
				KAUTH_DEBUG("  ERROR - got %d trying to get caller UUID", error);
				/* XXX ENOENT here - no GUID - should perhaps become EPERM */
				goto out;
			}
			if (!kauth_guid_equal(&vap->va_uuuid, &changer)) {
				KAUTH_DEBUG("  ERROR - cannot create item with supplied owner UUID - not us");
				error = EPERM;
				goto out;
			}
		}
		if (VATTR_IS_ACTIVE(vap, va_guuid)) {
			if ((error = kauth_cred_ismember_guid(cred, &vap->va_guuid, &ismember)) != 0) {
				KAUTH_DEBUG("  ERROR - got %d trying to check group membership", error);
				goto out;
			}
			if (!ismember) {
				KAUTH_DEBUG("  ERROR - cannot create item with supplied group UUID - not a member");
				error = EPERM;
				goto out;
			}
		}
	}
out:
	if (inherit_flags) {
		/* Apply SF_RESTRICTED to the file if its parent directory was
		 * restricted.  This is done at the end so that root is not
		 * required if this flag is only set due to inheritance. */
		VATTR_SET(vap, va_flags, (vap->va_flags | inherit_flags));
	}
	if (defaulted_fieldsp) {
		if (defaulted_mode) {
			*defaulted_fieldsp |= VATTR_PREPARE_DEFAULTED_MODE;
		}
		if (defaulted_group) {
			*defaulted_fieldsp |= VATTR_PREPARE_DEFAULTED_GID;
		}
		if (defaulted_owner) {
			*defaulted_fieldsp |= VATTR_PREPARE_DEFAULTED_UID;
		}
	}
	return error;
}

/*
 * Check that the attribute information in vap can be legally written by the
 * context.
 *
 * Call this when you're not sure about the vnode_attr; either its contents
 * have come from an unknown source, or when they are variable.
 *
 * Returns errno, or zero and sets *actionp to the KAUTH_VNODE_* actions that
 * must be authorized to be permitted to write the vattr.
 */
int
vnode_authattr(vnode_t vp, struct vnode_attr *vap, kauth_action_t *actionp, vfs_context_t ctx)
{
	struct vnode_attr ova;
	kauth_action_t  required_action;
	int             error, has_priv_suser, ismember, chowner, chgroup, clear_suid, clear_sgid;
	guid_t          changer;
	gid_t           group;
	uid_t           owner;
	mode_t          newmode;
	kauth_cred_t    cred;
	uint32_t        fdelta;

	VATTR_INIT(&ova);
	required_action = 0;
	error = 0;

	/*
	 * Quickly check for enforcement applicability.
	 */
	if (vfs_authopaque(vp->v_mount)) {
		goto out;
	}

	/*
	 * Check for attempts to set nonsensical fields.
	 */
	if (vap->va_active & VNODE_ATTR_RDONLY) {
		KAUTH_DEBUG("ATTR - ERROR: attempt to set readonly attribute(s)");
		error = EINVAL;
		goto out;
	}

	/*
	 * We need to know if the caller is the superuser.
	 */
	cred = vfs_context_ucred(ctx);
	has_priv_suser = kauth_cred_issuser(cred);

	/*
	 * If any of the following are changing, we need information from the old file:
	 * va_uid
	 * va_gid
	 * va_mode
	 * va_uuuid
	 * va_guuid
	 */
	if (VATTR_IS_ACTIVE(vap, va_uid) ||
	    VATTR_IS_ACTIVE(vap, va_gid) ||
	    VATTR_IS_ACTIVE(vap, va_mode) ||
	    VATTR_IS_ACTIVE(vap, va_uuuid) ||
	    VATTR_IS_ACTIVE(vap, va_guuid)) {
		VATTR_WANTED(&ova, va_mode);
		VATTR_WANTED(&ova, va_uid);
		VATTR_WANTED(&ova, va_gid);
		VATTR_WANTED(&ova, va_uuuid);
		VATTR_WANTED(&ova, va_guuid);
		KAUTH_DEBUG("ATTR - security information changing, fetching existing attributes");
	}

	/*
	 * If timestamps are being changed, we need to know who the file is owned
	 * by.
	 */
	if (VATTR_IS_ACTIVE(vap, va_create_time) ||
	    VATTR_IS_ACTIVE(vap, va_change_time) ||
	    VATTR_IS_ACTIVE(vap, va_modify_time) ||
	    VATTR_IS_ACTIVE(vap, va_access_time) ||
	    VATTR_IS_ACTIVE(vap, va_backup_time) ||
	    VATTR_IS_ACTIVE(vap, va_addedtime)) {
		VATTR_WANTED(&ova, va_uid);
#if 0   /* enable this when we support UUIDs as official owners */
		VATTR_WANTED(&ova, va_uuuid);
#endif
		KAUTH_DEBUG("ATTR - timestamps changing, fetching uid and GUID");
	}

	/*
	 * If flags are being changed, we need the old flags.
	 */
	if (VATTR_IS_ACTIVE(vap, va_flags)) {
		KAUTH_DEBUG("ATTR - flags changing, fetching old flags");
		VATTR_WANTED(&ova, va_flags);
	}

	/*
	 * If ACLs are being changed, we need the old ACLs.
	 */
	if (VATTR_IS_ACTIVE(vap, va_acl)) {
		KAUTH_DEBUG("ATTR - acl changing, fetching old flags");
		VATTR_WANTED(&ova, va_acl);
	}

	/*
	 * If the size is being set, make sure it's not a directory.
	 */
	if (VATTR_IS_ACTIVE(vap, va_data_size)) {
		/* size is only meaningful on regular files, don't permit otherwise */
		if (!vnode_isreg(vp)) {
			KAUTH_DEBUG("ATTR - ERROR: size change requested on non-file");
			error = vnode_isdir(vp) ? EISDIR : EINVAL;
			goto out;
		}
	}

	/*
	 * Get old data.
	 */
	KAUTH_DEBUG("ATTR - fetching old attributes %016llx", ova.va_active);
	if ((error = vnode_getattr(vp, &ova, ctx)) != 0) {
		KAUTH_DEBUG("  ERROR - got %d trying to get attributes", error);
		goto out;
	}

	/*
	 * Size changes require write access to the file data.
	 */
	if (VATTR_IS_ACTIVE(vap, va_data_size)) {
		/* if we can't get the size, or it's different, we need write access */
		KAUTH_DEBUG("ATTR - size change, requiring WRITE_DATA");
		required_action |= KAUTH_VNODE_WRITE_DATA;
	}

	/*
	 * Changing timestamps?
	 *
	 * Note that we are only called to authorize user-requested time changes;
	 * side-effect time changes are not authorized.  Authorisation is only
	 * required for existing files.
	 *
	 * Non-owners are not permitted to change the time on an existing
	 * file to anything other than the current time.
	 */
	if (VATTR_IS_ACTIVE(vap, va_create_time) ||
	    VATTR_IS_ACTIVE(vap, va_change_time) ||
	    VATTR_IS_ACTIVE(vap, va_modify_time) ||
	    VATTR_IS_ACTIVE(vap, va_access_time) ||
	    VATTR_IS_ACTIVE(vap, va_backup_time) ||
	    VATTR_IS_ACTIVE(vap, va_addedtime)) {
		/*
		 * The owner and root may set any timestamps they like,
		 * provided that the file is not immutable.  The owner still needs
		 * WRITE_ATTRIBUTES (implied by ownership but still deniable).
		 */
		if (has_priv_suser || vauth_node_owner(&ova, cred)) {
			KAUTH_DEBUG("ATTR - root or owner changing timestamps");
			required_action |= KAUTH_VNODE_CHECKIMMUTABLE | KAUTH_VNODE_WRITE_ATTRIBUTES;
		} else {
			/* just setting the current time? */
			if (vap->va_vaflags & VA_UTIMES_NULL) {
				KAUTH_DEBUG("ATTR - non-root/owner changing timestamps, requiring WRITE_ATTRIBUTES");
				required_action |= KAUTH_VNODE_WRITE_ATTRIBUTES;
			} else {
				KAUTH_DEBUG("ATTR - ERROR: illegal timestamp modification attempted");
				error = EACCES;
				goto out;
			}
		}
	}

	/*
	 * Changing file mode?
	 */
	if (VATTR_IS_ACTIVE(vap, va_mode) && VATTR_IS_SUPPORTED(&ova, va_mode) && (ova.va_mode != vap->va_mode)) {
		KAUTH_DEBUG("ATTR - mode change from %06o to %06o", ova.va_mode, vap->va_mode);

		/*
		 * Mode changes always have the same basic auth requirements.
		 */
		if (has_priv_suser) {
			KAUTH_DEBUG("ATTR - superuser mode change, requiring immutability check");
			required_action |= KAUTH_VNODE_CHECKIMMUTABLE;
		} else {
			/* need WRITE_SECURITY */
			KAUTH_DEBUG("ATTR - non-superuser mode change, requiring WRITE_SECURITY");
			required_action |= KAUTH_VNODE_WRITE_SECURITY;
		}

		/*
		 * Can't set the setgid bit if you're not in the group and not root.  Have to have
		 * existing group information in the case we're not setting it right now.
		 */
		if (vap->va_mode & S_ISGID) {
			required_action |= KAUTH_VNODE_CHECKIMMUTABLE;  /* always required */
			if (!has_priv_suser) {
				if (VATTR_IS_ACTIVE(vap, va_gid)) {
					group = vap->va_gid;
				} else if (VATTR_IS_SUPPORTED(&ova, va_gid)) {
					group = ova.va_gid;
				} else {
					KAUTH_DEBUG("ATTR - ERROR: setgid but no gid available");
					error = EINVAL;
					goto out;
				}
				/*
				 * This might be too restrictive; WRITE_SECURITY might be implied by
				 * membership in this case, rather than being an additional requirement.
				 */
				if ((error = kauth_cred_ismember_gid(cred, group, &ismember)) != 0) {
					KAUTH_DEBUG("ATTR - ERROR: got %d checking for membership in %d", error, vap->va_gid);
					goto out;
				}
				if (!ismember) {
					KAUTH_DEBUG("  DENIED - can't set SGID bit, not a member of %d", group);
					error = EPERM;
					goto out;
				}
			}
		}

		/*
		 * Can't set the setuid bit unless you're root or the file's owner.
		 */
		if (vap->va_mode & S_ISUID) {
			required_action |= KAUTH_VNODE_CHECKIMMUTABLE;  /* always required */
			if (!has_priv_suser) {
				if (VATTR_IS_ACTIVE(vap, va_uid)) {
					owner = vap->va_uid;
				} else if (VATTR_IS_SUPPORTED(&ova, va_uid)) {
					owner = ova.va_uid;
				} else {
					KAUTH_DEBUG("ATTR - ERROR: setuid but no uid available");
					error = EINVAL;
					goto out;
				}
				if (owner != kauth_cred_getuid(cred)) {
					/*
					 * We could allow this if WRITE_SECURITY is permitted, perhaps.
					 */
					KAUTH_DEBUG("ATTR - ERROR: illegal attempt to set the setuid bit");
					error = EPERM;
					goto out;
				}
			}
		}
	}

	/*
	 * Validate/mask flags changes.  This checks that only the flags in
	 * the UF_SETTABLE mask are being set, and preserves the flags in
	 * the SF_SETTABLE case.
	 *
	 * Since flags changes may be made in conjunction with other changes,
	 * we will ask the auth code to ignore immutability in the case that
	 * the SF_* flags are not set and we are only manipulating the file flags.
	 *
	 */
	if (VATTR_IS_ACTIVE(vap, va_flags)) {
		/* compute changing flags bits */
		vap->va_flags &= ~SF_SYNTHETIC;
		ova.va_flags &= ~SF_SYNTHETIC;
		if (VATTR_IS_SUPPORTED(&ova, va_flags)) {
			fdelta = vap->va_flags ^ ova.va_flags;
		} else {
			fdelta = vap->va_flags;
		}

		if (fdelta != 0) {
			KAUTH_DEBUG("ATTR - flags changing, requiring WRITE_SECURITY");
			required_action |= KAUTH_VNODE_WRITE_SECURITY;

			/* check that changing bits are legal */
			if (has_priv_suser) {
				/*
				 * The immutability check will prevent us from clearing the SF_*
				 * flags unless the system securelevel permits it, so just check
				 * for legal flags here.
				 */
				if (fdelta & ~(UF_SETTABLE | SF_SETTABLE)) {
					error = EPERM;
					KAUTH_DEBUG("  DENIED - superuser attempt to set illegal flag(s)");
					goto out;
				}
			} else {
				if (fdelta & ~UF_SETTABLE) {
					error = EPERM;
					KAUTH_DEBUG("  DENIED - user attempt to set illegal flag(s)");
					goto out;
				}
			}
			/*
			 * If the caller has the ability to manipulate file flags,
			 * security is not reduced by ignoring them for this operation.
			 *
			 * A more complete test here would consider the 'after' states of the flags
			 * to determine whether it would permit the operation, but this becomes
			 * very complex.
			 *
			 * Ignoring immutability is conditional on securelevel; this does not bypass
			 * the SF_* flags if securelevel > 0.
			 */
			required_action |= KAUTH_VNODE_NOIMMUTABLE;
		}
	}

	/*
	 * Validate ownership information.
	 */
	chowner = 0;
	chgroup = 0;
	clear_suid = 0;
	clear_sgid = 0;

	/*
	 * uid changing
	 * Note that if the filesystem didn't give us a UID, we expect that it doesn't
	 * support them in general, and will ignore it if/when we try to set it.
	 * We might want to clear the uid out of vap completely here.
	 */
	if (VATTR_IS_ACTIVE(vap, va_uid)) {
		if (VATTR_IS_SUPPORTED(&ova, va_uid) && (vap->va_uid != ova.va_uid)) {
			if (!has_priv_suser && (kauth_cred_getuid(cred) != vap->va_uid)) {
				KAUTH_DEBUG("  DENIED - non-superuser cannot change ownershipt to a third party");
				error = EPERM;
				goto out;
			}
			chowner = 1;
		}
		clear_suid = 1;
	}

	/*
	 * gid changing
	 * Note that if the filesystem didn't give us a GID, we expect that it doesn't
	 * support them in general, and will ignore it if/when we try to set it.
	 * We might want to clear the gid out of vap completely here.
	 */
	if (VATTR_IS_ACTIVE(vap, va_gid)) {
		if (VATTR_IS_SUPPORTED(&ova, va_gid) && (vap->va_gid != ova.va_gid)) {
			if (!has_priv_suser) {
				if ((error = kauth_cred_ismember_gid(cred, vap->va_gid, &ismember)) != 0) {
					KAUTH_DEBUG("  ERROR - got %d checking for membership in %d", error, vap->va_gid);
					goto out;
				}
				if (!ismember) {
					KAUTH_DEBUG("  DENIED - group change from %d to %d but not a member of target group",
					    ova.va_gid, vap->va_gid);
					error = EPERM;
					goto out;
				}
			}
			chgroup = 1;
		}
		clear_sgid = 1;
	}

	/*
	 * Owner UUID being set or changed.
	 */
	if (VATTR_IS_ACTIVE(vap, va_uuuid)) {
		/* if the owner UUID is not actually changing ... */
		if (VATTR_IS_SUPPORTED(&ova, va_uuuid)) {
			if (kauth_guid_equal(&vap->va_uuuid, &ova.va_uuuid)) {
				goto no_uuuid_change;
			}

			/*
			 * If the current owner UUID is a null GUID, check
			 * it against the UUID corresponding to the owner UID.
			 */
			if (kauth_guid_equal(&ova.va_uuuid, &kauth_null_guid) &&
			    VATTR_IS_SUPPORTED(&ova, va_uid)) {
				guid_t uid_guid;

				if (kauth_cred_uid2guid(ova.va_uid, &uid_guid) == 0 &&
				    kauth_guid_equal(&vap->va_uuuid, &uid_guid)) {
					goto no_uuuid_change;
				}
			}
		}

		/*
		 * The owner UUID cannot be set by a non-superuser to anything other than
		 * their own or a null GUID (to "unset" the owner UUID).
		 * Note that file systems must be prepared to handle the
		 * null UUID case in a manner appropriate for that file
		 * system.
		 */
		if (!has_priv_suser) {
			if ((error = kauth_cred_getguid(cred, &changer)) != 0) {
				KAUTH_DEBUG("  ERROR - got %d trying to get caller UUID", error);
				/* XXX ENOENT here - no UUID - should perhaps become EPERM */
				goto out;
			}
			if (!kauth_guid_equal(&vap->va_uuuid, &changer) &&
			    !kauth_guid_equal(&vap->va_uuuid, &kauth_null_guid)) {
				KAUTH_DEBUG("  ERROR - cannot set supplied owner UUID - not us / null");
				error = EPERM;
				goto out;
			}
		}
		chowner = 1;
		clear_suid = 1;
	}
no_uuuid_change:
	/*
	 * Group UUID being set or changed.
	 */
	if (VATTR_IS_ACTIVE(vap, va_guuid)) {
		/* if the group UUID is not actually changing ... */
		if (VATTR_IS_SUPPORTED(&ova, va_guuid)) {
			if (kauth_guid_equal(&vap->va_guuid, &ova.va_guuid)) {
				goto no_guuid_change;
			}

			/*
			 * If the current group UUID is a null UUID, check
			 * it against the UUID corresponding to the group GID.
			 */
			if (kauth_guid_equal(&ova.va_guuid, &kauth_null_guid) &&
			    VATTR_IS_SUPPORTED(&ova, va_gid)) {
				guid_t gid_guid;

				if (kauth_cred_gid2guid(ova.va_gid, &gid_guid) == 0 &&
				    kauth_guid_equal(&vap->va_guuid, &gid_guid)) {
					goto no_guuid_change;
				}
			}
		}

		/*
		 * The group UUID cannot be set by a non-superuser to anything other than
		 * one of which they are a member or a null GUID (to "unset"
		 * the group UUID).
		 * Note that file systems must be prepared to handle the
		 * null UUID case in a manner appropriate for that file
		 * system.
		 */
		if (!has_priv_suser) {
			if (kauth_guid_equal(&vap->va_guuid, &kauth_null_guid)) {
				ismember = 1;
			} else if ((error = kauth_cred_ismember_guid(cred, &vap->va_guuid, &ismember)) != 0) {
				KAUTH_DEBUG("  ERROR - got %d trying to check group membership", error);
				goto out;
			}
			if (!ismember) {
				KAUTH_DEBUG("  ERROR - cannot set supplied group UUID - not a member / null");
				error = EPERM;
				goto out;
			}
		}
		chgroup = 1;
	}
no_guuid_change:

	/*
	 * Compute authorisation for group/ownership changes.
	 */
	if (chowner || chgroup || clear_suid || clear_sgid) {
		if (has_priv_suser) {
			KAUTH_DEBUG("ATTR - superuser changing file owner/group, requiring immutability check");
			required_action |= KAUTH_VNODE_CHECKIMMUTABLE;
		} else {
			if (chowner) {
				KAUTH_DEBUG("ATTR - ownership change, requiring TAKE_OWNERSHIP");
				required_action |= KAUTH_VNODE_TAKE_OWNERSHIP;
			}
			if (chgroup && !chowner) {
				KAUTH_DEBUG("ATTR - group change, requiring WRITE_SECURITY");
				required_action |= KAUTH_VNODE_WRITE_SECURITY;
			}
		}

		/*
		 * clear set-uid and set-gid bits. POSIX only requires this for
		 * non-privileged processes but we do it even for root.
		 */
		if (VATTR_IS_ACTIVE(vap, va_mode)) {
			newmode = vap->va_mode;
		} else if (VATTR_IS_SUPPORTED(&ova, va_mode)) {
			newmode = ova.va_mode;
		} else {
			KAUTH_DEBUG("CHOWN - trying to change owner but cannot get mode from filesystem to mask setugid bits");
			newmode = 0;
		}

		/* chown always clears setuid/gid bits. An exception is made for
		 * setattrlist which can set both at the same time: <uid, gid, mode> on a file:
		 * setattrlist is allowed to set the new mode on the file and change (chown)
		 * uid/gid.
		 */
		if (newmode & (S_ISUID | S_ISGID)) {
			if (!VATTR_IS_ACTIVE(vap, va_mode)) {
				KAUTH_DEBUG("CHOWN - masking setugid bits from mode %o to %o",
				    newmode, newmode & ~(S_ISUID | S_ISGID));
				newmode &= ~(S_ISUID | S_ISGID);
			}
			VATTR_SET(vap, va_mode, newmode);
		}
	}

	/*
	 * Authorise changes in the ACL.
	 */
	if (VATTR_IS_ACTIVE(vap, va_acl)) {
		/* no existing ACL */
		if (!VATTR_IS_ACTIVE(&ova, va_acl) || (ova.va_acl == NULL)) {
			/* adding an ACL */
			if (vap->va_acl != NULL) {
				required_action |= KAUTH_VNODE_WRITE_SECURITY;
				KAUTH_DEBUG("CHMOD - adding ACL");
			}

			/* removing an existing ACL */
		} else if (vap->va_acl == NULL) {
			required_action |= KAUTH_VNODE_WRITE_SECURITY;
			KAUTH_DEBUG("CHMOD - removing ACL");

			/* updating an existing ACL */
		} else {
			if (vap->va_acl->acl_entrycount != ova.va_acl->acl_entrycount) {
				/* entry count changed, must be different */
				required_action |= KAUTH_VNODE_WRITE_SECURITY;
				KAUTH_DEBUG("CHMOD - adding/removing ACL entries");
			} else if (vap->va_acl->acl_entrycount > 0) {
				/* both ACLs have the same ACE count, said count is 1 or more, bitwise compare ACLs */
				if (memcmp(&vap->va_acl->acl_ace[0], &ova.va_acl->acl_ace[0],
				    sizeof(struct kauth_ace) * vap->va_acl->acl_entrycount)) {
					required_action |= KAUTH_VNODE_WRITE_SECURITY;
					KAUTH_DEBUG("CHMOD - changing ACL entries");
				}
			}
		}
	}

	/*
	 * Other attributes that require authorisation.
	 */
	if (VATTR_IS_ACTIVE(vap, va_encoding)) {
		required_action |= KAUTH_VNODE_WRITE_ATTRIBUTES;
	}

out:
	if (VATTR_IS_SUPPORTED(&ova, va_acl) && (ova.va_acl != NULL)) {
		kauth_acl_free(ova.va_acl);
	}
	if (error == 0) {
		*actionp = required_action;
	}
	return error;
}

static int
setlocklocal_callback(struct vnode *vp, __unused void *cargs)
{
	vnode_lock_spin(vp);
	vp->v_flag |= VLOCKLOCAL;
	vnode_unlock(vp);

	return VNODE_RETURNED;
}

void
vfs_setlocklocal(mount_t mp)
{
	mount_lock_spin(mp);
	mp->mnt_kern_flag |= MNTK_LOCK_LOCAL;
	mount_unlock(mp);

	/*
	 * The number of active vnodes is expected to be
	 * very small when vfs_setlocklocal is invoked.
	 */
	vnode_iterate(mp, 0, setlocklocal_callback, NULL);
}

void
vfs_setcompoundopen(mount_t mp)
{
	mount_lock_spin(mp);
	mp->mnt_compound_ops |= COMPOUND_VNOP_OPEN;
	mount_unlock(mp);
}

void
vnode_setswapmount(vnode_t vp)
{
	mount_lock(vp->v_mount);
	vp->v_mount->mnt_kern_flag |= MNTK_SWAP_MOUNT;
	mount_unlock(vp->v_mount);
}

void
vfs_setfskit(mount_t mp)
{
	mount_lock_spin(mp);
	mp->mnt_kern_flag |= MNTK_FSKIT;
	mount_unlock(mp);
}

uint32_t
vfs_getextflags(mount_t mp)
{
	uint32_t flags_ext = 0;

	if (mp->mnt_kern_flag & MNTK_SYSTEMDATA) {
		flags_ext |= MNT_EXT_ROOT_DATA_VOL;
	}
	if (mp->mnt_kern_flag & MNTK_FSKIT) {
		flags_ext |= MNT_EXT_FSKIT;
	}
	return flags_ext;
}

char *
vfs_getfstypenameref_locked(mount_t mp, size_t *lenp)
{
	char *name;

	if (mp->mnt_kern_flag & MNTK_TYPENAME_OVERRIDE) {
		name = mp->fstypename_override;
	} else {
		name = mp->mnt_vfsstat.f_fstypename;
	}
	if (lenp != NULL) {
		*lenp = strlen(name);
	}
	return name;
}

void
vfs_getfstypename(mount_t mp, char *buf, size_t buflen)
{
	mount_lock_spin(mp);
	strlcpy(buf, vfs_getfstypenameref_locked(mp, NULL), buflen);
	mount_unlock(mp);
}

void
vfs_setfstypename_locked(mount_t mp, const char *name)
{
	if (name == NULL || name[0] == '\0') {
		mp->mnt_kern_flag &= ~MNTK_TYPENAME_OVERRIDE;
		mp->fstypename_override[0] = '\0';
	} else {
		strlcpy(mp->fstypename_override, name,
		    sizeof(mp->fstypename_override));
		mp->mnt_kern_flag |= MNTK_TYPENAME_OVERRIDE;
	}
}

void
vfs_setfstypename(mount_t mp, const char *name)
{
	mount_lock_spin(mp);
	vfs_setfstypename_locked(mp, name);
	mount_unlock(mp);
}

int64_t
vnode_getswappin_avail(vnode_t vp)
{
	int64_t max_swappin_avail = 0;

	mount_lock(vp->v_mount);
	if (vp->v_mount->mnt_ioflags & MNT_IOFLAGS_SWAPPIN_SUPPORTED) {
		max_swappin_avail = vp->v_mount->mnt_max_swappin_available;
	}
	mount_unlock(vp->v_mount);

	return max_swappin_avail;
}


void
vn_setunionwait(vnode_t vp)
{
	vnode_lock_spin(vp);
	vp->v_flag |= VISUNION;
	vnode_unlock(vp);
}


void
vn_checkunionwait(vnode_t vp)
{
	vnode_lock_spin(vp);
	while ((vp->v_flag & VISUNION) == VISUNION) {
		msleep((caddr_t)&vp->v_flag, &vp->v_lock, 0, 0, 0);
	}
	vnode_unlock(vp);
}

void
vn_clearunionwait(vnode_t vp, int locked)
{
	if (!locked) {
		vnode_lock_spin(vp);
	}
	if ((vp->v_flag & VISUNION) == VISUNION) {
		vp->v_flag &= ~VISUNION;
		wakeup((caddr_t)&vp->v_flag);
	}
	if (!locked) {
		vnode_unlock(vp);
	}
}

/*
 * Removes orphaned apple double files during a rmdir
 * Works by:
 * 1. vnode_suspend().
 * 2. Call VNOP_READDIR() till the end of directory is reached.
 * 3. Check if the directory entries returned are regular files with name starting with "._".  If not, return ENOTEMPTY.
 * 4. Continue (2) and (3) till end of directory is reached.
 * 5. If all the entries in the directory were files with "._" name, delete all the files.
 * 6. vnode_resume()
 * 7. If deletion of all files succeeded, call VNOP_RMDIR() again.
 */

errno_t
rmdir_remove_orphaned_appleDouble(vnode_t vp, vfs_context_t ctx, int * restart_flag)
{
#define UIO_BUFF_SIZE 2048
	uio_t auio = NULL;
	int eofflag, siz = UIO_BUFF_SIZE, alloc_size = 0, nentries = 0;
	int open_flag = 0, full_erase_flag = 0;
	UIO_STACKBUF(uio_buf, 1);
	char *rbuf = NULL;
	void *dir_pos;
	void *dir_end;
	struct dirent *dp;
	errno_t error;

	error = vnode_suspend(vp);

	/*
	 * restart_flag is set so that the calling rmdir sleeps and resets
	 */
	if (error == EBUSY) {
		*restart_flag = 1;
	}
	if (error != 0) {
		return error;
	}

	/*
	 * Prevent dataless fault materialization while we have
	 * a suspended vnode.
	 */
	uthread_t ut = current_uthread();
	bool saved_nodatalessfaults =
	    (ut->uu_flag & UT_NSPACE_NODATALESSFAULTS) ? true : false;
	ut->uu_flag |= UT_NSPACE_NODATALESSFAULTS;

	/*
	 * set up UIO
	 */
	rbuf = kalloc_data(siz, Z_WAITOK);
	alloc_size = siz;
	if (rbuf) {
		auio = uio_createwithbuffer(1, 0, UIO_SYSSPACE, UIO_READ,
		    &uio_buf[0], sizeof(uio_buf));
	}
	if (!rbuf || !auio) {
		error = ENOMEM;
		goto outsc;
	}

	uio_setoffset(auio, 0);

	eofflag = 0;

	if ((error = VNOP_OPEN(vp, FREAD, ctx))) {
		goto outsc;
	} else {
		open_flag = 1;
	}

	/*
	 * First pass checks if all files are appleDouble files.
	 */

	do {
		siz = UIO_BUFF_SIZE;
		uio_reset(auio, uio_offset(auio), UIO_SYSSPACE, UIO_READ);
		uio_addiov(auio, CAST_USER_ADDR_T(rbuf), UIO_BUFF_SIZE);

		if ((error = VNOP_READDIR(vp, auio, 0, &eofflag, &nentries, ctx))) {
			goto outsc;
		}

		if (uio_resid(auio) != 0) {
			siz -= uio_resid(auio);
		}

		/*
		 * Iterate through directory
		 */
		dir_pos = (void*) rbuf;
		dir_end = (void*) (rbuf + siz);
		dp = (struct dirent*) (dir_pos);

		if (dir_pos == dir_end) {
			eofflag = 1;
		}

		while (dir_pos < dir_end) {
			/*
			 * Check for . and .. as well as directories
			 */
			if (dp->d_ino != 0 &&
			    !((dp->d_namlen == 1 && dp->d_name[0] == '.') ||
			    (dp->d_namlen == 2 && dp->d_name[0] == '.' && dp->d_name[1] == '.'))) {
				/*
				 * Check for irregular files and ._ files
				 * If there is a ._._ file abort the op
				 */
				if (dp->d_namlen < 2 ||
				    strncmp(dp->d_name, "._", 2) ||
				    (dp->d_namlen >= 4 && !strncmp(&(dp->d_name[2]), "._", 2))) {
					error = ENOTEMPTY;
					goto outsc;
				}
			}
			dir_pos = (void*) ((uint8_t*)dir_pos + dp->d_reclen);
			dp = (struct dirent*)dir_pos;
		}

		/*
		 * workaround for HFS/NFS setting eofflag before end of file
		 */
		if (vp->v_tag == VT_HFS && nentries > 2) {
			eofflag = 0;
		}

		if (vp->v_tag == VT_NFS) {
			if (eofflag && !full_erase_flag) {
				full_erase_flag = 1;
				eofflag = 0;
				uio_reset(auio, 0, UIO_SYSSPACE, UIO_READ);
			} else if (!eofflag && full_erase_flag) {
				full_erase_flag = 0;
			}
		}
	} while (!eofflag);
	/*
	 * If we've made it here all the files in the dir are ._ files.
	 * We can delete the files even though the node is suspended
	 * because we are the owner of the file.
	 */

	uio_reset(auio, 0, UIO_SYSSPACE, UIO_READ);
	eofflag = 0;
	full_erase_flag = 0;

	do {
		siz = UIO_BUFF_SIZE;
		uio_reset(auio, uio_offset(auio), UIO_SYSSPACE, UIO_READ);
		uio_addiov(auio, CAST_USER_ADDR_T(rbuf), UIO_BUFF_SIZE);

		error = VNOP_READDIR(vp, auio, 0, &eofflag, &nentries, ctx);

		if (error != 0) {
			goto outsc;
		}

		if (uio_resid(auio) != 0) {
			siz -= uio_resid(auio);
		}

		/*
		 * Iterate through directory
		 */
		dir_pos = (void*) rbuf;
		dir_end = (void*) (rbuf + siz);
		dp = (struct dirent*) dir_pos;

		if (dir_pos == dir_end) {
			eofflag = 1;
		}

		while (dir_pos < dir_end) {
			/*
			 * Check for . and .. as well as directories
			 */
			if (dp->d_ino != 0 &&
			    !((dp->d_namlen == 1 && dp->d_name[0] == '.') ||
			    (dp->d_namlen == 2 && dp->d_name[0] == '.' && dp->d_name[1] == '.'))
			    ) {
				error = unlink1(ctx, vp,
				    CAST_USER_ADDR_T(dp->d_name), UIO_SYSSPACE,
				    VNODE_REMOVE_SKIP_NAMESPACE_EVENT |
				    VNODE_REMOVE_NO_AUDIT_PATH);

				if (error && error != ENOENT) {
					goto outsc;
				}
			}
			dir_pos = (void*) ((uint8_t*)dir_pos + dp->d_reclen);
			dp = (struct dirent*)dir_pos;
		}

		/*
		 * workaround for HFS/NFS setting eofflag before end of file
		 */
		if (vp->v_tag == VT_HFS && nentries > 2) {
			eofflag = 0;
		}

		if (vp->v_tag == VT_NFS) {
			if (eofflag && !full_erase_flag) {
				full_erase_flag = 1;
				eofflag = 0;
				uio_reset(auio, 0, UIO_SYSSPACE, UIO_READ);
			} else if (!eofflag && full_erase_flag) {
				full_erase_flag = 0;
			}
		}
	} while (!eofflag);


	error = 0;

outsc:
	if (open_flag) {
		VNOP_CLOSE(vp, FREAD, ctx);
	}

	if (auio) {
		uio_free(auio);
	}
	kfree_data(rbuf, alloc_size);

	if (saved_nodatalessfaults == false) {
		ut->uu_flag &= ~UT_NSPACE_NODATALESSFAULTS;
	}

	vnode_resume(vp);

	return error;
}


void
lock_vnode_and_post(vnode_t vp, int kevent_num)
{
	/* Only take the lock if there's something there! */
	if (vp->v_knotes.slh_first != NULL) {
		vnode_lock(vp);
		KNOTE(&vp->v_knotes, kevent_num);
		vnode_unlock(vp);
	}
}

void panic_print_vnodes(void);

/* define PANIC_PRINTS_VNODES only if investigation is required. */
#ifdef PANIC_PRINTS_VNODES

static const char *
__vtype(uint16_t vtype)
{
	switch (vtype) {
	case VREG:
		return "R";
	case VDIR:
		return "D";
	case VBLK:
		return "B";
	case VCHR:
		return "C";
	case VLNK:
		return "L";
	case VSOCK:
		return "S";
	case VFIFO:
		return "F";
	case VBAD:
		return "x";
	case VSTR:
		return "T";
	case VCPLX:
		return "X";
	default:
		return "?";
	}
}

/*
 * build a path from the bottom up
 * NOTE: called from the panic path - no alloc'ing of memory and no locks!
 */
static char *
__vpath(vnode_t vp, char *str, int len, int depth)
{
	int vnm_len;
	const char *src;
	char *dst;

	if (len <= 0) {
		return str;
	}
	/* str + len is the start of the string we created */
	if (!vp->v_name) {
		return str + len;
	}

	/* follow mount vnodes to get the full path */
	if ((vp->v_flag & VROOT)) {
		if (vp->v_mount != NULL && vp->v_mount->mnt_vnodecovered) {
			return __vpath(vp->v_mount->mnt_vnodecovered,
			           str, len, depth + 1);
		}
		return str + len;
	}

	src = vp->v_name;
	vnm_len = strlen(src);
	if (vnm_len > len) {
		/* truncate the name to fit in the string */
		src += (vnm_len - len);
		vnm_len = len;
	}

	/* start from the back and copy just characters (no NULLs) */

	/* this will chop off leaf path (file) names */
	if (depth > 0) {
		dst = str + len - vnm_len;
		memcpy(dst, src, vnm_len);
		len -= vnm_len;
	} else {
		dst = str + len;
	}

	if (vp->v_parent && len > 1) {
		/* follow parents up the chain */
		len--;
		*(dst - 1) = '/';
		return __vpath(vp->v_parent, str, len, depth + 1);
	}

	return dst;
}

#define SANE_VNODE_PRINT_LIMIT 5000
void
panic_print_vnodes(void)
{
	mount_t mnt;
	vnode_t vp;
	int nvnodes = 0;
	const char *type;
	char *nm;
	char vname[257];

	paniclog_append_noflush("\n***** VNODES *****\n"
	    "TYPE UREF ICNT PATH\n");

	/* NULL-terminate the path name */
	vname[sizeof(vname) - 1] = '\0';

	/*
	 * iterate all vnodelist items in all mounts (mntlist) -> mnt_vnodelist
	 */
	TAILQ_FOREACH(mnt, &mountlist, mnt_list) {
		if (!ml_validate_nofault((vm_offset_t)mnt, sizeof(mount_t))) {
			paniclog_append_noflush("Unable to iterate the mount list %p - encountered an invalid mount pointer %p \n",
			    &mountlist, mnt);
			break;
		}

		TAILQ_FOREACH(vp, &mnt->mnt_vnodelist, v_mntvnodes) {
			if (!ml_validate_nofault((vm_offset_t)vp, sizeof(vnode_t))) {
				paniclog_append_noflush("Unable to iterate the vnode list %p - encountered an invalid vnode pointer %p \n",
				    &mnt->mnt_vnodelist, vp);
				break;
			}

			if (++nvnodes > SANE_VNODE_PRINT_LIMIT) {
				return;
			}
			type = __vtype(vp->v_type);
			nm = __vpath(vp, vname, sizeof(vname) - 1, 0);
			paniclog_append_noflush("%s %0d %0d %s\n",
			    type, vp->v_usecount, vp->v_iocount, nm);
		}
	}
}

#else /* !PANIC_PRINTS_VNODES */
void
panic_print_vnodes(void)
{
	return;
}
#endif


#ifdef CONFIG_IOCOUNT_TRACE
static void
record_iocount_trace_vnode(vnode_t vp, int type)
{
	void *stacks[IOCOUNT_TRACE_MAX_FRAMES] = {0};
	int idx = vp->v_iocount_trace[type].idx;

	if (idx >= IOCOUNT_TRACE_MAX_IDX) {
		return;
	}

	OSBacktrace((void **)&stacks[0], IOCOUNT_TRACE_MAX_FRAMES);

	/*
	 * To save index space, only store the unique backtraces. If dup is found,
	 * just bump the count and return.
	 */
	for (int i = 0; i < idx; i++) {
		if (memcmp(&stacks[0], &vp->v_iocount_trace[type].stacks[i][0],
		    sizeof(stacks)) == 0) {
			vp->v_iocount_trace[type].counts[i]++;
			return;
		}
	}

	memcpy(&vp->v_iocount_trace[type].stacks[idx][0], &stacks[0],
	    sizeof(stacks));
	vp->v_iocount_trace[type].counts[idx] = 1;
	vp->v_iocount_trace[type].idx++;
}

static void
record_iocount_trace_uthread(vnode_t vp, int count)
{
	struct uthread *ut;

	ut = current_uthread();
	ut->uu_iocount += count;

	if (count == 1) {
		if (ut->uu_vpindex < 32) {
			OSBacktrace((void **)&ut->uu_pcs[ut->uu_vpindex][0], 10);

			ut->uu_vps[ut->uu_vpindex] = vp;
			ut->uu_vpindex++;
		}
	}
}

static void
record_vp(vnode_t vp, int count)
{
	if (__probable(bootarg_vnode_iocount_trace == 0 &&
	    bootarg_uthread_iocount_trace == 0)) {
		return;
	}

#if CONFIG_TRIGGERS
	if (vp->v_resolve) {
		return;
	}
#endif
	if ((vp->v_flag & VSYSTEM)) {
		return;
	}

	if (bootarg_vnode_iocount_trace) {
		record_iocount_trace_vnode(vp,
		    (count > 0) ? IOCOUNT_TRACE_VGET : IOCOUNT_TRACE_VPUT);
	}
	if (bootarg_uthread_iocount_trace) {
		record_iocount_trace_uthread(vp, count);
	}
}
#endif /* CONFIG_IOCOUNT_TRACE */

#if CONFIG_TRIGGERS
#define __triggers_unused
#else
#define __triggers_unused       __unused
#endif

resolver_result_t
vfs_resolver_result(__triggers_unused uint32_t seq, __triggers_unused enum resolver_status stat, __triggers_unused int aux)
{
#if CONFIG_TRIGGERS
	/*
	 * |<---   32   --->|<---  28  --->|<- 4 ->|
	 *      sequence        auxiliary    status
	 */
	return (((uint64_t)seq) << 32) |
	       (((uint64_t)(aux & 0x0fffffff)) << 4) |
	       (uint64_t)(stat & 0x0000000F);
#else
	return (0x0ULL) | (((uint64_t)ENOTSUP) << 4) | (((uint64_t)RESOLVER_ERROR) & 0xF);
#endif
}

#if CONFIG_TRIGGERS

#define TRIG_DEBUG 0

#if TRIG_DEBUG
#define TRIG_LOG(...) do { printf("%s: ", __FUNCTION__); printf(__VA_ARGS__); } while (0)
#else
#define TRIG_LOG(...)
#endif

/*
 * Resolver result functions
 */


enum resolver_status
vfs_resolver_status(resolver_result_t result)
{
	/* lower 4 bits is status */
	return result & 0x0000000F;
}

uint32_t
vfs_resolver_sequence(resolver_result_t result)
{
	/* upper 32 bits is sequence */
	return (uint32_t)(result >> 32);
}

int
vfs_resolver_auxiliary(resolver_result_t result)
{
	/* 28 bits of auxiliary */
	return (int)(((uint32_t)(result & 0xFFFFFFF0)) >> 4);
}

/*
 * SPI
 * Call in for resolvers to update vnode trigger state
 */
int
vnode_trigger_update(vnode_t vp, resolver_result_t result)
{
	vnode_resolve_t rp;
	uint32_t seq;
	enum resolver_status stat;

	if (vp->v_resolve == NULL) {
		return EINVAL;
	}

	stat = vfs_resolver_status(result);
	seq = vfs_resolver_sequence(result);

	if ((stat != RESOLVER_RESOLVED) && (stat != RESOLVER_UNRESOLVED)) {
		return EINVAL;
	}

	rp = vp->v_resolve;
	lck_mtx_lock(&rp->vr_lock);

	if (seq > rp->vr_lastseq) {
		if (stat == RESOLVER_RESOLVED) {
			rp->vr_flags |= VNT_RESOLVED;
		} else {
			rp->vr_flags &= ~VNT_RESOLVED;
		}

		rp->vr_lastseq = seq;
	}

	lck_mtx_unlock(&rp->vr_lock);

	return 0;
}

static int
vnode_resolver_attach(vnode_t vp, vnode_resolve_t rp, boolean_t ref)
{
	int error;

	vnode_lock_spin(vp);
	if (vp->v_resolve != NULL) {
		vnode_unlock(vp);
		return EINVAL;
	} else {
		vp->v_resolve = rp;
	}
	vnode_unlock(vp);

	if (ref) {
		error = vnode_ref_ext(vp, O_EVTONLY, VNODE_REF_FORCE);
		if (error != 0) {
			panic("VNODE_REF_FORCE didn't help...");
		}
	}

	return 0;
}

/*
 * VFS internal interfaces for vnode triggers
 *
 * vnode must already have an io count on entry
 * v_resolve is stable when io count is non-zero
 */
static int
vnode_resolver_create(mount_t mp, vnode_t vp, struct vnode_trigger_param *tinfo, boolean_t external)
{
	vnode_resolve_t rp;
	int result;
	char byte;

#if 1
	/* minimum pointer test (debugging) */
	if (tinfo->vnt_data) {
		byte = *((char *)tinfo->vnt_data);
	}
#endif
	rp = kalloc_type(struct vnode_resolve, Z_WAITOK | Z_NOFAIL);

	lck_mtx_init(&rp->vr_lock, &trigger_vnode_lck_grp, &trigger_vnode_lck_attr);

	rp->vr_resolve_func = tinfo->vnt_resolve_func;
	rp->vr_unresolve_func = tinfo->vnt_unresolve_func;
	rp->vr_rearm_func = tinfo->vnt_rearm_func;
	rp->vr_reclaim_func = tinfo->vnt_reclaim_func;
	rp->vr_data = tinfo->vnt_data;
	rp->vr_lastseq = 0;
	rp->vr_flags = tinfo->vnt_flags & VNT_VALID_MASK;
	if (external) {
		rp->vr_flags |= VNT_EXTERNAL;
	}

	result = vnode_resolver_attach(vp, rp, external);
	if (result != 0) {
		goto out;
	}

	if (mp) {
		OSAddAtomic(1, &mp->mnt_numtriggers);
	}

	return result;

out:
	kfree_type(struct vnode_resolve, rp);
	return result;
}

static void
vnode_resolver_release(vnode_resolve_t rp)
{
	/*
	 * Give them a chance to free any private data
	 */
	if (rp->vr_data && rp->vr_reclaim_func) {
		rp->vr_reclaim_func(NULLVP, rp->vr_data);
	}

	lck_mtx_destroy(&rp->vr_lock, &trigger_vnode_lck_grp);
	kfree_type(struct vnode_resolve, rp);
}

/* Called after the vnode has been drained */
static void
vnode_resolver_detach(vnode_t vp)
{
	vnode_resolve_t rp;
	mount_t mp;

	mp = vnode_mount(vp);

	vnode_lock(vp);
	rp = vp->v_resolve;
	vp->v_resolve = NULL;
	vnode_unlock(vp);

	if ((rp->vr_flags & VNT_EXTERNAL) != 0) {
		vnode_rele_ext(vp, O_EVTONLY, 1);
	}

	vnode_resolver_release(rp);

	/* Keep count of active trigger vnodes per mount */
	OSAddAtomic(-1, &mp->mnt_numtriggers);
}

__private_extern__
void
vnode_trigger_rearm(vnode_t vp, vfs_context_t ctx)
{
	vnode_resolve_t rp;
	resolver_result_t result;
	enum resolver_status status;
	uint32_t seq;

	if ((vp->v_resolve == NULL) ||
	    (vp->v_resolve->vr_rearm_func == NULL) ||
	    (vp->v_resolve->vr_flags & VNT_AUTO_REARM) == 0) {
		return;
	}

	rp = vp->v_resolve;
	lck_mtx_lock(&rp->vr_lock);

	/*
	 * Check if VFS initiated this unmount. If so, we'll catch it after the unresolve completes.
	 */
	if (rp->vr_flags & VNT_VFS_UNMOUNTED) {
		lck_mtx_unlock(&rp->vr_lock);
		return;
	}

	/* Check if this vnode is already armed */
	if ((rp->vr_flags & VNT_RESOLVED) == 0) {
		lck_mtx_unlock(&rp->vr_lock);
		return;
	}

	lck_mtx_unlock(&rp->vr_lock);

	result = rp->vr_rearm_func(vp, 0, rp->vr_data, ctx);
	status = vfs_resolver_status(result);
	seq = vfs_resolver_sequence(result);

	lck_mtx_lock(&rp->vr_lock);
	if (seq > rp->vr_lastseq) {
		if (status == RESOLVER_UNRESOLVED) {
			rp->vr_flags &= ~VNT_RESOLVED;
		}
		rp->vr_lastseq = seq;
	}
	lck_mtx_unlock(&rp->vr_lock);
}

__private_extern__
int
vnode_trigger_resolve(vnode_t vp, struct nameidata *ndp, vfs_context_t ctx)
{
	vnode_resolve_t rp;
	enum path_operation op;
	resolver_result_t result;
	enum resolver_status status;
	uint32_t seq;

	/*
	 * N.B. we cannot call vfs_context_can_resolve_triggers()
	 * here because we really only want to suppress that in
	 * the event the trigger will be resolved by something in
	 * user-space.  Any triggers that are resolved by the kernel
	 * do not pose a threat of deadlock.
	 */

	/* Only trigger on topmost vnodes */
	if ((vp->v_resolve == NULL) ||
	    (vp->v_resolve->vr_resolve_func == NULL) ||
	    (vp->v_mountedhere != NULL)) {
		return 0;
	}

	rp = vp->v_resolve;
	lck_mtx_lock(&rp->vr_lock);

	/* Check if this vnode is already resolved */
	if (rp->vr_flags & VNT_RESOLVED) {
		lck_mtx_unlock(&rp->vr_lock);
		return 0;
	}

	lck_mtx_unlock(&rp->vr_lock);

#if CONFIG_MACF
	if ((rp->vr_flags & VNT_KERN_RESOLVE) == 0) {
		/*
		 * VNT_KERN_RESOLVE indicates this trigger has no parameters
		 * at the discression of the accessing process other than
		 * the act of access. All other triggers must be checked
		 */
		int rv = mac_vnode_check_trigger_resolve(ctx, vp, &ndp->ni_cnd);
		if (rv != 0) {
			return rv;
		}
	}
#endif

	/*
	 * XXX
	 * assumes that resolver will not access this trigger vnode (otherwise the kernel will deadlock)
	 * is there anyway to know this???
	 * there can also be other legitimate lookups in parallel
	 *
	 * XXX - should we call this on a separate thread with a timeout?
	 *
	 * XXX - should we use ISLASTCN to pick the op value???  Perhaps only leafs should
	 * get the richer set and non-leafs should get generic OP_LOOKUP?  TBD
	 */
	op = (ndp->ni_op < OP_MAXOP) ? ndp->ni_op: OP_LOOKUP;

	result = rp->vr_resolve_func(vp, &ndp->ni_cnd, op, 0, rp->vr_data, ctx);
	status = vfs_resolver_status(result);
	seq = vfs_resolver_sequence(result);

	lck_mtx_lock(&rp->vr_lock);
	if (seq > rp->vr_lastseq) {
		if (status == RESOLVER_RESOLVED) {
			rp->vr_flags |= VNT_RESOLVED;
		}
		rp->vr_lastseq = seq;
	}
	lck_mtx_unlock(&rp->vr_lock);

	/* On resolver errors, propagate the error back up */
	return status == RESOLVER_ERROR ? vfs_resolver_auxiliary(result) : 0;
}

static int
vnode_trigger_unresolve(vnode_t vp, int flags, vfs_context_t ctx)
{
	vnode_resolve_t rp;
	resolver_result_t result;
	enum resolver_status status;
	uint32_t seq;

	if ((vp->v_resolve == NULL) || (vp->v_resolve->vr_unresolve_func == NULL)) {
		return 0;
	}

	rp = vp->v_resolve;
	lck_mtx_lock(&rp->vr_lock);

	/* Check if this vnode is already resolved */
	if ((rp->vr_flags & VNT_RESOLVED) == 0) {
		printf("vnode_trigger_unresolve: not currently resolved\n");
		lck_mtx_unlock(&rp->vr_lock);
		return 0;
	}

	rp->vr_flags |= VNT_VFS_UNMOUNTED;

	lck_mtx_unlock(&rp->vr_lock);

	/*
	 * XXX
	 * assumes that resolver will not access this trigger vnode (otherwise the kernel will deadlock)
	 * there can also be other legitimate lookups in parallel
	 *
	 * XXX - should we call this on a separate thread with a timeout?
	 */

	result = rp->vr_unresolve_func(vp, flags, rp->vr_data, ctx);
	status = vfs_resolver_status(result);
	seq = vfs_resolver_sequence(result);

	lck_mtx_lock(&rp->vr_lock);
	if (seq > rp->vr_lastseq) {
		if (status == RESOLVER_UNRESOLVED) {
			rp->vr_flags &= ~VNT_RESOLVED;
		}
		rp->vr_lastseq = seq;
	}
	rp->vr_flags &= ~VNT_VFS_UNMOUNTED;
	lck_mtx_unlock(&rp->vr_lock);

	/* On resolver errors, propagate the error back up */
	return status == RESOLVER_ERROR ? vfs_resolver_auxiliary(result) : 0;
}

static int
triggerisdescendant(mount_t mp, mount_t rmp)
{
	int match = FALSE;

	/*
	 * walk up vnode covered chain looking for a match
	 */
	name_cache_lock_shared();

	while (1) {
		vnode_t vp;

		/* did we encounter "/" ? */
		if (mp->mnt_flag & MNT_ROOTFS) {
			break;
		}

		vp = mp->mnt_vnodecovered;
		if (vp == NULLVP) {
			break;
		}

		mp = vp->v_mount;
		if (mp == rmp) {
			match = TRUE;
			break;
		}
	}

	name_cache_unlock();

	return match;
}

struct trigger_unmount_info {
	vfs_context_t   ctx;
	mount_t         top_mp;
	vnode_t         trigger_vp;
	mount_t         trigger_mp;
	uint32_t        trigger_vid;
	int             flags;
};

static int
trigger_unmount_callback(mount_t mp, void * arg)
{
	struct trigger_unmount_info * infop = (struct trigger_unmount_info *)arg;
	boolean_t mountedtrigger = FALSE;

	/*
	 * When we encounter the top level mount we're done
	 */
	if (mp == infop->top_mp) {
		return VFS_RETURNED_DONE;
	}

	if ((mp->mnt_vnodecovered == NULL) ||
	    (vnode_getwithref(mp->mnt_vnodecovered) != 0)) {
		return VFS_RETURNED;
	}

	if ((mp->mnt_vnodecovered->v_mountedhere == mp) &&
	    (mp->mnt_vnodecovered->v_resolve != NULL) &&
	    (mp->mnt_vnodecovered->v_resolve->vr_flags & VNT_RESOLVED)) {
		mountedtrigger = TRUE;
	}
	vnode_put(mp->mnt_vnodecovered);

	/*
	 * When we encounter a mounted trigger, check if its under the top level mount
	 */
	if (!mountedtrigger || !triggerisdescendant(mp, infop->top_mp)) {
		return VFS_RETURNED;
	}

	/*
	 * Process any pending nested mount (now that its not referenced)
	 */
	if ((infop->trigger_vp != NULLVP) &&
	    (vnode_getwithvid(infop->trigger_vp, infop->trigger_vid) == 0)) {
		vnode_t vp = infop->trigger_vp;
		int error;

		vnode_drop(infop->trigger_vp);
		infop->trigger_vp = NULLVP;

		if (mp == vp->v_mountedhere) {
			vnode_put(vp);
			printf("trigger_unmount_callback: unexpected match '%s'\n",
			    mp->mnt_vfsstat.f_mntonname);
			return VFS_RETURNED;
		}
		if (infop->trigger_mp != vp->v_mountedhere) {
			vnode_put(vp);
			printf("trigger_unmount_callback: trigger mnt changed! (%p != %p)\n",
			    infop->trigger_mp, vp->v_mountedhere);
			goto savenext;
		}

		error = vnode_trigger_unresolve(vp, infop->flags, infop->ctx);
		vnode_put(vp);
		if (error) {
			printf("unresolving: '%s', err %d\n",
			    vp->v_mountedhere ? vp->v_mountedhere->mnt_vfsstat.f_mntonname :
			    "???", error);
			return VFS_RETURNED_DONE; /* stop iteration on errors */
		}
	} else if (infop->trigger_vp != NULLVP) {
		vnode_drop(infop->trigger_vp);
	}

savenext:
	/*
	 * We can't call resolver here since we hold a mount iter
	 * ref on mp so save its covered vp for later processing
	 */
	infop->trigger_vp = mp->mnt_vnodecovered;
	if ((infop->trigger_vp != NULLVP) &&
	    (vnode_getwithref(infop->trigger_vp) == 0)) {
		if (infop->trigger_vp->v_mountedhere == mp) {
			infop->trigger_vid = infop->trigger_vp->v_id;
			vnode_hold(infop->trigger_vp);
			infop->trigger_mp = mp;
		}
		vnode_put(infop->trigger_vp);
	}

	return VFS_RETURNED;
}

/*
 * Attempt to unmount any trigger mounts nested underneath a mount.
 * This is a best effort attempt and no retries are performed here.
 *
 * Note: mp->mnt_rwlock is held exclusively on entry (so be carefull)
 */
__private_extern__
void
vfs_nested_trigger_unmounts(mount_t mp, int flags, vfs_context_t ctx)
{
	struct trigger_unmount_info info;

	/* Must have trigger vnodes */
	if (mp->mnt_numtriggers == 0) {
		return;
	}
	/* Avoid recursive requests (by checking covered vnode) */
	if ((mp->mnt_vnodecovered != NULL) &&
	    (vnode_getwithref(mp->mnt_vnodecovered) == 0)) {
		boolean_t recursive = FALSE;

		if ((mp->mnt_vnodecovered->v_mountedhere == mp) &&
		    (mp->mnt_vnodecovered->v_resolve != NULL) &&
		    (mp->mnt_vnodecovered->v_resolve->vr_flags & VNT_VFS_UNMOUNTED)) {
			recursive = TRUE;
		}
		vnode_put(mp->mnt_vnodecovered);
		if (recursive) {
			return;
		}
	}

	/*
	 * Attempt to unmount any nested trigger mounts (best effort)
	 */
	info.ctx = ctx;
	info.top_mp = mp;
	info.trigger_vp = NULLVP;
	info.trigger_vid = 0;
	info.trigger_mp = NULL;
	info.flags = flags;

	(void) vfs_iterate(VFS_ITERATE_TAIL_FIRST, trigger_unmount_callback, &info);

	/*
	 * Process remaining nested mount (now that its not referenced)
	 */
	if ((info.trigger_vp != NULLVP) &&
	    (vnode_getwithvid(info.trigger_vp, info.trigger_vid) == 0)) {
		vnode_t vp = info.trigger_vp;

		if (info.trigger_mp == vp->v_mountedhere) {
			(void) vnode_trigger_unresolve(vp, flags, ctx);
		}
		vnode_put(vp);
		vnode_drop(vp);
	} else if (info.trigger_vp != NULLVP) {
		vnode_drop(info.trigger_vp);
	}
}

int
vfs_addtrigger(mount_t mp, const char *relpath, struct vnode_trigger_info *vtip, vfs_context_t ctx)
{
	struct nameidata *ndp;
	int res;
	vnode_t rvp, vp;
	struct vnode_trigger_param vtp;

	/*
	 * Must be called for trigger callback, wherein rwlock is held
	 */
	lck_rw_assert(&mp->mnt_rwlock, LCK_RW_ASSERT_HELD);

	TRIG_LOG("Adding trigger at %s\n", relpath);
	TRIG_LOG("Trying VFS_ROOT\n");

	ndp = kalloc_type(struct nameidata, Z_WAITOK | Z_NOFAIL);

	/*
	 * We do a lookup starting at the root of the mountpoint, unwilling
	 * to cross into other mountpoints.
	 */
	res = VFS_ROOT(mp, &rvp, ctx);
	if (res != 0) {
		goto out;
	}

	TRIG_LOG("Trying namei\n");

	NDINIT(ndp, LOOKUP, OP_LOOKUP, USEDVP | NOCROSSMOUNT | FOLLOW, UIO_SYSSPACE,
	    CAST_USER_ADDR_T(relpath), ctx);
	ndp->ni_dvp = rvp;
	res = namei(ndp);
	if (res != 0) {
		vnode_put(rvp);
		goto out;
	}

	vp = ndp->ni_vp;
	nameidone(ndp);
	vnode_put(rvp);

	TRIG_LOG("Trying vnode_resolver_create()\n");

	/*
	 * Set up blob.  vnode_create() takes a larger structure
	 * with creation info, and we needed something different
	 * for this case.  One needs to win, or we need to munge both;
	 * vnode_create() wins.
	 */
	bzero(&vtp, sizeof(vtp));
	vtp.vnt_resolve_func = vtip->vti_resolve_func;
	vtp.vnt_unresolve_func = vtip->vti_unresolve_func;
	vtp.vnt_rearm_func = vtip->vti_rearm_func;
	vtp.vnt_reclaim_func = vtip->vti_reclaim_func;
	vtp.vnt_reclaim_func = vtip->vti_reclaim_func;
	vtp.vnt_data = vtip->vti_data;
	vtp.vnt_flags = vtip->vti_flags;

	res = vnode_resolver_create(mp, vp, &vtp, TRUE);
	vnode_put(vp);
out:
	kfree_type(struct nameidata, ndp);
	TRIG_LOG("Returning %d\n", res);
	return res;
}

#endif /* CONFIG_TRIGGERS */

vm_offset_t
kdebug_vnode(vnode_t vp)
{
	return VM_KERNEL_ADDRPERM(vp);
}

static int flush_cache_on_write = 0;
SYSCTL_INT(_kern, OID_AUTO, flush_cache_on_write,
    CTLFLAG_RW | CTLFLAG_LOCKED, &flush_cache_on_write, 0,
    "always flush the drive cache on writes to uncached files");

int
vnode_should_flush_after_write(vnode_t vp, int ioflag)
{
	return flush_cache_on_write
	       && (ISSET(ioflag, IO_NOCACHE) || vnode_isnocache(vp));
}

/*
 * sysctl for use by disk I/O tracing tools to get the list of existing
 * vnodes' paths
 */

#define NPATH_WORDS (MAXPATHLEN / sizeof(unsigned long))
struct vnode_trace_paths_context {
	uint64_t count;
	/*
	 * Must be a multiple of 4, then -1, for tracing!
	 */
	unsigned long path[NPATH_WORDS + (4 - (NPATH_WORDS % 4)) - 1];
};

static int
vnode_trace_path_callback(struct vnode *vp, void *vctx)
{
	struct vnode_trace_paths_context *ctx = vctx;
	size_t path_len = sizeof(ctx->path);

	int getpath_len = (int)path_len;
	if (vn_getpath(vp, (char *)ctx->path, &getpath_len) == 0) {
		/* vn_getpath() NUL-terminates, and len includes the NUL. */
		assert(getpath_len >= 0);
		path_len = (size_t)getpath_len;

		assert(path_len <= sizeof(ctx->path));
		kdebug_vfs_lookup(ctx->path, (int)path_len, vp,
		    KDBG_VFS_LOOKUP_FLAG_LOOKUP | KDBG_VFS_LOOKUP_FLAG_NOPROCFILT);

		if (++(ctx->count) == 1000) {
			thread_yield_to_preemption();
			ctx->count = 0;
		}
	}

	return VNODE_RETURNED;
}

static int
vfs_trace_paths_callback(mount_t mp, void *arg)
{
	if (mp->mnt_flag & MNT_LOCAL) {
		vnode_iterate(mp, VNODE_ITERATE_ALL, vnode_trace_path_callback, arg);
	}

	return VFS_RETURNED;
}

static int sysctl_vfs_trace_paths SYSCTL_HANDLER_ARGS {
	struct vnode_trace_paths_context ctx;

	(void)oidp;
	(void)arg1;
	(void)arg2;
	(void)req;

	if (!kauth_cred_issuser(kauth_cred_get())) {
		return EPERM;
	}

	if (!kdebug_enable || !kdebug_debugid_enabled(VFS_LOOKUP)) {
		return EINVAL;
	}

	bzero(&ctx, sizeof(struct vnode_trace_paths_context));

	vfs_iterate(0, vfs_trace_paths_callback, &ctx);

	return 0;
}

SYSCTL_PROC(_vfs_generic, OID_AUTO, trace_paths, CTLFLAG_RD | CTLFLAG_LOCKED | CTLFLAG_MASKED, NULL, 0, &sysctl_vfs_trace_paths, "-", "trace_paths");

#if CONFIG_FILE_LEASES
#include <IOKit/IOBSD.h>
#include <sys/file_internal.h>

#define FILE_LEASES_ENTITLEMENT    "com.apple.private.vfs.file-leases"

static uint32_t lease_break_timeout = 60; /* secs */

#if (DEVELOPMENT || DEBUG)
static int lease_debug = 0;
static int lease_entitlement_override = 0;

SYSCTL_NODE(_vfs, OID_AUTO, lease, CTLFLAG_RW | CTLFLAG_LOCKED, NULL, "vfs lease");
SYSCTL_UINT(_vfs_lease, OID_AUTO, break_timeout, CTLFLAG_RW | CTLFLAG_LOCKED, &lease_break_timeout, 0, "");
SYSCTL_INT(_vfs_lease, OID_AUTO, debug, CTLFLAG_RW | CTLFLAG_LOCKED, &lease_debug, 0, "");
SYSCTL_INT(_vfs_lease, OID_AUTO, entitlement_override, CTLFLAG_RW | CTLFLAG_LOCKED, &lease_entitlement_override, 0, "");

#define LEASEDBG(fmt, args...)                                       \
do {                                                                 \
	if (__improbable(lease_debug)) {                                 \
	        pid_t cur_pid = proc_getpid(current_proc());             \
	        printf("%s(%d): " fmt "\n", __func__, cur_pid, ##args);  \
	}                                                                \
} while(0)
#else
#define LEASEDBG(fmt, args...)  /**/
#endif /* (DEVELOPMENT || DEBUG) */

static bool
allow_setlease(vfs_context_t ctx)
{
	bool entitled;

	entitled = IOTaskHasEntitlement(vfs_context_task(ctx),
	    FILE_LEASES_ENTITLEMENT);

#if (DEVELOPMENT || DEBUG)
	if (!entitled) {
		entitled = (lease_entitlement_override == 1);
	}
#endif

	return entitled;
}

static file_lease_t
file_lease_alloc(struct fileglob *fg, int fl_type, pid_t pid)
{
	file_lease_t fl;

	fl = kalloc_type(struct file_lease, Z_WAITOK);
	/*
	 * Duplicated file descriptors created by dup() or fork() would have the
	 * same 'fileglob' so the lease can be released or modified with the
	 * duplicated fds. Opening the same file (by either same or different
	 * process) would have different 'fileglob' so a lease always follows a
	 * 'fileglob'.
	 */
	fl->fl_fg = fg;
	fl->fl_type = fl_type;
	fl->fl_pid = pid;
	fl->fl_downgrade_start = fl->fl_release_start = 0;

	return fl;
}

static void
file_lease_free(file_lease_t fl)
{
	kfree_type(struct file_lease, fl);
}

/*
 * A read lease can be placed only on a file/directory that is opened for
 * read-only which means no other processes have the file/directory opened in
 * read-write/write-only mode or mmap'ed writable.
 * A write lease can be placed on a file only if there are no other opens
 * for the file.
 *
 * Needs to be called with vnode's lock held.
 */
static int
check_for_open_conflict(vnode_t vp, struct fileglob *fg, int fl_type,
    int expcounts)
{
	int error = 0;

	if (fl_type == F_RDLCK) {
		if (vp->v_writecount > expcounts &&
		    !(vp->v_writecount == 1 && (fg->fg_flag & FWRITE))) {
			error = EAGAIN;
		} else if (ubc_is_mapped_writable(vp)) {
			error = EAGAIN;
		}
	} else if (fl_type == F_WRLCK && vp->v_usecount > expcounts) {
		error = EAGAIN;
	}

	return error;
}

/* Needs to be called with vnode's lock held. */
static void
modify_file_lease(vnode_t vp, file_lease_t fl, int new_fl_type,
    struct fileglob *new_fg)
{
	LEASEDBG("fl %p changing fl_type from %d to %d (flags 0x%x)",
	    fl, fl->fl_type, new_fl_type, fl->fl_flags);

	fl->fl_type = new_fl_type;

	/*
	 * The lease being modified may be using a different file
	 * descriptor, so usurp the fileglob pointer here.  In this
	 * case the old descriptor no longer holds the lease.
	 */
	if (new_fg != NULL) {
		fl->fl_fg = new_fg;
	}

	if (fl->fl_flags & FL_FLAG_RELEASE_PENDING ||
	    fl->fl_flags & FL_FLAG_DOWNGRADE_PENDING) {
		wakeup(&vp->v_leases);
	}
}

static int
acquire_file_lease(vnode_t vp, struct fileglob *fg, int fl_type, int expcounts,
    vfs_context_t ctx)
{
	file_lease_t fl, new_fl, our_fl;
	int error;

	/* Make sure "expected count" looks sane. */
	if (expcounts < 0 || expcounts > OPEN_MAX) {
		return EINVAL;
	}

	new_fl = file_lease_alloc(fg, fl_type, vfs_context_pid(ctx));

	vnode_lock(vp);

	error = check_for_open_conflict(vp, fg, fl_type, expcounts);
	if (error) {
		LEASEDBG("open conflict on vp %p type %d writecnt %d usecnt %d "
		    "fl_type %d expcounts %d",
		    vp, vp->v_type, vp->v_writecount, vp->v_usecount, fl_type,
		    expcounts);
		goto out;
	}

	our_fl = NULL;
	LIST_FOREACH(fl, &vp->v_leases, fl_link) {
		/* Does the existing lease belong to us? */
		if (fl->fl_fg == new_fl->fl_fg ||
		    fl->fl_pid == new_fl->fl_pid) {
			our_fl = fl;
			continue;
		}

		/*
		 * We don't allow placing a new write lease when there is an existing
		 * read lease that doesn't belong to us. We also don't allow putting
		 * a new read lease if there is a pending release on the lease.
		 * Putting a new read lease when there is a pending downgrade on the
		 * lease is fine as it won't cause lease conflict.
		 */
		if (fl_type == F_WRLCK || fl->fl_flags & FL_FLAG_RELEASE_PENDING) {
			break;
		}
	}

	/*
	 * Found an existing lease that we don't own and it conflicts with the
	 * new lease.
	 */
	if (fl) {
		LEASEDBG("lease conflict on vp %p fl %p fl_type %d cur_fl_type %d",
		    vp, fl, fl_type, fl->fl_type);
		goto out;
	}

	/* Found an existing lease that we own so just change the type. */
	if (our_fl) {
		LEASEDBG("replace lease on vp %p fl %p old_fl_type %d new_fl_type %d",
		    vp, our_fl, our_fl->fl_type, fl_type);

		modify_file_lease(vp, our_fl, new_fl->fl_type, new_fl->fl_fg);
		goto out;
	}

	LEASEDBG("acquired lease on vp %p type %d fl %p fl_type %d fg %p",
	    vp, vp->v_type, new_fl, new_fl->fl_type, new_fl->fl_fg);

	LIST_INSERT_HEAD(&vp->v_leases, new_fl, fl_link);
	new_fl = NULL;

out:
	vnode_unlock(vp);

	if (new_fl) {
		file_lease_free(new_fl);
	}

	return error;
}

static int
release_file_lease(vnode_t vp, struct fileglob *fg)
{
	file_lease_t fl, fl_tmp;
	int error = 0;

	LEASEDBG("request to release lease on vp %p type %d fg %p",
	    vp, vp->v_type, fg);

	vnode_lock(vp);

	LIST_FOREACH_SAFE(fl, &vp->v_leases, fl_link, fl_tmp) {
		if (fl->fl_fg == fg) {
			LEASEDBG("released lease on vp %p fl %p type %d",
			    vp, fl, fl->fl_type);

			LIST_REMOVE(fl, fl_link);
			modify_file_lease(vp, fl, F_UNLCK, NULL);
			break;
		}
	}

	vnode_unlock(vp);

	if (fl) {
		file_lease_free(fl);
	} else {
		error = ENOLCK;
	}

	return error;
}

/*
 * Acquire or release a file lease according to the given type (F_RDLCK,
 * F_WRLCK or F_UNLCK).
 *
 * Returns:	0			Success
 *		EAGAIN			Failed to acquire a file lease due to conflicting opens
 *		ENOLCK			Failed to release a file lease due to lease not found
 *		EPERM           Current task doesn't have the entitlement
 */
int
vnode_setlease(vnode_t vp, struct fileglob *fg, int fl_type, int expcounts,
    vfs_context_t ctx)
{
	int error;

	if (!allow_setlease(ctx)) {
		return EPERM;
	}

	error = (fl_type == F_UNLCK) ? release_file_lease(vp, fg) :
	    acquire_file_lease(vp, fg, fl_type, expcounts, ctx);

	return error;
}

/*
 * Retrieve the currently in place lease for the file.
 *
 * Returns:
 *		F_RDLCK			Read lease
 *		F_WRLCK			Write lease
 *		F_UNLCK			No lease
 */
int
vnode_getlease(vnode_t vp)
{
	file_lease_t fl;
	int fl_type = F_UNLCK;

	vnode_lock(vp);

	/*
	 * There should be only one type of lease in the list as read and write
	 * leases can't co-exist for the same file.
	 */
	fl = LIST_FIRST(&vp->v_leases);
	if (fl) {
		fl_type = fl->fl_type;
	}

	vnode_unlock(vp);

	LEASEDBG("vp %p fl %p fl_type %d", vp, fl, fl_type);

	return fl_type;
}

/* Must be called with vnode's lock held. */
static bool
check_for_lease_conflict(vnode_t vp, int breaker_fl_type, vfs_context_t ctx)
{
	file_lease_t fl;
	pid_t pid = vfs_context_pid(ctx);
	bool is_conflict = false;

	LIST_FOREACH(fl, &vp->v_leases, fl_link) {
		if ((fl->fl_type == F_WRLCK && fl->fl_pid != pid) ||
		    (breaker_fl_type == F_WRLCK && fl->fl_pid != pid)) {
			LEASEDBG("conflict detected on vp %p type %d fl_type %d "
			    "breaker_fl_type %d",
			    vp, vp->v_type, fl->fl_type, breaker_fl_type);

			is_conflict = true;
			break;
		}
	}

	return is_conflict;
}

static uint64_t
absolutetime_elapsed_in_secs(uint64_t start)
{
	uint64_t elapsed, elapsed_sec;
	uint64_t now = mach_absolute_time();

	elapsed = now - start;
	absolutetime_to_nanoseconds(elapsed, &elapsed_sec);
	elapsed_sec /= NSEC_PER_SEC;

	return elapsed_sec;
}

/* Must be called with vnode's lock held. */
static void
handle_lease_break_timedout(vnode_t vp)
{
	file_lease_t fl, fl_tmp;
	uint64_t elapsed_sec;

	LIST_FOREACH_SAFE(fl, &vp->v_leases, fl_link, fl_tmp) {
		if (fl->fl_flags & FL_FLAG_DOWNGRADE_PENDING) {
			elapsed_sec = absolutetime_elapsed_in_secs(fl->fl_downgrade_start);

			if (elapsed_sec >= lease_break_timeout) {
				LEASEDBG("force downgrade on vp %p for fl %p elapsed %llu "
				    "timeout %u", vp, fl, elapsed_sec, lease_break_timeout);

				fl->fl_flags &= ~FL_FLAG_DOWNGRADE_PENDING;
				fl->fl_downgrade_start = 0;
				modify_file_lease(vp, fl, F_RDLCK, NULL);
				continue;
			}
		}
		if (fl->fl_flags & FL_FLAG_RELEASE_PENDING) {
			elapsed_sec = absolutetime_elapsed_in_secs(fl->fl_release_start);

			if (elapsed_sec >= lease_break_timeout) {
				LEASEDBG("force release on vp %p for fl %p elapsed %llu "
				    "timeout %u", vp, fl, elapsed_sec, lease_break_timeout);

				LIST_REMOVE(fl, fl_link);
				file_lease_free(fl);
				continue;
			}
		}
	}

	/* Wakeup the lease breaker(s). */
	wakeup(&vp->v_leases);
}

/* Must be called with vnode's lock held. */
static void
wait_for_lease_break(vnode_t vp, int breaker_fl_type, vfs_context_t ctx)
{
	file_lease_t fl;
	struct timespec ts;
	uint64_t elapsed_sec, start_time;
	int error;

restart:
	fl = LIST_FIRST(&vp->v_leases);
	assert(fl);

	/*
	 * In a rare case it is possible that the lease that we are blocked on has
	 * been released and a new lease has been put in place after we are
	 * signalled to wake up. In this particular, we would treat it as no
	 * conflict and proceed. This could only happen for directory leasing.
	 */
	if ((fl->fl_flags & (FL_FLAG_DOWNGRADE_PENDING | FL_FLAG_RELEASE_PENDING)) == 0) {
		LEASEDBG("new lease in place on vp %p fl %p fl_type %d "
		    "breaker_fl_type %d",
		    vp, fl, fl->fl_type, breaker_fl_type);

		return;
	}
	/*
	 * Figure out which timer to use for lease break timedout as we could have
	 * both timers active. If both timers active, pick the one with earliest
	 * start time.
	 */
	if (fl->fl_release_start) {
		if (fl->fl_downgrade_start == 0 ||
		    fl->fl_downgrade_start < fl->fl_release_start) {
			start_time = fl->fl_release_start;
		} else {
			start_time = fl->fl_downgrade_start;
		}
	} else {
		start_time = fl->fl_downgrade_start;
	}
	assert(start_time > 0);

	elapsed_sec = absolutetime_elapsed_in_secs(start_time);

	LEASEDBG("elapsed_sec %llu release_start %llu downgrade_start %llu",
	    elapsed_sec, fl->fl_release_start, fl->fl_downgrade_start);

	ts.tv_sec = (lease_break_timeout > elapsed_sec ?
	    (lease_break_timeout - elapsed_sec) : 0);
	ts.tv_nsec = (ts.tv_sec == 0 ? 1 : 0);
	error = msleep(&vp->v_leases, &vp->v_lock, PVFS, __func__, &ts);

	if (error == 0 || error != EWOULDBLOCK) {
		/*
		 * Woken up due to lease is released/downgraded by lease holder.
		 * We don't expect any other error from msleep() beside EWOULDBLOCK.
		 * Check if there is any further conflicts. If so, then continue to
		 * wait for the next conflict to resolve.
		 */
		if (check_for_lease_conflict(vp, breaker_fl_type, ctx)) {
			goto restart;
		}
	} else {
		/*
		 * Woken due to lease break timeout expired (EWOULDBLOCK returned).
		 * Break/downgrade all conflicting leases.
		 */
		handle_lease_break_timedout(vp);

		if (check_for_lease_conflict(vp, breaker_fl_type, ctx)) {
			goto restart;
		}
	}
}

/* Must be called with vnode's lock held. */
static void
send_lease_break_event(vnode_t vp, uint32_t event)
{
	if (vp->v_knotes.slh_first != NULL) {
		KNOTE(&vp->v_knotes, event);
	}
}

static bool
is_dataless_file(vnode_t vp, vfs_context_t ctx)
{
	struct vnode_attr va;
	bool is_dataless = false;
	int error;

	VATTR_INIT(&va);
	VATTR_WANTED(&va, va_flags);

	error = vnode_getattr(vp, &va, ctx);
	if (!error && (va.va_flags & SF_DATALESS)) {
		is_dataless = true;
	}

	return is_dataless;
}

/*
 * Break lease(s) in place for the file when there is conflict.
 * This function would return 0 for almost all call sites. The only exception
 * is when it is called from open1() with O_NONBLOCK flag and it needs to block
 * waiting for the lease conflict(s) to resolve. In this case EWOULDBLOCK is
 * returned.
 */
int
vnode_breaklease(vnode_t vp, uint32_t oflags, vfs_context_t ctx)
{
	file_lease_t fl;
	uint64_t now;
	int fl_type;
	int error = 0;

	vnode_lock(vp);

	if (__probable(LIST_EMPTY(&vp->v_leases))) {
		goto out_unlock;
	}

	/* Determine the access mode requested by the lease breaker. */
	fl_type = (oflags & (O_WRONLY | O_RDWR | O_CREAT | O_TRUNC)) ? F_WRLCK : F_RDLCK;

	/*
	 * If the lease-breaker is just reading, check that it can break
	 * leases first. If the lease-breaker is writing, or if the
	 * context was not specified, we always break.
	 * We skip lease break if the lease-breaker is dataless manipulator and
	 * the file is dataless.
	 */
	if ((fl_type == F_RDLCK && !vfs_context_can_break_leases(ctx)) ||
	    (vfs_context_is_dataless_manipulator(ctx) && (vp->v_type == VREG) &&
	    is_dataless_file(vp, ctx))) {
		goto out_unlock;
	}

	if (!check_for_lease_conflict(vp, fl_type, ctx)) {
		goto out_unlock;
	}

	now = mach_absolute_time();

	LEASEDBG("break lease on vp %p type %d oflags 0x%x cur_time %llu",
	    vp, vp->v_type, oflags, now);

	/*
	 * We get to this point then this means all lease(s) are conflict and
	 * we need to send the lease break event to the lease holder(s).
	 * It is possible that a lease could have both downgrade and release events
	 * pending triggered by multiple breakers trying to open the file in
	 * different modes. Both events would have different lease break timers.
	 * Consider the following case:
	 * 1. Process A holds the write lease on file X.
	 * 2. Provess B opens the file X in read-only mode.
	 *    This triggers downgrade lease event to Process A.
	 * 3. While downgrade is pending, Process C opens the file X in read-write
	 *    mode. This triggers release lease event to Process A.
	 */
	LIST_FOREACH(fl, &vp->v_leases, fl_link) {
		if (fl_type == F_WRLCK) {
			/* File is opened for writing or truncate. */
			if (fl->fl_flags & FL_FLAG_RELEASE_PENDING) {
				continue;
			}
			fl->fl_release_start = now;
			fl->fl_flags |= FL_FLAG_RELEASE_PENDING;
			send_lease_break_event(vp, NOTE_LEASE_RELEASE);
		} else {
			/* File is opened for reading. */
			if (fl->fl_flags & FL_FLAG_DOWNGRADE_PENDING ||
			    fl->fl_flags & FL_FLAG_RELEASE_PENDING) {
				continue;
			}
			fl->fl_downgrade_start = now;
			fl->fl_flags |= FL_FLAG_DOWNGRADE_PENDING;
			send_lease_break_event(vp, NOTE_LEASE_DOWNGRADE);
		}
	}

	/*
	 * If open is requested with O_NONBLOCK, then we can't block and wait for
	 * the lease to be released/downgraded. Just bail out with EWOULDBLOCK.
	 */
	if (oflags & O_NONBLOCK) {
		error = EWOULDBLOCK;
		goto out;
	}

	wait_for_lease_break(vp, fl_type, ctx);

out:
	LEASEDBG("break lease on vp %p oflags 0x%x, error %d", vp, oflags, error);

out_unlock:
	vnode_unlock(vp);

	return error;
}

/*
 * Get parent vnode by parent ID (only for file system that supports
 * MNTK_PATH_FROM_ID).
 * On success, the parent's vnode is returned with iocount held.
 */
static vnode_t
vnode_getparent_byid(vnode_t vp)
{
	struct vnode_attr va;
	vnode_t dvp = NULLVP;
	vfs_context_t ctx = vfs_context_current();
	int error;

	if (!(vp->v_mount->mnt_kern_flag & MNTK_PATH_FROM_ID)) {
		goto out;
	}

	VATTR_INIT(&va);
	VATTR_WANTED(&va, va_parentid);

	/* Get the vnode's parent id from the file system. */
	error = vnode_getattr(vp, &va, ctx);
	if (error || !VATTR_IS_SUPPORTED(&va, va_parentid)) {
		goto out;
	}

	/*
	 * Ask the file system for the parent vnode.
	 * We are ignoring the error here as we don't expect the parent vnode to be
	 * populated on error.
	 */
	(void)VFS_VGET(vp->v_mount, (ino64_t)va.va_parentid, &dvp, ctx);

out:
	return dvp;
}

/*
 * Break directory's lease.
 * If 'need_parent' is true, then parent is obtained via vnode_getparent() (or
 * vnode_getparent_byid()) on the provided 'vp'.
 */
void
vnode_breakdirlease(vnode_t vp, bool need_parent, uint32_t oflags)
{
	vnode_t dvp;

	if ((vnode_vtype(vp) != VREG && vnode_vtype(vp) != VDIR) ||
	    (vp == rootvnode)) {
		return;
	}

	/*
	 * If parent is not provided, first try to get it from the name cache.
	 * If failed, then we will attempt to ask the file system for parent vnode.
	 * This is just a best effort as both attempts could still fail.
	 */
	if (need_parent) {
		dvp = vnode_getparent(vp);
		if (__improbable(dvp == NULLVP)) {
			dvp = vnode_getparent_byid(vp);
		}
	} else {
		dvp = vp;
	}

	if (__probable(dvp != NULLVP)) {
		/* Always break dir leases. */
		(void)vnode_breaklease(dvp, oflags, vfs_context_current());
	}

	if (need_parent && (dvp != NULLVP)) {
		vnode_put(dvp);
	}
}

/*
 * Revoke all lease(s) in place for the file.
 * This is called when the vnode is reclaimed.
 */
void
vnode_revokelease(vnode_t vp, bool locked)
{
	file_lease_t fl, fl_tmp;
	bool need_wakeup = false;

	if ((vnode_vtype(vp) != VREG && vnode_vtype(vp) != VDIR)) {
		return;
	}

	if (!locked) {
		vnode_lock(vp);
	}

	LIST_FOREACH_SAFE(fl, &vp->v_leases, fl_link, fl_tmp) {
		LIST_REMOVE(fl, fl_link);
		file_lease_free(fl);
		need_wakeup = true;
	}

	/* Wakeup any lease breaker(s) that might be currently blocked. */
	if (__improbable(need_wakeup)) {
		wakeup(&vp->v_leases);
	}

	if (!locked) {
		vnode_unlock(vp);
	}
}

#endif /* CONFIG_FILE_LEASES */

errno_t
vnode_rdadvise(vnode_t vp, off_t offset, int len, vfs_context_t ctx)
{
	struct radvisory ra_struct;

	assert(vp);

	if (offset < 0 || len < 0) {
		return EINVAL;
	}

	ra_struct.ra_offset = offset;
	ra_struct.ra_count = len;

	return VNOP_IOCTL(vp, F_RDADVISE, (caddr_t)&ra_struct, 0, ctx);
}