fs/zfs/zfs_vfsops.c

	zfs_vfsops.c revision e802abbda8c322f24d47835734f4a793ef15ddc8
fa9e4066f08beec538e775443c5be79dd423fcabahrens/*
fa9e4066f08beec538e775443c5be79dd423fcabahrens * CDDL HEADER START
fa9e4066f08beec538e775443c5be79dd423fcabahrens *
fa9e4066f08beec538e775443c5be79dd423fcabahrens * The contents of this file are subject to the terms of the
6b4acc8bd9d480535a4d057e291dc7c049f664d9ahrens * Common Development and Distribution License (the "License").
6b4acc8bd9d480535a4d057e291dc7c049f664d9ahrens * You may not use this file except in compliance with the License.
fa9e4066f08beec538e775443c5be79dd423fcabahrens *
fa9e4066f08beec538e775443c5be79dd423fcabahrens * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
fa9e4066f08beec538e775443c5be79dd423fcabahrens * or http://www.opensolaris.org/os/licensing.
fa9e4066f08beec538e775443c5be79dd423fcabahrens * See the License for the specific language governing permissions
fa9e4066f08beec538e775443c5be79dd423fcabahrens * and limitations under the License.
fa9e4066f08beec538e775443c5be79dd423fcabahrens *
fa9e4066f08beec538e775443c5be79dd423fcabahrens * When distributing Covered Code, include this CDDL HEADER in each
fa9e4066f08beec538e775443c5be79dd423fcabahrens * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
fa9e4066f08beec538e775443c5be79dd423fcabahrens * If applicable, add the following below this CDDL HEADER, with the
fa9e4066f08beec538e775443c5be79dd423fcabahrens * fields enclosed by brackets "[]" replaced with your own identifying
fa9e4066f08beec538e775443c5be79dd423fcabahrens * information: Portions Copyright [yyyy] [name of copyright owner]
fa9e4066f08beec538e775443c5be79dd423fcabahrens *
fa9e4066f08beec538e775443c5be79dd423fcabahrens * CDDL HEADER END
fa9e4066f08beec538e775443c5be79dd423fcabahrens */
fa9e4066f08beec538e775443c5be79dd423fcabahrens/*
3f9d6ad73e45c6823b409f93b0c8d4f62861d2d5Lin Ling * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
2e4c998613148111f2fc5371085331ffb39122ffGeorge Wilson * Use is subject to license terms.
fa9e4066f08beec538e775443c5be79dd423fcabahrens */
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/types.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/param.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/systm.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/sysmacros.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/kmem.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/pathname.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/vnode.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/vfs.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/vfs_opreg.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/mntent.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/mount.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/cmn_err.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include "fs/fs_subr.h"
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/zfs_znode.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/zfs_dir.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/zil.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/fs/zfs.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/dmu.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/dsl_prop.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/dsl_dataset.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/dsl_deleg.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/spa.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/zap.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/varargs.h>
7fd05ac4dec0c343d2f68f310d3718b715ecfbafMatthew Ahrens#include <sys/policy.h>
7fd05ac4dec0c343d2f68f310d3718b715ecfbafMatthew Ahrens#include <sys/atomic.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/mkdev.h>
8363e80ae72609660f6090766ca8c2c18aa53f0cGeorge Wilson#include <sys/modctl.h>
8363e80ae72609660f6090766ca8c2c18aa53f0cGeorge Wilson#include <sys/refstr.h>
8363e80ae72609660f6090766ca8c2c18aa53f0cGeorge Wilson#include <sys/zfs_ioctl.h>
8363e80ae72609660f6090766ca8c2c18aa53f0cGeorge Wilson#include <sys/zfs_ctldir.h>
8363e80ae72609660f6090766ca8c2c18aa53f0cGeorge Wilson#include <sys/zfs_fuid.h>
8363e80ae72609660f6090766ca8c2c18aa53f0cGeorge Wilson#include <sys/bootconf.h>
8363e80ae72609660f6090766ca8c2c18aa53f0cGeorge Wilson#include <sys/sunddi.h>
8363e80ae72609660f6090766ca8c2c18aa53f0cGeorge Wilson#include <sys/dnlc.h>
8363e80ae72609660f6090766ca8c2c18aa53f0cGeorge Wilson#include <sys/dmu_objset.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens#include <sys/spa_boot.h>
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensint zfsfstype;
fa9e4066f08beec538e775443c5be79dd423fcabahrensvfsops_t *zfs_vfsops = NULL;
fa9e4066f08beec538e775443c5be79dd423fcabahrensstatic major_t zfs_major;
fa9e4066f08beec538e775443c5be79dd423fcabahrensstatic minor_t zfs_minor;
fa9e4066f08beec538e775443c5be79dd423fcabahrensstatic kmutex_t zfs_dev_mtx;
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensextern int sys_shutdown;
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensstatic int zfs_mount(vfs_t *vfsp, vnode_t *mvp, struct mounta *uap, cred_t *cr);
0125049cd6136d1d2ca9e982382a915b6d7916ceahrensstatic int zfs_umount(vfs_t *vfsp, int fflag, cred_t *cr);
0125049cd6136d1d2ca9e982382a915b6d7916ceahrensstatic int zfs_mountroot(vfs_t *vfsp, enum whymountroot);
3f9d6ad73e45c6823b409f93b0c8d4f62861d2d5Lin Lingstatic int zfs_root(vfs_t *vfsp, vnode_t **vpp);
3f9d6ad73e45c6823b409f93b0c8d4f62861d2d5Lin Lingstatic int zfs_statvfs(vfs_t *vfsp, struct statvfs64 *statp);
3f9d6ad73e45c6823b409f93b0c8d4f62861d2d5Lin Lingstatic int zfs_vget(vfs_t *vfsp, vnode_t **vpp, fid_t *fidp);
3f9d6ad73e45c6823b409f93b0c8d4f62861d2d5Lin Lingstatic void zfs_freevfs(vfs_t *vfsp);
3f9d6ad73e45c6823b409f93b0c8d4f62861d2d5Lin Ling
3f9d6ad73e45c6823b409f93b0c8d4f62861d2d5Lin Lingstatic const fs_operation_def_t zfs_vfsops_template[] = {
3f9d6ad73e45c6823b409f93b0c8d4f62861d2d5Lin Ling    VFSNAME_MOUNT,      { .vfs_mount = zfs_mount },
3f9d6ad73e45c6823b409f93b0c8d4f62861d2d5Lin Ling    VFSNAME_MOUNTROOT,  { .vfs_mountroot = zfs_mountroot },
3f9d6ad73e45c6823b409f93b0c8d4f62861d2d5Lin Ling    VFSNAME_UNMOUNT,    { .vfs_unmount = zfs_umount },
b4952e17e8858d3225793b28788278de9fe6038dGeorge Wilson    VFSNAME_ROOT,       { .vfs_root = zfs_root },
3f9d6ad73e45c6823b409f93b0c8d4f62861d2d5Lin Ling    VFSNAME_STATVFS,    { .vfs_statvfs = zfs_statvfs },
cd1c8b85eb30b568e9816221430c479ace7a559dMatthew Ahrens    VFSNAME_SYNC,       { .vfs_sync = zfs_sync },
cd1c8b85eb30b568e9816221430c479ace7a559dMatthew Ahrens    VFSNAME_VGET,       { .vfs_vget = zfs_vget },
cd1c8b85eb30b568e9816221430c479ace7a559dMatthew Ahrens    VFSNAME_FREEVFS,    { .vfs_freevfs = zfs_freevfs },
cd1c8b85eb30b568e9816221430c479ace7a559dMatthew Ahrens    NULL,           NULL
fa9e4066f08beec538e775443c5be79dd423fcabahrens};
fa9e4066f08beec538e775443c5be79dd423fcabahrens
fa9e4066f08beec538e775443c5be79dd423fcabahrensstatic const fs_operation_def_t zfs_vfsops_eio_template[] = {
fa9e4066f08beec538e775443c5be79dd423fcabahrens    VFSNAME_FREEVFS,    { .vfs_freevfs =  zfs_freevfs },
fa9e4066f08beec538e775443c5be79dd423fcabahrens    NULL,           NULL
};

/*
 * 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;

static char *noatime_cancel[] = { MNTOPT_ATIME, NULL };
static char *atime_cancel[] = { MNTOPT_NOATIME, NULL };
static char *noxattr_cancel[] = { MNTOPT_XATTR, NULL };
static char *xattr_cancel[] = { MNTOPT_NOXATTR, NULL };

/*
 * MO_DEFAULT is not used since the default value is determined
 * by the equivalent property.
 */
static mntopt_t mntopts[] = {
    { MNTOPT_NOXATTR, noxattr_cancel, NULL, 0, NULL },
    { MNTOPT_XATTR, xattr_cancel, NULL, 0, NULL },
    { MNTOPT_NOATIME, noatime_cancel, NULL, 0, NULL },
    { MNTOPT_ATIME, atime_cancel, NULL, 0, NULL }
};

static mntopts_t zfs_mntopts = {
    sizeof (mntopts) / sizeof (mntopt_t),
    mntopts
};

/*ARGSUSED*/
int
zfs_sync(vfs_t *vfsp, short flag, cred_t *cr)
{
    /*
     * 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);

    /*
     * SYNC_ATTR is used by fsflush() to force old filesystems like UFS
     * to sync metadata, which they would otherwise cache indefinitely.
     * Semantically, the only requirement is that the sync be initiated.
     * The DMU syncs out txgs frequently, so there's nothing to do.
     */
    if (flag & SYNC_ATTR)
        return (0);

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

        ZFS_ENTER(zfsvfs);
        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 (sys_shutdown && spa_suspended(dp->dp_spa)) {
            ZFS_EXIT(zfsvfs);
            return (0);
        }

        if (zfsvfs->z_log != NULL)
            zil_commit(zfsvfs->z_log, UINT64_MAX, 0);
        else
            txg_wait_synced(dp, 0);
        ZFS_EXIT(zfsvfs);
    } else {
        /*
         * Sync all ZFS filesystems.  This is what happens when you
         * run sync(1M).  Unlike other filesystems, ZFS honors the
         * request by waiting for all pools to commit all dirty data.
         */
        spa_sync_allpools();
    }

    return (0);
}

static int
zfs_create_unique_device(dev_t *dev)
{
    major_t new_major;

    do {
        ASSERT3U(zfs_minor, <=, MAXMIN32);
        minor_t start = zfs_minor;
        do {
            mutex_enter(&zfs_dev_mtx);
            if (zfs_minor >= MAXMIN32) {
                /*
                 * If we're still using the real major
                 * keep out of /dev/zfs and /dev/zvol minor
                 * number space.  If we're using a getudev()'ed
                 * major number, we can use all of its minors.
                 */
                if (zfs_major == ddi_name_to_major(ZFS_DRIVER))
                    zfs_minor = ZFS_MIN_MINOR;
                else
                    zfs_minor = 0;
            } else {
                zfs_minor++;
            }
            *dev = makedevice(zfs_major, zfs_minor);
            mutex_exit(&zfs_dev_mtx);
        } while (vfs_devismounted(*dev) && zfs_minor != start);
        if (zfs_minor == start) {
            /*
             * We are using all ~262,000 minor numbers for the
             * current major number.  Create a new major number.
             */
            if ((new_major = getudev()) == (major_t)-1) {
                cmn_err(CE_WARN,
                    "zfs_mount: Can't get unique major "
                    "device number.");
                return (-1);
            }
            mutex_enter(&zfs_dev_mtx);
            zfs_major = new_major;
            zfs_minor = 0;

            mutex_exit(&zfs_dev_mtx);
        } else {
            break;
        }
        /* CONSTANTCONDITION */
    } while (1);

    return (0);
}

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

    if (newval == TRUE) {
        zfsvfs->z_atime = TRUE;
        vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_NOATIME);
        vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_ATIME, NULL, 0);
    } else {
        zfsvfs->z_atime = FALSE;
        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 == TRUE) {
        /* XXX locking on vfs_flag? */
        zfsvfs->z_vfs->vfs_flag |= VFS_XATTR;
        vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_NOXATTR);
        vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_XATTR, NULL, 0);
    } else {
        /* XXX locking on vfs_flag? */
        zfsvfs->z_vfs->vfs_flag &= ~VFS_XATTR;
        vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_XATTR);
        vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_NOXATTR, NULL, 0);
    }
}

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

    if (newval < SPA_MINBLOCKSIZE ||
        newval > SPA_MAXBLOCKSIZE || !ISP2(newval))
        newval = SPA_MAXBLOCKSIZE;

    zfsvfs->z_max_blksz = newval;
    zfsvfs->z_vfs->vfs_bsize = 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
devices_changed_cb(void *arg, uint64_t newval)
{
    zfsvfs_t *zfsvfs = arg;

    if (newval == FALSE) {
        zfsvfs->z_vfs->vfs_flag |= VFS_NODEVICES;
        vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_DEVICES);
        vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_NODEVICES, NULL, 0);
    } else {
        zfsvfs->z_vfs->vfs_flag &= ~VFS_NODEVICES;
        vfs_clearmntopt(zfsvfs->z_vfs, MNTOPT_NODEVICES);
        vfs_setmntopt(zfsvfs->z_vfs, MNTOPT_DEVICES, 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
vscan_changed_cb(void *arg, uint64_t newval)
{
    zfsvfs_t *zfsvfs = arg;

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

    ASSERT(vfsp);
    zfsvfs = vfsp->vfs_data;
    ASSERT(zfsvfs);
    os = zfsvfs->z_os;

    /*
     * 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)) {
        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_NOSUID, NULL)) {
        devices = B_FALSE;
        setuid = B_FALSE;
        do_devices = B_TRUE;
        do_setuid = B_TRUE;
    } else {
        if (vfs_optionisset(vfsp, MNTOPT_NODEVICES, NULL)) {
            devices = B_FALSE;
            do_devices = B_TRUE;
        } else if (vfs_optionisset(vfsp, MNTOPT_DEVICES, NULL)) {
            devices = B_TRUE;
            do_devices = 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)) {
        xattr = B_FALSE;
        do_xattr = B_TRUE;
    } else if (vfs_optionisset(vfsp, MNTOPT_XATTR, NULL)) {
        xattr = B_TRUE;
        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;
    }

    /*
     * 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 {
        char osname[MAXNAMELEN];

        dmu_objset_name(os, osname);
        if (error = dsl_prop_get_integer(osname, "nbmand", &nbmand,
            NULL)) {
            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...
     */
    ds = dmu_objset_ds(os);
    error = dsl_prop_register(ds, "atime", atime_changed_cb, zfsvfs);
    error = error ? error : dsl_prop_register(ds,
        "xattr", xattr_changed_cb, zfsvfs);
    error = error ? error : dsl_prop_register(ds,
        "recordsize", blksz_changed_cb, zfsvfs);
    error = error ? error : dsl_prop_register(ds,
        "readonly", readonly_changed_cb, zfsvfs);
    error = error ? error : dsl_prop_register(ds,
        "devices", devices_changed_cb, zfsvfs);
    error = error ? error : dsl_prop_register(ds,
        "setuid", setuid_changed_cb, zfsvfs);
    error = error ? error : dsl_prop_register(ds,
        "exec", exec_changed_cb, zfsvfs);
    error = error ? error : dsl_prop_register(ds,
        "snapdir", snapdir_changed_cb, zfsvfs);
    error = error ? error : dsl_prop_register(ds,
        "aclmode", acl_mode_changed_cb, zfsvfs);
    error = error ? error : dsl_prop_register(ds,
        "aclinherit", acl_inherit_changed_cb, zfsvfs);
    error = error ? error : dsl_prop_register(ds,
        "vscan", vscan_changed_cb, zfsvfs);
    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_devices)
        devices_changed_cb(zfsvfs, devices);
    if (do_xattr)
        xattr_changed_cb(zfsvfs, xattr);
    if (do_atime)
        atime_changed_cb(zfsvfs, atime);

    nbmand_changed_cb(zfsvfs, nbmand);

    return (0);

unregister:
    /*
     * We may attempt to unregister some callbacks that are not
     * registered, but this is OK; it will simply return ENOMSG,
     * which we will ignore.
     */
    (void) dsl_prop_unregister(ds, "atime", atime_changed_cb, zfsvfs);
    (void) dsl_prop_unregister(ds, "xattr", xattr_changed_cb, zfsvfs);
    (void) dsl_prop_unregister(ds, "recordsize", blksz_changed_cb, zfsvfs);
    (void) dsl_prop_unregister(ds, "readonly", readonly_changed_cb, zfsvfs);
    (void) dsl_prop_unregister(ds, "devices", devices_changed_cb, zfsvfs);
    (void) dsl_prop_unregister(ds, "setuid", setuid_changed_cb, zfsvfs);
    (void) dsl_prop_unregister(ds, "exec", exec_changed_cb, zfsvfs);
    (void) dsl_prop_unregister(ds, "snapdir", snapdir_changed_cb, zfsvfs);
    (void) dsl_prop_unregister(ds, "aclmode", acl_mode_changed_cb, zfsvfs);
    (void) dsl_prop_unregister(ds, "aclinherit", acl_inherit_changed_cb,
        zfsvfs);
    (void) dsl_prop_unregister(ds, "vscan", vscan_changed_cb, zfsvfs);
    return (error);

}

static void
uidacct(objset_t *os, boolean_t isgroup, uint64_t fuid,
    int64_t delta, dmu_tx_t *tx)
{
    uint64_t used = 0;
    char buf[32];
    int err;
    uint64_t obj = isgroup ? DMU_GROUPUSED_OBJECT : DMU_USERUSED_OBJECT;

    if (delta == 0)
        return;

    (void) snprintf(buf, sizeof (buf), "%llx", (longlong_t)fuid);
    err = zap_lookup(os, obj, buf, 8, 1, &used);
    ASSERT(err == 0 || err == ENOENT);
    /* no underflow/overflow */
    ASSERT(delta > 0 || used >= -delta);
    ASSERT(delta < 0 || used + delta > used);
    used += delta;
    if (used == 0)
        err = zap_remove(os, obj, buf, tx);
    else
        err = zap_update(os, obj, buf, 8, 1, &used, tx);
    ASSERT(err == 0);
}

static void
zfs_space_delta_cb(objset_t *os, dmu_object_type_t bonustype,
    void *oldbonus, void *newbonus,
    uint64_t oldused, uint64_t newused, dmu_tx_t *tx)
{
    znode_phys_t *oldznp = oldbonus;
    znode_phys_t *newznp = newbonus;

    if (bonustype != DMU_OT_ZNODE)
        return;

    /* We charge 512 for the dnode (if it's allocated). */
    if (oldznp->zp_gen != 0)
        oldused += DNODE_SIZE;
    if (newznp->zp_gen != 0)
        newused += DNODE_SIZE;

    if (oldznp->zp_uid == newznp->zp_uid) {
        uidacct(os, B_FALSE, oldznp->zp_uid, newused-oldused, tx);
    } else {
        uidacct(os, B_FALSE, oldznp->zp_uid, -oldused, tx);
        uidacct(os, B_FALSE, newznp->zp_uid, newused, tx);
    }

    if (oldznp->zp_gid == newznp->zp_gid) {
        uidacct(os, B_TRUE, oldznp->zp_gid, newused-oldused, tx);
    } else {
        uidacct(os, B_TRUE, oldznp->zp_gid, -oldused, tx);
        uidacct(os, B_TRUE, newznp->zp_gid, newused, tx);
    }
}

static void
fuidstr_to_sid(zfsvfs_t *zfsvfs, const char *fuidstr,
    char *domainbuf, int buflen, uid_t *ridp)
{
    extern uint64_t strtonum(const char *str, char **nptr);
    uint64_t fuid;
    const char *domain;

    fuid = strtonum(fuidstr, NULL);

    domain = zfs_fuid_find_by_idx(zfsvfs, FUID_INDEX(fuid));
    if (domain)
        (void) strlcpy(domainbuf, domain, buflen);
    else
        domainbuf[0] = '\0';
    *ridp = FUID_RID(fuid);
}

static uint64_t
zfs_userquota_prop_to_obj(zfsvfs_t *zfsvfs, zfs_userquota_prop_t type)
{
    switch (type) {
    case ZFS_PROP_USERUSED:
        return (DMU_USERUSED_OBJECT);
    case ZFS_PROP_GROUPUSED:
        return (DMU_GROUPUSED_OBJECT);
    case ZFS_PROP_USERQUOTA:
        return (zfsvfs->z_userquota_obj);
    case ZFS_PROP_GROUPQUOTA:
        return (zfsvfs->z_groupquota_obj);
    }
    return (0);
}

int
zfs_userspace_many(zfsvfs_t *zfsvfs, zfs_userquota_prop_t type,
    uint64_t *cookiep, void *vbuf, uint64_t *bufsizep)
{
    int error;
    zap_cursor_t zc;
    zap_attribute_t za;
    zfs_useracct_t *buf = vbuf;
    uint64_t obj;

    if (!dmu_objset_userspace_present(zfsvfs->z_os))
        return (ENOTSUP);

    obj = zfs_userquota_prop_to_obj(zfsvfs, type);
    if (obj == 0) {
        *bufsizep = 0;
        return (0);
    }

    for (zap_cursor_init_serialized(&zc, zfsvfs->z_os, obj, *cookiep);
        (error = zap_cursor_retrieve(&zc, &za)) == 0;
        zap_cursor_advance(&zc)) {
        if ((uintptr_t)buf - (uintptr_t)vbuf + sizeof (zfs_useracct_t) >
            *bufsizep)
            break;

        fuidstr_to_sid(zfsvfs, za.za_name,
            buf->zu_domain, sizeof (buf->zu_domain), &buf->zu_rid);

        buf->zu_space = za.za_first_integer;
        buf++;
    }
    if (error == ENOENT)
        error = 0;

    ASSERT3U((uintptr_t)buf - (uintptr_t)vbuf, <=, *bufsizep);
    *bufsizep = (uintptr_t)buf - (uintptr_t)vbuf;
    *cookiep = zap_cursor_serialize(&zc);
    zap_cursor_fini(&zc);
    return (error);
}

/*
 * buf must be big enough (eg, 32 bytes)
 */
static int
id_to_fuidstr(zfsvfs_t *zfsvfs, const char *domain, uid_t rid,
    char *buf, boolean_t addok)
{
    uint64_t fuid;
    int domainid = 0;

    if (domain && domain[0]) {
        domainid = zfs_fuid_find_by_domain(zfsvfs, domain, NULL, addok);
        if (domainid == -1)
            return (ENOENT);
    }
    fuid = FUID_ENCODE(domainid, rid);
    (void) sprintf(buf, "%llx", (longlong_t)fuid);
    return (0);
}

int
zfs_userspace_one(zfsvfs_t *zfsvfs, zfs_userquota_prop_t type,
    const char *domain, uint64_t rid, uint64_t *valp)
{
    char buf[32];
    int err;
    uint64_t obj;

    *valp = 0;

    if (!dmu_objset_userspace_present(zfsvfs->z_os))
        return (ENOTSUP);

    obj = zfs_userquota_prop_to_obj(zfsvfs, type);
    if (obj == 0)
        return (0);

    err = id_to_fuidstr(zfsvfs, domain, rid, buf, B_FALSE);
    if (err)
        return (err);

    err = zap_lookup(zfsvfs->z_os, obj, buf, 8, 1, valp);
    if (err == ENOENT)
        err = 0;
    return (err);
}

int
zfs_set_userquota(zfsvfs_t *zfsvfs, zfs_userquota_prop_t type,
    const char *domain, uint64_t rid, uint64_t quota)
{
    char buf[32];
    int err;
    dmu_tx_t *tx;
    uint64_t *objp;
    boolean_t fuid_dirtied;

    if (type != ZFS_PROP_USERQUOTA && type != ZFS_PROP_GROUPQUOTA)
        return (EINVAL);

    if (zfsvfs->z_version < ZPL_VERSION_USERSPACE)
        return (ENOTSUP);

    objp = (type == ZFS_PROP_USERQUOTA) ? &zfsvfs->z_userquota_obj :
        &zfsvfs->z_groupquota_obj;

    err = id_to_fuidstr(zfsvfs, domain, rid, buf, B_TRUE);
    if (err)
        return (err);
    fuid_dirtied = zfsvfs->z_fuid_dirty;

    tx = dmu_tx_create(zfsvfs->z_os);
    dmu_tx_hold_zap(tx, *objp ? *objp : DMU_NEW_OBJECT, B_TRUE, NULL);
    if (*objp == 0) {
        dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, B_TRUE,
            zfs_userquota_prop_prefixes[type]);
    }
    if (fuid_dirtied)
        zfs_fuid_txhold(zfsvfs, tx);
    err = dmu_tx_assign(tx, TXG_WAIT);
    if (err) {
        dmu_tx_abort(tx);
        return (err);
    }

    mutex_enter(&zfsvfs->z_lock);
    if (*objp == 0) {
        *objp = zap_create(zfsvfs->z_os, DMU_OT_USERGROUP_QUOTA,
            DMU_OT_NONE, 0, tx);
        VERIFY(0 == zap_add(zfsvfs->z_os, MASTER_NODE_OBJ,
            zfs_userquota_prop_prefixes[type], 8, 1, objp, tx));
    }
    mutex_exit(&zfsvfs->z_lock);

    if (quota == 0) {
        err = zap_remove(zfsvfs->z_os, *objp, buf, tx);
        if (err == ENOENT)
            err = 0;
    } else {
        err = zap_update(zfsvfs->z_os, *objp, buf, 8, 1, &quota, tx);
    }
    ASSERT(err == 0);
    if (fuid_dirtied)
        zfs_fuid_sync(zfsvfs, tx);
    dmu_tx_commit(tx);
    return (err);
}

boolean_t
zfs_usergroup_overquota(zfsvfs_t *zfsvfs, boolean_t isgroup, uint64_t fuid)
{
    char buf[32];
    uint64_t used, quota, usedobj, quotaobj;
    int err;

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

    if (quotaobj == 0 || zfsvfs->z_replay)
        return (B_FALSE);

    (void) sprintf(buf, "%llx", (longlong_t)fuid);
    err = zap_lookup(zfsvfs->z_os, quotaobj, buf, 8, 1, &quota);
    if (err != 0)
        return (B_FALSE);

    err = zap_lookup(zfsvfs->z_os, usedobj, buf, 8, 1, &used);
    if (err != 0)
        return (B_FALSE);
    return (used >= quota);
}

int
zfsvfs_create(const char *osname, int mode, zfsvfs_t **zvp)
{
    objset_t *os;
    zfsvfs_t *zfsvfs;
    uint64_t zval;
    int i, error;

    if (error = dsl_prop_get_integer(osname, "readonly", &zval, NULL))
        return (error);
    if (zval)
        mode |= DS_MODE_READONLY;

    error = dmu_objset_open(osname, DMU_OST_ZFS, mode, &os);
    if (error == EROFS) {
        mode |= DS_MODE_READONLY;
        error = dmu_objset_open(osname, DMU_OST_ZFS, mode, &os);
    }
    if (error)
        return (error);

    /*
     * Initialize the zfs-specific filesystem structure.
     * Should probably make this a kmem cache, shuffle fields,
     * and just bzero up to z_hold_mtx[].
     */
    zfsvfs = kmem_zalloc(sizeof (zfsvfs_t), KM_SLEEP);
    zfsvfs->z_vfs = NULL;
    zfsvfs->z_parent = zfsvfs;
    zfsvfs->z_max_blksz = SPA_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) {
        goto out;
    } else if (zfsvfs->z_version > ZPL_VERSION) {
        (void) printf("Mismatched versions:  File system "
            "is version %llu on-disk format, which is "
            "incompatible with this software version %lld!",
            (u_longlong_t)zfsvfs->z_version, ZPL_VERSION);
        error = ENOTSUP;
        goto out;
    }

    if ((error = zfs_get_zplprop(os, ZFS_PROP_NORMALIZE, &zval)) != 0)
        goto out;
    zfsvfs->z_norm = (int)zval;

    if ((error = zfs_get_zplprop(os, ZFS_PROP_UTF8ONLY, &zval)) != 0)
        goto out;
    zfsvfs->z_utf8 = (zval != 0);

    if ((error = zfs_get_zplprop(os, ZFS_PROP_CASE, &zval)) != 0)
        goto out;
    zfsvfs->z_case = (uint_t)zval;

    /*
     * 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);

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

    error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_UNLINKED_SET, 8, 1,
        &zfsvfs->z_unlinkedobj);
    if (error)
        goto out;

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

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

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

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

    mutex_init(&zfsvfs->z_znodes_lock, NULL, MUTEX_DEFAULT, NULL);
    mutex_init(&zfsvfs->z_online_recv_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));
    rrw_init(&zfsvfs->z_teardown_lock);
    rw_init(&zfsvfs->z_teardown_inactive_lock, NULL, RW_DEFAULT, NULL);
    rw_init(&zfsvfs->z_fuid_lock, NULL, RW_DEFAULT, NULL);
    for (i = 0; i != ZFS_OBJ_MTX_SZ; i++)
        mutex_init(&zfsvfs->z_hold_mtx[i], NULL, MUTEX_DEFAULT, NULL);

    *zvp = zfsvfs;
    return (0);

out:
    dmu_objset_close(os);
    *zvp = NULL;
    kmem_free(zfsvfs, sizeof (zfsvfs_t));
    return (error);
}

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

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

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

    zfsvfs->z_log = zil_open(zfsvfs->z_os, zfs_get_data);
    if (zil_disable) {
        zil_destroy(zfsvfs->z_log, 0);
        zfsvfs->z_log = NULL;
    }

    /*
     * 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;

        /*
         * 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
            zfs_unlinked_drain(zfsvfs);

        if (zfsvfs->z_log) {
            /*
             * 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.
             */
            zfsvfs->z_replay = B_TRUE;
            zil_replay(zfsvfs->z_os, zfsvfs, zfs_replay_vector);
            zfsvfs->z_replay = B_FALSE;
        }
        zfsvfs->z_vfs->vfs_flag |= readonly; /* restore readonly bit */
    }

    return (0);
}

void
zfsvfs_free(zfsvfs_t *zfsvfs)
{
    int i;

    zfs_fuid_destroy(zfsvfs);

    mutex_destroy(&zfsvfs->z_znodes_lock);
    mutex_destroy(&zfsvfs->z_online_recv_lock);
    mutex_destroy(&zfsvfs->z_lock);
    list_destroy(&zfsvfs->z_all_znodes);
    rrw_destroy(&zfsvfs->z_teardown_lock);
    rw_destroy(&zfsvfs->z_teardown_inactive_lock);
    rw_destroy(&zfsvfs->z_fuid_lock);
    for (i = 0; i != ZFS_OBJ_MTX_SZ; i++)
        mutex_destroy(&zfsvfs->z_hold_mtx[i]);
    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);
    if (zfsvfs->z_use_fuids && zfsvfs->z_vfs) {
        vfs_set_feature(zfsvfs->z_vfs, VFSFT_XVATTR);
        vfs_set_feature(zfsvfs->z_vfs, VFSFT_SYSATTR_VIEWS);
        vfs_set_feature(zfsvfs->z_vfs, VFSFT_ACEMASKONACCESS);
        vfs_set_feature(zfsvfs->z_vfs, VFSFT_ACLONCREATE);
        vfs_set_feature(zfsvfs->z_vfs, VFSFT_ACCESS_FILTER);
    }
}

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

    ASSERT(vfsp);
    ASSERT(osname);

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

    /* Initialize the generic filesystem structure. */
    vfsp->vfs_bcount = 0;
    vfsp->vfs_data = NULL;

    if (zfs_create_unique_device(&mount_dev) == -1) {
        error = ENODEV;
        goto out;
    }
    ASSERT(vfs_devismounted(mount_dev) == 0);

    if (error = dsl_prop_get_integer(osname, "recordsize", &recordsize,
        NULL))
        goto out;

    vfsp->vfs_dev = mount_dev;
    vfsp->vfs_fstype = zfsfstype;
    vfsp->vfs_bsize = recordsize;
    vfsp->vfs_flag |= VFS_NOTRUNC;
    vfsp->vfs_data = zfsvfs;

    /*
     * 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);
    ASSERT((fsid_guid & ~((1ULL<<56)-1)) == 0);
    vfsp->vfs_fsid.val[0] = fsid_guid;
    vfsp->vfs_fsid.val[1] = ((fsid_guid>>32) << 8) |
        zfsfstype & 0xFF;

    /*
     * Set features for file system.
     */
    zfs_set_fuid_feature(zfsvfs);
    if (zfsvfs->z_case == ZFS_CASE_INSENSITIVE) {
        vfs_set_feature(vfsp, VFSFT_DIRENTFLAGS);
        vfs_set_feature(vfsp, VFSFT_CASEINSENSITIVE);
        vfs_set_feature(vfsp, VFSFT_NOCASESENSITIVE);
    } else if (zfsvfs->z_case == ZFS_CASE_MIXED) {
        vfs_set_feature(vfsp, VFSFT_DIRENTFLAGS);
        vfs_set_feature(vfsp, VFSFT_CASEINSENSITIVE);
    }

    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);
        zfsvfs->z_issnap = B_TRUE;

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

    if (!zfsvfs->z_issnap)
        zfsctl_create(zfsvfs);
out:
    if (error) {
        dmu_objset_close(zfsvfs->z_os);
        zfsvfs_free(zfsvfs);
    } else {
        atomic_add_32(&zfs_active_fs_count, 1);
    }

    return (error);
}

void
zfs_unregister_callbacks(zfsvfs_t *zfsvfs)
{
    objset_t *os = zfsvfs->z_os;
    struct dsl_dataset *ds;

    /*
     * Unregister properties.
     */
    if (!dmu_objset_is_snapshot(os)) {
        ds = dmu_objset_ds(os);
        VERIFY(dsl_prop_unregister(ds, "atime", atime_changed_cb,
            zfsvfs) == 0);

        VERIFY(dsl_prop_unregister(ds, "xattr", xattr_changed_cb,
            zfsvfs) == 0);

        VERIFY(dsl_prop_unregister(ds, "recordsize", blksz_changed_cb,
            zfsvfs) == 0);

        VERIFY(dsl_prop_unregister(ds, "readonly", readonly_changed_cb,
            zfsvfs) == 0);

        VERIFY(dsl_prop_unregister(ds, "devices", devices_changed_cb,
            zfsvfs) == 0);

        VERIFY(dsl_prop_unregister(ds, "setuid", setuid_changed_cb,
            zfsvfs) == 0);

        VERIFY(dsl_prop_unregister(ds, "exec", exec_changed_cb,
            zfsvfs) == 0);

        VERIFY(dsl_prop_unregister(ds, "snapdir", snapdir_changed_cb,
            zfsvfs) == 0);

        VERIFY(dsl_prop_unregister(ds, "aclmode", acl_mode_changed_cb,
            zfsvfs) == 0);

        VERIFY(dsl_prop_unregister(ds, "aclinherit",
            acl_inherit_changed_cb, zfsvfs) == 0);

        VERIFY(dsl_prop_unregister(ds, "vscan",
            vscan_changed_cb, zfsvfs) == 0);
    }
}

/*
 * Convert a decimal digit string to a uint64_t integer.
 */
static int
str_to_uint64(char *str, uint64_t *objnum)
{
    uint64_t num = 0;

    while (*str) {
        if (*str < '0' || *str > '9')
            return (EINVAL);

        num = num*10 + *str++ - '0';
    }

    *objnum = num;
    return (0);
}

/*
 * The boot path passed from the boot loader is in the form of
 * "rootpool-name/root-filesystem-object-number'. Convert this
 * string to a dataset name: "rootpool-name/root-filesystem-name".
 */
static int
zfs_parse_bootfs(char *bpath, char *outpath)
{
    char *slashp;
    uint64_t objnum;
    int error;

    if (*bpath == 0 || *bpath == '/')
        return (EINVAL);

    (void) strcpy(outpath, bpath);

    slashp = strchr(bpath, '/');

    /* if no '/', just return the pool name */
    if (slashp == NULL) {
        return (0);
    }

    /* if not a number, just return the root dataset name */
    if (str_to_uint64(slashp+1, &objnum)) {
        return (0);
    }

    *slashp = '\0';
    error = dsl_dsobj_to_dsname(bpath, objnum, outpath);
    *slashp = '/';

    return (error);
}

static int
zfs_mountroot(vfs_t *vfsp, enum whymountroot why)
{
    int error = 0;
    static int zfsrootdone = 0;
    zfsvfs_t *zfsvfs = NULL;
    znode_t *zp = NULL;
    vnode_t *vp = NULL;
    char *zfs_bootfs;
    char *zfs_devid;

    ASSERT(vfsp);

    /*
     * The filesystem that we mount as root is defined in the
     * boot property "zfs-bootfs" with a format of
     * "poolname/root-dataset-objnum".
     */
    if (why == ROOT_INIT) {
        if (zfsrootdone++)
            return (EBUSY);
        /*
         * the process of doing a spa_load will require the
         * clock to be set before we could (for example) do
         * something better by looking at the timestamp on
         * an uberblock, so just set it to -1.
         */
        clkset(-1);

        if ((zfs_bootfs = spa_get_bootprop("zfs-bootfs")) == NULL) {
            cmn_err(CE_NOTE, "spa_get_bootfs: can not get "
                "bootfs name");
            return (EINVAL);
        }
        zfs_devid = spa_get_bootprop("diskdevid");
        error = spa_import_rootpool(rootfs.bo_name, zfs_devid);
        if (zfs_devid)
            spa_free_bootprop(zfs_devid);
        if (error) {
            spa_free_bootprop(zfs_bootfs);
            cmn_err(CE_NOTE, "spa_import_rootpool: error %d",
                error);
            return (error);
        }
        if (error = zfs_parse_bootfs(zfs_bootfs, rootfs.bo_name)) {
            spa_free_bootprop(zfs_bootfs);
            cmn_err(CE_NOTE, "zfs_parse_bootfs: error %d",
                error);
            return (error);
        }

        spa_free_bootprop(zfs_bootfs);

        if (error = vfs_lock(vfsp))
            return (error);

        if (error = zfs_domount(vfsp, rootfs.bo_name)) {
            cmn_err(CE_NOTE, "zfs_domount: error %d", error);
            goto out;
        }

        zfsvfs = (zfsvfs_t *)vfsp->vfs_data;
        ASSERT(zfsvfs);
        if (error = zfs_zget(zfsvfs, zfsvfs->z_root, &zp)) {
            cmn_err(CE_NOTE, "zfs_zget: error %d", error);
            goto out;
        }

        vp = ZTOV(zp);
        mutex_enter(&vp->v_lock);
        vp->v_flag |= VROOT;
        mutex_exit(&vp->v_lock);
        rootvp = vp;

        /*
         * Leave rootvp held.  The root file system is never unmounted.
         */

        vfs_add((struct vnode *)0, vfsp,
            (vfsp->vfs_flag & VFS_RDONLY) ? MS_RDONLY : 0);
out:
        vfs_unlock(vfsp);
        return (error);
    } else if (why == ROOT_REMOUNT) {
        readonly_changed_cb(vfsp->vfs_data, B_FALSE);
        vfsp->vfs_flag |= VFS_REMOUNT;

        /* refresh mount options */
        zfs_unregister_callbacks(vfsp->vfs_data);
        return (zfs_register_callbacks(vfsp));

    } else if (why == ROOT_UNMOUNT) {
        zfs_unregister_callbacks((zfsvfs_t *)vfsp->vfs_data);
        (void) zfs_sync(vfsp, 0, 0);
        return (0);
    }

    /*
     * if "why" is equal to anything else other than ROOT_INIT,
     * ROOT_REMOUNT, or ROOT_UNMOUNT, we do not support it.
     */
    return (ENOTSUP);
}

/*ARGSUSED*/
static int
zfs_mount(vfs_t *vfsp, vnode_t *mvp, struct mounta *uap, cred_t *cr)
{
    char        *osname;
    pathname_t  spn;
    int     error = 0;
    uio_seg_t   fromspace = (uap->flags & MS_SYSSPACE) ?
        UIO_SYSSPACE : UIO_USERSPACE;
    int     canwrite;

    if (mvp->v_type != VDIR)
        return (ENOTDIR);

    mutex_enter(&mvp->v_lock);
    if ((uap->flags & MS_REMOUNT) == 0 &&
        (uap->flags & MS_OVERLAY) == 0 &&
        (mvp->v_count != 1 || (mvp->v_flag & VROOT))) {
        mutex_exit(&mvp->v_lock);
        return (EBUSY);
    }
    mutex_exit(&mvp->v_lock);

    /*
     * ZFS does not support passing unparsed data in via MS_DATA.
     * Users should use the MS_OPTIONSTR interface; this means
     * that all option parsing is already done and the options struct
     * can be interrogated.
     */
    if ((uap->flags & MS_DATA) && uap->datalen > 0)
        return (EINVAL);

    /*
     * Get the objset name (the "special" mount argument).
     */
    if (error = pn_get(uap->spec, fromspace, &spn))
        return (error);

    osname = spn.pn_path;

    /*
     * 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) {
        error = dsl_deleg_access(osname, ZFS_DELEG_PERM_MOUNT, cr);
        if (error == 0) {
            vattr_t     vattr;

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

            vattr.va_mask = AT_UID;

            if (error = VOP_GETATTR(mvp, &vattr, 0, cr, NULL)) {
                goto out;
            }

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

            secpolicy_fs_mount_clearopts(cr, vfsp);
        } else {
            goto out;
        }
    }

    /*
     * 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 = EPERM;
        goto out;
    }

    /*
     * When doing a remount, we simply refresh our temporary properties
     * according to those options set in the current VFS options.
     */
    if (uap->flags & MS_REMOUNT) {
        /* refresh mount options */
        zfs_unregister_callbacks(vfsp->vfs_data);
        error = zfs_register_callbacks(vfsp);
        goto out;
    }

    error = zfs_domount(vfsp, osname);

    /*
     * Add an extra VFS_HOLD on our parent vfs so that it can't
     * disappear due to a forced unmount.
     */
    if (error == 0 && ((zfsvfs_t *)vfsp->vfs_data)->z_issnap)
        VFS_HOLD(mvp->v_vfsp);

out:
    pn_free(&spn);
    return (error);
}

static int
zfs_statvfs(vfs_t *vfsp, struct statvfs64 *statp)
{
    zfsvfs_t *zfsvfs = vfsp->vfs_data;
    dev32_t d32;
    uint64_t refdbytes, availbytes, usedobjs, availobjs;

    ZFS_ENTER(zfsvfs);

    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_frsize = 1UL << SPA_MINBLOCKSHIFT;
    statp->f_bsize = zfsvfs->z_max_blksz;

    /*
     * 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 >> SPA_MINBLOCKSHIFT;
    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_favail = statp->f_ffree;   /* no "root reservation" */
    statp->f_files = statp->f_ffree + usedobjs;

    (void) cmpldev(&d32, vfsp->vfs_dev);
    statp->f_fsid = d32;

    /*
     * We're a zfs filesystem.
     */
    (void) strcpy(statp->f_basetype, vfssw[vfsp->vfs_fstype].vsw_name);

    statp->f_flag = vf_to_stf(vfsp->vfs_flag);

    statp->f_namemax = ZFS_MAXNAMELEN;

    /*
     * We have all of 32 characters to stuff a string here.
     * Is there anything useful we could/should provide?
     */
    bzero(statp->f_fstr, sizeof (statp->f_fstr));

    ZFS_EXIT(zfsvfs);
    return (0);
}

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

    ZFS_ENTER(zfsvfs);

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

    ZFS_EXIT(zfsvfs);
    return (error);
}

/*
 * Teardown the zfsvfs::z_os.
 *
 * Note, if 'unmounting' if 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;

    rrw_enter(&zfsvfs->z_teardown_lock, RW_WRITER, 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.
         */
        (void) dnlc_purge_vfsp(zfsvfs->z_parent->z_vfs, 0);
    }

    /*
     * 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;
    }

    rw_enter(&zfsvfs->z_teardown_inactive_lock, RW_WRITER);

    /*
     * 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)) {
        rw_exit(&zfsvfs->z_teardown_inactive_lock);
        rrw_exit(&zfsvfs->z_teardown_lock, FTAG);
        return (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
     * relavent 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_dbuf) {
            ASSERT(ZTOV(zp)->v_count > 0);
            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;
        rrw_exit(&zfsvfs->z_teardown_lock, FTAG);
        rw_exit(&zfsvfs->z_teardown_inactive_lock);
    }

    /*
     * 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 (dmu_objset_evict_dbufs(zfsvfs->z_os)) {
        txg_wait_synced(dmu_objset_pool(zfsvfs->z_os), 0);
        (void) dmu_objset_evict_dbufs(zfsvfs->z_os);
    }

    return (0);
}

/*ARGSUSED*/
static int
zfs_umount(vfs_t *vfsp, int fflag, cred_t *cr)
{
    zfsvfs_t *zfsvfs = vfsp->vfs_data;
    objset_t *os;
    int ret;

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

    /*
     * 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.
     */
    (void) dnlc_purge_vfsp(zfsvfs->z_parent->z_vfs, 0);

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

    if (!(fflag & MS_FORCE)) {
        /*
         * Check the number of active vnodes in the file system.
         * Our count is maintained in the vfs structure, but the
         * number is off by 1 to indicate a hold on the vfs
         * structure itself.
         *
         * The '.zfs' directory maintains a reference of its
         * own, and any active references underneath are
         * reflected in the vnode count.
         */
        if (zfsvfs->z_ctldir == NULL) {
            if (vfsp->vfs_count > 1)
                return (EBUSY);
        } else {
            if (vfsp->vfs_count > 2 ||
                zfsvfs->z_ctldir->v_count > 1)
                return (EBUSY);
        }
    }

    vfsp->vfs_flag |= VFS_UNMOUNTED;

    VERIFY(zfsvfs_teardown(zfsvfs, B_TRUE) == 0);
    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->os_user_ptr_lock);
        dmu_objset_set_user(os, NULL);
        mutex_exit(&os->os->os_user_ptr_lock);

        /*
         * Finally release the objset
         */
        dmu_objset_close(os);
    }

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

    return (0);
}

static int
zfs_vget(vfs_t *vfsp, vnode_t **vpp, fid_t *fidp)
{
    zfsvfs_t    *zfsvfs = vfsp->vfs_data;
    znode_t     *zp;
    uint64_t    object = 0;
    uint64_t    fid_gen = 0;
    uint64_t    gen_mask;
    uint64_t    zp_gen;
    int         i, err;

    *vpp = NULL;

    ZFS_ENTER(zfsvfs);

    if (fidp->fid_len == LONG_FID_LEN) {
        zfid_long_t *zlfid = (zfid_long_t *)fidp;
        uint64_t    objsetid = 0;
        uint64_t    setgen = 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);

        err = zfsctl_lookup_objset(vfsp, objsetid, &zfsvfs);
        if (err)
            return (EINVAL);
        ZFS_ENTER(zfsvfs);
    }

    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);
        return (EINVAL);
    }

    /* A zero fid_gen means we are in the .zfs control directories */
    if (fid_gen == 0 &&
        (object == ZFSCTL_INO_ROOT || object == ZFSCTL_INO_SNAPDIR)) {
        *vpp = zfsvfs->z_ctldir;
        ASSERT(*vpp != NULL);
        if (object == ZFSCTL_INO_SNAPDIR) {
            VERIFY(zfsctl_root_lookup(*vpp, "snapshot", vpp, NULL,
                0, NULL, NULL, NULL, NULL, NULL) == 0);
        } else {
            VN_HOLD(*vpp);
        }
        ZFS_EXIT(zfsvfs);
        return (0);
    }

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

    dprintf("getting %llu [%u mask %llx]\n", object, fid_gen, gen_mask);
    if (err = zfs_zget(zfsvfs, object, &zp)) {
        ZFS_EXIT(zfsvfs);
        return (err);
    }
    zp_gen = zp->z_phys->zp_gen & gen_mask;
    if (zp_gen == 0)
        zp_gen = 1;
    if (zp->z_unlinked || zp_gen != fid_gen) {
        dprintf("znode gen (%u) != fid gen (%u)\n", zp_gen, fid_gen);
        VN_RELE(ZTOV(zp));
        ZFS_EXIT(zfsvfs);
        return (EINVAL);
    }

    *vpp = ZTOV(zp);
    ZFS_EXIT(zfsvfs);
    return (0);
}

/*
 * 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.
 */
int
zfs_suspend_fs(zfsvfs_t *zfsvfs, char *name, int *modep)
{
    int error;

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

    *modep = zfsvfs->z_os->os_mode;
    if (name)
        dmu_objset_name(zfsvfs->z_os, name);
    dmu_objset_close(zfsvfs->z_os);

    return (0);
}

/*
 * Reopen zfsvfs_t::z_os and release VOPs.
 */
int
zfs_resume_fs(zfsvfs_t *zfsvfs, const char *osname, int mode)
{
    int err;

    ASSERT(RRW_WRITE_HELD(&zfsvfs->z_teardown_lock));
    ASSERT(RW_WRITE_HELD(&zfsvfs->z_teardown_inactive_lock));

    err = dmu_objset_open(osname, DMU_OST_ZFS, mode, &zfsvfs->z_os);
    if (err) {
        zfsvfs->z_os = NULL;
    } else {
        znode_t *zp;

        VERIFY(zfsvfs_setup(zfsvfs, B_FALSE) == 0);

        /*
         * 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_VP
         * 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);

    }

    /* release the VOPs */
    rw_exit(&zfsvfs->z_teardown_inactive_lock);
    rrw_exit(&zfsvfs->z_teardown_lock, FTAG);

    if (err) {
        /*
         * Since we couldn't reopen zfsvfs::z_os, force
         * unmount this file system.
         */
        if (vn_vfswlock(zfsvfs->z_vfs->vfs_vnodecovered) == 0)
            (void) dounmount(zfsvfs->z_vfs, MS_FORCE, CRED());
    }
    return (err);
}

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

    /*
     * If this is a snapshot, we have an extra VFS_HOLD on our parent
     * from zfs_mount().  Release it here.
     */
    if (zfsvfs->z_issnap)
        VFS_RELE(zfsvfs->z_parent->z_vfs);

    zfsvfs_free(zfsvfs);

    atomic_add_32(&zfs_active_fs_count, -1);
}

/*
 * VFS_INIT() initialization.  Note that there is no VFS_FINI(),
 * so we can't safely do any non-idempotent initialization here.
 * Leave that to zfs_init() and zfs_fini(), which are called
 * from the module's _init() and _fini() entry points.
 */
/*ARGSUSED*/
static int
zfs_vfsinit(int fstype, char *name)
{
    int error;

    zfsfstype = fstype;

    /*
     * Setup vfsops and vnodeops tables.
     */
    error = vfs_setfsops(fstype, zfs_vfsops_template, &zfs_vfsops);
    if (error != 0) {
        cmn_err(CE_WARN, "zfs: bad vfs ops template");
    }

    error = zfs_create_op_tables();
    if (error) {
        zfs_remove_op_tables();
        cmn_err(CE_WARN, "zfs: bad vnode ops template");
        (void) vfs_freevfsops_by_type(zfsfstype);
        return (error);
    }

    mutex_init(&zfs_dev_mtx, NULL, MUTEX_DEFAULT, NULL);

    /*
     * Unique major number for all zfs mounts.
     * If we run out of 32-bit minors, we'll getudev() another major.
     */
    zfs_major = ddi_name_to_major(ZFS_DRIVER);
    zfs_minor = ZFS_MIN_MINOR;

    return (0);
}

void
zfs_init(void)
{
    /*
     * Initialize .zfs directory structures
     */
    zfsctl_init();

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

    dmu_objset_register_type(DMU_OST_ZFS, zfs_space_delta_cb);
}

void
zfs_fini(void)
{
    zfsctl_fini();
    zfs_znode_fini();
}

int
zfs_busy(void)
{
    return (zfs_active_fs_count != 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 (EINVAL);

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

    tx = dmu_tx_create(os);
    dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, B_FALSE, ZPL_VERSION_STR);
    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);
    }

    spa_history_internal_log(LOG_DS_UPGRADE,
        dmu_objset_spa(os), tx, CRED(),
        "oldver=%llu newver=%llu dataset = %llu",
        zfsvfs->z_version, newvers, dmu_objset_id(os));

    dmu_tx_commit(tx);

    zfsvfs->z_version = newvers;

    if (zfsvfs->z_version >= ZPL_VERSION_FUID)
        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)
{
    const char *pname;
    int error = ENOENT;

    /*
     * Look up the file system's value for the property.  For the
     * version property, we look up a slightly different string.
     */
    if (prop == ZFS_PROP_VERSION)
        pname = ZPL_VERSION_STR;
    else
        pname = zfs_prop_to_name(prop);

    if (os != NULL)
        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;
        default:
            return (error);
        }
        error = 0;
    }
    return (error);
}

static vfsdef_t vfw = {
    VFSDEF_VERSION,
    MNTTYPE_ZFS,
    zfs_vfsinit,
    VSW_HASPROTO|VSW_CANRWRO|VSW_CANREMOUNT|VSW_VOLATILEDEV|VSW_STATS|
        VSW_XID,
    &zfs_mntopts
};

struct modlfs zfs_modlfs = {
    &mod_fsops, "ZFS filesystem version " SPA_VERSION_STRING, &vfw
};