Merge branch 'dracut'

[mirror_zfs.git] / module / 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 http://www.opensolaris.org/os/licensing.
 * 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.
 */

/* Portions Copyright 2010 Robert Milkowski */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysmacros.h>
#include <sys/kmem.h>
#include <sys/pathname.h>
#include <sys/vnode.h>
#include <sys/vfs.h>
#include <sys/vfs_opreg.h>
#include <sys/mntent.h>
#include <sys/mount.h>
#include <sys/cmn_err.h>
#include "fs/fs_subr.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/varargs.h>
#include <sys/policy.h>
#include <sys/atomic.h>
#include <sys/mkdev.h>
#include <sys/modctl.h>
#include <sys/refstr.h>
#include <sys/zfs_ioctl.h>
#include <sys/zfs_fuid.h>
#include <sys/bootconf.h>
#include <sys/sunddi.h>
#include <sys/dnlc.h>
#include <sys/dmu_objset.h>
#include <sys/spa_boot.h>
#include <sys/sa.h>
#include <sys/zpl.h>
#include "zfs_comutil.h"


/*ARGSUSED*/
int
zfs_sync(struct super_block *sb, int wait, cred_t *cr)
{
        zfs_sb_t *zsb = sb->s_fs_info;

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

        /*
         * Semantically, the only requirement is that the sync be initiated.
         * The DMU syncs out txgs frequently, so there's nothing to do.
         */
        if (!wait)
                return (0);

        if (zsb != NULL) {
                /*
                 * Sync a specific filesystem.
                 */
                dsl_pool_t *dp;

                ZFS_ENTER(zsb);
                dp = dmu_objset_pool(zsb->z_os);

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

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

                ZFS_EXIT(zsb);
        } 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);
}
EXPORT_SYMBOL(zfs_sync);

static void
atime_changed_cb(void *arg, uint64_t newval)
{
        zfs_sb_t *zsb = arg;
        struct super_block *sb = zsb->z_sb;
        struct vfsmount *vfs = zsb->z_vfs;

        if (newval == TRUE) {
                vfs->mnt_flags &= ~MNT_NOATIME;
                sb->s_flags &= ~MS_NOATIME;
                zsb->z_atime = TRUE;
        } else {
                vfs->mnt_flags |= MNT_NOATIME;
                sb->s_flags |= MS_NOATIME;
                zsb->z_atime = FALSE;
        }
}

static void
xattr_changed_cb(void *arg, uint64_t newval)
{
        zfs_sb_t *zsb = arg;

        if (newval == TRUE) {
                zsb->z_flags |= ZSB_XATTR_USER;
        } else {
                zsb->z_flags &= ~ZSB_XATTR_USER;
        }
}

static void
blksz_changed_cb(void *arg, uint64_t newval)
{
        zfs_sb_t *zsb = arg;

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

        zsb->z_max_blksz = newval;
}

static void
readonly_changed_cb(void *arg, uint64_t newval)
{
        zfs_sb_t *zsb = arg;
        struct super_block *sb = zsb->z_sb;
        struct vfsmount *vfs = zsb->z_vfs;

        if (newval) {
                vfs->mnt_flags |= MNT_READONLY;
                sb->s_flags |= MS_RDONLY;
        } else {
                vfs->mnt_flags &= ~MNT_READONLY;
                sb->s_flags &= ~MS_RDONLY;
        }
}

static void
devices_changed_cb(void *arg, uint64_t newval)
{
        zfs_sb_t *zsb = arg;
        struct super_block *sb = zsb->z_sb;
        struct vfsmount *vfs = zsb->z_vfs;

        if (newval == FALSE) {
                vfs->mnt_flags |= MNT_NODEV;
                sb->s_flags |= MS_NODEV;
        } else {
                vfs->mnt_flags &= ~MNT_NODEV;
                sb->s_flags &= ~MS_NODEV;
        }
}

static void
setuid_changed_cb(void *arg, uint64_t newval)
{
        zfs_sb_t *zsb = arg;
        struct super_block *sb = zsb->z_sb;
        struct vfsmount *vfs = zsb->z_vfs;

        if (newval == FALSE) {
                vfs->mnt_flags |= MNT_NOSUID;
                sb->s_flags |= MS_NOSUID;
        } else {
                vfs->mnt_flags &= ~MNT_NOSUID;
                sb->s_flags &= ~MS_NOSUID;
        }
}

static void
exec_changed_cb(void *arg, uint64_t newval)
{
        zfs_sb_t *zsb = arg;
        struct super_block *sb = zsb->z_sb;
        struct vfsmount *vfs = zsb->z_vfs;

        if (newval == FALSE) {
                vfs->mnt_flags |= MNT_NOEXEC;
                sb->s_flags |= MS_NOEXEC;
        } else {
                vfs->mnt_flags &= ~MNT_NOEXEC;
                sb->s_flags &= ~MS_NOEXEC;
        }
}

/*
 * 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)
{
        zfs_sb_t *zsb = arg;
        struct super_block *sb = zsb->z_sb;

        if (newval == TRUE) {
                sb->s_flags |= MS_MANDLOCK;
        } else {
                sb->s_flags &= ~MS_MANDLOCK;
        }
}

static void
snapdir_changed_cb(void *arg, uint64_t newval)
{
        ((zfs_sb_t *)arg)->z_show_ctldir = newval;
}

static void
vscan_changed_cb(void *arg, uint64_t newval)
{
        ((zfs_sb_t *)arg)->z_vscan = newval;
}

static void
acl_inherit_changed_cb(void *arg, uint64_t newval)
{
        ((zfs_sb_t *)arg)->z_acl_inherit = newval;
}

int
zfs_register_callbacks(zfs_sb_t *zsb)
{
        struct vfsmount *vfsp = zsb->z_vfs;
        struct dsl_dataset *ds = NULL;
        objset_t *os = zsb->z_os;
        uint64_t nbmand;
        boolean_t readonly = B_FALSE;
        boolean_t setuid = B_TRUE;
        boolean_t exec = B_TRUE;
        boolean_t devices = B_TRUE;
        boolean_t xattr = B_TRUE;
        boolean_t atime = B_TRUE;
        char osname[MAXNAMELEN];
        int error = 0;

        /*
         * While Linux allows multiple vfs mounts per super block we have
         * limited it artificially to one in zfs_fill_super.  Thus it is
         * safe for us to modify the vfs mount fails through the callbacks.
         */
        if ((vfsp->mnt_flags & MNT_READONLY) ||
            !spa_writeable(dmu_objset_spa(os)))
                readonly = B_TRUE;

        if (vfsp->mnt_flags & MNT_NOSUID) {
                devices = B_FALSE;
                setuid = B_FALSE;
        } else {
                if (vfsp->mnt_flags & MNT_NODEV)
                        devices = B_FALSE;
        }

        if (vfsp->mnt_flags & MNT_NOEXEC)
                exec = B_FALSE;

        if (vfsp->mnt_flags & MNT_NOATIME)
                atime = B_FALSE;

        /*
         * nbmand is a special property which may only be changed at
         * mount time.  Unfortunately, Linux does not have a VFS mount
         * flag instead this is a super block flag.  So setting this
         * option at mount time will have to wait until we can parse
         * the mount option string.  For now we rely on the nbmand
         * value stored with the object set.  Additional mount option
         * string to be handled:
         *
         *   case: sensitive|insensitive|mixed
         *   zerocopy: on|off
         */

        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, zsb);
        error = error ? error : dsl_prop_register(ds,
            "xattr", xattr_changed_cb, zsb);
        error = error ? error : dsl_prop_register(ds,
            "recordsize", blksz_changed_cb, zsb);
        error = error ? error : dsl_prop_register(ds,
            "readonly", readonly_changed_cb, zsb);
        error = error ? error : dsl_prop_register(ds,
            "devices", devices_changed_cb, zsb);
        error = error ? error : dsl_prop_register(ds,
            "setuid", setuid_changed_cb, zsb);
        error = error ? error : dsl_prop_register(ds,
            "exec", exec_changed_cb, zsb);
        error = error ? error : dsl_prop_register(ds,
            "snapdir", snapdir_changed_cb, zsb);
        error = error ? error : dsl_prop_register(ds,
            "aclinherit", acl_inherit_changed_cb, zsb);
        error = error ? error : dsl_prop_register(ds,
            "vscan", vscan_changed_cb, zsb);
        if (error)
                goto unregister;

        /*
         * Invoke our callbacks to set required flags.
         */
        readonly_changed_cb(zsb, readonly);
        setuid_changed_cb(zsb, setuid);
        exec_changed_cb(zsb, exec);
        devices_changed_cb(zsb, devices);
        xattr_changed_cb(zsb, xattr);
        atime_changed_cb(zsb, atime);
        nbmand_changed_cb(zsb, 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, zsb);
        (void) dsl_prop_unregister(ds, "xattr", xattr_changed_cb, zsb);
        (void) dsl_prop_unregister(ds, "recordsize", blksz_changed_cb, zsb);
        (void) dsl_prop_unregister(ds, "readonly", readonly_changed_cb, zsb);
        (void) dsl_prop_unregister(ds, "devices", devices_changed_cb, zsb);
        (void) dsl_prop_unregister(ds, "setuid", setuid_changed_cb, zsb);
        (void) dsl_prop_unregister(ds, "exec", exec_changed_cb, zsb);
        (void) dsl_prop_unregister(ds, "snapdir", snapdir_changed_cb, zsb);
        (void) dsl_prop_unregister(ds, "aclinherit", acl_inherit_changed_cb,
            zsb);
        (void) dsl_prop_unregister(ds, "vscan", vscan_changed_cb, zsb);

        return (error);
}
EXPORT_SYMBOL(zfs_register_callbacks);

static int
zfs_space_delta_cb(dmu_object_type_t bonustype, void *data,
    uint64_t *userp, uint64_t *groupp)
{
        znode_phys_t *znp = data;
        int error = 0;

        /*
         * Is it a valid type of object to track?
         */
        if (bonustype != DMU_OT_ZNODE && bonustype != DMU_OT_SA)
                return (ENOENT);

        /*
         * If we have a NULL data pointer
         * then assume the id's aren't changing and
         * return EEXIST to the dmu to let it know to
         * use the same ids
         */
        if (data == NULL)
                return (EEXIST);

        if (bonustype == DMU_OT_ZNODE) {
                *userp = znp->zp_uid;
                *groupp = znp->zp_gid;
        } else {
                int hdrsize;

                ASSERT(bonustype == DMU_OT_SA);
                hdrsize = sa_hdrsize(data);

                if (hdrsize != 0) {
                        *userp = *((uint64_t *)((uintptr_t)data + hdrsize +
                            SA_UID_OFFSET));
                        *groupp = *((uint64_t *)((uintptr_t)data + hdrsize +
                            SA_GID_OFFSET));
                } else {
                        /*
                         * This should only happen for newly created
                         * files that haven't had the znode data filled
                         * in yet.
                         */
                        *userp = 0;
                        *groupp = 0;
                }
        }
        return (error);
}

static void
fuidstr_to_sid(zfs_sb_t *zsb, const char *fuidstr,
    char *domainbuf, int buflen, uid_t *ridp)
{
        uint64_t fuid;
        const char *domain;

        fuid = strtonum(fuidstr, NULL);

        domain = zfs_fuid_find_by_idx(zsb, 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(zfs_sb_t *zsb, 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 (zsb->z_userquota_obj);
        case ZFS_PROP_GROUPQUOTA:
                return (zsb->z_groupquota_obj);
        default:
                return (ENOTSUP);
        }
        return (0);
}

int
zfs_userspace_many(zfs_sb_t *zsb, 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(zsb->z_os))
                return (ENOTSUP);

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

        for (zap_cursor_init_serialized(&zc, zsb->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(zsb, 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);
}
EXPORT_SYMBOL(zfs_userspace_many);

/*
 * buf must be big enough (eg, 32 bytes)
 */
static int
id_to_fuidstr(zfs_sb_t *zsb, 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(zsb, 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(zfs_sb_t *zsb, 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(zsb->z_os))
                return (ENOTSUP);

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

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

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

int
zfs_set_userquota(zfs_sb_t *zsb, 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 (zsb->z_version < ZPL_VERSION_USERSPACE)
                return (ENOTSUP);

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

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

        tx = dmu_tx_create(zsb->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(zsb, tx);
        err = dmu_tx_assign(tx, TXG_WAIT);
        if (err) {
                dmu_tx_abort(tx);
                return (err);
        }

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

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

boolean_t
zfs_fuid_overquota(zfs_sb_t *zsb, 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 ? zsb->z_groupquota_obj : zsb->z_userquota_obj;

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

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

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

boolean_t
zfs_owner_overquota(zfs_sb_t *zsb, znode_t *zp, boolean_t isgroup)
{
        uint64_t fuid;
        uint64_t quotaobj;

        quotaobj = isgroup ? zsb->z_groupquota_obj : zsb->z_userquota_obj;

        fuid = isgroup ? zp->z_gid : zp->z_uid;

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

        return (zfs_fuid_overquota(zsb, isgroup, fuid));
}
EXPORT_SYMBOL(zfs_owner_overquota);

int
zfs_sb_create(const char *osname, zfs_sb_t **zsbp)
{
        objset_t *os;
        zfs_sb_t *zsb;
        uint64_t zval;
        int i, error;
        uint64_t sa_obj;

        zsb = kmem_zalloc(sizeof (zfs_sb_t), KM_SLEEP);

        /*
         * We claim to always be readonly so we can open snapshots;
         * other ZPL code will prevent us from writing to snapshots.
         */
        error = dmu_objset_own(osname, DMU_OST_ZFS, B_TRUE, zsb, &os);
        if (error) {
                kmem_free(zsb, sizeof (zfs_sb_t));
                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[].
         */
        zsb->z_vfs = NULL;
        zsb->z_parent = zsb;
        zsb->z_max_blksz = SPA_MAXBLOCKSIZE;
        zsb->z_show_ctldir = ZFS_SNAPDIR_VISIBLE;
        zsb->z_os = os;

        error = zfs_get_zplprop(os, ZFS_PROP_VERSION, &zsb->z_version);
        if (error) {
                goto out;
        } else if (zsb->z_version >
            zfs_zpl_version_map(spa_version(dmu_objset_spa(os)))) {
                (void) printk("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)zsb->z_version,
                    (u_longlong_t)spa_version(dmu_objset_spa(os)));
                error = ENOTSUP;
                goto out;
        }
        if ((error = zfs_get_zplprop(os, ZFS_PROP_NORMALIZE, &zval)) != 0)
                goto out;
        zsb->z_norm = (int)zval;

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

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

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

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

        if (zsb->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)
                        return (error);
        } else {
                /*
                 * Pre SA versions file systems should never touch
                 * either the attribute registration or layout objects.
                 */
                sa_obj = 0;
        }

        error = sa_setup(os, sa_obj, zfs_attr_table, ZPL_END,
            &zsb->z_attr_table);
        if (error)
                goto out;

        if (zsb->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,
            &zsb->z_root);
        if (error)
                goto out;
        ASSERT(zsb->z_root != 0);

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

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

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

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

        mutex_init(&zsb->z_znodes_lock, NULL, MUTEX_DEFAULT, NULL);
        mutex_init(&zsb->z_lock, NULL, MUTEX_DEFAULT, NULL);
        list_create(&zsb->z_all_znodes, sizeof (znode_t),
            offsetof(znode_t, z_link_node));
        rrw_init(&zsb->z_teardown_lock);
        rw_init(&zsb->z_teardown_inactive_lock, NULL, RW_DEFAULT, NULL);
        rw_init(&zsb->z_fuid_lock, NULL, RW_DEFAULT, NULL);
        for (i = 0; i != ZFS_OBJ_MTX_SZ; i++)
                mutex_init(&zsb->z_hold_mtx[i], NULL, MUTEX_DEFAULT, NULL);

        *zsbp = zsb;
        return (0);

out:
        dmu_objset_disown(os, zsb);
        *zsbp = NULL;
        kmem_free(zsb, sizeof (zfs_sb_t));
        return (error);
}

static int
zfs_sb_setup(zfs_sb_t *zsb, boolean_t mounting)
{
        int error;

        error = zfs_register_callbacks(zsb);
        if (error)
                return (error);

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

        zsb->z_log = zil_open(zsb->z_os, zfs_get_data);

        /*
         * 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 = zsb->z_vfs->mnt_flags & MNT_READONLY;
                if (readonly != 0)
                        zsb->z_vfs->mnt_flags &= ~MNT_READONLY;
                else
                        zfs_unlinked_drain(zsb);

                /*
                 * 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(zsb->z_os))) {
                        if (zil_replay_disable) {
                                zil_destroy(zsb->z_log, B_FALSE);
                        } else {
                                zsb->z_replay = B_TRUE;
                                zil_replay(zsb->z_os, zsb,
                                    zfs_replay_vector);
                                zsb->z_replay = B_FALSE;
                        }
                }
                zsb->z_vfs->mnt_flags |= readonly; /* restore readonly bit */
        }

        return (0);
}

void
zfs_sb_free(zfs_sb_t *zsb)
{
        int i;

        zfs_fuid_destroy(zsb);

        mutex_destroy(&zsb->z_znodes_lock);
        mutex_destroy(&zsb->z_lock);
        list_destroy(&zsb->z_all_znodes);
        rrw_destroy(&zsb->z_teardown_lock);
        rw_destroy(&zsb->z_teardown_inactive_lock);
        rw_destroy(&zsb->z_fuid_lock);
        for (i = 0; i != ZFS_OBJ_MTX_SZ; i++)
                mutex_destroy(&zsb->z_hold_mtx[i]);
        kmem_free(zsb, sizeof (zfs_sb_t));
}

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

void
zfs_unregister_callbacks(zfs_sb_t *zsb)
{
        objset_t *os = zsb->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,
                    zsb) == 0);

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

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

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

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

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

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

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

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

                VERIFY(dsl_prop_unregister(ds, "vscan",
                    vscan_changed_cb, zsb) == 0);
        }
}
EXPORT_SYMBOL(zfs_unregister_callbacks);

#ifdef HAVE_MLSLABEL
/*
 * zfs_check_global_label:
 *      Check that the hex label string is appropriate for the dataset
 *      being mounted into the global_zone proper.
 *
 *      Return an error if the hex label string is not default or
 *      admin_low/admin_high.  For admin_low labels, the corresponding
 *      dataset must be readonly.
 */
int
zfs_check_global_label(const char *dsname, const char *hexsl)
{
        if (strcasecmp(hexsl, ZFS_MLSLABEL_DEFAULT) == 0)
                return (0);
        if (strcasecmp(hexsl, ADMIN_HIGH) == 0)
                return (0);
        if (strcasecmp(hexsl, ADMIN_LOW) == 0) {
                /* must be readonly */
                uint64_t rdonly;

                if (dsl_prop_get_integer(dsname,
                    zfs_prop_to_name(ZFS_PROP_READONLY), &rdonly, NULL))
                        return (EACCES);
                return (rdonly ? 0 : EACCES);
        }
        return (EACCES);
}
#endif /* HAVE_MLSLABEL */

int
zfs_statvfs(struct dentry *dentry, struct kstatfs *statp)
{
        zfs_sb_t *zsb = dentry->d_sb->s_fs_info;
        uint64_t refdbytes, availbytes, usedobjs, availobjs;
        uint32_t bshift;

        ZFS_ENTER(zsb);

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

        /*
         * The underlying storage pool actually uses multiple block
         * size.  Under Solaris frsize (fragment size) is reported as
         * the smallest block size we support, and bsize (block size)
         * as the filesystem's maximum block size.  Unfortunately,
         * under Linux the fragment size and block size are often used
         * interchangeably.  Thus we are forced to report both of them
         * as the filesystem's maximum block size.
         */
        statp->f_frsize = zsb->z_max_blksz;
        statp->f_bsize = zsb->z_max_blksz;
        bshift = fls(statp->f_bsize) - 1;

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

        statp->f_blocks = (refdbytes + availbytes) >> bshift;
        statp->f_bfree = availbytes >> bshift;
        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;
        statp->f_fsid.val[0] = dentry->d_sb->s_dev;
        statp->f_fsid.val[1] = 0;
        statp->f_type = ZFS_SUPER_MAGIC;
        statp->f_namelen = ZFS_MAXNAMELEN;

        /*
         * We have all of 40 characters to stuff a string here.
         * Is there anything useful we could/should provide?
         */
        bzero(statp->f_spare, sizeof (statp->f_spare));

        ZFS_EXIT(zsb);
        return (0);
}
EXPORT_SYMBOL(zfs_statvfs);

int
zfs_root(zfs_sb_t *zsb, struct inode **ipp)
{
        znode_t *rootzp;
        int error;

        ZFS_ENTER(zsb);

        error = zfs_zget(zsb, zsb->z_root, &rootzp);
        if (error == 0)
                *ipp = ZTOI(rootzp);

        ZFS_EXIT(zsb);
        return (error);
}
EXPORT_SYMBOL(zfs_root);

/*
 * Teardown the zfs_sb_t::z_os.
 *
 * Note, if 'unmounting' if FALSE, we return with the 'z_teardown_lock'
 * and 'z_teardown_inactive_lock' held.
 */
int
zfsvfs_teardown(zfs_sb_t *zsb, boolean_t unmounting)
{
        znode_t *zp;

        rrw_enter(&zsb->z_teardown_lock, RW_WRITER, FTAG);

        if (!unmounting) {
                /*
                 * We purge the parent filesystem's super block as the
                 * parent filesystem and all of its snapshots have their
                 * inode's super block set to the parent's filesystem's
                 * super block.  Note,  'z_parent' is self referential
                 * for non-snapshots.
                 */
                shrink_dcache_sb(zsb->z_parent->z_sb);
                invalidate_inodes(zsb->z_parent->z_sb);
        }

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

        rw_enter(&zsb->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 && (zsb->z_unmounted || zsb->z_os == NULL)) {
                rw_exit(&zsb->z_teardown_inactive_lock);
                rrw_exit(&zsb->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(&zsb->z_znodes_lock);
        for (zp = list_head(&zsb->z_all_znodes); zp != NULL;
            zp = list_next(&zsb->z_all_znodes, zp))
                if (zp->z_sa_hdl) {
                        ASSERT(atomic_read(&ZTOI(zp)->i_count) > 0);
                        zfs_znode_dmu_fini(zp);
                }
        mutex_exit(&zsb->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) {
                zsb->z_unmounted = B_TRUE;
                rrw_exit(&zsb->z_teardown_lock, FTAG);
                rw_exit(&zsb->z_teardown_inactive_lock);
        }

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

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

        /*
         * Evict cached data
         */
        if (dmu_objset_is_dirty_anywhere(zsb->z_os))
                if (!(zsb->z_vfs->mnt_flags & MNT_READONLY))
                        txg_wait_synced(dmu_objset_pool(zsb->z_os), 0);
        (void) dmu_objset_evict_dbufs(zsb->z_os);

        return (0);
}

int
zfs_domount(struct super_block *sb, void *data, int silent)
{
        zpl_mount_data_t *zmd = data;
        const char *osname = zmd->z_osname;
        zfs_sb_t *zsb;
        struct inode *root_inode;
        uint64_t recordsize;
        int error;

        /*
         * Linux allows multiple vfs mounts per super block.  However, the
         * zfs_sb_t only contains a pointer for a single vfs mount.  This
         * back reference in the long term could be extended to a list of
         * vfs mounts if a hook were added to the kernel to notify us when
         * a vfsmount is destroyed.  Until then we must limit the number
         * of mounts per super block to one.
         */
        if (atomic_read(&sb->s_active) > 1)
                return (EBUSY);

        error = zfs_sb_create(osname, &zsb);
        if (error)
                return (error);

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

        zsb->z_sb = sb;
        zsb->z_vfs = zmd->z_vfs;
        sb->s_fs_info = zsb;
        sb->s_magic = ZFS_SUPER_MAGIC;
        sb->s_maxbytes = MAX_LFS_FILESIZE;
        sb->s_time_gran = 1;
        sb->s_blocksize = recordsize;
        sb->s_blocksize_bits = ilog2(recordsize);

        /* Set callback operations for the file system. */
        sb->s_op = &zpl_super_operations;
        sb->s_xattr = zpl_xattr_handlers;
#ifdef HAVE_EXPORTS
        sb->s_export_op = &zpl_export_operations;
#endif /* HAVE_EXPORTS */

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

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

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

                mutex_enter(&zsb->z_os->os_user_ptr_lock);
                dmu_objset_set_user(zsb->z_os, zsb);
                mutex_exit(&zsb->z_os->os_user_ptr_lock);
        } else {
                error = zfs_sb_setup(zsb, B_TRUE);
#ifdef HAVE_SNAPSHOT
                (void) zfs_snap_create(zsb);
#endif /* HAVE_SNAPSHOT */
        }

        /* Allocate a root inode for the filesystem. */
        error = zfs_root(zsb, &root_inode);
        if (error) {
                (void) zfs_umount(sb);
                goto out;
        }

        /* Allocate a root dentry for the filesystem */
        sb->s_root = d_alloc_root(root_inode);
        if (sb->s_root == NULL) {
                (void) zfs_umount(sb);
                error = ENOMEM;
                goto out;
        }
out:
        if (error) {
                dmu_objset_disown(zsb->z_os, zsb);
                zfs_sb_free(zsb);
        }

        return (error);
}
EXPORT_SYMBOL(zfs_domount);

/*ARGSUSED*/
int
zfs_umount(struct super_block *sb)
{
        zfs_sb_t *zsb = sb->s_fs_info;
        objset_t *os;

        VERIFY(zfsvfs_teardown(zsb, B_TRUE) == 0);
        os = zsb->z_os;

        /*
         * z_os will be NULL if there was an error in
         * attempting to reopen zsb.
         */
        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, zsb);
        }

        zfs_sb_free(zsb);
        return (0);
}
EXPORT_SYMBOL(zfs_umount);

int
zfs_remount(struct super_block *sb, int *flags, char *data)
{
        zfs_sb_t *zsb = sb->s_fs_info;
        boolean_t readonly = B_FALSE;
        boolean_t setuid = B_TRUE;
        boolean_t exec = B_TRUE;
        boolean_t devices = B_TRUE;
        boolean_t atime = B_TRUE;

        if (*flags & MS_RDONLY)
                readonly = B_TRUE;

        if (*flags & MS_NOSUID) {
                devices = B_FALSE;
                setuid = B_FALSE;
        } else {
                if (*flags & MS_NODEV)
                        devices = B_FALSE;
        }

        if (*flags & MS_NOEXEC)
                exec = B_FALSE;

        if (*flags & MS_NOATIME)
                atime = B_FALSE;

        /*
         * Invoke our callbacks to set required flags.
         */
        readonly_changed_cb(zsb, readonly);
        setuid_changed_cb(zsb, setuid);
        exec_changed_cb(zsb, exec);
        devices_changed_cb(zsb, devices);
        atime_changed_cb(zsb, atime);

        return (0);
}
EXPORT_SYMBOL(zfs_remount);

int
zfs_vget(struct vfsmount *vfsp, struct inode **ipp, fid_t *fidp)
{
        zfs_sb_t        *zsb = VTOZSB(vfsp);
        znode_t         *zp;
        uint64_t        object = 0;
        uint64_t        fid_gen = 0;
        uint64_t        gen_mask;
        uint64_t        zp_gen;
        int             i, err;

        *ipp = NULL;

        ZFS_ENTER(zsb);

        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(zsb);

#ifdef HAVE_SNAPSHOT
                err = zfsctl_lookup_objset(vfsp, objsetid, &zsb);
                if (err)
                        return (EINVAL);
#endif /* HAVE_SNAPSHOT */
                ZFS_ENTER(zsb);
        }

        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(zsb);
                return (EINVAL);
        }

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

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

        dprintf("getting %llu [%u mask %llx]\n", object, fid_gen, gen_mask);
        if ((err = zfs_zget(zsb, object, &zp))) {
                ZFS_EXIT(zsb);
                return (err);
        }
        (void) sa_lookup(zp->z_sa_hdl, SA_ZPL_GEN(zsb), &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 (%u) != fid gen (%u)\n", zp_gen, fid_gen);
                iput(ZTOI(zp));
                ZFS_EXIT(zsb);
                return (EINVAL);
        }

        *ipp = ZTOI(zp);
        if (*ipp)
                zfs_inode_update(ITOZ(*ipp));

        ZFS_EXIT(zsb);
        return (0);
}
EXPORT_SYMBOL(zfs_vget);

/*
 * Block out VOPs and close zfs_sb_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(zfs_sb_t *zsb)
{
        int error;

        if ((error = zfsvfs_teardown(zsb, B_FALSE)) != 0)
                return (error);
        dmu_objset_disown(zsb->z_os, zsb);

        return (0);
}
EXPORT_SYMBOL(zfs_suspend_fs);

/*
 * Reopen zfs_sb_t::z_os and release VOPs.
 */
int
zfs_resume_fs(zfs_sb_t *zsb, const char *osname)
{
        int err, err2;

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

        err = dmu_objset_own(osname, DMU_OST_ZFS, B_FALSE, zsb, &zsb->z_os);
        if (err) {
                zsb->z_os = NULL;
        } else {
                znode_t *zp;
                uint64_t sa_obj = 0;

                err2 = zap_lookup(zsb->z_os, MASTER_NODE_OBJ,
                    ZFS_SA_ATTRS, 8, 1, &sa_obj);

                if ((err || err2) && zsb->z_version >= ZPL_VERSION_SA)
                        goto bail;


                if ((err = sa_setup(zsb->z_os, sa_obj,
                    zfs_attr_table,  ZPL_END, &zsb->z_attr_table)) != 0)
                        goto bail;

                VERIFY(zfs_sb_setup(zsb, 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(&zsb->z_znodes_lock);
                for (zp = list_head(&zsb->z_all_znodes); zp;
                    zp = list_next(&zsb->z_all_znodes, zp)) {
                        (void) zfs_rezget(zp);
                }
                mutex_exit(&zsb->z_znodes_lock);

        }

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

        if (err) {
                /*
                 * Since we couldn't reopen zfs_sb_t::z_os, force
                 * unmount this file system.
                 */
                (void) zfs_umount(zsb->z_sb);
        }
        return (err);
}
EXPORT_SYMBOL(zfs_resume_fs);

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

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

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

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

        tx = dmu_tx_create(os);
        dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, B_FALSE, ZPL_VERSION_STR);
        if (newvers >= ZPL_VERSION_SA && !zsb->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 && !zsb->z_use_sa) {
                uint64_t sa_obj;

                ASSERT3U(spa_version(dmu_objset_spa(zsb->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);
                ASSERT3U(error, ==, 0);

                VERIFY(0 == sa_set_sa_object(os, sa_obj));
                sa_register_update_callback(os, zfs_sa_upgrade);
        }

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

        dmu_tx_commit(tx);

        zsb->z_version = newvers;

        if (zsb->z_version >= ZPL_VERSION_FUID)
                zfs_set_fuid_feature(zsb);

        return (0);
}
EXPORT_SYMBOL(zfs_set_version);

/*
 * 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);
}

void
zfs_init(void)
{
        zfs_znode_init();
        dmu_objset_register_type(DMU_OST_ZFS, zfs_space_delta_cb);
        register_filesystem(&zpl_fs_type);
}

void
zfs_fini(void)
{
        unregister_filesystem(&zpl_fs_type);
        zfs_znode_fini();
}