uint64_t
dsl_dir_create_sync(dsl_pool_t *dp, dsl_dir_t *pds, const char *name,
    dmu_tx_t *tx)
{
	objset_t *mos = dp->dp_meta_objset;
	uint64_t ddobj;
	dsl_dir_phys_t *dsphys;
	dmu_buf_t *dbuf;

	ddobj = dmu_object_alloc(mos, DMU_OT_DSL_DIR, 0,
	    DMU_OT_DSL_DIR, sizeof (dsl_dir_phys_t), tx);
	if (pds) {
		VERIFY(0 == zap_add(mos, pds->dd_phys->dd_child_dir_zapobj,
		    name, sizeof (uint64_t), 1, &ddobj, tx));
	} else {
		/* it's the root dir */
		VERIFY(0 == zap_add(mos, DMU_POOL_DIRECTORY_OBJECT,
		    DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1, &ddobj, tx));
	}
	VERIFY(0 == dmu_bonus_hold(mos, ddobj, FTAG, &dbuf));
	dmu_buf_will_dirty(dbuf, tx);
	dsphys = dbuf->db_data;

	dsphys->dd_creation_time = gethrestime_sec();
	if (pds)
		dsphys->dd_parent_obj = pds->dd_object;
	dsphys->dd_props_zapobj = zap_create(mos,
	    DMU_OT_DSL_PROPS, DMU_OT_NONE, 0, tx);
	dsphys->dd_child_dir_zapobj = zap_create(mos,
	    DMU_OT_DSL_DIR_CHILD_MAP, DMU_OT_NONE, 0, tx);
	dmu_buf_rele(dbuf, FTAG);

	return (ddobj);
}

void
spa_history_create_obj(spa_t *spa, dmu_tx_t *tx)
{
	dmu_buf_t *dbp;
	spa_history_phys_t *shpp;
	objset_t *mos = spa->spa_meta_objset;

	ASSERT(spa->spa_history == 0);
	spa->spa_history = dmu_object_alloc(mos, DMU_OT_SPA_HISTORY,
	    SPA_MAXBLOCKSIZE, DMU_OT_SPA_HISTORY_OFFSETS,
	    sizeof (spa_history_phys_t), tx);

	VERIFY(zap_add(mos, DMU_POOL_DIRECTORY_OBJECT,
	    DMU_POOL_HISTORY, sizeof (uint64_t), 1,
	    &spa->spa_history, tx) == 0);

	VERIFY(0 == dmu_bonus_hold(mos, spa->spa_history, FTAG, &dbp));
	ASSERT(dbp->db_size >= sizeof (spa_history_phys_t));

	shpp = dbp->db_data;
	dmu_buf_will_dirty(dbp, tx);

	/*
	 * Figure out maximum size of history log.  We set it at
	 * 0.1% of pool size, with a max of 1G and min of 128KB.
	 */
	shpp->sh_phys_max_off =
	    metaslab_class_get_dspace(spa_normal_class(spa)) / 1000;
	shpp->sh_phys_max_off = MIN(shpp->sh_phys_max_off, 1<<30);
	shpp->sh_phys_max_off = MAX(shpp->sh_phys_max_off, 128<<10);

	dmu_buf_rele(dbp, FTAG);
}

/*
 * load initial fuid domain and idx trees.  This function is used by
 * both the kernel and zdb.
 */
uint64_t
zfs_fuid_table_load(objset_t *os, uint64_t fuid_obj, avl_tree_t *idx_tree,
    avl_tree_t *domain_tree)
{
	dmu_buf_t *db;
	uint64_t fuid_size;

	avl_create(idx_tree, idx_compare,
	    sizeof (fuid_domain_t), offsetof(fuid_domain_t, f_idxnode));
	avl_create(domain_tree, domain_compare,
	    sizeof (fuid_domain_t), offsetof(fuid_domain_t, f_domnode));

	VERIFY(0 == dmu_bonus_hold(os, fuid_obj, FTAG, &db));
	fuid_size = *(uint64_t *)db->db_data;
	dmu_buf_rele(db, FTAG);

	if (fuid_size)  {
		nvlist_t **fuidnvp;
		nvlist_t *nvp = NULL;
		uint_t count;
		char *packed;
		int i;

		packed = kmem_alloc(fuid_size, KM_SLEEP);
		VERIFY(dmu_read(os, fuid_obj, 0, fuid_size, packed) == 0);
		VERIFY(nvlist_unpack(packed, fuid_size,
		    &nvp, 0) == 0);
		VERIFY(nvlist_lookup_nvlist_array(nvp, FUID_NVP_ARRAY,
		    &fuidnvp, &count) == 0);

		for (i = 0; i != count; i++) {
			fuid_domain_t *domnode;
			char *domain;
			uint64_t idx;

			VERIFY(nvlist_lookup_string(fuidnvp[i], FUID_DOMAIN,
			    &domain) == 0);
			VERIFY(nvlist_lookup_uint64(fuidnvp[i], FUID_IDX,
			    &idx) == 0);

			domnode = kmem_alloc(sizeof (fuid_domain_t), KM_SLEEP);

			domnode->f_idx = idx;
			domnode->f_ksid = ksid_lookupdomain(domain);
			avl_add(idx_tree, domnode);
			avl_add(domain_tree, domnode);
		}
		nvlist_free(nvp);
		kmem_free(packed, fuid_size);
	}
	return (fuid_size);
}

int
sa_handle_get(objset_t *objset, uint64_t objid, void *userp,
    sa_handle_type_t hdl_type, sa_handle_t **handlepp)
{
	dmu_buf_t *db;
	int error;

	if (error = dmu_bonus_hold(objset, objid, NULL, &db))
		return (error);

	return (sa_handle_get_from_db(objset, db, userp, hdl_type,
	    handlepp));
}

static int
bplist_hold(bplist_t *bpl)
{
	ASSERT(MUTEX_HELD(&bpl->bpl_lock));
	if (bpl->bpl_dbuf == NULL) {
		int err = dmu_bonus_hold(bpl->bpl_mos,
		    bpl->bpl_object, bpl, &bpl->bpl_dbuf);
		if (err)
			return (err);
		bpl->bpl_phys = bpl->bpl_dbuf->db_data;
	}
	return (0);
}

int
vdev_metaslab_init(vdev_t *vd, uint64_t txg)
{
	spa_t *spa = vd->vdev_spa;
	objset_t *mos = spa->spa_meta_objset;
	metaslab_class_t *mc = spa_metaslab_class_select(spa);
	uint64_t m;
	uint64_t oldc = vd->vdev_ms_count;
	uint64_t newc = vd->vdev_asize >> vd->vdev_ms_shift;
	metaslab_t **mspp;
	int error;

	if (vd->vdev_ms_shift == 0)	/* not being allocated from yet */
		return (0);

	dprintf("%s oldc %llu newc %llu\n", vdev_description(vd), oldc, newc);

	ASSERT(oldc <= newc);

	if (vd->vdev_mg == NULL)
		vd->vdev_mg = metaslab_group_create(mc, vd);

	mspp = kmem_zalloc(newc * sizeof (*mspp), KM_SLEEP);

	if (oldc != 0) {
		bcopy(vd->vdev_ms, mspp, oldc * sizeof (*mspp));
		kmem_free(vd->vdev_ms, oldc * sizeof (*mspp));
	}

	vd->vdev_ms = mspp;
	vd->vdev_ms_count = newc;

	for (m = oldc; m < newc; m++) {
		space_map_obj_t smo = { 0, 0, 0 };
		if (txg == 0) {
			uint64_t object = 0;
			error = dmu_read(mos, vd->vdev_ms_array,
			    m * sizeof (uint64_t), sizeof (uint64_t), &object);
			if (error)
				return (error);
			if (object != 0) {
				dmu_buf_t *db;
				error = dmu_bonus_hold(mos, object, FTAG, &db);
				if (error)
					return (error);
				ASSERT3U(db->db_size, ==, sizeof (smo));
				bcopy(db->db_data, &smo, db->db_size);
				ASSERT3U(smo.smo_object, ==, object);
				dmu_buf_rele(db, FTAG);
			}
		}

static int
zvol_first_open(zvol_state_t *zv)
{
	objset_t *os;
	uint64_t volsize;
	int error;
	uint64_t ro;

	/* lie and say we're read-only */
	error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, 1, zvol_tag, &os);
	if (error)
		return (SET_ERROR(-error));

	zv->zv_objset = os;

	error = dsl_prop_get_integer(zv->zv_name, "readonly", &ro, NULL);
	if (error)
		goto out_owned;

	error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
	if (error)
		goto out_owned;

	error = dmu_bonus_hold(os, ZVOL_OBJ, zvol_tag, &zv->zv_dbuf);
	if (error)
		goto out_owned;

	set_capacity(zv->zv_disk, volsize >> 9);
	zv->zv_volsize = volsize;
	zv->zv_zilog = zil_open(os, zvol_get_data);

	if (ro || dmu_objset_is_snapshot(os) ||
	    !spa_writeable(dmu_objset_spa(os))) {
		set_disk_ro(zv->zv_disk, 1);
		zv->zv_flags |= ZVOL_RDONLY;
	} else {
		set_disk_ro(zv->zv_disk, 0);
		zv->zv_flags &= ~ZVOL_RDONLY;
	}

out_owned:
	if (error) {
		dmu_objset_disown(os, zvol_tag);
		zv->zv_objset = NULL;
	}

	return (SET_ERROR(-error));
}

int
dmu_objset_userspace_upgrade(objset_t *os)
{
	uint64_t obj;
	int err = 0;

	if (dmu_objset_userspace_present(os))
		return (0);
	if (!dmu_objset_userused_enabled(os->os))
		return (ENOTSUP);
	if (dmu_objset_is_snapshot(os))
		return (EINVAL);

	/*
	 * We simply need to mark every object dirty, so that it will be
	 * synced out and now accounted.  If this is called
	 * concurrently, or if we already did some work before crashing,
	 * that's fine, since we track each object's accounted state
	 * independently.
	 */

	for (obj = 0; err == 0; err = dmu_object_next(os, &obj, FALSE, 0)) {
		dmu_tx_t *tx;
		dmu_buf_t *db;
		int objerr;

		if (issig(JUSTLOOKING) && issig(FORREAL))
			return (EINTR);

		objerr = dmu_bonus_hold(os, obj, FTAG, &db);
		if (objerr)
			continue;
		tx = dmu_tx_create(os);
		dmu_tx_hold_bonus(tx, obj);
		objerr = dmu_tx_assign(tx, TXG_WAIT);
		if (objerr) {
			dmu_tx_abort(tx);
			continue;
		}
		dmu_buf_will_dirty(db, tx);
		dmu_buf_rele(db, FTAG);
		dmu_tx_commit(tx);
	}

	os->os->os_flags |= OBJSET_FLAG_USERACCOUNTING_COMPLETE;
	txg_wait_synced(dmu_objset_pool(os), 0);
	return (0);
}

vdev_indirect_births_t *
vdev_indirect_births_open(objset_t *os, uint64_t births_object)
{
	vdev_indirect_births_t *vib = kmem_zalloc(sizeof (*vib), KM_SLEEP);

	vib->vib_objset = os;
	vib->vib_object = births_object;

	VERIFY0(dmu_bonus_hold(os, vib->vib_object, vib, &vib->vib_dbuf));
	vib->vib_phys = vib->vib_dbuf->db_data;

	if (vib->vib_phys->vib_count > 0) {
		uint64_t births_size = vdev_indirect_births_size_impl(vib);
		vib->vib_entries = kmem_alloc(births_size, KM_SLEEP);
		VERIFY0(dmu_read(vib->vib_objset, vib->vib_object, 0,
		    births_size, vib->vib_entries, DMU_READ_PREFETCH));
	}

	ASSERT(vdev_indirect_births_verify(vib));

	return (vib);
}

/*
 * Read out the command history.
 */
int
spa_history_get(spa_t *spa, uint64_t *offp, uint64_t *len, char *buf)
{
	objset_t *mos = spa->spa_meta_objset;
	dmu_buf_t *dbp;
	uint64_t read_len, phys_read_off, phys_eof;
	uint64_t leftover = 0;
	spa_history_phys_t *shpp;
	int err;

	/*
	 * If the command history  doesn't exist (older pool),
	 * that's ok, just return ENOENT.
	 */
	if (!spa->spa_history)
		return (ENOENT);

	/*
	 * The history is logged asynchronously, so when they request
	 * the first chunk of history, make sure everything has been
	 * synced to disk so that we get it.
	 */
	if (*offp == 0 && spa_writeable(spa))
		txg_wait_synced(spa_get_dsl(spa), 0);

	if ((err = dmu_bonus_hold(mos, spa->spa_history, FTAG, &dbp)) != 0)
		return (err);
	shpp = dbp->db_data;

#ifdef ZFS_DEBUG
	{
		dmu_object_info_t doi;
		dmu_object_info_from_db(dbp, &doi);
		ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_SPA_HISTORY_OFFSETS);
	}
#endif

	mutex_enter(&spa->spa_history_lock);
	phys_eof = spa_history_log_to_phys(shpp->sh_eof, shpp);

	if (*offp < shpp->sh_pool_create_len) {
		/* read in just the zpool create history */
		phys_read_off = *offp;
		read_len = MIN(*len, shpp->sh_pool_create_len -
		    phys_read_off);
	} else {
		/*
		 * Need to reset passed in offset to BOF if the passed in
		 * offset has since been overwritten.
		 */
		*offp = MAX(*offp, shpp->sh_bof);
		phys_read_off = spa_history_log_to_phys(*offp, shpp);

		/*
		 * Read up to the minimum of what the user passed down or
		 * the EOF (physical or logical).  If we hit physical EOF,
		 * use 'leftover' to read from the physical BOF.
		 */
		if (phys_read_off <= phys_eof) {
			read_len = MIN(*len, phys_eof - phys_read_off);
		} else {
			read_len = MIN(*len,
			    shpp->sh_phys_max_off - phys_read_off);
			if (phys_read_off + *len > shpp->sh_phys_max_off) {
				leftover = MIN(*len - read_len,
				    phys_eof - shpp->sh_pool_create_len);
			}
		}
	}

	/* offset for consumer to use next */
	*offp += read_len + leftover;

	/* tell the consumer how much you actually read */
	*len = read_len + leftover;

	if (read_len == 0) {
		mutex_exit(&spa->spa_history_lock);
		dmu_buf_rele(dbp, FTAG);
		return (0);
	}

	err = dmu_read(mos, spa->spa_history, phys_read_off, read_len, buf,
	    DMU_READ_PREFETCH);
	if (leftover && err == 0) {
		err = dmu_read(mos, spa->spa_history, shpp->sh_pool_create_len,
		    leftover, buf + read_len, DMU_READ_PREFETCH);
	}
	mutex_exit(&spa->spa_history_lock);

	dmu_buf_rele(dbp, FTAG);
	return (err);
}

/*ARGSUSED*/
static void
spa_history_log_sync(void *arg1, void *arg2, dmu_tx_t *tx)
{
	spa_t		*spa = arg1;
	history_arg_t	*hap = arg2;
	const char	*history_str = hap->ha_history_str;
	objset_t	*mos = spa->spa_meta_objset;
	dmu_buf_t	*dbp;
	spa_history_phys_t *shpp;
	size_t		reclen;
	uint64_t	le_len;
	nvlist_t	*nvrecord;
	char		*record_packed = NULL;
	int		ret;

	/*
	 * If we have an older pool that doesn't have a command
	 * history object, create it now.
	 */
	mutex_enter(&spa->spa_history_lock);
	if (!spa->spa_history)
		spa_history_create_obj(spa, tx);
	mutex_exit(&spa->spa_history_lock);

	/*
	 * Get the offset of where we need to write via the bonus buffer.
	 * Update the offset when the write completes.
	 */
	VERIFY(0 == dmu_bonus_hold(mos, spa->spa_history, FTAG, &dbp));
	shpp = dbp->db_data;

	dmu_buf_will_dirty(dbp, tx);

#ifdef ZFS_DEBUG
	{
		dmu_object_info_t doi;
		dmu_object_info_from_db(dbp, &doi);
		ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_SPA_HISTORY_OFFSETS);
	}
#endif

	VERIFY(nvlist_alloc(&nvrecord, NV_UNIQUE_NAME, KM_SLEEP) == 0);
	VERIFY(nvlist_add_uint64(nvrecord, ZPOOL_HIST_TIME,
	    gethrestime_sec()) == 0);
	VERIFY(nvlist_add_uint64(nvrecord, ZPOOL_HIST_WHO, hap->ha_uid) == 0);
	if (hap->ha_zone != NULL)
		VERIFY(nvlist_add_string(nvrecord, ZPOOL_HIST_ZONE,
		    hap->ha_zone) == 0);
#ifdef _KERNEL
	VERIFY(nvlist_add_string(nvrecord, ZPOOL_HIST_HOST,
	    utsname.nodename) == 0);
#endif
	if (hap->ha_log_type == LOG_CMD_POOL_CREATE ||
	    hap->ha_log_type == LOG_CMD_NORMAL) {
		VERIFY(nvlist_add_string(nvrecord, ZPOOL_HIST_CMD,
		    history_str) == 0);

		zfs_dbgmsg("command: %s", history_str);
	} else {
		VERIFY(nvlist_add_uint64(nvrecord, ZPOOL_HIST_INT_EVENT,
		    hap->ha_event) == 0);
		VERIFY(nvlist_add_uint64(nvrecord, ZPOOL_HIST_TXG,
		    tx->tx_txg) == 0);
		VERIFY(nvlist_add_string(nvrecord, ZPOOL_HIST_INT_STR,
		    history_str) == 0);

		zfs_dbgmsg("internal %s pool:%s txg:%llu %s",
		    zfs_history_event_names[hap->ha_event], spa_name(spa),
		    (longlong_t)tx->tx_txg, history_str);

	}

	VERIFY(nvlist_size(nvrecord, &reclen, NV_ENCODE_XDR) == 0);
	record_packed = kmem_alloc(reclen, KM_SLEEP);

	VERIFY(nvlist_pack(nvrecord, &record_packed, &reclen,
	    NV_ENCODE_XDR, KM_SLEEP) == 0);

	mutex_enter(&spa->spa_history_lock);
	if (hap->ha_log_type == LOG_CMD_POOL_CREATE)
		VERIFY(shpp->sh_eof == shpp->sh_pool_create_len);

	/* write out the packed length as little endian */
	le_len = LE_64((uint64_t)reclen);
	ret = spa_history_write(spa, &le_len, sizeof (le_len), shpp, tx);
	if (!ret)
		ret = spa_history_write(spa, record_packed, reclen, shpp, tx);

	if (!ret && hap->ha_log_type == LOG_CMD_POOL_CREATE) {
		shpp->sh_pool_create_len += sizeof (le_len) + reclen;
		shpp->sh_bof = shpp->sh_pool_create_len;
	}

	mutex_exit(&spa->spa_history_lock);
	nvlist_free(nvrecord);
	kmem_free(record_packed, reclen);
	dmu_buf_rele(dbp, FTAG);

	strfree(hap->ha_history_str);
//.........这里部分代码省略.........

/*ARGSUSED*/
static void
spa_history_log_sync(void *arg, dmu_tx_t *tx)
{
	nvlist_t	*nvl = arg;
	spa_t		*spa = dmu_tx_pool(tx)->dp_spa;
	objset_t	*mos = spa->spa_meta_objset;
	dmu_buf_t	*dbp;
	spa_history_phys_t *shpp;
	size_t		reclen;
	uint64_t	le_len;
	char		*record_packed = NULL;
	int		ret;

	/*
	 * If we have an older pool that doesn't have a command
	 * history object, create it now.
	 */
	mutex_enter(&spa->spa_history_lock);
	if (!spa->spa_history)
		spa_history_create_obj(spa, tx);
	mutex_exit(&spa->spa_history_lock);

	/*
	 * Get the offset of where we need to write via the bonus buffer.
	 * Update the offset when the write completes.
	 */
	VERIFY0(dmu_bonus_hold(mos, spa->spa_history, FTAG, &dbp));
	shpp = dbp->db_data;

	dmu_buf_will_dirty(dbp, tx);

#ifdef ZFS_DEBUG
	{
		dmu_object_info_t doi;
		dmu_object_info_from_db(dbp, &doi);
		ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_SPA_HISTORY_OFFSETS);
	}
#endif

	fnvlist_add_uint64(nvl, ZPOOL_HIST_TIME, gethrestime_sec());
#ifdef _KERNEL
	fnvlist_add_string(nvl, ZPOOL_HIST_HOST, utsname.nodename);
#endif
	if (nvlist_exists(nvl, ZPOOL_HIST_CMD)) {
		zfs_dbgmsg("command: %s",
		    fnvlist_lookup_string(nvl, ZPOOL_HIST_CMD));
	} else if (nvlist_exists(nvl, ZPOOL_HIST_INT_NAME)) {
		if (nvlist_exists(nvl, ZPOOL_HIST_DSNAME)) {
			zfs_dbgmsg("txg %lld %s %s (id %llu) %s",
			    fnvlist_lookup_uint64(nvl, ZPOOL_HIST_TXG),
			    fnvlist_lookup_string(nvl, ZPOOL_HIST_INT_NAME),
			    fnvlist_lookup_string(nvl, ZPOOL_HIST_DSNAME),
			    fnvlist_lookup_uint64(nvl, ZPOOL_HIST_DSID),
			    fnvlist_lookup_string(nvl, ZPOOL_HIST_INT_STR));
		} else {
			zfs_dbgmsg("txg %lld %s %s",
			    fnvlist_lookup_uint64(nvl, ZPOOL_HIST_TXG),
			    fnvlist_lookup_string(nvl, ZPOOL_HIST_INT_NAME),
			    fnvlist_lookup_string(nvl, ZPOOL_HIST_INT_STR));
		}
	} else if (nvlist_exists(nvl, ZPOOL_HIST_IOCTL)) {
		zfs_dbgmsg("ioctl %s",
		    fnvlist_lookup_string(nvl, ZPOOL_HIST_IOCTL));
	}

	record_packed = fnvlist_pack(nvl, &reclen);

	mutex_enter(&spa->spa_history_lock);

	/* write out the packed length as little endian */
	le_len = LE_64((uint64_t)reclen);
	ret = spa_history_write(spa, &le_len, sizeof (le_len), shpp, tx);
	if (!ret)
		ret = spa_history_write(spa, record_packed, reclen, shpp, tx);

	/* The first command is the create, which we keep forever */
	if (ret == 0 && shpp->sh_pool_create_len == 0 &&
	    nvlist_exists(nvl, ZPOOL_HIST_CMD)) {
		shpp->sh_pool_create_len = shpp->sh_bof = shpp->sh_eof;
	}

	mutex_exit(&spa->spa_history_lock);
	fnvlist_pack_free(record_packed, reclen);
	dmu_buf_rele(dbp, FTAG);
	fnvlist_free(nvl);
}

/*ARGSUSED*/
static void
spa_history_log_sync(void *arg, dmu_tx_t *tx)
{
	nvlist_t	*nvl = arg;
	spa_t		*spa = dmu_tx_pool(tx)->dp_spa;
	objset_t	*mos = spa->spa_meta_objset;
	dmu_buf_t	*dbp;
	spa_history_phys_t *shpp;
	size_t		reclen;
	uint64_t	le_len;
	char		*record_packed = NULL;
	int		ret;

	/*
	 * If we have an older pool that doesn't have a command
	 * history object, create it now.
	 */
	mutex_enter(&spa->spa_history_lock);
	if (!spa->spa_history)
		spa_history_create_obj(spa, tx);
	mutex_exit(&spa->spa_history_lock);

	/*
	 * Get the offset of where we need to write via the bonus buffer.
	 * Update the offset when the write completes.
	 */
	VERIFY0(dmu_bonus_hold(mos, spa->spa_history, FTAG, &dbp));
	shpp = dbp->db_data;

	dmu_buf_will_dirty(dbp, tx);

#ifdef ZFS_DEBUG
	{
		dmu_object_info_t doi;
		dmu_object_info_from_db(dbp, &doi);
		ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_SPA_HISTORY_OFFSETS);
	}
#endif

	fnvlist_add_uint64(nvl, ZPOOL_HIST_TIME, gethrestime_sec());
	fnvlist_add_string(nvl, ZPOOL_HIST_HOST, utsname()->nodename);

	if (nvlist_exists(nvl, ZPOOL_HIST_CMD)) {
		zfs_dbgmsg("command: %s",
		    fnvlist_lookup_string(nvl, ZPOOL_HIST_CMD));
	} else if (nvlist_exists(nvl, ZPOOL_HIST_INT_NAME)) {
		if (nvlist_exists(nvl, ZPOOL_HIST_DSNAME)) {
			zfs_dbgmsg("txg %lld %s %s (id %llu) %s",
			    fnvlist_lookup_uint64(nvl, ZPOOL_HIST_TXG),
			    fnvlist_lookup_string(nvl, ZPOOL_HIST_INT_NAME),
			    fnvlist_lookup_string(nvl, ZPOOL_HIST_DSNAME),
			    fnvlist_lookup_uint64(nvl, ZPOOL_HIST_DSID),
			    fnvlist_lookup_string(nvl, ZPOOL_HIST_INT_STR));
		} else {
			zfs_dbgmsg("txg %lld %s %s",
			    fnvlist_lookup_uint64(nvl, ZPOOL_HIST_TXG),
			    fnvlist_lookup_string(nvl, ZPOOL_HIST_INT_NAME),
			    fnvlist_lookup_string(nvl, ZPOOL_HIST_INT_STR));
		}
		/*
		 * The history sysevent is posted only for internal history
		 * messages to show what has happened, not how it happened. For
		 * example, the following command:
		 *
		 * # zfs destroy -r tank/foo
		 *
		 * will result in one sysevent posted per dataset that is
		 * destroyed as a result of the command - which could be more
		 * than one event in total.  By contrast, if the sysevent was
		 * posted as a result of the ZPOOL_HIST_CMD key being present
		 * it would result in only one sysevent being posted with the
		 * full command line arguments, requiring the consumer to know
		 * how to parse and understand zfs(1M) command invocations.
		 */
		spa_history_log_notify(spa, nvl);
	} else if (nvlist_exists(nvl, ZPOOL_HIST_IOCTL)) {
		zfs_dbgmsg("ioctl %s",
		    fnvlist_lookup_string(nvl, ZPOOL_HIST_IOCTL));
	}

	VERIFY3U(nvlist_pack(nvl, &record_packed, &reclen, NV_ENCODE_NATIVE,
	    KM_SLEEP), ==, 0);

	mutex_enter(&spa->spa_history_lock);

	/* write out the packed length as little endian */
	le_len = LE_64((uint64_t)reclen);
	ret = spa_history_write(spa, &le_len, sizeof (le_len), shpp, tx);
	if (!ret)
		ret = spa_history_write(spa, record_packed, reclen, shpp, tx);

	/* The first command is the create, which we keep forever */
	if (ret == 0 && shpp->sh_pool_create_len == 0 &&
	    nvlist_exists(nvl, ZPOOL_HIST_CMD)) {
		shpp->sh_pool_create_len = shpp->sh_bof = shpp->sh_eof;
	}

	mutex_exit(&spa->spa_history_lock);
	fnvlist_pack_free(record_packed, reclen);
//.........这里部分代码省略.........

int
sa_buf_hold(objset_t *objset, uint64_t obj_num, void *tag, dmu_buf_t **db)
{
	return (dmu_bonus_hold(objset, obj_num, tag, db));
}

int
dsl_dir_open_obj(dsl_pool_t *dp, uint64_t ddobj,
    const char *tail, void *tag, dsl_dir_t **ddp)
{
	dmu_buf_t *dbuf;
	dsl_dir_t *dd;
	int err;

	ASSERT(RW_LOCK_HELD(&dp->dp_config_rwlock) ||
	    dsl_pool_sync_context(dp));

	err = dmu_bonus_hold(dp->dp_meta_objset, ddobj, tag, &dbuf);
	if (err)
		return (err);
	dd = dmu_buf_get_user(dbuf);
#ifdef ZFS_DEBUG
	{
		dmu_object_info_t doi;
		dmu_object_info_from_db(dbuf, &doi);
		ASSERT3U(doi.doi_type, ==, DMU_OT_DSL_DIR);
	}
#endif
	/* XXX assert bonus buffer size is correct */
	if (dd == NULL) {
		dsl_dir_t *winner;
#ifndef __APPLE__
		int err;
#endif

		dd = kmem_zalloc(sizeof (dsl_dir_t), KM_SLEEP);
		dd->dd_object = ddobj;
		dd->dd_dbuf = dbuf;
		dd->dd_pool = dp;
		dd->dd_phys = dbuf->db_data;
		dd->dd_used_bytes = dd->dd_phys->dd_used_bytes;
		mutex_init(&dd->dd_lock, NULL, MUTEX_DEFAULT, NULL);

		list_create(&dd->dd_prop_cbs, sizeof (dsl_prop_cb_record_t),
		    offsetof(dsl_prop_cb_record_t, cbr_node));

		if (dd->dd_phys->dd_parent_obj) {
			err = dsl_dir_open_obj(dp, dd->dd_phys->dd_parent_obj,
			    NULL, dd, &dd->dd_parent);
			if (err) {
				mutex_destroy(&dd->dd_lock);
				kmem_free(dd, sizeof (dsl_dir_t));
				dmu_buf_rele(dbuf, tag);
				return (err);
			}
			if (tail) {
#ifdef ZFS_DEBUG
				uint64_t foundobj;

				err = zap_lookup(dp->dp_meta_objset,
				    dd->dd_parent->dd_phys->dd_child_dir_zapobj,
				    tail, sizeof (foundobj), 1, &foundobj);
				ASSERT(err || foundobj == ddobj);
#endif
				(void) strcpy(dd->dd_myname, tail);
			} else {
				err = zap_value_search(dp->dp_meta_objset,
				    dd->dd_parent->dd_phys->dd_child_dir_zapobj,
				    ddobj, 0, dd->dd_myname);
			}
			if (err) {
				dsl_dir_close(dd->dd_parent, dd);
				mutex_destroy(&dd->dd_lock);
				kmem_free(dd, sizeof (dsl_dir_t));
				dmu_buf_rele(dbuf, tag);
				return (err);
			}
		} else {
			(void) strcpy(dd->dd_myname, spa_name(dp->dp_spa));
		}

		winner = dmu_buf_set_user_ie(dbuf, dd, &dd->dd_phys,
		    dsl_dir_evict);
		if (winner) {
			if (dd->dd_parent)
				dsl_dir_close(dd->dd_parent, dd);
			mutex_destroy(&dd->dd_lock);
			kmem_free(dd, sizeof (dsl_dir_t));
			dd = winner;
		} else {
			spa_open_ref(dp->dp_spa, dd);
		}
	}

	/*
	 * The dsl_dir_t has both open-to-close and instantiate-to-evict
	 * holds on the spa.  We need the open-to-close holds because
	 * otherwise the spa_refcnt wouldn't change when we open a
	 * dir which the spa also has open, so we could incorrectly
	 * think it was OK to unload/export/destroy the pool.  We need
	 * the instantiate-to-evict hold because the dsl_dir_t has a
	 * pointer to the dd_pool, which has a pointer to the spa_t.
	 */
	spa_open_ref(dp->dp_spa, tag);
	ASSERT3P(dd->dd_pool, ==, dp);
	ASSERT3U(dd->dd_object, ==, ddobj);
//.........这里部分代码省略.........

int
dsl_dir_hold_obj(dsl_pool_t *dp, uint64_t ddobj,
    const char *tail, void *tag, dsl_dir_t **ddp)
{
	dmu_buf_t *dbuf;
	dsl_dir_t *dd;
	int err;

	ASSERT(dsl_pool_config_held(dp));

	err = dmu_bonus_hold(dp->dp_meta_objset, ddobj, tag, &dbuf);
	if (err != 0)
		return (err);
	dd = dmu_buf_get_user(dbuf);
#ifdef ZFS_DEBUG
	{
		dmu_object_info_t doi;
		dmu_object_info_from_db(dbuf, &doi);
		ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_DSL_DIR);
		ASSERT3U(doi.doi_bonus_size, >=, sizeof (dsl_dir_phys_t));
	}
#endif
	if (dd == NULL) {
		dsl_dir_t *winner;

		dd = kmem_zalloc(sizeof (dsl_dir_t), KM_SLEEP);
		dd->dd_object = ddobj;
		dd->dd_dbuf = dbuf;
		dd->dd_pool = dp;
		dd->dd_phys = dbuf->db_data;
		mutex_init(&dd->dd_lock, NULL, MUTEX_DEFAULT, NULL);

		list_create(&dd->dd_prop_cbs, sizeof (dsl_prop_cb_record_t),
		    offsetof(dsl_prop_cb_record_t, cbr_node));

		dsl_dir_snap_cmtime_update(dd);

		if (dd->dd_phys->dd_parent_obj) {
			err = dsl_dir_hold_obj(dp, dd->dd_phys->dd_parent_obj,
			    NULL, dd, &dd->dd_parent);
			if (err != 0)
				goto errout;
			if (tail) {
#ifdef ZFS_DEBUG
				uint64_t foundobj;

				err = zap_lookup(dp->dp_meta_objset,
				    dd->dd_parent->dd_phys->dd_child_dir_zapobj,
				    tail, sizeof (foundobj), 1, &foundobj);
				ASSERT(err || foundobj == ddobj);
#endif
				(void) strcpy(dd->dd_myname, tail);
			} else {
				err = zap_value_search(dp->dp_meta_objset,
				    dd->dd_parent->dd_phys->dd_child_dir_zapobj,
				    ddobj, 0, dd->dd_myname);
			}
			if (err != 0)
				goto errout;
		} else {
			(void) strcpy(dd->dd_myname, spa_name(dp->dp_spa));
		}

		if (dsl_dir_is_clone(dd)) {
			dmu_buf_t *origin_bonus;
			dsl_dataset_phys_t *origin_phys;

			/*
			 * We can't open the origin dataset, because
			 * that would require opening this dsl_dir.
			 * Just look at its phys directly instead.
			 */
			err = dmu_bonus_hold(dp->dp_meta_objset,
			    dd->dd_phys->dd_origin_obj, FTAG, &origin_bonus);
			if (err != 0)
				goto errout;
			origin_phys = origin_bonus->db_data;
			dd->dd_origin_txg =
			    origin_phys->ds_creation_txg;
			dmu_buf_rele(origin_bonus, FTAG);
		}

		winner = dmu_buf_set_user_ie(dbuf, dd, &dd->dd_phys,
		    dsl_dir_evict);
		if (winner) {
			if (dd->dd_parent)
				dsl_dir_rele(dd->dd_parent, dd);
			mutex_destroy(&dd->dd_lock);
			kmem_free(dd, sizeof (dsl_dir_t));
			dd = winner;
		} else {
			spa_open_ref(dp->dp_spa, dd);
		}
	}

	/*
	 * The dsl_dir_t has both open-to-close and instantiate-to-evict
	 * holds on the spa.  We need the open-to-close holds because
	 * otherwise the spa_refcnt wouldn't change when we open a
	 * dir which the spa also has open, so we could incorrectly
//.........这里部分代码省略.........

static int
zvol_first_open(zvol_state_t *zv)
{
	objset_t *os;
	uint64_t volsize;
	int locked = 0;
	int error;
	uint64_t ro;

	/*
	 * In all other cases the spa_namespace_lock is taken before the
	 * bdev->bd_mutex lock.  But in this case the Linux __blkdev_get()
	 * function calls fops->open() with the bdev->bd_mutex lock held.
	 *
	 * To avoid a potential lock inversion deadlock we preemptively
	 * try to take the spa_namespace_lock().  Normally it will not
	 * be contended and this is safe because spa_open_common() handles
	 * the case where the caller already holds the spa_namespace_lock.
	 *
	 * When it is contended we risk a lock inversion if we were to
	 * block waiting for the lock.  Luckily, the __blkdev_get()
	 * function allows us to return -ERESTARTSYS which will result in
	 * bdev->bd_mutex being dropped, reacquired, and fops->open() being
	 * called again.  This process can be repeated safely until both
	 * locks are acquired.
	 */
	if (!mutex_owned(&spa_namespace_lock)) {
		locked = mutex_tryenter(&spa_namespace_lock);
		if (!locked)
			return (-ERESTARTSYS);
	}

	/* lie and say we're read-only */
	error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, 1, zvol_tag, &os);
	if (error)
		goto out_mutex;

	error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
	if (error) {
		dmu_objset_disown(os, zvol_tag);
		goto out_mutex;
	}

	zv->zv_objset = os;
	error = dmu_bonus_hold(os, ZVOL_OBJ, zvol_tag, &zv->zv_dbuf);
	if (error) {
		dmu_objset_disown(os, zvol_tag);
		goto out_mutex;
	}

	set_capacity(zv->zv_disk, volsize >> 9);
	zv->zv_volsize = volsize;
	zv->zv_zilog = zil_open(os, zvol_get_data);

	VERIFY(dsl_prop_get_integer(zv->zv_name, "readonly", &ro, NULL) == 0);
	if (ro || dmu_objset_is_snapshot(os) ||
	    !spa_writeable(dmu_objset_spa(os))) {
		set_disk_ro(zv->zv_disk, 1);
		zv->zv_flags |= ZVOL_RDONLY;
	} else {
		set_disk_ro(zv->zv_disk, 0);
		zv->zv_flags &= ~ZVOL_RDONLY;
	}

out_mutex:
	if (locked)
		mutex_exit(&spa_namespace_lock);

	return (-error);
}

static
#endif
int
zfs_fuid_find_by_domain(zfsvfs_t *zfsvfs, const char *domain, char **retdomain,
    dmu_tx_t *tx)
{
	fuid_domain_t searchnode, *findnode;
	avl_index_t loc;

	/*
	 * If the dummy "nobody" domain then return an index of 0
	 * to cause the created FUID to be a standard POSIX id
	 * for the user nobody.
	 */
	if (domain[0] == '\0') {
		*retdomain = "";
		return (0);
	}

	searchnode.f_ksid = ksid_lookupdomain(domain);
	if (retdomain) {
		*retdomain = searchnode.f_ksid->kd_name;
	}
	if (!zfsvfs->z_fuid_loaded)
		zfs_fuid_init(zfsvfs, tx);

	rw_enter(&zfsvfs->z_fuid_lock, RW_READER);
	findnode = avl_find(&zfsvfs->z_fuid_domain, &searchnode, &loc);
	rw_exit(&zfsvfs->z_fuid_lock);

	if (findnode) {
		ksiddomain_rele(searchnode.f_ksid);
		return (findnode->f_idx);
	} else {
		fuid_domain_t *domnode;
		nvlist_t *nvp;
		nvlist_t **fuids;
		uint64_t retidx;
		size_t nvsize = 0;
		char *packed;
		dmu_buf_t *db;
		int i = 0;

		domnode = kmem_alloc(sizeof (fuid_domain_t), KM_SLEEP);
		domnode->f_ksid = searchnode.f_ksid;

		rw_enter(&zfsvfs->z_fuid_lock, RW_WRITER);
		retidx = domnode->f_idx = avl_numnodes(&zfsvfs->z_fuid_idx) + 1;

		avl_add(&zfsvfs->z_fuid_domain, domnode);
		avl_add(&zfsvfs->z_fuid_idx, domnode);
		/*
		 * Now resync the on-disk nvlist.
		 */
		VERIFY(nvlist_alloc(&nvp, NV_UNIQUE_NAME, KM_SLEEP) == 0);

		domnode = avl_first(&zfsvfs->z_fuid_domain);
		fuids = kmem_alloc(retidx * sizeof (void *), KM_SLEEP);
		while (domnode) {
			VERIFY(nvlist_alloc(&fuids[i],
			    NV_UNIQUE_NAME, KM_SLEEP) == 0);
			VERIFY(nvlist_add_uint64(fuids[i], FUID_IDX,
			    domnode->f_idx) == 0);
			VERIFY(nvlist_add_uint64(fuids[i],
			    FUID_OFFSET, 0) == 0);
			VERIFY(nvlist_add_string(fuids[i++], FUID_DOMAIN,
			    domnode->f_ksid->kd_name) == 0);
			domnode = AVL_NEXT(&zfsvfs->z_fuid_domain, domnode);
		}
		VERIFY(nvlist_add_nvlist_array(nvp, FUID_NVP_ARRAY,
		    fuids, retidx) == 0);
		for (i = 0; i != retidx; i++)
			nvlist_free(fuids[i]);
		kmem_free(fuids, retidx * sizeof (void *));
		VERIFY(nvlist_size(nvp, &nvsize, NV_ENCODE_XDR) == 0);
		packed = kmem_alloc(nvsize, KM_SLEEP);
		VERIFY(nvlist_pack(nvp, &packed, &nvsize,
		    NV_ENCODE_XDR, KM_SLEEP) == 0);
		nvlist_free(nvp);
		zfsvfs->z_fuid_size = nvsize;
		dmu_write(zfsvfs->z_os, zfsvfs->z_fuid_obj, 0,
		    zfsvfs->z_fuid_size, packed, tx);
		kmem_free(packed, zfsvfs->z_fuid_size);
		VERIFY(0 == dmu_bonus_hold(zfsvfs->z_os, zfsvfs->z_fuid_obj,
		    FTAG, &db));
		dmu_buf_will_dirty(db, tx);
		*(uint64_t *)db->db_data = zfsvfs->z_fuid_size;
		dmu_buf_rele(db, FTAG);

		rw_exit(&zfsvfs->z_fuid_lock);
		return (retidx);
	}
}

/*
 * sync out AVL trees to persistent storage.
 */
void
zfs_fuid_sync(zfsvfs_t *zfsvfs, dmu_tx_t *tx)
{
#ifdef HAVE_ZPL
	nvlist_t *nvp;
	nvlist_t **fuids;
	size_t nvsize = 0;
	char *packed;
	dmu_buf_t *db;
	fuid_domain_t *domnode;
	int numnodes;
	int i;

	if (!zfsvfs->z_fuid_dirty) {
		return;
	}

	rw_enter(&zfsvfs->z_fuid_lock, RW_WRITER);

	/*
	 * First see if table needs to be created?
	 */
	if (zfsvfs->z_fuid_obj == 0) {
		zfsvfs->z_fuid_obj = dmu_object_alloc(zfsvfs->z_os,
		    DMU_OT_FUID, 1 << 14, DMU_OT_FUID_SIZE,
		    sizeof (uint64_t), tx);
		VERIFY(zap_add(zfsvfs->z_os, MASTER_NODE_OBJ,
		    ZFS_FUID_TABLES, sizeof (uint64_t), 1,
		    &zfsvfs->z_fuid_obj, tx) == 0);
	}

	VERIFY(nvlist_alloc(&nvp, NV_UNIQUE_NAME, KM_SLEEP) == 0);

	numnodes = avl_numnodes(&zfsvfs->z_fuid_idx);
	fuids = kmem_alloc(numnodes * sizeof (void *), KM_SLEEP);
	for (i = 0, domnode = avl_first(&zfsvfs->z_fuid_domain); domnode; i++,
	    domnode = AVL_NEXT(&zfsvfs->z_fuid_domain, domnode)) {
		VERIFY(nvlist_alloc(&fuids[i], NV_UNIQUE_NAME, KM_SLEEP) == 0);
		VERIFY(nvlist_add_uint64(fuids[i], FUID_IDX,
		    domnode->f_idx) == 0);
		VERIFY(nvlist_add_uint64(fuids[i], FUID_OFFSET, 0) == 0);
		VERIFY(nvlist_add_string(fuids[i], FUID_DOMAIN,
		    domnode->f_ksid->kd_name) == 0);
	}
	VERIFY(nvlist_add_nvlist_array(nvp, FUID_NVP_ARRAY,
	    fuids, numnodes) == 0);
	for (i = 0; i != numnodes; i++)
		nvlist_free(fuids[i]);
	kmem_free(fuids, numnodes * sizeof (void *));
	VERIFY(nvlist_size(nvp, &nvsize, NV_ENCODE_XDR) == 0);
	packed = kmem_alloc(nvsize, KM_SLEEP);
	VERIFY(nvlist_pack(nvp, &packed, &nvsize,
	    NV_ENCODE_XDR, KM_SLEEP) == 0);
	nvlist_free(nvp);
	zfsvfs->z_fuid_size = nvsize;
	dmu_write(zfsvfs->z_os, zfsvfs->z_fuid_obj, 0,
	    zfsvfs->z_fuid_size, packed, tx);
	kmem_free(packed, zfsvfs->z_fuid_size);
	VERIFY(0 == dmu_bonus_hold(zfsvfs->z_os, zfsvfs->z_fuid_obj,
	    FTAG, &db));
	dmu_buf_will_dirty(db, tx);
	*(uint64_t *)db->db_data = zfsvfs->z_fuid_size;
	dmu_buf_rele(db, FTAG);

	zfsvfs->z_fuid_dirty = B_FALSE;
	rw_exit(&zfsvfs->z_fuid_lock);
#endif /* HAVE_ZPL */
}