/*      $NetBSD: vfs_subr.c,v 1.503 2026/05/08 04:18:32 perseant Exp $  */

/*-
 * Copyright (c) 1997, 1998, 2004, 2005, 2007, 2008, 2019, 2020
 *     The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center, by Charles M. Hannum, by Andrew Doran,
 * by Marshall Kirk McKusick and Greg Ganger at the University of Michigan.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Copyright (c) 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)vfs_subr.c  8.13 (Berkeley) 4/18/94
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: vfs_subr.c,v 1.503 2026/05/08 04:18:32 perseant Exp $");

#ifdef _KERNEL_OPT
#include "opt_compat_43.h"
#include "opt_compat_netbsd.h"
#include "opt_ddb.h"
#endif

#include <sys/param.h>
#include <sys/types.h>

#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/dirent.h>
#include <sys/errno.h>
#include <sys/filedesc.h>
#include <sys/fstrans.h>
#include <sys/kauth.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/module.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/sdt.h>
#include <sys/stat.h>
#include <sys/syscallargs.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/vnode_impl.h>

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

#include <uvm/uvm_ddb.h>

SDT_PROBE_DEFINE3(vfs, syncer, worklist, vnode__add,
    "struct vnode *"/*vp*/,
    "int"/*delayx*/,
    "int"/*slot*/);
SDT_PROBE_DEFINE4(vfs, syncer, worklist, vnode__update,
    "struct vnode *"/*vp*/,
    "int"/*delayx*/,
    "int"/*oslot*/,
    "int"/*nslot*/);
SDT_PROBE_DEFINE1(vfs, syncer, worklist, vnode__remove,
    "struct vnode *"/*vp*/);

SDT_PROBE_DEFINE3(vfs, syncer, worklist, mount__add,
    "struct mount *"/*mp*/,
    "int"/*vdelay*/,
    "int"/*slot*/);
SDT_PROBE_DEFINE4(vfs, syncer, worklist, mount__update,
    "struct mount *"/*vp*/,
    "int"/*vdelay*/,
    "int"/*oslot*/,
    "int"/*nslot*/);
SDT_PROBE_DEFINE1(vfs, syncer, worklist, mount__remove,
    "struct mount *"/*mp*/);

SDT_PROBE_DEFINE1(vfs, syncer, sync, start,
    "int"/*starttime*/);
SDT_PROBE_DEFINE1(vfs, syncer, sync, mount__start,
    "struct mount *"/*mp*/);
SDT_PROBE_DEFINE2(vfs, syncer, sync, mount__done,
    "struct mount *"/*mp*/,
    "int"/*error*/);
SDT_PROBE_DEFINE1(vfs, syncer, sync, mount__skip,
    "struct mount *"/*mp*/);
SDT_PROBE_DEFINE1(vfs, syncer, sync, vnode__start,
    "struct vnode *"/*vp*/);
SDT_PROBE_DEFINE2(vfs, syncer, sync, vnode__done,
    "struct vnode *"/*vp*/,
    "int"/*error*/);
SDT_PROBE_DEFINE2(vfs, syncer, sync, vnode__fail__lock,
    "struct vnode *"/*vp*/,
    "int"/*error*/);
SDT_PROBE_DEFINE2(vfs, syncer, sync, vnode__fail__vget,
    "struct vnode *"/*vp*/,
    "int"/*error*/);
SDT_PROBE_DEFINE2(vfs, syncer, sync, done,
    "int"/*starttime*/,
    "int"/*endtime*/);

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

/*
 * Insq/Remq for the vnode usage lists.
 */
#define bufinsvn(bp, dp)        LIST_INSERT_HEAD(dp, bp, b_vnbufs)
#define bufremvn(bp) {                                                  \
        LIST_REMOVE(bp, b_vnbufs);                                      \
        (bp)->b_vnbufs.le_next = NOLIST;                                \
}

int doforce = 1;                /* 1 => permit forcible unmounting */

/*
 * Local declarations.
 */

static void vn_initialize_syncerd(void);

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

        vn_initialize_syncerd();
        vfs_mount_sysinit();
        vfs_vnode_sysinit();
}

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

        /* XXXUBC this doesn't look at flags or slp* */
        rw_enter(vp->v_uobj.vmobjlock, RW_WRITER);
        error = VOP_PUTPAGES(vp, 0, 0, flushflags);
        if (error) {
                return error;
        }

        if (flags & V_SAVE) {
                error = VOP_FSYNC(vp, cred, FSYNC_WAIT|FSYNC_RECLAIM, 0, 0);
                if (error)
                        return error;
                KASSERT(LIST_EMPTY(&vp->v_dirtyblkhd));
        }

        mutex_enter(&bufcache_lock);
restart:
        for (bp = LIST_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
                KASSERT(bp->b_vp == vp);
                nbp = LIST_NEXT(bp, b_vnbufs);
                error = bbusy(bp, catch_p, slptimeo, NULL);
                if (error != 0) {
                        if (error == EPASSTHROUGH)
                                goto restart;
                        mutex_exit(&bufcache_lock);
                        return error;
                }
                brelsel(bp, BC_INVAL | BC_VFLUSH);
        }

        for (bp = LIST_FIRST(&vp->v_cleanblkhd); bp; bp = nbp) {
                KASSERT(bp->b_vp == vp);
                nbp = LIST_NEXT(bp, b_vnbufs);
                error = bbusy(bp, catch_p, slptimeo, NULL);
                if (error != 0) {
                        if (error == EPASSTHROUGH)
                                goto restart;
                        mutex_exit(&bufcache_lock);
                        return error;
                }
                /*
                 * XXX Since there are no node locks for NFS, I believe
                 * there is a slight chance that a delayed write will
                 * occur while sleeping just above, so check for it.
                 */
                if ((bp->b_oflags & BO_DELWRI) && (flags & V_SAVE)) {
#ifdef DEBUG
                        printf("buffer still DELWRI\n");
#endif
                        bp->b_cflags |= BC_BUSY | BC_VFLUSH;
                        mutex_exit(&bufcache_lock);
                        VOP_BWRITE(bp->b_vp, bp);
                        mutex_enter(&bufcache_lock);
                        goto restart;
                }
                brelsel(bp, BC_INVAL | BC_VFLUSH);
        }

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

        mutex_exit(&bufcache_lock);

        return 0;
}

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

        off = round_page((voff_t)lbn << vp->v_mount->mnt_fs_bshift);
        rw_enter(vp->v_uobj.vmobjlock, RW_WRITER);
        error = VOP_PUTPAGES(vp, off, 0, PGO_FREE | PGO_SYNCIO);
        if (error) {
                return error;
        }

        mutex_enter(&bufcache_lock);
restart:
        for (bp = LIST_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
                KASSERT(bp->b_vp == vp);
                nbp = LIST_NEXT(bp, b_vnbufs);
                if (bp->b_lblkno < lbn)
                        continue;
                error = bbusy(bp, catch_p, slptimeo, NULL);
                if (error != 0) {
                        if (error == EPASSTHROUGH)
                                goto restart;
                        mutex_exit(&bufcache_lock);
                        return error;
                }
                brelsel(bp, BC_INVAL | BC_VFLUSH);
        }

        for (bp = LIST_FIRST(&vp->v_cleanblkhd); bp; bp = nbp) {
                KASSERT(bp->b_vp == vp);
                nbp = LIST_NEXT(bp, b_vnbufs);
                if (bp->b_lblkno < lbn)
                        continue;
                error = bbusy(bp, catch_p, slptimeo, NULL);
                if (error != 0) {
                        if (error == EPASSTHROUGH)
                                goto restart;
                        mutex_exit(&bufcache_lock);
                        return error;
                }
                brelsel(bp, BC_INVAL | BC_VFLUSH);
        }
        mutex_exit(&bufcache_lock);

        return 0;
}

/*
 * Flush all dirty buffers from a vnode.
 * Called with the underlying vnode locked, which should prevent new dirty
 * buffers from being queued.
 */
int
vflushbuf(struct vnode *vp, int flags)
{
        struct buf *bp, *nbp;
        int error, pflags;
        bool dirty, sync;

        sync = (flags & FSYNC_WAIT) != 0;
        pflags = PGO_CLEANIT | PGO_ALLPAGES |
            (sync ? PGO_SYNCIO : 0) |
            ((flags & FSYNC_LAZY) ? PGO_LAZY : 0);
        rw_enter(vp->v_uobj.vmobjlock, RW_WRITER);
        (void) VOP_PUTPAGES(vp, 0, 0, pflags);

loop:
        mutex_enter(&bufcache_lock);
        for (bp = LIST_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
                KASSERT(bp->b_vp == vp);
                nbp = LIST_NEXT(bp, b_vnbufs);
                if ((bp->b_cflags & BC_BUSY))
                        continue;
                if ((bp->b_oflags & BO_DELWRI) == 0)
                        panic("vflushbuf: not dirty, bp %p", bp);
                bp->b_cflags |= BC_BUSY | BC_VFLUSH;
                mutex_exit(&bufcache_lock);
                /*
                 * Wait for I/O associated with indirect blocks to complete,
                 * since there is no way to quickly wait for them below.
                 */
                if (bp->b_vp == vp || !sync)
                        (void) bawrite(bp);
                else {
                        error = bwrite(bp);
                        if (error)
                                return error;
                }
                goto loop;
        }
        mutex_exit(&bufcache_lock);

        if (!sync)
                return 0;

        mutex_enter(vp->v_interlock);
        while (vp->v_numoutput != 0)
                cv_wait(&vp->v_cv, vp->v_interlock);
        dirty = !LIST_EMPTY(&vp->v_dirtyblkhd);
        mutex_exit(vp->v_interlock);

        if (dirty) {
                vprint("vflushbuf: dirty", vp);
                goto loop;
        }

        return 0;
}

/*
 * Create a vnode for a block device.
 * Used for root filesystem and swap areas.
 * Also used for memory file system special devices.
 */
int
bdevvp(dev_t dev, vnode_t **vpp)
{
        struct vattr va;

        vattr_null(&va);
        va.va_type = VBLK;
        va.va_rdev = dev;

        return vcache_new(dead_rootmount, NULL, &va, NOCRED, NULL, vpp);
}

/*
 * Create a vnode for a character device.
 * Used for kernfs and some console handling.
 */
int
cdevvp(dev_t dev, vnode_t **vpp)
{
        struct vattr va;

        vattr_null(&va);
        va.va_type = VCHR;
        va.va_rdev = dev;

        return vcache_new(dead_rootmount, NULL, &va, NOCRED, NULL, vpp);
}

/*
 * Associate a buffer with a vnode.  There must already be a hold on
 * the vnode.
 */
void
bgetvp(struct vnode *vp, struct buf *bp)
{

        KASSERT(bp->b_vp == NULL);
        KASSERT(bp->b_objlock == &buffer_lock);
        KASSERT(mutex_owned(vp->v_interlock));
        KASSERT(mutex_owned(&bufcache_lock));
        KASSERT((bp->b_cflags & BC_BUSY) != 0);
        KASSERT(!cv_has_waiters(&bp->b_done));

        vholdl(vp);
        bp->b_vp = vp;
        if (vp->v_type == VBLK || vp->v_type == VCHR)
                bp->b_dev = vp->v_rdev;
        else
                bp->b_dev = NODEV;

        /*
         * Insert onto list for new vnode.
         */
        bufinsvn(bp, &vp->v_cleanblkhd);
        bp->b_objlock = vp->v_interlock;
}

/*
 * Disassociate a buffer from a vnode.
 */
void
brelvp(struct buf *bp)
{
        struct vnode *vp = bp->b_vp;

        KASSERT(vp != NULL);
        KASSERT(bp->b_objlock == vp->v_interlock);
        KASSERT(mutex_owned(vp->v_interlock));
        KASSERT(mutex_owned(&bufcache_lock));
        KASSERT((bp->b_cflags & BC_BUSY) != 0);
        KASSERT(!cv_has_waiters(&bp->b_done));

        /*
         * Delete from old vnode list, if on one.
         */
        if (LIST_NEXT(bp, b_vnbufs) != NOLIST)
                bufremvn(bp);

        if ((vp->v_iflag & (VI_ONWORKLST | VI_PAGES)) == VI_ONWORKLST &&
            LIST_FIRST(&vp->v_dirtyblkhd) == NULL)
                vn_syncer_remove_from_worklist(vp);

        bp->b_objlock = &buffer_lock;
        bp->b_vp = NULL;
        holdrelel(vp);
}

/*
 * Reassign a buffer from one vnode list to another.
 * The list reassignment must be within the same vnode.
 * Used to assign file specific control information
 * (indirect blocks) to the list to which they belong.
 */
void
reassignbuf(struct buf *bp, struct vnode *vp)
{
        struct buflists *listheadp;
        int delayx;

        KASSERT(mutex_owned(&bufcache_lock));
        KASSERT(bp->b_objlock == vp->v_interlock);
        KASSERT(mutex_owned(vp->v_interlock));
        KASSERT((bp->b_cflags & BC_BUSY) != 0);

        /*
         * Delete from old vnode list, if on one.
         */
        if (LIST_NEXT(bp, b_vnbufs) != NOLIST)
                bufremvn(bp);

        /*
         * If dirty, put on list of dirty buffers;
         * otherwise insert onto list of clean buffers.
         */
        if ((bp->b_oflags & BO_DELWRI) == 0) {
                listheadp = &vp->v_cleanblkhd;
                if ((vp->v_iflag & (VI_ONWORKLST | VI_PAGES)) ==
                    VI_ONWORKLST &&
                    LIST_FIRST(&vp->v_dirtyblkhd) == NULL)
                        vn_syncer_remove_from_worklist(vp);
        } else {
                listheadp = &vp->v_dirtyblkhd;
                if ((vp->v_iflag & VI_ONWORKLST) == 0) {
                        switch (vp->v_type) {
                        case VDIR:
                                delayx = dirdelay;
                                break;
                        case VBLK:
                                if (spec_node_getmountedfs(vp) != NULL) {
                                        delayx = metadelay;
                                        break;
                                }
                                /* fall through */
                        default:
                                delayx = filedelay;
                                break;
                        }
                        if (!vp->v_mount ||
                            (vp->v_mount->mnt_flag & MNT_ASYNC) == 0)
                                vn_syncer_add_to_worklist(vp, delayx);
                }
        }
        bufinsvn(bp, listheadp);
}

/*
 * Lookup a vnode by device number and return it referenced.
 */
int
vfinddev(dev_t dev, enum vtype type, vnode_t **vpp)
{

        return (spec_node_lookup_by_dev(type, dev, VDEAD_NOWAIT, vpp) == 0);
}

/*
 * Revoke all the vnodes corresponding to the specified minor number
 * range (endpoints inclusive) of the specified major.
 */
void
vdevgone(int maj, int minl, int minh, enum vtype type)
{
        vnode_t *vp;
        dev_t dev;
        int mn;

        for (mn = minl; mn <= minh; mn++) {
                dev = makedev(maj, mn);
                /*
                 * Notify anyone trying to get at this device that it
                 * has been detached, and then revoke it.
                 */
                switch (type) {
                case VBLK:
                        bdev_detached(dev);
                        break;
                case VCHR:
                        cdev_detached(dev);
                        break;
                default:
                        panic("invalid specnode type: %d", type);
                }
                /*
                 * Passing 0 as flags, instead of VDEAD_NOWAIT, means
                 * spec_node_lookup_by_dev will wait for vnodes it
                 * finds concurrently being revoked before returning.
                 */
                while (spec_node_lookup_by_dev(type, dev, 0, &vp) == 0) {
                        VOP_REVOKE(vp, REVOKEALL);
                        vrele(vp);
                }
        }
}

/*
 * The filesystem synchronizer mechanism - syncer.
 *
 * It is useful to delay writes of file data and filesystem metadata for
 * a certain amount of time so that quickly created and deleted files need
 * not waste disk bandwidth being created and removed.  To implement this,
 * vnodes are appended to a "workitem" queue.
 *
 * Most pending metadata should not wait for more than ten seconds.  Thus,
 * mounted on block devices are delayed only about a half the time that file
 * data is delayed.  Similarly, directory updates are more critical, so are
 * only delayed about a third the time that file data is delayed.
 *
 * There are SYNCER_MAXDELAY queues that are processed in a round-robin
 * manner at a rate of one each second (driven off the filesystem syner
 * thread). The syncer_delayno variable indicates the next queue that is
 * to be processed.  Items that need to be processed soon are placed in
 * this queue:
 *
 *      syncer_workitem_pending[syncer_delayno]
 *
 * A delay of e.g. fifteen seconds is done by placing the request fifteen
 * entries later in the queue:
 *
 *      syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
 *
 * Flag VI_ONWORKLST indicates that vnode is added into the queue.
 */

#define SYNCER_MAXDELAY         32

typedef TAILQ_HEAD(synclist, vnode_impl) synclist_t;

static void     vn_syncer_add1(struct vnode *, int);
static void     sysctl_vfs_syncfs_setup(struct sysctllog **);

/*
 * Defines and variables for the syncer process.
 */
int syncer_maxdelay = SYNCER_MAXDELAY;  /* maximum delay time */
time_t syncdelay = 30;                  /* max time to delay syncing data */
time_t filedelay = 30;                  /* time to delay syncing files */
time_t dirdelay  = 15;                  /* time to delay syncing directories */
time_t metadelay = 10;                  /* time to delay syncing metadata */
time_t lockdelay = 1;                   /* time to delay if locking fails */

static kmutex_t         syncer_data_lock; /* short term lock on data structs */

static int              syncer_delayno = 0;
static long             syncer_last;
static synclist_t *     syncer_workitem_pending;

static void
vn_initialize_syncerd(void)
{
        int i;

        syncer_last = SYNCER_MAXDELAY + 2;

        sysctl_vfs_syncfs_setup(NULL);

        syncer_workitem_pending =
            kmem_alloc(syncer_last * sizeof (struct synclist), KM_SLEEP);

        for (i = 0; i < syncer_last; i++)
                TAILQ_INIT(&syncer_workitem_pending[i]);

        mutex_init(&syncer_data_lock, MUTEX_DEFAULT, IPL_NONE);
}

/*
 * Return delay factor appropriate for the given file system.   For
 * WAPBL we use the sync vnode to burst out metadata updates: sync
 * those file systems more frequently.
 */
static inline int
sync_delay(struct mount *mp)
{

        return mp->mnt_wapbl != NULL ? metadelay : syncdelay;
}

/*
 * Compute the next slot index from delay.
 */
static inline int
sync_delay_slot(int delayx)
{

        if (delayx > syncer_maxdelay - 2)
                delayx = syncer_maxdelay - 2;
        return (syncer_delayno + delayx) % syncer_last;
}

/*
 * Add an item to the syncer work queue.
 */
static void
vn_syncer_add1(struct vnode *vp, int delayx)
{
        synclist_t *slp;
        vnode_impl_t *vip = VNODE_TO_VIMPL(vp);

        KASSERT(mutex_owned(&syncer_data_lock));

        if (vp->v_iflag & VI_ONWORKLST) {
                /*
                 * Remove in order to adjust the position of the vnode.
                 * Note: called from sched_sync(), which will not hold
                 * interlock, therefore we cannot modify v_iflag here.
                 */
                slp = &syncer_workitem_pending[vip->vi_synclist_slot];
                TAILQ_REMOVE(slp, vip, vi_synclist);
        } else {
                KASSERT(mutex_owned(vp->v_interlock));
                vp->v_iflag |= VI_ONWORKLST;
        }

        vip->vi_synclist_slot = sync_delay_slot(delayx);

        slp = &syncer_workitem_pending[vip->vi_synclist_slot];
        TAILQ_INSERT_TAIL(slp, vip, vi_synclist);
}

void
vn_syncer_add_to_worklist(struct vnode *vp, int delayx)
{
        vnode_impl_t *vip = VNODE_TO_VIMPL(vp);

        KASSERT(mutex_owned(vp->v_interlock));

        mutex_enter(&syncer_data_lock);
        vn_syncer_add1(vp, delayx);
        SDT_PROBE3(vfs, syncer, worklist, vnode__add,
            vp, delayx, vip->vi_synclist_slot);
        mutex_exit(&syncer_data_lock);
}

/*
 * Remove an item from the syncer work queue.
 */
void
vn_syncer_remove_from_worklist(struct vnode *vp)
{
        synclist_t *slp;
        vnode_impl_t *vip = VNODE_TO_VIMPL(vp);

        KASSERT(mutex_owned(vp->v_interlock));

        if (vp->v_iflag & VI_ONWORKLST) {
                mutex_enter(&syncer_data_lock);
                SDT_PROBE1(vfs, syncer, worklist, vnode__remove,  vp);
                vp->v_iflag &= ~VI_ONWORKLST;
                slp = &syncer_workitem_pending[vip->vi_synclist_slot];
                TAILQ_REMOVE(slp, vip, vi_synclist);
                mutex_exit(&syncer_data_lock);
        }
}

/*
 * Add this mount point to the syncer.
 */
void
vfs_syncer_add_to_worklist(struct mount *mp)
{
        static int start, incr, next;
        int vdelay;

        KASSERT(mutex_owned(mp->mnt_updating));
        KASSERT((mp->mnt_iflag & IMNT_ONWORKLIST) == 0);

        /*
         * We attempt to scatter the mount points on the list
         * so that they will go off at evenly distributed times
         * even if all the filesystems are mounted at once.
         */

        next += incr;
        if (next == 0 || next > syncer_maxdelay) {
                start /= 2;
                incr /= 2;
                if (start == 0) {
                        start = syncer_maxdelay / 2;
                        incr = syncer_maxdelay;
                }
                next = start;
        }
        mp->mnt_iflag |= IMNT_ONWORKLIST;
        vdelay = sync_delay(mp);
        mp->mnt_synclist_slot = vdelay > 0 ? next % vdelay : 0;
        SDT_PROBE3(vfs, syncer, worklist, mount__add,
            mp, vdelay, mp->mnt_synclist_slot);
}

/*
 * Remove the mount point from the syncer.
 */
void
vfs_syncer_remove_from_worklist(struct mount *mp)
{

        KASSERT(mutex_owned(mp->mnt_updating));
        KASSERT((mp->mnt_iflag & IMNT_ONWORKLIST) != 0);

        SDT_PROBE1(vfs, syncer, worklist, mount__remove,  mp);
        mp->mnt_iflag &= ~IMNT_ONWORKLIST;
}

/*
 * Try lazy sync, return true on success.
 */
static bool
lazy_sync_vnode(struct vnode *vp)
{
        bool synced;
        int error;

        KASSERT(mutex_owned(&syncer_data_lock));

        synced = false;
        if ((error = vcache_tryvget(vp)) == 0) {
                mutex_exit(&syncer_data_lock);
                if ((error = vn_lock(vp, LK_EXCLUSIVE | LK_NOWAIT)) == 0) {
                        synced = true;
                        SDT_PROBE1(vfs, syncer, sync, vnode__start,  vp);
                        error = VOP_FSYNC(vp, curlwp->l_cred,
                            FSYNC_LAZY, 0, 0);
                        SDT_PROBE2(vfs, syncer, sync, vnode__done,  vp, error);
                        vput(vp);
                } else {
                        SDT_PROBE2(vfs, syncer, sync, vnode__fail__lock,
                            vp, error);
                        vrele(vp);
                }
                mutex_enter(&syncer_data_lock);
        } else {
                SDT_PROBE2(vfs, syncer, sync, vnode__fail__vget,  vp, error);
        }
        return synced;
}

/*
 * System filesystem synchronizer daemon.
 */
void
sched_sync(void *arg)
{
        mount_iterator_t *iter;
        synclist_t *slp;
        struct vnode_impl *vi;
        struct vnode *vp;
        struct mount *mp;
        time_t starttime, endtime;
        int vdelay, oslot, nslot, delayx;
        bool synced;
        int error;

        for (;;) {
                starttime = time_second;
                SDT_PROBE1(vfs, syncer, sync, start,  starttime);

                /*
                 * Sync mounts whose dirty time has expired.
                 */
                mountlist_iterator_init(&iter);
                while ((mp = mountlist_iterator_trynext(iter)) != NULL) {
                        if ((mp->mnt_iflag & IMNT_ONWORKLIST) == 0 ||
                            mp->mnt_synclist_slot != syncer_delayno) {
                                SDT_PROBE1(vfs, syncer, sync, mount__skip,
                                    mp);
                                continue;
                        }

                        vdelay = sync_delay(mp);
                        oslot = mp->mnt_synclist_slot;
                        nslot = sync_delay_slot(vdelay);
                        mp->mnt_synclist_slot = nslot;
                        SDT_PROBE4(vfs, syncer, worklist, mount__update,
                            mp, vdelay, oslot, nslot);

                        SDT_PROBE1(vfs, syncer, sync, mount__start,  mp);
                        error = VFS_SYNC(mp, MNT_LAZY, curlwp->l_cred);
                        SDT_PROBE2(vfs, syncer, sync, mount__done,
                            mp, error);
                }
                mountlist_iterator_destroy(iter);

                mutex_enter(&syncer_data_lock);

                /*
                 * Push files whose dirty time has expired.
                 */
                slp = &syncer_workitem_pending[syncer_delayno];
                syncer_delayno += 1;
                if (syncer_delayno >= syncer_last)
                        syncer_delayno = 0;

                while ((vi = TAILQ_FIRST(slp)) != NULL) {
                        vp = VIMPL_TO_VNODE(vi);
                        synced = lazy_sync_vnode(vp);

                        /*
                         * XXX The vnode may have been recycled, in which
                         * case it may have a new identity.
                         */
                        vi = TAILQ_FIRST(slp);
                        if (vi != NULL && VIMPL_TO_VNODE(vi) == vp) {
                                /*
                                 * Put us back on the worklist.  The worklist
                                 * routine will remove us from our current
                                 * position and then add us back in at a later
                                 * position.
                                 *
                                 * Try again sooner rather than later if
                                 * we were unable to lock the vnode.  Lock
                                 * failure should not prevent us from doing
                                 * the sync "soon".
                                 *
                                 * If we locked it yet arrive here, it's
                                 * likely that lazy sync is in progress and
                                 * so the vnode still has dirty metadata.
                                 * syncdelay is mainly to get this vnode out
                                 * of the way so we do not consider it again
                                 * "soon" in this loop, so the delay time is
                                 * not critical as long as it is not "soon".
                                 * While write-back strategy is the file
                                 * system's domain, we expect write-back to
                                 * occur no later than syncdelay seconds
                                 * into the future.
                                 */
                                delayx = synced ? syncdelay : lockdelay;
                                oslot = vi->vi_synclist_slot;
                                vn_syncer_add1(vp, delayx);
                                nslot = vi->vi_synclist_slot;
                                SDT_PROBE4(vfs, syncer, worklist,
                                    vnode__update,
                                    vp, delayx, oslot, nslot);
                        }
                }

                endtime = time_second;

                SDT_PROBE2(vfs, syncer, sync, done,  starttime, endtime);

                /*
                 * If it has taken us less than a second to process the
                 * current work, then wait.  Otherwise start right over
                 * again.  We can still lose time if any single round
                 * takes more than two seconds, but it does not really
                 * matter as we are just trying to generally pace the
                 * filesystem activity.
                 */
                if (endtime == starttime) {
                        kpause("syncer", false, hz, &syncer_data_lock);
                }
                mutex_exit(&syncer_data_lock);
        }
}

static void
sysctl_vfs_syncfs_setup(struct sysctllog **clog)
{
        const struct sysctlnode *rnode, *cnode;

        sysctl_createv(clog, 0, NULL, &rnode,
            CTLFLAG_PERMANENT,
            CTLTYPE_NODE, "sync",
            SYSCTL_DESCR("syncer options"),
            NULL, 0, NULL, 0,
            CTL_VFS, CTL_CREATE, CTL_EOL);

        sysctl_createv(clog, 0, &rnode, &cnode,
            CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
            CTLTYPE_QUAD, "delay",
            SYSCTL_DESCR("max time to delay syncing data"),
            NULL, 0, &syncdelay, 0,
            CTL_CREATE, CTL_EOL);

        sysctl_createv(clog, 0, &rnode, &cnode,
            CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
            CTLTYPE_QUAD, "filedelay",
            SYSCTL_DESCR("time to delay syncing files"),
            NULL, 0, &filedelay, 0,
            CTL_CREATE, CTL_EOL);

        sysctl_createv(clog, 0, &rnode, &cnode,
            CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
            CTLTYPE_QUAD, "dirdelay",
            SYSCTL_DESCR("time to delay syncing directories"),
            NULL, 0, &dirdelay, 0,
            CTL_CREATE, CTL_EOL);

        sysctl_createv(clog, 0, &rnode, &cnode,
            CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
            CTLTYPE_QUAD, "metadelay",
            SYSCTL_DESCR("time to delay syncing metadata"),
            NULL, 0, &metadelay, 0,
            CTL_CREATE, CTL_EOL);
}

/*
 * sysctl helper routine to return list of supported fstypes
 */
int
sysctl_vfs_generic_fstypes(SYSCTLFN_ARGS)
{
        char bf[sizeof(((struct statvfs *)NULL)->f_fstypename)];
        char *where = oldp;
        struct vfsops *v;
        size_t needed, left, slen;
        int error, first;

        if (newp != NULL)
                return SET_ERROR(EPERM);
        if (namelen != 0)
                return SET_ERROR(EINVAL);

        first = 1;
        error = 0;
        needed = 0;
        left = *oldlenp;

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

int kinfo_vdebug = 1;
int kinfo_vgetfailed;

#define KINFO_VNODESLOP 10

/*
 * Dump vnode list (via sysctl).
 * Copyout address of vnode followed by vnode.
 */
int
sysctl_kern_vnode(SYSCTLFN_ARGS)
{
        char *where = oldp;
        size_t *sizep = oldlenp;
        struct mount *mp;
        vnode_t *vp, vbuf;
        mount_iterator_t *iter;
        struct vnode_iterator *marker;
        char *bp = where;
        char *ewhere;
        int error;

        if (namelen != 0)
                return SET_ERROR(EOPNOTSUPP);
        if (newp != NULL)
                return SET_ERROR(EPERM);

#define VPTRSZ  sizeof(vnode_t *)
#define VNODESZ sizeof(vnode_t)
        if (where == NULL) {
                *sizep = (numvnodes + KINFO_VNODESLOP) * (VPTRSZ + VNODESZ);
                return 0;
        }
        ewhere = where + *sizep;

        sysctl_unlock();
        mountlist_iterator_init(&iter);
        while ((mp = mountlist_iterator_next(iter)) != NULL) {
                vfs_vnode_iterator_init(mp, &marker);
                while ((vp = vfs_vnode_iterator_next(marker, NULL, NULL))) {
                        if (bp + VPTRSZ + VNODESZ > ewhere) {
                                vrele(vp);
                                vfs_vnode_iterator_destroy(marker);
                                mountlist_iterator_destroy(iter);
                                sysctl_relock();
                                *sizep = bp - where;
                                return SET_ERROR(ENOMEM);
                        }
                        memcpy(&vbuf, vp, VNODESZ);
                        if ((error = copyout(&vp, bp, VPTRSZ)) ||
                            (error = copyout(&vbuf, bp + VPTRSZ, VNODESZ))) {
                                vrele(vp);
                                vfs_vnode_iterator_destroy(marker);
                                mountlist_iterator_destroy(iter);
                                sysctl_relock();
                                return error;
                        }
                        vrele(vp);
                        bp += VPTRSZ + VNODESZ;
                }
                vfs_vnode_iterator_destroy(marker);
        }
        mountlist_iterator_destroy(iter);
        sysctl_relock();

        *sizep = bp - where;
        return 0;
}

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

        memset(vap, 0, sizeof(*vap));

        vap->va_type = VNON;

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

/*
 * Vnode state to string.
 */
const char *
vstate_name(enum vnode_state state)
{

        switch (state) {
        case VS_ACTIVE:
                return "ACTIVE";
        case VS_MARKER:
                return "MARKER";
        case VS_LOADING:
                return "LOADING";
        case VS_LOADED:
                return "LOADED";
        case VS_BLOCKED:
                return "BLOCKED";
        case VS_RECLAIMING:
                return "RECLAIMING";
        case VS_RECLAIMED:
                return "RECLAIMED";
        default:
                return "ILLEGAL";
        }
}

/*
 * Print a description of a vnode (common part).
 */
static void
vprint_common(struct vnode *vp, const char *prefix,
    void (*pr)(const char *, ...) __printflike(1, 2))
{
        int n;
        char bf[96];
        const uint8_t *cp;
        vnode_impl_t *vip;
        const char * const vnode_tags[] = { VNODE_TAGS };
        const char * const vnode_types[] = { VNODE_TYPES };
        const char vnode_flagbits[] = VNODE_FLAGBITS;

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

        vip = VNODE_TO_VIMPL(vp);

        snprintb(bf, sizeof(bf),
            vnode_flagbits, vp->v_iflag | vp->v_vflag | vp->v_uflag);

        (*pr)("vnode %p flags %s\n", vp, bf);
        (*pr)("%stag %s(%d) type %s(%d) mount %p typedata %p\n", prefix,
            ARRAY_PRINT(vp->v_tag, vnode_tags), vp->v_tag,
            ARRAY_PRINT(vp->v_type, vnode_types), vp->v_type,
            vp->v_mount, vp->v_mountedhere);
        (*pr)("%susecount %d writecount %d holdcount %d\n", prefix,
            vrefcnt(vp), vp->v_writecount, vp->v_holdcnt);
        (*pr)("%ssize %" PRIx64 " writesize %" PRIx64 " numoutput %d\n",
            prefix, vp->v_size, vp->v_writesize, vp->v_numoutput);
        (*pr)("%sdata %p lock %p\n", prefix, vp->v_data, &vip->vi_lock);

        (*pr)("%sstate %s key(%p %zd)", prefix, vstate_name(vip->vi_state),
            vip->vi_key.vk_mount, vip->vi_key.vk_key_len);
        n = vip->vi_key.vk_key_len;
        cp = vip->vi_key.vk_key;
        while (n-- > 0)
                (*pr)(" %02x", *cp++);
        (*pr)("\n");
        (*pr)("%slrulisthd %p\n", prefix, vip->vi_lrulisthd);

#undef ARRAY_PRINT
#undef ARRAY_SIZE
}

/*
 * Print out a description of a vnode.
 */
void
vprint(const char *label, struct vnode *vp)
{

        if (label != NULL)
                printf("%s: ", label);
        vprint_common(vp, "\t", printf);
        if (vp->v_data != NULL) {
                printf("\t");
                VOP_PRINT(vp);
        }
}

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

        mutex_enter(&vfs_list_lock);
        LIST_FOREACH(v, &vfs_list, vfs_list) {
                if (strcmp(v->vfs_name, name) == 0)
                        break;
        }
        if (v != NULL)
                v->vfs_refcount++;
        mutex_exit(&vfs_list_lock);

        return v;
}

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

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

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

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

        (void)strlcpy(mp->mnt_stat.f_fstypename, vfsname,
            sizeof(mp->mnt_stat.f_fstypename));

        if (onp) {
                struct cwdinfo *cwdi = l->l_proc->p_cwdi;
                fun = (ukon == UIO_SYSSPACE) ? copystr : copyinstr;
                if (cwdi->cwdi_rdir != NULL) {
                        size_t len;
                        char *bp;
                        char *path = PNBUF_GET();

                        bp = path + MAXPATHLEN;
                        *--bp = '\0';
                        rw_enter(&cwdi->cwdi_lock, RW_READER);
                        error = getcwd_common(cwdi->cwdi_rdir, rootvnode, &bp,
                            path, MAXPATHLEN / 2, 0, l);
                        rw_exit(&cwdi->cwdi_lock);
                        if (error) {
                                PNBUF_PUT(path);
                                return error;
                        }

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

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

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

/*
 * Knob to control the precision of file timestamps:
 *
 *   0 = seconds only; nanoseconds zeroed.
 *   1 = seconds and nanoseconds, accurate within 1/HZ.
 *   2 = seconds and nanoseconds, truncated to microseconds.
 * >=3 = seconds and nanoseconds, maximum precision.
 */
enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };

int vfs_timestamp_precision __read_mostly = TSP_NSEC;

void
vfs_timestamp(struct timespec *tsp)
{
        struct timeval tv;

        switch (vfs_timestamp_precision) {
        case TSP_SEC:
                tsp->tv_sec = time_second;
                tsp->tv_nsec = 0;
                break;
        case TSP_HZ:
                getnanotime(tsp);
                break;
        case TSP_USEC:
                microtime(&tv);
                TIMEVAL_TO_TIMESPEC(&tv, tsp);
                break;
        case TSP_NSEC:
        default:
                nanotime(tsp);
                break;
        }
}

/*
 * The purpose of this routine is to remove granularity from accmode_t,
 * reducing it into standard unix access bits - VEXEC, VREAD, VWRITE,
 * VADMIN and VAPPEND.
 *
 * If it returns 0, the caller is supposed to continue with the usual
 * access checks using 'accmode' as modified by this routine.  If it
 * returns nonzero value, the caller is supposed to return that value
 * as errno.
 *
 * Note that after this routine runs, accmode may be zero.
 */
int
vfs_unixify_accmode(accmode_t *accmode)
{

        /*
         * There is no way to specify explicit "deny" rule using
         * file mode or POSIX.1e ACLs.
         */
        if (*accmode & VEXPLICIT_DENY) {
                *accmode = 0;
                return 0;
        }

        /*
         * None of these can be translated into usual access bits.
         * Also, the common case for NFSv4 ACLs is to not contain
         * either of these bits. Caller should check for VWRITE
         * on the containing directory instead.
         */
        if (*accmode & (VDELETE_CHILD | VDELETE))
                return SET_ERROR(EPERM);

        if (*accmode & VADMIN_PERMS) {
                *accmode &= ~VADMIN_PERMS;
                *accmode |= VADMIN;
        }

        /*
         * There is no way to deny VREAD_ATTRIBUTES, VREAD_ACL
         * or VSYNCHRONIZE using file mode or POSIX.1e ACL.
         */
        *accmode &= ~(VSTAT_PERMS | VSYNCHRONIZE);

        return 0;
}

time_t  rootfstime;                     /* recorded root fs time, if known */
void
setrootfstime(time_t t)
{

        rootfstime = t;
}

static const uint8_t vttodt_tab[] = {
        [VNON]  =       DT_UNKNOWN,
        [VREG]  =       DT_REG,
        [VDIR]  =       DT_DIR,
        [VBLK]  =       DT_BLK,
        [VCHR]  =       DT_CHR,
        [VLNK]  =       DT_LNK,
        [VSOCK] =       DT_SOCK,
        [VFIFO] =       DT_FIFO,
        [VBAD]  =       DT_UNKNOWN
};

uint8_t
vtype2dt(enum vtype vt)
{

        CTASSERT(VBAD == __arraycount(vttodt_tab) - 1);
        return vttodt_tab[vt];
}

int
VFS_MOUNT(struct mount *mp, const char *a, void *b, size_t *c)
{
        int mpsafe = mp->mnt_iflag & IMNT_MPSAFE;
        int error;

        /*
         * Note: The first time through, the vfs_mount function may set
         * IMNT_MPSAFE, so we have to cache it on entry in order to
         * avoid leaking a kernel lock.
         *
         * XXX Maybe the MPSAFE bit should be set in struct vfsops and
         * not in struct mount.
         */
        if (!mpsafe) {
                KERNEL_LOCK(1, NULL);
        }
        error = (*(mp->mnt_op->vfs_mount))(mp, a, b, c);
        if (!mpsafe) {
                KERNEL_UNLOCK_ONE(NULL);
        }

        return error;
}

int
VFS_START(struct mount *mp, int a)
{
        int error;

        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_LOCK(1, NULL);
        }
        error = (*(mp->mnt_op->vfs_start))(mp, a);
        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_UNLOCK_ONE(NULL);
        }

        return error;
}

int
VFS_UNMOUNT(struct mount *mp, int a)
{
        int error;

        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_LOCK(1, NULL);
        }
        error = (*(mp->mnt_op->vfs_unmount))(mp, a);
        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_UNLOCK_ONE(NULL);
        }

        return error;
}

int
VFS_ROOT(struct mount *mp, int lktype, struct vnode **a)
{
        int error;

        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_LOCK(1, NULL);
        }
        error = (*(mp->mnt_op->vfs_root))(mp, lktype, a);
        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_UNLOCK_ONE(NULL);
        }

        return error;
}

int
VFS_QUOTACTL(struct mount *mp, struct quotactl_args *args)
{
        int error;

        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_LOCK(1, NULL);
        }
        error = (*(mp->mnt_op->vfs_quotactl))(mp, args);
        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_UNLOCK_ONE(NULL);
        }

        return error;
}

int
VFS_STATVFS(struct mount *mp, struct statvfs *a)
{
        int error;

        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_LOCK(1, NULL);
        }
        error = (*(mp->mnt_op->vfs_statvfs))(mp, a);
        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_UNLOCK_ONE(NULL);
        }

        return error;
}

int
VFS_SYNC(struct mount *mp, int a, struct kauth_cred *b)
{
        int error;

        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_LOCK(1, NULL);
        }
        error = (*(mp->mnt_op->vfs_sync))(mp, a, b);
        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_UNLOCK_ONE(NULL);
        }

        return error;
}

int
VFS_FHTOVP(struct mount *mp, struct fid *a, int b, struct vnode **c)
{
        int error;

        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_LOCK(1, NULL);
        }
        error = (*(mp->mnt_op->vfs_fhtovp))(mp, a, b, c);
        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_UNLOCK_ONE(NULL);
        }

        return error;
}

int
VFS_VPTOFH(struct vnode *vp, struct fid *a, size_t *b)
{
        int error;

        if ((vp->v_vflag & VV_MPSAFE) == 0) {
                KERNEL_LOCK(1, NULL);
        }
        error = (*(vp->v_mount->mnt_op->vfs_vptofh))(vp, a, b);
        if ((vp->v_vflag & VV_MPSAFE) == 0) {
                KERNEL_UNLOCK_ONE(NULL);
        }

        return error;
}

int
VFS_SNAPSHOT(struct mount *mp, struct vnode *a, struct timespec *b)
{
        int error;

        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_LOCK(1, NULL);
        }
        error = (*(mp->mnt_op->vfs_snapshot))(mp, a, b);
        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_UNLOCK_ONE(NULL);
        }

        return error;
}

int
VFS_EXTATTRCTL(struct mount *mp, int a, struct vnode *b, int c, const char *d)
{
        int error;

        KERNEL_LOCK(1, NULL);           /* XXXSMP check ffs */
        error = (*(mp->mnt_op->vfs_extattrctl))(mp, a, b, c, d);
        KERNEL_UNLOCK_ONE(NULL);        /* XXX */

        return error;
}

int
VFS_SUSPENDCTL(struct mount *mp, int a)
{
        int error;

        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_LOCK(1, NULL);
        }
        error = (*(mp->mnt_op->vfs_suspendctl))(mp, a);
        if ((mp->mnt_iflag & IMNT_MPSAFE) == 0) {
                KERNEL_UNLOCK_ONE(NULL);
        }

        return error;
}

#if defined(DDB) || defined(DEBUGPRINT)
static const char buf_flagbits[] = BUF_FLAGBITS;

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

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

        snprintb(bf, sizeof(bf),
            buf_flagbits, bp->b_flags | bp->b_oflags | bp->b_cflags);
        (*pr)("  error %d flags %s\n", bp->b_error, bf);

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

void
vfs_vnode_print(struct vnode *vp, int full, void (*pr)(const char *, ...))
{

        uvm_object_printit(&vp->v_uobj, full, pr);
        (*pr)("\n");
        vprint_common(vp, "", pr);
        if (full) {
                struct buf *bp;

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

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

void
vfs_vnode_lock_print(void *vlock, int full, void (*pr)(const char *, ...))
{
        struct mount *mp;
        vnode_impl_t *vip;

        for (mp = _mountlist_next(NULL); mp; mp = _mountlist_next(mp)) {
                TAILQ_FOREACH(vip, &mp->mnt_vnodelist, vi_mntvnodes) {
                        if (&vip->vi_lock == vlock ||
                            VIMPL_TO_VNODE(vip)->v_interlock == vlock)
                                vfs_vnode_print(VIMPL_TO_VNODE(vip), full, pr);
                }
        }
}

void
vfs_mount_print_all(int full, void (*pr)(const char *, ...))
{
        struct mount *mp;
        for (mp = _mountlist_next(NULL); mp; mp = _mountlist_next(mp))
                vfs_mount_print(mp, full, pr);
}

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

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

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

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

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

        (*pr)("refcnt = %d updating @ %p\n", mp->mnt_refcnt, mp->mnt_updating);

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

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

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

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

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

        snprintb(sbuf, sizeof(sbuf), __MNT_FLAG_BITS, mp->mnt_stat.f_flag);

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

        {
                int cnt = 0;
                vnode_t *vp;
                vnode_impl_t *vip;
                (*pr)("locked vnodes =");
                TAILQ_FOREACH(vip, &mp->mnt_vnodelist, vi_mntvnodes) {
                        vp = VIMPL_TO_VNODE(vip);
                        if (VOP_ISLOCKED(vp)) {
                                if ((++cnt % 6) == 0) {
                                        (*pr)(" %p,\n\t", vp);
                                } else {
                                        (*pr)(" %p,", vp);
                                }
                        }
                }
                (*pr)("\n");
        }

        if (full) {
                int cnt = 0;
                vnode_t *vp;
                vnode_impl_t *vip;

                (*pr)("all vnodes =");
                TAILQ_FOREACH(vip, &mp->mnt_vnodelist, vi_mntvnodes) {
                        vp = VIMPL_TO_VNODE(vip);
                        if (!TAILQ_NEXT(vip, vi_mntvnodes)) {
                                (*pr)(" %p", vp);
                        } else if ((++cnt % 6) == 0) {
                                (*pr)(" %p,\n\t", vp);
                        } else {
                                (*pr)(" %p,", vp);
                        }
                }
                (*pr)("\n");
        }
}

/*
 * List all of the locked vnodes in the system.
 */
void printlockedvnodes(void);

void
printlockedvnodes(void)
{
        struct mount *mp;
        vnode_t *vp;
        vnode_impl_t *vip;

        printf("Locked vnodes\n");
        for (mp = _mountlist_next(NULL); mp; mp = _mountlist_next(mp)) {
                TAILQ_FOREACH(vip, &mp->mnt_vnodelist, vi_mntvnodes) {
                        vp = VIMPL_TO_VNODE(vip);
                        if (VOP_ISLOCKED(vp))
                                vprint(NULL, vp);
                }
        }
}

#endif /* DDB || DEBUGPRINT */