FreeBSD: Fix a pair of bugs in zfs_fhtovp()

[zfs.git] / module / os / freebsd / zfs / zfs_vfsops.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or https://opensource.org/licenses/CDDL-1.0.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2011 Pawel Jakub Dawidek <pawel@dawidek.net>.
 * All rights reserved.
 * Copyright (c) 2012, 2015 by Delphix. All rights reserved.
 * Copyright (c) 2014 Integros [integros.com]
 * Copyright 2016 Nexenta Systems, Inc. All rights reserved.
 */

/* Portions Copyright 2010 Robert Milkowski */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/sysmacros.h>
#include <sys/kmem.h>
#include <sys/acl.h>
#include <sys/vnode.h>
#include <sys/vfs.h>
#include <sys/mntent.h>
#include <sys/mount.h>
#include <sys/cmn_err.h>
#include <sys/zfs_znode.h>
#include <sys/zfs_vnops.h>
#include <sys/zfs_dir.h>
#include <sys/zil.h>
#include <sys/fs/zfs.h>
#include <sys/dmu.h>
#include <sys/dsl_prop.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_deleg.h>
#include <sys/spa.h>
#include <sys/zap.h>
#include <sys/sa.h>
#include <sys/sa_impl.h>
#include <sys/policy.h>
#include <sys/atomic.h>
#include <sys/zfs_ioctl.h>
#include <sys/zfs_ctldir.h>
#include <sys/zfs_fuid.h>
#include <sys/sunddi.h>
#include <sys/dmu_objset.h>
#include <sys/dsl_dir.h>
#include <sys/jail.h>
#include <ufs/ufs/quota.h>
#include <sys/zfs_quota.h>

#include "zfs_comutil.h"

#ifndef MNTK_VMSETSIZE_BUG
#define MNTK_VMSETSIZE_BUG      0
#endif
#ifndef MNTK_NOMSYNC
#define MNTK_NOMSYNC    8
#endif

struct mtx zfs_debug_mtx;
MTX_SYSINIT(zfs_debug_mtx, &zfs_debug_mtx, "zfs_debug", MTX_DEF);

SYSCTL_NODE(_vfs, OID_AUTO, zfs, CTLFLAG_RW, 0, "ZFS file system");

int zfs_super_owner;
SYSCTL_INT(_vfs_zfs, OID_AUTO, super_owner, CTLFLAG_RW, &zfs_super_owner, 0,
        "File system owners can perform privileged operation on file systems");

int zfs_debug_level;
SYSCTL_INT(_vfs_zfs, OID_AUTO, debug, CTLFLAG_RWTUN, &zfs_debug_level, 0,
        "Debug level");

SYSCTL_NODE(_vfs_zfs, OID_AUTO, version, CTLFLAG_RD, 0, "ZFS versions");
static int zfs_version_acl = ZFS_ACL_VERSION;
SYSCTL_INT(_vfs_zfs_version, OID_AUTO, acl, CTLFLAG_RD, &zfs_version_acl, 0,
        "ZFS_ACL_VERSION");
static int zfs_version_spa = SPA_VERSION;
SYSCTL_INT(_vfs_zfs_version, OID_AUTO, spa, CTLFLAG_RD, &zfs_version_spa, 0,
        "SPA_VERSION");
static int zfs_version_zpl = ZPL_VERSION;
SYSCTL_INT(_vfs_zfs_version, OID_AUTO, zpl, CTLFLAG_RD, &zfs_version_zpl, 0,
        "ZPL_VERSION");

#if __FreeBSD_version >= 1400018
static int zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg,
    bool *mp_busy);
#else
static int zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg);
#endif
static int zfs_mount(vfs_t *vfsp);
static int zfs_umount(vfs_t *vfsp, int fflag);
static int zfs_root(vfs_t *vfsp, int flags, vnode_t **vpp);
static int zfs_statfs(vfs_t *vfsp, struct statfs *statp);
static int zfs_vget(vfs_t *vfsp, ino_t ino, int flags, vnode_t **vpp);
static int zfs_sync(vfs_t *vfsp, int waitfor);
#if __FreeBSD_version >= 1300098
static int zfs_checkexp(vfs_t *vfsp, struct sockaddr *nam, uint64_t *extflagsp,
    struct ucred **credanonp, int *numsecflavors, int *secflavors);
#else
static int zfs_checkexp(vfs_t *vfsp, struct sockaddr *nam, int *extflagsp,
    struct ucred **credanonp, int *numsecflavors, int **secflavors);
#endif
static int zfs_fhtovp(vfs_t *vfsp, fid_t *fidp, int flags, vnode_t **vpp);
static void zfs_freevfs(vfs_t *vfsp);

struct vfsops zfs_vfsops = {
        .vfs_mount =            zfs_mount,
        .vfs_unmount =          zfs_umount,
#if __FreeBSD_version >= 1300049
        .vfs_root =             vfs_cache_root,
        .vfs_cachedroot = zfs_root,
#else
        .vfs_root =             zfs_root,
#endif
        .vfs_statfs =           zfs_statfs,
        .vfs_vget =             zfs_vget,
        .vfs_sync =             zfs_sync,
        .vfs_checkexp =         zfs_checkexp,
        .vfs_fhtovp =           zfs_fhtovp,
        .vfs_quotactl =         zfs_quotactl,
};

VFS_SET(zfs_vfsops, zfs, VFCF_JAIL | VFCF_DELEGADMIN);

/*
 * We need to keep a count of active fs's.
 * This is necessary to prevent our module
 * from being unloaded after a umount -f
 */
static uint32_t zfs_active_fs_count = 0;

int
zfs_get_temporary_prop(dsl_dataset_t *ds, zfs_prop_t zfs_prop, uint64_t *val,
    char *setpoint)
{
        int error;
        zfsvfs_t *zfvp;
        vfs_t *vfsp;
        objset_t *os;
        uint64_t tmp = *val;

        error = dmu_objset_from_ds(ds, &os);
        if (error != 0)
                return (error);

        error = getzfsvfs_impl(os, &zfvp);
        if (error != 0)
                return (error);
        if (zfvp == NULL)
                return (ENOENT);
        vfsp = zfvp->z_vfs;
        switch (zfs_prop) {
        case ZFS_PROP_ATIME:
                if (vfs_optionisset(vfsp, MNTOPT_NOATIME, NULL))
                        tmp = 0;
                if (vfs_optionisset(vfsp, MNTOPT_ATIME, NULL))
                        tmp = 1;
                break;
        case ZFS_PROP_DEVICES:
                if (vfs_optionisset(vfsp, MNTOPT_NODEVICES, NULL))
                        tmp = 0;
                if (vfs_optionisset(vfsp, MNTOPT_DEVICES, NULL))
                        tmp = 1;
                break;
        case ZFS_PROP_EXEC:
                if (vfs_optionisset(vfsp, MNTOPT_NOEXEC, NULL))
                        tmp = 0;
                if (vfs_optionisset(vfsp, MNTOPT_EXEC, NULL))
                        tmp = 1;
                break;
        case ZFS_PROP_SETUID:
                if (vfs_optionisset(vfsp, MNTOPT_NOSETUID, NULL))
                        tmp = 0;
                if (vfs_optionisset(vfsp, MNTOPT_SETUID, NULL))
                        tmp = 1;
                break;
        case ZFS_PROP_READONLY:
                if (vfs_optionisset(vfsp, MNTOPT_RW, NULL))
                        tmp = 0;
                if (vfs_optionisset(vfsp, MNTOPT_RO, NULL))
                        tmp = 1;
                break;
        case ZFS_PROP_XATTR:
                if (zfvp->z_flags & ZSB_XATTR)
                        tmp = zfvp->z_xattr;
                break;
        case ZFS_PROP_NBMAND:
                if (vfs_optionisset(vfsp, MNTOPT_NONBMAND, NULL))
                        tmp = 0;
                if (vfs_optionisset(vfsp, MNTOPT_NBMAND, NULL))
                        tmp = 1;
                break;
        default:
                vfs_unbusy(vfsp);
                return (ENOENT);
        }

        vfs_unbusy(vfsp);
        if (tmp != *val) {
                (void) strcpy(setpoint, "temporary");
                *val = tmp;
        }
        return (0);
}

static int
zfs_getquota(zfsvfs_t *zfsvfs, uid_t id, int isgroup, struct dqblk64 *dqp)
{
        int error = 0;
        char buf[32];
        uint64_t usedobj, quotaobj;
        uint64_t quota, used = 0;
        timespec_t now;

        usedobj = isgroup ? DMU_GROUPUSED_OBJECT : DMU_USERUSED_OBJECT;
        quotaobj = isgroup ? zfsvfs->z_groupquota_obj : zfsvfs->z_userquota_obj;

        if (quotaobj == 0 || zfsvfs->z_replay) {
                error = ENOENT;
                goto done;
        }
        (void) sprintf(buf, "%llx", (longlong_t)id);
        if ((error = zap_lookup(zfsvfs->z_os, quotaobj,
            buf, sizeof (quota), 1, &quota)) != 0) {
                dprintf("%s(%d): quotaobj lookup failed\n",
                    __FUNCTION__, __LINE__);
                goto done;
        }
        /*
         * quota(8) uses bsoftlimit as "quoota", and hardlimit as "limit".
         * So we set them to be the same.
         */
        dqp->dqb_bsoftlimit = dqp->dqb_bhardlimit = btodb(quota);
        error = zap_lookup(zfsvfs->z_os, usedobj, buf, sizeof (used), 1, &used);
        if (error && error != ENOENT) {
                dprintf("%s(%d):  usedobj failed; %d\n",
                    __FUNCTION__, __LINE__, error);
                goto done;
        }
        dqp->dqb_curblocks = btodb(used);
        dqp->dqb_ihardlimit = dqp->dqb_isoftlimit = 0;
        vfs_timestamp(&now);
        /*
         * Setting this to 0 causes FreeBSD quota(8) to print
         * the number of days since the epoch, which isn't
         * particularly useful.
         */
        dqp->dqb_btime = dqp->dqb_itime = now.tv_sec;
done:
        return (error);
}

static int
#if __FreeBSD_version >= 1400018
zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg, bool *mp_busy)
#else
zfs_quotactl(vfs_t *vfsp, int cmds, uid_t id, void *arg)
#endif
{
        zfsvfs_t *zfsvfs = vfsp->vfs_data;
        struct thread *td;
        int cmd, type, error = 0;
        int bitsize;
        zfs_userquota_prop_t quota_type;
        struct dqblk64 dqblk = { 0 };

        td = curthread;
        cmd = cmds >> SUBCMDSHIFT;
        type = cmds & SUBCMDMASK;

        if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
                return (error);
        if (id == -1) {
                switch (type) {
                case USRQUOTA:
                        id = td->td_ucred->cr_ruid;
                        break;
                case GRPQUOTA:
                        id = td->td_ucred->cr_rgid;
                        break;
                default:
                        error = EINVAL;
#if __FreeBSD_version < 1400018
                        if (cmd == Q_QUOTAON || cmd == Q_QUOTAOFF)
                                vfs_unbusy(vfsp);
#endif
                        goto done;
                }
        }
        /*
         * Map BSD type to:
         * ZFS_PROP_USERUSED,
         * ZFS_PROP_USERQUOTA,
         * ZFS_PROP_GROUPUSED,
         * ZFS_PROP_GROUPQUOTA
         */
        switch (cmd) {
        case Q_SETQUOTA:
        case Q_SETQUOTA32:
                if (type == USRQUOTA)
                        quota_type = ZFS_PROP_USERQUOTA;
                else if (type == GRPQUOTA)
                        quota_type = ZFS_PROP_GROUPQUOTA;
                else
                        error = EINVAL;
                break;
        case Q_GETQUOTA:
        case Q_GETQUOTA32:
                if (type == USRQUOTA)
                        quota_type = ZFS_PROP_USERUSED;
                else if (type == GRPQUOTA)
                        quota_type = ZFS_PROP_GROUPUSED;
                else
                        error = EINVAL;
                break;
        }

        /*
         * Depending on the cmd, we may need to get
         * the ruid and domain (see fuidstr_to_sid?),
         * the fuid (how?), or other information.
         * Create fuid using zfs_fuid_create(zfsvfs, id,
         * ZFS_OWNER or ZFS_GROUP, cr, &fuidp)?
         * I think I can use just the id?
         *
         * Look at zfs_id_overquota() to look up a quota.
         * zap_lookup(something, quotaobj, fuidstring,
         *     sizeof (long long), 1, &quota)
         *
         * See zfs_set_userquota() to set a quota.
         */
        if ((uint32_t)type >= MAXQUOTAS) {
                error = EINVAL;
                goto done;
        }

        switch (cmd) {
        case Q_GETQUOTASIZE:
                bitsize = 64;
                error = copyout(&bitsize, arg, sizeof (int));
                break;
        case Q_QUOTAON:
                // As far as I can tell, you can't turn quotas on or off on zfs
                error = 0;
#if __FreeBSD_version < 1400018
                vfs_unbusy(vfsp);
#endif
                break;
        case Q_QUOTAOFF:
                error = ENOTSUP;
#if __FreeBSD_version < 1400018
                vfs_unbusy(vfsp);
#endif
                break;
        case Q_SETQUOTA:
                error = copyin(arg, &dqblk, sizeof (dqblk));
                if (error == 0)
                        error = zfs_set_userquota(zfsvfs, quota_type,
                            "", id, dbtob(dqblk.dqb_bhardlimit));
                break;
        case Q_GETQUOTA:
                error = zfs_getquota(zfsvfs, id, type == GRPQUOTA, &dqblk);
                if (error == 0)
                        error = copyout(&dqblk, arg, sizeof (dqblk));
                break;
        default:
                error = EINVAL;
                break;
        }
done:
        zfs_exit(zfsvfs, FTAG);
        return (error);
}


boolean_t
zfs_is_readonly(zfsvfs_t *zfsvfs)
{
        return (!!(zfsvfs->z_vfs->vfs_flag & VFS_RDONLY));
}

static int
zfs_sync(vfs_t *vfsp, int waitfor)
{

        /*
         * Data integrity is job one.  We don't want a compromised kernel
         * writing to the storage pool, so we never sync during panic.
         */
        if (panicstr)
                return (0);

        /*
         * Ignore the system syncher.  ZFS already commits async data
         * at zfs_txg_timeout intervals.
         */
        if (waitfor == MNT_LAZY)
                return (0);

        if (vfsp != NULL) {
                /*
                 * Sync a specific filesystem.
                 */
                zfsvfs_t *zfsvfs = vfsp->vfs_data;
                dsl_pool_t *dp;
                int error;

                error = vfs_stdsync(vfsp, waitfor);
                if (error != 0)
                        return (error);

                if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
                        return (error);
                dp = dmu_objset_pool(zfsvfs->z_os);

                /*
                 * If the system is shutting down, then skip any
                 * filesystems which may exist on a suspended pool.
                 */
                if (rebooting && spa_suspended(dp->dp_spa)) {
                        zfs_exit(zfsvfs, FTAG);
                        return (0);
                }

                if (zfsvfs->z_log != NULL)
                        zil_commit(zfsvfs->z_log, 0);

                zfs_exit(zfsvfs, FTAG);
        } else {
                /*
                 * Sync all ZFS filesystems.  This is what happens when you
                 * run sync(8).  Unlike other filesystems, ZFS honors the
                 * request by waiting for all pools to commit all dirty data.
                 */
                spa_sync_allpools();
        }

        return (0);
}

static void
atime_changed_cb(void *arg, uint64_t newval)
{
        zfsvfs_t *zfsvfs = arg;

        if (newval == TRUE) {
                zfsvfs->z_atime = TRUE;
                zfsvfs->z_vfs->vfs_flag &= ~MNT_NOATIME;
                vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_NOATIME);
                vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_ATIME, NULL, 0);
        } else {
                zfsvfs->z_atime = FALSE;
                zfsvfs->z_vfs->vfs_flag |= MNT_NOATIME;
                vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_ATIME);
                vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_NOATIME, NULL, 0);
        }
}

static void
xattr_changed_cb(void *arg, uint64_t newval)
{
        zfsvfs_t *zfsvfs = arg;

        if (newval == ZFS_XATTR_OFF) {
                zfsvfs->z_flags &= ~ZSB_XATTR;
        } else {
                zfsvfs->z_flags |= ZSB_XATTR;

                if (newval == ZFS_XATTR_SA)
                        zfsvfs->z_xattr_sa = B_TRUE;
                else
                        zfsvfs->z_xattr_sa = B_FALSE;
        }
}

static void
blksz_changed_cb(void *arg, uint64_t newval)
{
        zfsvfs_t *zfsvfs = arg;
        ASSERT3U(newval, <=, spa_maxblocksize(dmu_objset_spa(zfsvfs->z_os)));
        ASSERT3U(newval, >=, SPA_MINBLOCKSIZE);
        ASSERT(ISP2(newval));

        zfsvfs->z_max_blksz = newval;
        zfsvfs->z_vfs->mnt_stat.f_iosize = newval;
}

static void
readonly_changed_cb(void *arg, uint64_t newval)
{
        zfsvfs_t *zfsvfs = arg;

        if (newval) {
                /* XXX locking on vfs_flag? */
                zfsvfs->z_vfs->vfs_flag |= VFS_RDONLY;
                vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_RW);
                vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_RO, NULL, 0);
        } else {
                /* XXX locking on vfs_flag? */
                zfsvfs->z_vfs->vfs_flag &= ~VFS_RDONLY;
                vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_RO);
                vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_RW, NULL, 0);
        }
}

static void
setuid_changed_cb(void *arg, uint64_t newval)
{
        zfsvfs_t *zfsvfs = arg;

        if (newval == FALSE) {
                zfsvfs->z_vfs->vfs_flag |= VFS_NOSETUID;
                vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_SETUID);
                vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_NOSETUID, NULL, 0);
        } else {
                zfsvfs->z_vfs->vfs_flag &= ~VFS_NOSETUID;
                vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_NOSETUID);
                vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_SETUID, NULL, 0);
        }
}

static void
exec_changed_cb(void *arg, uint64_t newval)
{
        zfsvfs_t *zfsvfs = arg;

        if (newval == FALSE) {
                zfsvfs->z_vfs->vfs_flag |= VFS_NOEXEC;
                vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_EXEC);
                vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_NOEXEC, NULL, 0);
        } else {
                zfsvfs->z_vfs->vfs_flag &= ~VFS_NOEXEC;
                vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_NOEXEC);
                vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_EXEC, NULL, 0);
        }
}

/*
 * The nbmand mount option can be changed at mount time.
 * We can't allow it to be toggled on live file systems or incorrect
 * behavior may be seen from cifs clients
 *
 * This property isn't registered via dsl_prop_register(), but this callback
 * will be called when a file system is first mounted
 */
static void
nbmand_changed_cb(void *arg, uint64_t newval)
{
        zfsvfs_t *zfsvfs = arg;
        if (newval == FALSE) {
                vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_NBMAND);
                vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_NONBMAND, NULL, 0);
        } else {
                vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_NONBMAND);
                vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_NBMAND, NULL, 0);
        }
}

static void
snapdir_changed_cb(void *arg, uint64_t newval)
{
        zfsvfs_t *zfsvfs = arg;

        zfsvfs->z_show_ctldir = newval;
}

static void
acl_mode_changed_cb(void *arg, uint64_t newval)
{
        zfsvfs_t *zfsvfs = arg;

        zfsvfs->z_acl_mode = newval;
}

static void
acl_inherit_changed_cb(void *arg, uint64_t newval)
{
        zfsvfs_t *zfsvfs = arg;

        zfsvfs->z_acl_inherit = newval;
}

static void
acl_type_changed_cb(void *arg, uint64_t newval)
{
        zfsvfs_t *zfsvfs = arg;

        zfsvfs->z_acl_type = newval;
}

static int
zfs_register_callbacks(vfs_t *vfsp)
{
        struct dsl_dataset *ds = NULL;
        objset_t *os = NULL;
        zfsvfs_t *zfsvfs = NULL;
        uint64_t nbmand;
        boolean_t readonly = B_FALSE;
        boolean_t do_readonly = B_FALSE;
        boolean_t setuid = B_FALSE;
        boolean_t do_setuid = B_FALSE;
        boolean_t exec = B_FALSE;
        boolean_t do_exec = B_FALSE;
        boolean_t xattr = B_FALSE;
        boolean_t atime = B_FALSE;
        boolean_t do_atime = B_FALSE;
        boolean_t do_xattr = B_FALSE;
        int error = 0;

        ASSERT3P(vfsp, !=, NULL);
        zfsvfs = vfsp->vfs_data;
        ASSERT3P(zfsvfs, !=, NULL);
        os = zfsvfs->z_os;

        /*
         * This function can be called for a snapshot when we update snapshot's
         * mount point, which isn't really supported.
         */
        if (dmu_objset_is_snapshot(os))
                return (EOPNOTSUPP);

        /*
         * The act of registering our callbacks will destroy any mount
         * options we may have.  In order to enable temporary overrides
         * of mount options, we stash away the current values and
         * restore them after we register the callbacks.
         */
        if (vfs_optionisset(vfsp, MNTOPT_RO, NULL) ||
            !spa_writeable(dmu_objset_spa(os))) {
                readonly = B_TRUE;
                do_readonly = B_TRUE;
        } else if (vfs_optionisset(vfsp, MNTOPT_RW, NULL)) {
                readonly = B_FALSE;
                do_readonly = B_TRUE;
        }
        if (vfs_optionisset(vfsp, MNTOPT_NOSETUID, NULL)) {
                setuid = B_FALSE;
                do_setuid = B_TRUE;
        } else if (vfs_optionisset(vfsp, MNTOPT_SETUID, NULL)) {
                setuid = B_TRUE;
                do_setuid = B_TRUE;
        }
        if (vfs_optionisset(vfsp, MNTOPT_NOEXEC, NULL)) {
                exec = B_FALSE;
                do_exec = B_TRUE;
        } else if (vfs_optionisset(vfsp, MNTOPT_EXEC, NULL)) {
                exec = B_TRUE;
                do_exec = B_TRUE;
        }
        if (vfs_optionisset(vfsp, MNTOPT_NOXATTR, NULL)) {
                zfsvfs->z_xattr = xattr = ZFS_XATTR_OFF;
                do_xattr = B_TRUE;
        } else if (vfs_optionisset(vfsp, MNTOPT_XATTR, NULL)) {
                zfsvfs->z_xattr = xattr = ZFS_XATTR_DIR;
                do_xattr = B_TRUE;
        } else if (vfs_optionisset(vfsp, MNTOPT_DIRXATTR, NULL)) {
                zfsvfs->z_xattr = xattr = ZFS_XATTR_DIR;
                do_xattr = B_TRUE;
        } else if (vfs_optionisset(vfsp, MNTOPT_SAXATTR, NULL)) {
                zfsvfs->z_xattr = xattr = ZFS_XATTR_SA;
                do_xattr = B_TRUE;
        }
        if (vfs_optionisset(vfsp, MNTOPT_NOATIME, NULL)) {
                atime = B_FALSE;
                do_atime = B_TRUE;
        } else if (vfs_optionisset(vfsp, MNTOPT_ATIME, NULL)) {
                atime = B_TRUE;
                do_atime = B_TRUE;
        }

        /*
         * We need to enter pool configuration here, so that we can use
         * dsl_prop_get_int_ds() to handle the special nbmand property below.
         * dsl_prop_get_integer() can not be used, because it has to acquire
         * spa_namespace_lock and we can not do that because we already hold
         * z_teardown_lock.  The problem is that spa_write_cachefile() is called
         * with spa_namespace_lock held and the function calls ZFS vnode
         * operations to write the cache file and thus z_teardown_lock is
         * acquired after spa_namespace_lock.
         */
        ds = dmu_objset_ds(os);
        dsl_pool_config_enter(dmu_objset_pool(os), FTAG);

        /*
         * nbmand is a special property.  It can only be changed at
         * mount time.
         *
         * This is weird, but it is documented to only be changeable
         * at mount time.
         */
        if (vfs_optionisset(vfsp, MNTOPT_NONBMAND, NULL)) {
                nbmand = B_FALSE;
        } else if (vfs_optionisset(vfsp, MNTOPT_NBMAND, NULL)) {
                nbmand = B_TRUE;
        } else if ((error = dsl_prop_get_int_ds(ds, "nbmand", &nbmand) != 0)) {
                dsl_pool_config_exit(dmu_objset_pool(os), FTAG);
                return (error);
        }

        /*
         * Register property callbacks.
         *
         * It would probably be fine to just check for i/o error from
         * the first prop_register(), but I guess I like to go
         * overboard...
         */
        error = dsl_prop_register(ds,
            zfs_prop_to_name(ZFS_PROP_ATIME), atime_changed_cb, zfsvfs);
        error = error ? error : dsl_prop_register(ds,
            zfs_prop_to_name(ZFS_PROP_XATTR), xattr_changed_cb, zfsvfs);
        error = error ? error : dsl_prop_register(ds,
            zfs_prop_to_name(ZFS_PROP_RECORDSIZE), blksz_changed_cb, zfsvfs);
        error = error ? error : dsl_prop_register(ds,
            zfs_prop_to_name(ZFS_PROP_READONLY), readonly_changed_cb, zfsvfs);
        error = error ? error : dsl_prop_register(ds,
            zfs_prop_to_name(ZFS_PROP_SETUID), setuid_changed_cb, zfsvfs);
        error = error ? error : dsl_prop_register(ds,
            zfs_prop_to_name(ZFS_PROP_EXEC), exec_changed_cb, zfsvfs);
        error = error ? error : dsl_prop_register(ds,
            zfs_prop_to_name(ZFS_PROP_SNAPDIR), snapdir_changed_cb, zfsvfs);
        error = error ? error : dsl_prop_register(ds,
            zfs_prop_to_name(ZFS_PROP_ACLTYPE), acl_type_changed_cb, zfsvfs);
        error = error ? error : dsl_prop_register(ds,
            zfs_prop_to_name(ZFS_PROP_ACLMODE), acl_mode_changed_cb, zfsvfs);
        error = error ? error : dsl_prop_register(ds,
            zfs_prop_to_name(ZFS_PROP_ACLINHERIT), acl_inherit_changed_cb,
            zfsvfs);
        dsl_pool_config_exit(dmu_objset_pool(os), FTAG);
        if (error)
                goto unregister;

        /*
         * Invoke our callbacks to restore temporary mount options.
         */
        if (do_readonly)
                readonly_changed_cb(zfsvfs, readonly);
        if (do_setuid)
                setuid_changed_cb(zfsvfs, setuid);
        if (do_exec)
                exec_changed_cb(zfsvfs, exec);
        if (do_xattr)
                xattr_changed_cb(zfsvfs, xattr);
        if (do_atime)
                atime_changed_cb(zfsvfs, atime);

        nbmand_changed_cb(zfsvfs, nbmand);

        return (0);

unregister:
        dsl_prop_unregister_all(ds, zfsvfs);
        return (error);
}

/*
 * Associate this zfsvfs with the given objset, which must be owned.
 * This will cache a bunch of on-disk state from the objset in the
 * zfsvfs.
 */
static int
zfsvfs_init(zfsvfs_t *zfsvfs, objset_t *os)
{
        int error;
        uint64_t val;

        zfsvfs->z_max_blksz = SPA_OLD_MAXBLOCKSIZE;
        zfsvfs->z_show_ctldir = ZFS_SNAPDIR_VISIBLE;
        zfsvfs->z_os = os;

        error = zfs_get_zplprop(os, ZFS_PROP_VERSION, &zfsvfs->z_version);
        if (error != 0)
                return (error);
        if (zfsvfs->z_version >
            zfs_zpl_version_map(spa_version(dmu_objset_spa(os)))) {
                (void) printf("Can't mount a version %lld file system "
                    "on a version %lld pool\n. Pool must be upgraded to mount "
                    "this file system.", (u_longlong_t)zfsvfs->z_version,
                    (u_longlong_t)spa_version(dmu_objset_spa(os)));
                return (SET_ERROR(ENOTSUP));
        }
        error = zfs_get_zplprop(os, ZFS_PROP_NORMALIZE, &val);
        if (error != 0)
                return (error);
        zfsvfs->z_norm = (int)val;

        error = zfs_get_zplprop(os, ZFS_PROP_UTF8ONLY, &val);
        if (error != 0)
                return (error);
        zfsvfs->z_utf8 = (val != 0);

        error = zfs_get_zplprop(os, ZFS_PROP_CASE, &val);
        if (error != 0)
                return (error);
        zfsvfs->z_case = (uint_t)val;

        error = zfs_get_zplprop(os, ZFS_PROP_ACLTYPE, &val);
        if (error != 0)
                return (error);
        zfsvfs->z_acl_type = (uint_t)val;

        /*
         * Fold case on file systems that are always or sometimes case
         * insensitive.
         */
        if (zfsvfs->z_case == ZFS_CASE_INSENSITIVE ||
            zfsvfs->z_case == ZFS_CASE_MIXED)
                zfsvfs->z_norm |= U8_TEXTPREP_TOUPPER;

        zfsvfs->z_use_fuids = USE_FUIDS(zfsvfs->z_version, zfsvfs->z_os);
        zfsvfs->z_use_sa = USE_SA(zfsvfs->z_version, zfsvfs->z_os);

        uint64_t sa_obj = 0;
        if (zfsvfs->z_use_sa) {
                /* should either have both of these objects or none */
                error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_SA_ATTRS, 8, 1,
                    &sa_obj);
                if (error != 0)
                        return (error);

                error = zfs_get_zplprop(os, ZFS_PROP_XATTR, &val);
                if (error == 0 && val == ZFS_XATTR_SA)
                        zfsvfs->z_xattr_sa = B_TRUE;
        }

        error = sa_setup(os, sa_obj, zfs_attr_table, ZPL_END,
            &zfsvfs->z_attr_table);
        if (error != 0)
                return (error);

        if (zfsvfs->z_version >= ZPL_VERSION_SA)
                sa_register_update_callback(os, zfs_sa_upgrade);

        error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_ROOT_OBJ, 8, 1,
            &zfsvfs->z_root);
        if (error != 0)
                return (error);
        ASSERT3U(zfsvfs->z_root, !=, 0);

        error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_UNLINKED_SET, 8, 1,
            &zfsvfs->z_unlinkedobj);
        if (error != 0)
                return (error);

        error = zap_lookup(os, MASTER_NODE_OBJ,
            zfs_userquota_prop_prefixes[ZFS_PROP_USERQUOTA],
            8, 1, &zfsvfs->z_userquota_obj);
        if (error == ENOENT)
                zfsvfs->z_userquota_obj = 0;
        else if (error != 0)
                return (error);

        error = zap_lookup(os, MASTER_NODE_OBJ,
            zfs_userquota_prop_prefixes[ZFS_PROP_GROUPQUOTA],
            8, 1, &zfsvfs->z_groupquota_obj);
        if (error == ENOENT)
                zfsvfs->z_groupquota_obj = 0;
        else if (error != 0)
                return (error);

        error = zap_lookup(os, MASTER_NODE_OBJ,
            zfs_userquota_prop_prefixes[ZFS_PROP_PROJECTQUOTA],
            8, 1, &zfsvfs->z_projectquota_obj);
        if (error == ENOENT)
                zfsvfs->z_projectquota_obj = 0;
        else if (error != 0)
                return (error);

        error = zap_lookup(os, MASTER_NODE_OBJ,
            zfs_userquota_prop_prefixes[ZFS_PROP_USEROBJQUOTA],
            8, 1, &zfsvfs->z_userobjquota_obj);
        if (error == ENOENT)
                zfsvfs->z_userobjquota_obj = 0;
        else if (error != 0)
                return (error);

        error = zap_lookup(os, MASTER_NODE_OBJ,
            zfs_userquota_prop_prefixes[ZFS_PROP_GROUPOBJQUOTA],
            8, 1, &zfsvfs->z_groupobjquota_obj);
        if (error == ENOENT)
                zfsvfs->z_groupobjquota_obj = 0;
        else if (error != 0)
                return (error);

        error = zap_lookup(os, MASTER_NODE_OBJ,
            zfs_userquota_prop_prefixes[ZFS_PROP_PROJECTOBJQUOTA],
            8, 1, &zfsvfs->z_projectobjquota_obj);
        if (error == ENOENT)
                zfsvfs->z_projectobjquota_obj = 0;
        else if (error != 0)
                return (error);

        error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_FUID_TABLES, 8, 1,
            &zfsvfs->z_fuid_obj);
        if (error == ENOENT)
                zfsvfs->z_fuid_obj = 0;
        else if (error != 0)
                return (error);

        error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_SHARES_DIR, 8, 1,
            &zfsvfs->z_shares_dir);
        if (error == ENOENT)
                zfsvfs->z_shares_dir = 0;
        else if (error != 0)
                return (error);

        /*
         * Only use the name cache if we are looking for a
         * name on a file system that does not require normalization
         * or case folding.  We can also look there if we happen to be
         * on a non-normalizing, mixed sensitivity file system IF we
         * are looking for the exact name (which is always the case on
         * FreeBSD).
         */
        zfsvfs->z_use_namecache = !zfsvfs->z_norm ||
            ((zfsvfs->z_case == ZFS_CASE_MIXED) &&
            !(zfsvfs->z_norm & ~U8_TEXTPREP_TOUPPER));

        return (0);
}

taskq_t *zfsvfs_taskq;

static void
zfsvfs_task_unlinked_drain(void *context, int pending __unused)
{

        zfs_unlinked_drain((zfsvfs_t *)context);
}

int
zfsvfs_create(const char *osname, boolean_t readonly, zfsvfs_t **zfvp)
{
        objset_t *os;
        zfsvfs_t *zfsvfs;
        int error;
        boolean_t ro = (readonly || (strchr(osname, '@') != NULL));

        /*
         * XXX: Fix struct statfs so this isn't necessary!
         *
         * The 'osname' is used as the filesystem's special node, which means
         * it must fit in statfs.f_mntfromname, or else it can't be
         * enumerated, so libzfs_mnttab_find() returns NULL, which causes
         * 'zfs unmount' to think it's not mounted when it is.
         */
        if (strlen(osname) >= MNAMELEN)
                return (SET_ERROR(ENAMETOOLONG));

        zfsvfs = kmem_zalloc(sizeof (zfsvfs_t), KM_SLEEP);

        error = dmu_objset_own(osname, DMU_OST_ZFS, ro, B_TRUE, zfsvfs,
            &os);
        if (error != 0) {
                kmem_free(zfsvfs, sizeof (zfsvfs_t));
                return (error);
        }

        error = zfsvfs_create_impl(zfvp, zfsvfs, os);

        return (error);
}


int
zfsvfs_create_impl(zfsvfs_t **zfvp, zfsvfs_t *zfsvfs, objset_t *os)
{
        int error;

        zfsvfs->z_vfs = NULL;
        zfsvfs->z_parent = zfsvfs;

        mutex_init(&zfsvfs->z_znodes_lock, NULL, MUTEX_DEFAULT, NULL);
        mutex_init(&zfsvfs->z_lock, NULL, MUTEX_DEFAULT, NULL);
        list_create(&zfsvfs->z_all_znodes, sizeof (znode_t),
            offsetof(znode_t, z_link_node));
        TASK_INIT(&zfsvfs->z_unlinked_drain_task, 0,
            zfsvfs_task_unlinked_drain, zfsvfs);
        ZFS_TEARDOWN_INIT(zfsvfs);
        ZFS_TEARDOWN_INACTIVE_INIT(zfsvfs);
        rw_init(&zfsvfs->z_fuid_lock, NULL, RW_DEFAULT, NULL);
        for (int i = 0; i != ZFS_OBJ_MTX_SZ; i++)
                mutex_init(&zfsvfs->z_hold_mtx[i], NULL, MUTEX_DEFAULT, NULL);

        error = zfsvfs_init(zfsvfs, os);
        if (error != 0) {
                dmu_objset_disown(os, B_TRUE, zfsvfs);
                *zfvp = NULL;
                kmem_free(zfsvfs, sizeof (zfsvfs_t));
                return (error);
        }

        *zfvp = zfsvfs;
        return (0);
}

static int
zfsvfs_setup(zfsvfs_t *zfsvfs, boolean_t mounting)
{
        int error;

        /*
         * Check for a bad on-disk format version now since we
         * lied about owning the dataset readonly before.
         */
        if (!(zfsvfs->z_vfs->vfs_flag & VFS_RDONLY) &&
            dmu_objset_incompatible_encryption_version(zfsvfs->z_os))
                return (SET_ERROR(EROFS));

        error = zfs_register_callbacks(zfsvfs->z_vfs);
        if (error)
                return (error);

        /*
         * If we are not mounting (ie: online recv), then we don't
         * have to worry about replaying the log as we blocked all
         * operations out since we closed the ZIL.
         */
        if (mounting) {
                boolean_t readonly;

                ASSERT3P(zfsvfs->z_kstat.dk_kstats, ==, NULL);
                error = dataset_kstats_create(&zfsvfs->z_kstat, zfsvfs->z_os);
                if (error)
                        return (error);
                zfsvfs->z_log = zil_open(zfsvfs->z_os, zfs_get_data,
                    &zfsvfs->z_kstat.dk_zil_sums);

                /*
                 * During replay we remove the read only flag to
                 * allow replays to succeed.
                 */
                readonly = zfsvfs->z_vfs->vfs_flag & VFS_RDONLY;
                if (readonly != 0) {
                        zfsvfs->z_vfs->vfs_flag &= ~VFS_RDONLY;
                } else {
                        dsl_dir_t *dd;
                        zap_stats_t zs;

                        if (zap_get_stats(zfsvfs->z_os, zfsvfs->z_unlinkedobj,
                            &zs) == 0) {
                                dataset_kstats_update_nunlinks_kstat(
                                    &zfsvfs->z_kstat, zs.zs_num_entries);
                                dprintf_ds(zfsvfs->z_os->os_dsl_dataset,
                                    "num_entries in unlinked set: %llu",
                                    (u_longlong_t)zs.zs_num_entries);
                        }

                        zfs_unlinked_drain(zfsvfs);
                        dd = zfsvfs->z_os->os_dsl_dataset->ds_dir;
                        dd->dd_activity_cancelled = B_FALSE;
                }

                /*
                 * Parse and replay the intent log.
                 *
                 * Because of ziltest, this must be done after
                 * zfs_unlinked_drain().  (Further note: ziltest
                 * doesn't use readonly mounts, where
                 * zfs_unlinked_drain() isn't called.)  This is because
                 * ziltest causes spa_sync() to think it's committed,
                 * but actually it is not, so the intent log contains
                 * many txg's worth of changes.
                 *
                 * In particular, if object N is in the unlinked set in
                 * the last txg to actually sync, then it could be
                 * actually freed in a later txg and then reallocated
                 * in a yet later txg.  This would write a "create
                 * object N" record to the intent log.  Normally, this
                 * would be fine because the spa_sync() would have
                 * written out the fact that object N is free, before
                 * we could write the "create object N" intent log
                 * record.
                 *
                 * But when we are in ziltest mode, we advance the "open
                 * txg" without actually spa_sync()-ing the changes to
                 * disk.  So we would see that object N is still
                 * allocated and in the unlinked set, and there is an
                 * intent log record saying to allocate it.
                 */
                if (spa_writeable(dmu_objset_spa(zfsvfs->z_os))) {
                        if (zil_replay_disable) {
                                zil_destroy(zfsvfs->z_log, B_FALSE);
                        } else {
                                boolean_t use_nc = zfsvfs->z_use_namecache;
                                zfsvfs->z_use_namecache = B_FALSE;
                                zfsvfs->z_replay = B_TRUE;
                                zil_replay(zfsvfs->z_os, zfsvfs,
                                    zfs_replay_vector);
                                zfsvfs->z_replay = B_FALSE;
                                zfsvfs->z_use_namecache = use_nc;
                        }
                }

                /* restore readonly bit */
                if (readonly != 0)
                        zfsvfs->z_vfs->vfs_flag |= VFS_RDONLY;
        } else {
                ASSERT3P(zfsvfs->z_kstat.dk_kstats, !=, NULL);
                zfsvfs->z_log = zil_open(zfsvfs->z_os, zfs_get_data,
                    &zfsvfs->z_kstat.dk_zil_sums);
        }

        /*
         * Set the objset user_ptr to track its zfsvfs.
         */
        mutex_enter(&zfsvfs->z_os->os_user_ptr_lock);
        dmu_objset_set_user(zfsvfs->z_os, zfsvfs);
        mutex_exit(&zfsvfs->z_os->os_user_ptr_lock);

        return (0);
}

void
zfsvfs_free(zfsvfs_t *zfsvfs)
{
        int i;

        zfs_fuid_destroy(zfsvfs);

        mutex_destroy(&zfsvfs->z_znodes_lock);
        mutex_destroy(&zfsvfs->z_lock);
        ASSERT3U(zfsvfs->z_nr_znodes, ==, 0);
        list_destroy(&zfsvfs->z_all_znodes);
        ZFS_TEARDOWN_DESTROY(zfsvfs);
        ZFS_TEARDOWN_INACTIVE_DESTROY(zfsvfs);
        rw_destroy(&zfsvfs->z_fuid_lock);
        for (i = 0; i != ZFS_OBJ_MTX_SZ; i++)
                mutex_destroy(&zfsvfs->z_hold_mtx[i]);
        dataset_kstats_destroy(&zfsvfs->z_kstat);
        kmem_free(zfsvfs, sizeof (zfsvfs_t));
}

static void
zfs_set_fuid_feature(zfsvfs_t *zfsvfs)
{
        zfsvfs->z_use_fuids = USE_FUIDS(zfsvfs->z_version, zfsvfs->z_os);
        zfsvfs->z_use_sa = USE_SA(zfsvfs->z_version, zfsvfs->z_os);
}

static int
zfs_domount(vfs_t *vfsp, char *osname)
{
        uint64_t recordsize, fsid_guid;
        int error = 0;
        zfsvfs_t *zfsvfs;

        ASSERT3P(vfsp, !=, NULL);
        ASSERT3P(osname, !=, NULL);

        error = zfsvfs_create(osname, vfsp->mnt_flag & MNT_RDONLY, &zfsvfs);
        if (error)
                return (error);
        zfsvfs->z_vfs = vfsp;

        if ((error = dsl_prop_get_integer(osname,
            "recordsize", &recordsize, NULL)))
                goto out;
        zfsvfs->z_vfs->vfs_bsize = SPA_MINBLOCKSIZE;
        zfsvfs->z_vfs->mnt_stat.f_iosize = recordsize;

        vfsp->vfs_data = zfsvfs;
        vfsp->mnt_flag |= MNT_LOCAL;
        vfsp->mnt_kern_flag |= MNTK_LOOKUP_SHARED;
        vfsp->mnt_kern_flag |= MNTK_SHARED_WRITES;
        vfsp->mnt_kern_flag |= MNTK_EXTENDED_SHARED;
        /*
         * This can cause a loss of coherence between ARC and page cache
         * on ZoF - unclear if the problem is in FreeBSD or ZoF
         */
        vfsp->mnt_kern_flag |= MNTK_NO_IOPF;    /* vn_io_fault can be used */
        vfsp->mnt_kern_flag |= MNTK_NOMSYNC;
        vfsp->mnt_kern_flag |= MNTK_VMSETSIZE_BUG;

#if defined(_KERNEL) && !defined(KMEM_DEBUG)
        vfsp->mnt_kern_flag |= MNTK_FPLOOKUP;
#endif
        /*
         * The fsid is 64 bits, composed of an 8-bit fs type, which
         * separates our fsid from any other filesystem types, and a
         * 56-bit objset unique ID.  The objset unique ID is unique to
         * all objsets open on this system, provided by unique_create().
         * The 8-bit fs type must be put in the low bits of fsid[1]
         * because that's where other Solaris filesystems put it.
         */
        fsid_guid = dmu_objset_fsid_guid(zfsvfs->z_os);
        ASSERT3U((fsid_guid & ~((1ULL << 56) - 1)), ==, 0);
        vfsp->vfs_fsid.val[0] = fsid_guid;
        vfsp->vfs_fsid.val[1] = ((fsid_guid >> 32) << 8) |
            (vfsp->mnt_vfc->vfc_typenum & 0xFF);

        /*
         * Set features for file system.
         */
        zfs_set_fuid_feature(zfsvfs);

        if (dmu_objset_is_snapshot(zfsvfs->z_os)) {
                uint64_t pval;

                atime_changed_cb(zfsvfs, B_FALSE);
                readonly_changed_cb(zfsvfs, B_TRUE);
                if ((error = dsl_prop_get_integer(osname,
                    "xattr", &pval, NULL)))
                        goto out;
                xattr_changed_cb(zfsvfs, pval);
                if ((error = dsl_prop_get_integer(osname,
                    "acltype", &pval, NULL)))
                        goto out;
                acl_type_changed_cb(zfsvfs, pval);
                zfsvfs->z_issnap = B_TRUE;
                zfsvfs->z_os->os_sync = ZFS_SYNC_DISABLED;

                mutex_enter(&zfsvfs->z_os->os_user_ptr_lock);
                dmu_objset_set_user(zfsvfs->z_os, zfsvfs);
                mutex_exit(&zfsvfs->z_os->os_user_ptr_lock);
        } else {
                if ((error = zfsvfs_setup(zfsvfs, B_TRUE)))
                        goto out;
        }

        vfs_mountedfrom(vfsp, osname);

        if (!zfsvfs->z_issnap)
                zfsctl_create(zfsvfs);
out:
        if (error) {
                dmu_objset_disown(zfsvfs->z_os, B_TRUE, zfsvfs);
                zfsvfs_free(zfsvfs);
        } else {
                atomic_inc_32(&zfs_active_fs_count);
        }

        return (error);
}

static void
zfs_unregister_callbacks(zfsvfs_t *zfsvfs)
{
        objset_t *os = zfsvfs->z_os;

        if (!dmu_objset_is_snapshot(os))
                dsl_prop_unregister_all(dmu_objset_ds(os), zfsvfs);
}

static int
getpoolname(const char *osname, char *poolname)
{
        char *p;

        p = strchr(osname, '/');
        if (p == NULL) {
                if (strlen(osname) >= MAXNAMELEN)
                        return (ENAMETOOLONG);
                (void) strcpy(poolname, osname);
        } else {
                if (p - osname >= MAXNAMELEN)
                        return (ENAMETOOLONG);
                (void) strlcpy(poolname, osname, p - osname + 1);
        }
        return (0);
}

static void
fetch_osname_options(char *name, bool *checkpointrewind)
{

        if (name[0] == '!') {
                *checkpointrewind = true;
                memmove(name, name + 1, strlen(name));
        } else {
                *checkpointrewind = false;
        }
}

static int
zfs_mount(vfs_t *vfsp)
{
        kthread_t       *td = curthread;
        vnode_t         *mvp = vfsp->mnt_vnodecovered;
        cred_t          *cr = td->td_ucred;
        char            *osname;
        int             error = 0;
        int             canwrite;
        bool            checkpointrewind;

        if (vfs_getopt(vfsp->mnt_optnew, "from", (void **)&osname, NULL))
                return (SET_ERROR(EINVAL));

        /*
         * If full-owner-access is enabled and delegated administration is
         * turned on, we must set nosuid.
         */
        if (zfs_super_owner &&
            dsl_deleg_access(osname, ZFS_DELEG_PERM_MOUNT, cr) != ECANCELED) {
                secpolicy_fs_mount_clearopts(cr, vfsp);
        }

        fetch_osname_options(osname, &checkpointrewind);

        /*
         * Check for mount privilege?
         *
         * If we don't have privilege then see if
         * we have local permission to allow it
         */
        error = secpolicy_fs_mount(cr, mvp, vfsp);
        if (error) {
                if (dsl_deleg_access(osname, ZFS_DELEG_PERM_MOUNT, cr) != 0)
                        goto out;

                if (!(vfsp->vfs_flag & MS_REMOUNT)) {
                        vattr_t         vattr;

                        /*
                         * Make sure user is the owner of the mount point
                         * or has sufficient privileges.
                         */

                        vattr.va_mask = AT_UID;

                        vn_lock(mvp, LK_SHARED | LK_RETRY);
                        if (VOP_GETATTR(mvp, &vattr, cr)) {
                                VOP_UNLOCK1(mvp);
                                goto out;
                        }

                        if (secpolicy_vnode_owner(mvp, cr, vattr.va_uid) != 0 &&
                            VOP_ACCESS(mvp, VWRITE, cr, td) != 0) {
                                VOP_UNLOCK1(mvp);
                                goto out;
                        }
                        VOP_UNLOCK1(mvp);
                }

                secpolicy_fs_mount_clearopts(cr, vfsp);
        }

        /*
         * Refuse to mount a filesystem if we are in a local zone and the
         * dataset is not visible.
         */
        if (!INGLOBALZONE(curproc) &&
            (!zone_dataset_visible(osname, &canwrite) || !canwrite)) {
                error = SET_ERROR(EPERM);
                goto out;
        }

        vfsp->vfs_flag |= MNT_NFS4ACLS;

        /*
         * When doing a remount, we simply refresh our temporary properties
         * according to those options set in the current VFS options.
         */
        if (vfsp->vfs_flag & MS_REMOUNT) {
                zfsvfs_t *zfsvfs = vfsp->vfs_data;

                /*
                 * Refresh mount options with z_teardown_lock blocking I/O while
                 * the filesystem is in an inconsistent state.
                 * The lock also serializes this code with filesystem
                 * manipulations between entry to zfs_suspend_fs() and return
                 * from zfs_resume_fs().
                 */
                ZFS_TEARDOWN_ENTER_WRITE(zfsvfs, FTAG);
                zfs_unregister_callbacks(zfsvfs);
                error = zfs_register_callbacks(vfsp);
                ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
                goto out;
        }

        /* Initial root mount: try hard to import the requested root pool. */
        if ((vfsp->vfs_flag & MNT_ROOTFS) != 0 &&
            (vfsp->vfs_flag & MNT_UPDATE) == 0) {
                char pname[MAXNAMELEN];

                error = getpoolname(osname, pname);
                if (error == 0)
                        error = spa_import_rootpool(pname, checkpointrewind);
                if (error)
                        goto out;
        }
        DROP_GIANT();
        error = zfs_domount(vfsp, osname);
        PICKUP_GIANT();

out:
        return (error);
}

static int
zfs_statfs(vfs_t *vfsp, struct statfs *statp)
{
        zfsvfs_t *zfsvfs = vfsp->vfs_data;
        uint64_t refdbytes, availbytes, usedobjs, availobjs;
        int error;

        statp->f_version = STATFS_VERSION;

        if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
                return (error);

        dmu_objset_space(zfsvfs->z_os,
            &refdbytes, &availbytes, &usedobjs, &availobjs);

        /*
         * The underlying storage pool actually uses multiple block sizes.
         * We report the fragsize as the smallest block size we support,
         * and we report our blocksize as the filesystem's maximum blocksize.
         */
        statp->f_bsize = SPA_MINBLOCKSIZE;
        statp->f_iosize = zfsvfs->z_vfs->mnt_stat.f_iosize;

        /*
         * The following report "total" blocks of various kinds in the
         * file system, but reported in terms of f_frsize - the
         * "fragment" size.
         */

        statp->f_blocks = (refdbytes + availbytes) >> SPA_MINBLOCKSHIFT;
        statp->f_bfree = availbytes / statp->f_bsize;
        statp->f_bavail = statp->f_bfree; /* no root reservation */

        /*
         * statvfs() should really be called statufs(), because it assumes
         * static metadata.  ZFS doesn't preallocate files, so the best
         * we can do is report the max that could possibly fit in f_files,
         * and that minus the number actually used in f_ffree.
         * For f_ffree, report the smaller of the number of object available
         * and the number of blocks (each object will take at least a block).
         */
        statp->f_ffree = MIN(availobjs, statp->f_bfree);
        statp->f_files = statp->f_ffree + usedobjs;

        /*
         * We're a zfs filesystem.
         */
        strlcpy(statp->f_fstypename, "zfs",
            sizeof (statp->f_fstypename));

        strlcpy(statp->f_mntfromname, vfsp->mnt_stat.f_mntfromname,
            sizeof (statp->f_mntfromname));
        strlcpy(statp->f_mntonname, vfsp->mnt_stat.f_mntonname,
            sizeof (statp->f_mntonname));

        statp->f_namemax = MAXNAMELEN - 1;

        zfs_exit(zfsvfs, FTAG);
        return (0);
}

static int
zfs_root(vfs_t *vfsp, int flags, vnode_t **vpp)
{
        zfsvfs_t *zfsvfs = vfsp->vfs_data;
        znode_t *rootzp;
        int error;

        if ((error = zfs_enter(zfsvfs, FTAG)) != 0)
                return (error);

        error = zfs_zget(zfsvfs, zfsvfs->z_root, &rootzp);
        if (error == 0)
                *vpp = ZTOV(rootzp);

        zfs_exit(zfsvfs, FTAG);

        if (error == 0) {
                error = vn_lock(*vpp, flags);
                if (error != 0) {
                        VN_RELE(*vpp);
                        *vpp = NULL;
                }
        }
        return (error);
}

/*
 * Teardown the zfsvfs::z_os.
 *
 * Note, if 'unmounting' is FALSE, we return with the 'z_teardown_lock'
 * and 'z_teardown_inactive_lock' held.
 */
static int
zfsvfs_teardown(zfsvfs_t *zfsvfs, boolean_t unmounting)
{
        znode_t *zp;
        dsl_dir_t *dd;

        /*
         * If someone has not already unmounted this file system,
         * drain the zrele_taskq to ensure all active references to the
         * zfsvfs_t have been handled only then can it be safely destroyed.
         */
        if (zfsvfs->z_os) {
                /*
                 * If we're unmounting we have to wait for the list to
                 * drain completely.
                 *
                 * If we're not unmounting there's no guarantee the list
                 * will drain completely, but zreles run from the taskq
                 * may add the parents of dir-based xattrs to the taskq
                 * so we want to wait for these.
                 *
                 * We can safely read z_nr_znodes without locking because the
                 * VFS has already blocked operations which add to the
                 * z_all_znodes list and thus increment z_nr_znodes.
                 */
                int round = 0;
                while (zfsvfs->z_nr_znodes > 0) {
                        taskq_wait_outstanding(dsl_pool_zrele_taskq(
                            dmu_objset_pool(zfsvfs->z_os)), 0);
                        if (++round > 1 && !unmounting)
                                break;
                }
        }
        ZFS_TEARDOWN_ENTER_WRITE(zfsvfs, FTAG);

        if (!unmounting) {
                /*
                 * We purge the parent filesystem's vfsp as the parent
                 * filesystem and all of its snapshots have their vnode's
                 * v_vfsp set to the parent's filesystem's vfsp.  Note,
                 * 'z_parent' is self referential for non-snapshots.
                 */
#ifdef FREEBSD_NAMECACHE
#if __FreeBSD_version >= 1300117
                cache_purgevfs(zfsvfs->z_parent->z_vfs);
#else
                cache_purgevfs(zfsvfs->z_parent->z_vfs, true);
#endif
#endif
        }

        /*
         * Close the zil. NB: Can't close the zil while zfs_inactive
         * threads are blocked as zil_close can call zfs_inactive.
         */
        if (zfsvfs->z_log) {
                zil_close(zfsvfs->z_log);
                zfsvfs->z_log = NULL;
        }

        ZFS_TEARDOWN_INACTIVE_ENTER_WRITE(zfsvfs);

        /*
         * If we are not unmounting (ie: online recv) and someone already
         * unmounted this file system while we were doing the switcheroo,
         * or a reopen of z_os failed then just bail out now.
         */
        if (!unmounting && (zfsvfs->z_unmounted || zfsvfs->z_os == NULL)) {
                ZFS_TEARDOWN_INACTIVE_EXIT_WRITE(zfsvfs);
                ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
                return (SET_ERROR(EIO));
        }

        /*
         * At this point there are no vops active, and any new vops will
         * fail with EIO since we have z_teardown_lock for writer (only
         * relevant for forced unmount).
         *
         * Release all holds on dbufs.
         */
        mutex_enter(&zfsvfs->z_znodes_lock);
        for (zp = list_head(&zfsvfs->z_all_znodes); zp != NULL;
            zp = list_next(&zfsvfs->z_all_znodes, zp)) {
                if (zp->z_sa_hdl != NULL) {
                        zfs_znode_dmu_fini(zp);
                }
        }
        mutex_exit(&zfsvfs->z_znodes_lock);

        /*
         * If we are unmounting, set the unmounted flag and let new vops
         * unblock.  zfs_inactive will have the unmounted behavior, and all
         * other vops will fail with EIO.
         */
        if (unmounting) {
                zfsvfs->z_unmounted = B_TRUE;
                ZFS_TEARDOWN_INACTIVE_EXIT_WRITE(zfsvfs);
                ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
        }

        /*
         * z_os will be NULL if there was an error in attempting to reopen
         * zfsvfs, so just return as the properties had already been
         * unregistered and cached data had been evicted before.
         */
        if (zfsvfs->z_os == NULL)
                return (0);

        /*
         * Unregister properties.
         */
        zfs_unregister_callbacks(zfsvfs);

        /*
         * Evict cached data
         */
        if (!zfs_is_readonly(zfsvfs))
                txg_wait_synced(dmu_objset_pool(zfsvfs->z_os), 0);
        dmu_objset_evict_dbufs(zfsvfs->z_os);
        dd = zfsvfs->z_os->os_dsl_dataset->ds_dir;
        dsl_dir_cancel_waiters(dd);

        return (0);
}

static int
zfs_umount(vfs_t *vfsp, int fflag)
{
        kthread_t *td = curthread;
        zfsvfs_t *zfsvfs = vfsp->vfs_data;
        objset_t *os;
        cred_t *cr = td->td_ucred;
        int ret;

        ret = secpolicy_fs_unmount(cr, vfsp);
        if (ret) {
                if (dsl_deleg_access((char *)vfsp->vfs_resource,
                    ZFS_DELEG_PERM_MOUNT, cr))
                        return (ret);
        }

        /*
         * Unmount any snapshots mounted under .zfs before unmounting the
         * dataset itself.
         */
        if (zfsvfs->z_ctldir != NULL) {
                if ((ret = zfsctl_umount_snapshots(vfsp, fflag, cr)) != 0)
                        return (ret);
        }

        if (fflag & MS_FORCE) {
                /*
                 * Mark file system as unmounted before calling
                 * vflush(FORCECLOSE). This way we ensure no future vnops
                 * will be called and risk operating on DOOMED vnodes.
                 */
                ZFS_TEARDOWN_ENTER_WRITE(zfsvfs, FTAG);
                zfsvfs->z_unmounted = B_TRUE;
                ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);
        }

        /*
         * Flush all the files.
         */
        ret = vflush(vfsp, 0, (fflag & MS_FORCE) ? FORCECLOSE : 0, td);
        if (ret != 0)
                return (ret);
        while (taskqueue_cancel(zfsvfs_taskq->tq_queue,
            &zfsvfs->z_unlinked_drain_task, NULL) != 0)
                taskqueue_drain(zfsvfs_taskq->tq_queue,
                    &zfsvfs->z_unlinked_drain_task);

        VERIFY0(zfsvfs_teardown(zfsvfs, B_TRUE));
        os = zfsvfs->z_os;

        /*
         * z_os will be NULL if there was an error in
         * attempting to reopen zfsvfs.
         */
        if (os != NULL) {
                /*
                 * Unset the objset user_ptr.
                 */
                mutex_enter(&os->os_user_ptr_lock);
                dmu_objset_set_user(os, NULL);
                mutex_exit(&os->os_user_ptr_lock);

                /*
                 * Finally release the objset
                 */
                dmu_objset_disown(os, B_TRUE, zfsvfs);
        }

        /*
         * We can now safely destroy the '.zfs' directory node.
         */
        if (zfsvfs->z_ctldir != NULL)
                zfsctl_destroy(zfsvfs);
        zfs_freevfs(vfsp);

        return (0);
}

static int
zfs_vget(vfs_t *vfsp, ino_t ino, int flags, vnode_t **vpp)
{
        zfsvfs_t        *zfsvfs = vfsp->vfs_data;
        znode_t         *zp;
        int             err;

        /*
         * zfs_zget() can't operate on virtual entries like .zfs/ or
         * .zfs/snapshot/ directories, that's why we return EOPNOTSUPP.
         * This will make NFS to switch to LOOKUP instead of using VGET.
         */
        if (ino == ZFSCTL_INO_ROOT || ino == ZFSCTL_INO_SNAPDIR ||
            (zfsvfs->z_shares_dir != 0 && ino == zfsvfs->z_shares_dir))
                return (EOPNOTSUPP);

        if ((err = zfs_enter(zfsvfs, FTAG)) != 0)
                return (err);
        err = zfs_zget(zfsvfs, ino, &zp);
        if (err == 0 && zp->z_unlinked) {
                vrele(ZTOV(zp));
                err = EINVAL;
        }
        if (err == 0)
                *vpp = ZTOV(zp);
        zfs_exit(zfsvfs, FTAG);
        if (err == 0) {
                err = vn_lock(*vpp, flags);
                if (err != 0)
                        vrele(*vpp);
        }
        if (err != 0)
                *vpp = NULL;
        return (err);
}

static int
#if __FreeBSD_version >= 1300098
zfs_checkexp(vfs_t *vfsp, struct sockaddr *nam, uint64_t *extflagsp,
    struct ucred **credanonp, int *numsecflavors, int *secflavors)
#else
zfs_checkexp(vfs_t *vfsp, struct sockaddr *nam, int *extflagsp,
    struct ucred **credanonp, int *numsecflavors, int **secflavors)
#endif
{
        zfsvfs_t *zfsvfs = vfsp->vfs_data;

        /*
         * If this is regular file system vfsp is the same as
         * zfsvfs->z_parent->z_vfs, but if it is snapshot,
         * zfsvfs->z_parent->z_vfs represents parent file system
         * which we have to use here, because only this file system
         * has mnt_export configured.
         */
        return (vfs_stdcheckexp(zfsvfs->z_parent->z_vfs, nam, extflagsp,
            credanonp, numsecflavors, secflavors));
}

_Static_assert(sizeof (struct fid) >= SHORT_FID_LEN,
        "struct fid bigger than SHORT_FID_LEN");
_Static_assert(sizeof (struct fid) >= LONG_FID_LEN,
        "struct fid bigger than LONG_FID_LEN");

static int
zfs_fhtovp(vfs_t *vfsp, fid_t *fidp, int flags, vnode_t **vpp)
{
        struct componentname cn;
        zfsvfs_t        *zfsvfs = vfsp->vfs_data;
        znode_t         *zp;
        vnode_t         *dvp;
        uint64_t        object = 0;
        uint64_t        fid_gen = 0;
        uint64_t        setgen = 0;
        uint64_t        gen_mask;
        uint64_t        zp_gen;
        int             i, err;

        *vpp = NULL;

        if ((err = zfs_enter(zfsvfs, FTAG)) != 0)
                return (err);

        /*
         * On FreeBSD we can get snapshot's mount point or its parent file
         * system mount point depending if snapshot is already mounted or not.
         */
        if (zfsvfs->z_parent == zfsvfs && fidp->fid_len == LONG_FID_LEN) {
                zfid_long_t     *zlfid = (zfid_long_t *)fidp;
                uint64_t        objsetid = 0;

                for (i = 0; i < sizeof (zlfid->zf_setid); i++)
                        objsetid |= ((uint64_t)zlfid->zf_setid[i]) << (8 * i);

                for (i = 0; i < sizeof (zlfid->zf_setgen); i++)
                        setgen |= ((uint64_t)zlfid->zf_setgen[i]) << (8 * i);

                zfs_exit(zfsvfs, FTAG);

                err = zfsctl_lookup_objset(vfsp, objsetid, &zfsvfs);
                if (err)
                        return (SET_ERROR(EINVAL));
                if ((err = zfs_enter(zfsvfs, FTAG)) != 0)
                        return (err);
        }

        if (fidp->fid_len == SHORT_FID_LEN || fidp->fid_len == LONG_FID_LEN) {
                zfid_short_t    *zfid = (zfid_short_t *)fidp;

                for (i = 0; i < sizeof (zfid->zf_object); i++)
                        object |= ((uint64_t)zfid->zf_object[i]) << (8 * i);

                for (i = 0; i < sizeof (zfid->zf_gen); i++)
                        fid_gen |= ((uint64_t)zfid->zf_gen[i]) << (8 * i);
        } else {
                zfs_exit(zfsvfs, FTAG);
                return (SET_ERROR(EINVAL));
        }

        if (fidp->fid_len == LONG_FID_LEN && setgen != 0) {
                zfs_exit(zfsvfs, FTAG);
                dprintf("snapdir fid: fid_gen (%llu) and setgen (%llu)\n",
                    (u_longlong_t)fid_gen, (u_longlong_t)setgen);
                return (SET_ERROR(EINVAL));
        }

        /*
         * A zero fid_gen means we are in .zfs or the .zfs/snapshot
         * directory tree. If the object == zfsvfs->z_shares_dir, then
         * we are in the .zfs/shares directory tree.
         */
        if ((fid_gen == 0 &&
            (object == ZFSCTL_INO_ROOT || object == ZFSCTL_INO_SNAPDIR)) ||
            (zfsvfs->z_shares_dir != 0 && object == zfsvfs->z_shares_dir)) {
                zfs_exit(zfsvfs, FTAG);
                VERIFY0(zfsctl_root(zfsvfs, LK_SHARED, &dvp));
                if (object == ZFSCTL_INO_SNAPDIR) {
                        cn.cn_nameptr = "snapshot";
                        cn.cn_namelen = strlen(cn.cn_nameptr);
                        cn.cn_nameiop = LOOKUP;
                        cn.cn_flags = ISLASTCN | LOCKLEAF;
                        cn.cn_lkflags = flags;
                        VERIFY0(VOP_LOOKUP(dvp, vpp, &cn));
                        vput(dvp);
                } else if (object == zfsvfs->z_shares_dir) {
                        /*
                         * XXX This branch must not be taken,
                         * if it is, then the lookup below will
                         * explode.
                         */
                        cn.cn_nameptr = "shares";
                        cn.cn_namelen = strlen(cn.cn_nameptr);
                        cn.cn_nameiop = LOOKUP;
                        cn.cn_flags = ISLASTCN;
                        cn.cn_lkflags = flags;
                        VERIFY0(VOP_LOOKUP(dvp, vpp, &cn));
                        vput(dvp);
                } else {
                        *vpp = dvp;
                }
                return (err);
        }

        gen_mask = -1ULL >> (64 - 8 * i);

        dprintf("getting %llu [%llu mask %llx]\n", (u_longlong_t)object,
            (u_longlong_t)fid_gen,
            (u_longlong_t)gen_mask);
        if ((err = zfs_zget(zfsvfs, object, &zp))) {
                zfs_exit(zfsvfs, FTAG);
                return (err);
        }
        (void) sa_lookup(zp->z_sa_hdl, SA_ZPL_GEN(zfsvfs), &zp_gen,
            sizeof (uint64_t));
        zp_gen = zp_gen & gen_mask;
        if (zp_gen == 0)
                zp_gen = 1;
        if (zp->z_unlinked || zp_gen != fid_gen) {
                dprintf("znode gen (%llu) != fid gen (%llu)\n",
                    (u_longlong_t)zp_gen, (u_longlong_t)fid_gen);
                vrele(ZTOV(zp));
                zfs_exit(zfsvfs, FTAG);
                return (SET_ERROR(EINVAL));
        }

        *vpp = ZTOV(zp);
        zfs_exit(zfsvfs, FTAG);
        err = vn_lock(*vpp, flags);
        if (err == 0)
                vnode_create_vobject(*vpp, zp->z_size, curthread);
        else
                *vpp = NULL;
        return (err);
}

/*
 * Block out VOPs and close zfsvfs_t::z_os
 *
 * Note, if successful, then we return with the 'z_teardown_lock' and
 * 'z_teardown_inactive_lock' write held.  We leave ownership of the underlying
 * dataset and objset intact so that they can be atomically handed off during
 * a subsequent rollback or recv operation and the resume thereafter.
 */
int
zfs_suspend_fs(zfsvfs_t *zfsvfs)
{
        int error;

        if ((error = zfsvfs_teardown(zfsvfs, B_FALSE)) != 0)
                return (error);

        return (0);
}

/*
 * Rebuild SA and release VOPs.  Note that ownership of the underlying dataset
 * is an invariant across any of the operations that can be performed while the
 * filesystem was suspended.  Whether it succeeded or failed, the preconditions
 * are the same: the relevant objset and associated dataset are owned by
 * zfsvfs, held, and long held on entry.
 */
int
zfs_resume_fs(zfsvfs_t *zfsvfs, dsl_dataset_t *ds)
{
        int err;
        znode_t *zp;

        ASSERT(ZFS_TEARDOWN_WRITE_HELD(zfsvfs));
        ASSERT(ZFS_TEARDOWN_INACTIVE_WRITE_HELD(zfsvfs));

        /*
         * We already own this, so just update the objset_t, as the one we
         * had before may have been evicted.
         */
        objset_t *os;
        VERIFY3P(ds->ds_owner, ==, zfsvfs);
        VERIFY(dsl_dataset_long_held(ds));
        dsl_pool_t *dp = spa_get_dsl(dsl_dataset_get_spa(ds));
        dsl_pool_config_enter(dp, FTAG);
        VERIFY0(dmu_objset_from_ds(ds, &os));
        dsl_pool_config_exit(dp, FTAG);

        err = zfsvfs_init(zfsvfs, os);
        if (err != 0)
                goto bail;

        ds->ds_dir->dd_activity_cancelled = B_FALSE;
        VERIFY0(zfsvfs_setup(zfsvfs, B_FALSE));

        zfs_set_fuid_feature(zfsvfs);

        /*
         * Attempt to re-establish all the active znodes with
         * their dbufs.  If a zfs_rezget() fails, then we'll let
         * any potential callers discover that via zfs_enter_verify_zp
         * when they try to use their znode.
         */
        mutex_enter(&zfsvfs->z_znodes_lock);
        for (zp = list_head(&zfsvfs->z_all_znodes); zp;
            zp = list_next(&zfsvfs->z_all_znodes, zp)) {
                (void) zfs_rezget(zp);
        }
        mutex_exit(&zfsvfs->z_znodes_lock);

bail:
        /* release the VOPs */
        ZFS_TEARDOWN_INACTIVE_EXIT_WRITE(zfsvfs);
        ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);

        if (err) {
                /*
                 * Since we couldn't setup the sa framework, try to force
                 * unmount this file system.
                 */
                if (vn_vfswlock(zfsvfs->z_vfs->vfs_vnodecovered) == 0) {
                        vfs_ref(zfsvfs->z_vfs);
                        (void) dounmount(zfsvfs->z_vfs, MS_FORCE, curthread);
                }
        }
        return (err);
}

static void
zfs_freevfs(vfs_t *vfsp)
{
        zfsvfs_t *zfsvfs = vfsp->vfs_data;

        zfsvfs_free(zfsvfs);

        atomic_dec_32(&zfs_active_fs_count);
}

#ifdef __i386__
static int desiredvnodes_backup;
#include <sys/vmmeter.h>


#include <vm/vm_page.h>
#include <vm/vm_object.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#endif

static void
zfs_vnodes_adjust(void)
{
#ifdef __i386__
        int newdesiredvnodes;

        desiredvnodes_backup = desiredvnodes;

        /*
         * We calculate newdesiredvnodes the same way it is done in
         * vntblinit(). If it is equal to desiredvnodes, it means that
         * it wasn't tuned by the administrator and we can tune it down.
         */
        newdesiredvnodes = min(maxproc + vm_cnt.v_page_count / 4, 2 *
            vm_kmem_size / (5 * (sizeof (struct vm_object) +
            sizeof (struct vnode))));
        if (newdesiredvnodes == desiredvnodes)
                desiredvnodes = (3 * newdesiredvnodes) / 4;
#endif
}

static void
zfs_vnodes_adjust_back(void)
{

#ifdef __i386__
        desiredvnodes = desiredvnodes_backup;
#endif
}

void
zfs_init(void)
{

        printf("ZFS filesystem version: " ZPL_VERSION_STRING "\n");

        /*
         * Initialize .zfs directory structures
         */
        zfsctl_init();

        /*
         * Initialize znode cache, vnode ops, etc...
         */
        zfs_znode_init();

        /*
         * Reduce number of vnodes. Originally number of vnodes is calculated
         * with UFS inode in mind. We reduce it here, because it's too big for
         * ZFS/i386.
         */
        zfs_vnodes_adjust();

        dmu_objset_register_type(DMU_OST_ZFS, zpl_get_file_info);

        zfsvfs_taskq = taskq_create("zfsvfs", 1, minclsyspri, 0, 0, 0);
}

void
zfs_fini(void)
{
        taskq_destroy(zfsvfs_taskq);
        zfsctl_fini();
        zfs_znode_fini();
        zfs_vnodes_adjust_back();
}

int
zfs_busy(void)
{
        return (zfs_active_fs_count != 0);
}

/*
 * Release VOPs and unmount a suspended filesystem.
 */
int
zfs_end_fs(zfsvfs_t *zfsvfs, dsl_dataset_t *ds)
{
        ASSERT(ZFS_TEARDOWN_WRITE_HELD(zfsvfs));
        ASSERT(ZFS_TEARDOWN_INACTIVE_WRITE_HELD(zfsvfs));

        /*
         * We already own this, so just hold and rele it to update the
         * objset_t, as the one we had before may have been evicted.
         */
        objset_t *os;
        VERIFY3P(ds->ds_owner, ==, zfsvfs);
        VERIFY(dsl_dataset_long_held(ds));
        dsl_pool_t *dp = spa_get_dsl(dsl_dataset_get_spa(ds));
        dsl_pool_config_enter(dp, FTAG);
        VERIFY0(dmu_objset_from_ds(ds, &os));
        dsl_pool_config_exit(dp, FTAG);
        zfsvfs->z_os = os;

        /* release the VOPs */
        ZFS_TEARDOWN_INACTIVE_EXIT_WRITE(zfsvfs);
        ZFS_TEARDOWN_EXIT(zfsvfs, FTAG);

        /*
         * Try to force unmount this file system.
         */
        (void) zfs_umount(zfsvfs->z_vfs, 0);
        zfsvfs->z_unmounted = B_TRUE;
        return (0);
}

int
zfs_set_version(zfsvfs_t *zfsvfs, uint64_t newvers)
{
        int error;
        objset_t *os = zfsvfs->z_os;
        dmu_tx_t *tx;

        if (newvers < ZPL_VERSION_INITIAL || newvers > ZPL_VERSION)
                return (SET_ERROR(EINVAL));

        if (newvers < zfsvfs->z_version)
                return (SET_ERROR(EINVAL));

        if (zfs_spa_version_map(newvers) >
            spa_version(dmu_objset_spa(zfsvfs->z_os)))
                return (SET_ERROR(ENOTSUP));

        tx = dmu_tx_create(os);
        dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, B_FALSE, ZPL_VERSION_STR);
        if (newvers >= ZPL_VERSION_SA && !zfsvfs->z_use_sa) {
                dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, B_TRUE,
                    ZFS_SA_ATTRS);
                dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, FALSE, NULL);
        }
        error = dmu_tx_assign(tx, TXG_WAIT);
        if (error) {
                dmu_tx_abort(tx);
                return (error);
        }

        error = zap_update(os, MASTER_NODE_OBJ, ZPL_VERSION_STR,
            8, 1, &newvers, tx);

        if (error) {
                dmu_tx_commit(tx);
                return (error);
        }

        if (newvers >= ZPL_VERSION_SA && !zfsvfs->z_use_sa) {
                uint64_t sa_obj;

                ASSERT3U(spa_version(dmu_objset_spa(zfsvfs->z_os)), >=,
                    SPA_VERSION_SA);
                sa_obj = zap_create(os, DMU_OT_SA_MASTER_NODE,
                    DMU_OT_NONE, 0, tx);

                error = zap_add(os, MASTER_NODE_OBJ,
                    ZFS_SA_ATTRS, 8, 1, &sa_obj, tx);
                ASSERT0(error);

                VERIFY0(sa_set_sa_object(os, sa_obj));
                sa_register_update_callback(os, zfs_sa_upgrade);
        }

        spa_history_log_internal_ds(dmu_objset_ds(os), "upgrade", tx,
            "from %ju to %ju", (uintmax_t)zfsvfs->z_version,
            (uintmax_t)newvers);
        dmu_tx_commit(tx);

        zfsvfs->z_version = newvers;
        os->os_version = newvers;

        zfs_set_fuid_feature(zfsvfs);

        return (0);
}

/*
 * Read a property stored within the master node.
 */
int
zfs_get_zplprop(objset_t *os, zfs_prop_t prop, uint64_t *value)
{
        uint64_t *cached_copy = NULL;

        /*
         * Figure out where in the objset_t the cached copy would live, if it
         * is available for the requested property.
         */
        if (os != NULL) {
                switch (prop) {
                case ZFS_PROP_VERSION:
                        cached_copy = &os->os_version;
                        break;
                case ZFS_PROP_NORMALIZE:
                        cached_copy = &os->os_normalization;
                        break;
                case ZFS_PROP_UTF8ONLY:
                        cached_copy = &os->os_utf8only;
                        break;
                case ZFS_PROP_CASE:
                        cached_copy = &os->os_casesensitivity;
                        break;
                default:
                        break;
                }
        }
        if (cached_copy != NULL && *cached_copy != OBJSET_PROP_UNINITIALIZED) {
                *value = *cached_copy;
                return (0);
        }

        /*
         * If the property wasn't cached, look up the file system's value for
         * the property. For the version property, we look up a slightly
         * different string.
         */
        const char *pname;
        int error = ENOENT;
        if (prop == ZFS_PROP_VERSION) {
                pname = ZPL_VERSION_STR;
        } else {
                pname = zfs_prop_to_name(prop);
        }

        if (os != NULL) {
                ASSERT3U(os->os_phys->os_type, ==, DMU_OST_ZFS);
                error = zap_lookup(os, MASTER_NODE_OBJ, pname, 8, 1, value);
        }

        if (error == ENOENT) {
                /* No value set, use the default value */
                switch (prop) {
                case ZFS_PROP_VERSION:
                        *value = ZPL_VERSION;
                        break;
                case ZFS_PROP_NORMALIZE:
                case ZFS_PROP_UTF8ONLY:
                        *value = 0;
                        break;
                case ZFS_PROP_CASE:
                        *value = ZFS_CASE_SENSITIVE;
                        break;
                case ZFS_PROP_ACLTYPE:
                        *value = ZFS_ACLTYPE_NFSV4;
                        break;
                default:
                        return (error);
                }
                error = 0;
        }

        /*
         * If one of the methods for getting the property value above worked,
         * copy it into the objset_t's cache.
         */
        if (error == 0 && cached_copy != NULL) {
                *cached_copy = *value;
        }

        return (error);
}

/*
 * Return true if the corresponding vfs's unmounted flag is set.
 * Otherwise return false.
 * If this function returns true we know VFS unmount has been initiated.
 */
boolean_t
zfs_get_vfs_flag_unmounted(objset_t *os)
{
        zfsvfs_t *zfvp;
        boolean_t unmounted = B_FALSE;

        ASSERT3U(dmu_objset_type(os), ==, DMU_OST_ZFS);

        mutex_enter(&os->os_user_ptr_lock);
        zfvp = dmu_objset_get_user(os);
        if (zfvp != NULL && zfvp->z_vfs != NULL &&
            (zfvp->z_vfs->mnt_kern_flag & MNTK_UNMOUNT))
                unmounted = B_TRUE;
        mutex_exit(&os->os_user_ptr_lock);

        return (unmounted);
}

#ifdef _KERNEL
void
zfsvfs_update_fromname(const char *oldname, const char *newname)
{
        char tmpbuf[MAXPATHLEN];
        struct mount *mp;
        char *fromname;
        size_t oldlen;

        oldlen = strlen(oldname);

        mtx_lock(&mountlist_mtx);
        TAILQ_FOREACH(mp, &mountlist, mnt_list) {
                fromname = mp->mnt_stat.f_mntfromname;
                if (strcmp(fromname, oldname) == 0) {
                        (void) strlcpy(fromname, newname,
                            sizeof (mp->mnt_stat.f_mntfromname));
                        continue;
                }
                if (strncmp(fromname, oldname, oldlen) == 0 &&
                    (fromname[oldlen] == '/' || fromname[oldlen] == '@')) {
                        (void) snprintf(tmpbuf, sizeof (tmpbuf), "%s%s",
                            newname, fromname + oldlen);
                        (void) strlcpy(fromname, tmpbuf,
                            sizeof (mp->mnt_stat.f_mntfromname));
                        continue;
                }
        }
        mtx_unlock(&mountlist_mtx);
}
#endif