Move the world out of /zfs/ and seperate out module build tree

1 files changed, 4301 insertions, 0 deletions

diff --git a/module/zfs/spa.c b/module/zfs/spa.c
new file mode 100644
index 000000000..fb1b96f8b
--- /dev/null
+++ b/module/zfs/spa.c
@@ -0,0 +1,4301 @@
+/*
+ * 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 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+/*
+ * This file contains all the routines used when modifying on-disk SPA state.
+ * This includes opening, importing, destroying, exporting a pool, and syncing a
+ * pool.
+ */
+
+#include <sys/zfs_context.h>
+#include <sys/fm/fs/zfs.h>
+#include <sys/spa_impl.h>
+#include <sys/zio.h>
+#include <sys/zio_checksum.h>
+#include <sys/zio_compress.h>
+#include <sys/dmu.h>
+#include <sys/dmu_tx.h>
+#include <sys/zap.h>
+#include <sys/zil.h>
+#include <sys/vdev_impl.h>
+#include <sys/metaslab.h>
+#include <sys/uberblock_impl.h>
+#include <sys/txg.h>
+#include <sys/avl.h>
+#include <sys/dmu_traverse.h>
+#include <sys/dmu_objset.h>
+#include <sys/unique.h>
+#include <sys/dsl_pool.h>
+#include <sys/dsl_dataset.h>
+#include <sys/dsl_dir.h>
+#include <sys/dsl_prop.h>
+#include <sys/dsl_synctask.h>
+#include <sys/fs/zfs.h>
+#include <sys/arc.h>
+#include <sys/callb.h>
+#include <sys/systeminfo.h>
+#include <sys/sunddi.h>
+#include <sys/spa_boot.h>
+
+#include "zfs_prop.h"
+#include "zfs_comutil.h"
+
+int zio_taskq_threads[ZIO_TYPES][ZIO_TASKQ_TYPES] = {
+	/*	ISSUE	INTR					*/
+	{	1,	1	},	/* ZIO_TYPE_NULL	*/
+	{	1,	8	},	/* ZIO_TYPE_READ	*/
+	{	8,	1	},	/* ZIO_TYPE_WRITE	*/
+	{	1,	1	},	/* ZIO_TYPE_FREE	*/
+	{	1,	1	},	/* ZIO_TYPE_CLAIM	*/
+	{	1,	1	},	/* ZIO_TYPE_IOCTL	*/
+};
+
+static void spa_sync_props(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx);
+static boolean_t spa_has_active_shared_spare(spa_t *spa);
+
+/*
+ * ==========================================================================
+ * SPA properties routines
+ * ==========================================================================
+ */
+
+/*
+ * Add a (source=src, propname=propval) list to an nvlist.
+ */
+static void
+spa_prop_add_list(nvlist_t *nvl, zpool_prop_t prop, char *strval,
+    uint64_t intval, zprop_source_t src)
+{
+	const char *propname = zpool_prop_to_name(prop);
+	nvlist_t *propval;
+
+	VERIFY(nvlist_alloc(&propval, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+	VERIFY(nvlist_add_uint64(propval, ZPROP_SOURCE, src) == 0);
+
+	if (strval != NULL)
+		VERIFY(nvlist_add_string(propval, ZPROP_VALUE, strval) == 0);
+	else
+		VERIFY(nvlist_add_uint64(propval, ZPROP_VALUE, intval) == 0);
+
+	VERIFY(nvlist_add_nvlist(nvl, propname, propval) == 0);
+	nvlist_free(propval);
+}
+
+/*
+ * Get property values from the spa configuration.
+ */
+static void
+spa_prop_get_config(spa_t *spa, nvlist_t **nvp)
+{
+	uint64_t size = spa_get_space(spa);
+	uint64_t used = spa_get_alloc(spa);
+	uint64_t cap, version;
+	zprop_source_t src = ZPROP_SRC_NONE;
+	spa_config_dirent_t *dp;
+
+	ASSERT(MUTEX_HELD(&spa->spa_props_lock));
+
+	/*
+	 * readonly properties
+	 */
+	spa_prop_add_list(*nvp, ZPOOL_PROP_NAME, spa_name(spa), 0, src);
+	spa_prop_add_list(*nvp, ZPOOL_PROP_SIZE, NULL, size, src);
+	spa_prop_add_list(*nvp, ZPOOL_PROP_USED, NULL, used, src);
+	spa_prop_add_list(*nvp, ZPOOL_PROP_AVAILABLE, NULL, size - used, src);
+
+	cap = (size == 0) ? 0 : (used * 100 / size);
+	spa_prop_add_list(*nvp, ZPOOL_PROP_CAPACITY, NULL, cap, src);
+
+	spa_prop_add_list(*nvp, ZPOOL_PROP_GUID, NULL, spa_guid(spa), src);
+	spa_prop_add_list(*nvp, ZPOOL_PROP_HEALTH, NULL,
+	    spa->spa_root_vdev->vdev_state, src);
+
+	/*
+	 * settable properties that are not stored in the pool property object.
+	 */
+	version = spa_version(spa);
+	if (version == zpool_prop_default_numeric(ZPOOL_PROP_VERSION))
+		src = ZPROP_SRC_DEFAULT;
+	else
+		src = ZPROP_SRC_LOCAL;
+	spa_prop_add_list(*nvp, ZPOOL_PROP_VERSION, NULL, version, src);
+
+	if (spa->spa_root != NULL)
+		spa_prop_add_list(*nvp, ZPOOL_PROP_ALTROOT, spa->spa_root,
+		    0, ZPROP_SRC_LOCAL);
+
+	if ((dp = list_head(&spa->spa_config_list)) != NULL) {
+		if (dp->scd_path == NULL) {
+			spa_prop_add_list(*nvp, ZPOOL_PROP_CACHEFILE,
+			    "none", 0, ZPROP_SRC_LOCAL);
+		} else if (strcmp(dp->scd_path, spa_config_path) != 0) {
+			spa_prop_add_list(*nvp, ZPOOL_PROP_CACHEFILE,
+			    dp->scd_path, 0, ZPROP_SRC_LOCAL);
+		}
+	}
+}
+
+/*
+ * Get zpool property values.
+ */
+int
+spa_prop_get(spa_t *spa, nvlist_t **nvp)
+{
+	zap_cursor_t zc;
+	zap_attribute_t za;
+	objset_t *mos = spa->spa_meta_objset;
+	int err;
+
+	VERIFY(nvlist_alloc(nvp, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+
+	mutex_enter(&spa->spa_props_lock);
+
+	/*
+	 * Get properties from the spa config.
+	 */
+	spa_prop_get_config(spa, nvp);
+
+	/* If no pool property object, no more prop to get. */
+	if (spa->spa_pool_props_object == 0) {
+		mutex_exit(&spa->spa_props_lock);
+		return (0);
+	}
+
+	/*
+	 * Get properties from the MOS pool property object.
+	 */
+	for (zap_cursor_init(&zc, mos, spa->spa_pool_props_object);
+	    (err = zap_cursor_retrieve(&zc, &za)) == 0;
+	    zap_cursor_advance(&zc)) {
+		uint64_t intval = 0;
+		char *strval = NULL;
+		zprop_source_t src = ZPROP_SRC_DEFAULT;
+		zpool_prop_t prop;
+
+		if ((prop = zpool_name_to_prop(za.za_name)) == ZPROP_INVAL)
+			continue;
+
+		switch (za.za_integer_length) {
+		case 8:
+			/* integer property */
+			if (za.za_first_integer !=
+			    zpool_prop_default_numeric(prop))
+				src = ZPROP_SRC_LOCAL;
+
+			if (prop == ZPOOL_PROP_BOOTFS) {
+				dsl_pool_t *dp;
+				dsl_dataset_t *ds = NULL;
+
+				dp = spa_get_dsl(spa);
+				rw_enter(&dp->dp_config_rwlock, RW_READER);
+				if (err = dsl_dataset_hold_obj(dp,
+				    za.za_first_integer, FTAG, &ds)) {
+					rw_exit(&dp->dp_config_rwlock);
+					break;
+				}
+
+				strval = kmem_alloc(
+				    MAXNAMELEN + strlen(MOS_DIR_NAME) + 1,
+				    KM_SLEEP);
+				dsl_dataset_name(ds, strval);
+				dsl_dataset_rele(ds, FTAG);
+				rw_exit(&dp->dp_config_rwlock);
+			} else {
+				strval = NULL;
+				intval = za.za_first_integer;
+			}
+
+			spa_prop_add_list(*nvp, prop, strval, intval, src);
+
+			if (strval != NULL)
+				kmem_free(strval,
+				    MAXNAMELEN + strlen(MOS_DIR_NAME) + 1);
+
+			break;
+
+		case 1:
+			/* string property */
+			strval = kmem_alloc(za.za_num_integers, KM_SLEEP);
+			err = zap_lookup(mos, spa->spa_pool_props_object,
+			    za.za_name, 1, za.za_num_integers, strval);
+			if (err) {
+				kmem_free(strval, za.za_num_integers);
+				break;
+			}
+			spa_prop_add_list(*nvp, prop, strval, 0, src);
+			kmem_free(strval, za.za_num_integers);
+			break;
+
+		default:
+			break;
+		}
+	}
+	zap_cursor_fini(&zc);
+	mutex_exit(&spa->spa_props_lock);
+out:
+	if (err && err != ENOENT) {
+		nvlist_free(*nvp);
+		*nvp = NULL;
+		return (err);
+	}
+
+	return (0);
+}
+
+/*
+ * Validate the given pool properties nvlist and modify the list
+ * for the property values to be set.
+ */
+static int
+spa_prop_validate(spa_t *spa, nvlist_t *props)
+{
+	nvpair_t *elem;
+	int error = 0, reset_bootfs = 0;
+	uint64_t objnum;
+
+	elem = NULL;
+	while ((elem = nvlist_next_nvpair(props, elem)) != NULL) {
+		zpool_prop_t prop;
+		char *propname, *strval;
+		uint64_t intval;
+		objset_t *os;
+		char *slash;
+
+		propname = nvpair_name(elem);
+
+		if ((prop = zpool_name_to_prop(propname)) == ZPROP_INVAL)
+			return (EINVAL);
+
+		switch (prop) {
+		case ZPOOL_PROP_VERSION:
+			error = nvpair_value_uint64(elem, &intval);
+			if (!error &&
+			    (intval < spa_version(spa) || intval > SPA_VERSION))
+				error = EINVAL;
+			break;
+
+		case ZPOOL_PROP_DELEGATION:
+		case ZPOOL_PROP_AUTOREPLACE:
+		case ZPOOL_PROP_LISTSNAPS:
+			error = nvpair_value_uint64(elem, &intval);
+			if (!error && intval > 1)
+				error = EINVAL;
+			break;
+
+		case ZPOOL_PROP_BOOTFS:
+			if (spa_version(spa) < SPA_VERSION_BOOTFS) {
+				error = ENOTSUP;
+				break;
+			}
+
+			/*
+			 * Make sure the vdev config is bootable
+			 */
+			if (!vdev_is_bootable(spa->spa_root_vdev)) {
+				error = ENOTSUP;
+				break;
+			}
+
+			reset_bootfs = 1;
+
+			error = nvpair_value_string(elem, &strval);
+
+			if (!error) {
+				uint64_t compress;
+
+				if (strval == NULL || strval[0] == '\0') {
+					objnum = zpool_prop_default_numeric(
+					    ZPOOL_PROP_BOOTFS);
+					break;
+				}
+
+				if (error = dmu_objset_open(strval, DMU_OST_ZFS,
+				    DS_MODE_USER | DS_MODE_READONLY, &os))
+					break;
+
+				/* We don't support gzip bootable datasets */
+				if ((error = dsl_prop_get_integer(strval,
+				    zfs_prop_to_name(ZFS_PROP_COMPRESSION),
+				    &compress, NULL)) == 0 &&
+				    !BOOTFS_COMPRESS_VALID(compress)) {
+					error = ENOTSUP;
+				} else {
+					objnum = dmu_objset_id(os);
+				}
+				dmu_objset_close(os);
+			}
+			break;
+
+		case ZPOOL_PROP_FAILUREMODE:
+			error = nvpair_value_uint64(elem, &intval);
+			if (!error && (intval < ZIO_FAILURE_MODE_WAIT ||
+			    intval > ZIO_FAILURE_MODE_PANIC))
+				error = EINVAL;
+
+			/*
+			 * This is a special case which only occurs when
+			 * the pool has completely failed. This allows
+			 * the user to change the in-core failmode property
+			 * without syncing it out to disk (I/Os might
+			 * currently be blocked). We do this by returning
+			 * EIO to the caller (spa_prop_set) to trick it
+			 * into thinking we encountered a property validation
+			 * error.
+			 */
+			if (!error && spa_suspended(spa)) {
+				spa->spa_failmode = intval;
+				error = EIO;
+			}
+			break;
+
+		case ZPOOL_PROP_CACHEFILE:
+			if ((error = nvpair_value_string(elem, &strval)) != 0)
+				break;
+
+			if (strval[0] == '\0')
+				break;
+
+			if (strcmp(strval, "none") == 0)
+				break;
+
+			if (strval[0] != '/') {
+				error = EINVAL;
+				break;
+			}
+
+			slash = strrchr(strval, '/');
+			ASSERT(slash != NULL);
+
+			if (slash[1] == '\0' || strcmp(slash, "/.") == 0 ||
+			    strcmp(slash, "/..") == 0)
+				error = EINVAL;
+			break;
+		}
+
+		if (error)
+			break;
+	}
+
+	if (!error && reset_bootfs) {
+		error = nvlist_remove(props,
+		    zpool_prop_to_name(ZPOOL_PROP_BOOTFS), DATA_TYPE_STRING);
+
+		if (!error) {
+			error = nvlist_add_uint64(props,
+			    zpool_prop_to_name(ZPOOL_PROP_BOOTFS), objnum);
+		}
+	}
+
+	return (error);
+}
+
+int
+spa_prop_set(spa_t *spa, nvlist_t *nvp)
+{
+	int error;
+
+	if ((error = spa_prop_validate(spa, nvp)) != 0)
+		return (error);
+
+	return (dsl_sync_task_do(spa_get_dsl(spa), NULL, spa_sync_props,
+	    spa, nvp, 3));
+}
+
+/*
+ * If the bootfs property value is dsobj, clear it.
+ */
+void
+spa_prop_clear_bootfs(spa_t *spa, uint64_t dsobj, dmu_tx_t *tx)
+{
+	if (spa->spa_bootfs == dsobj && spa->spa_pool_props_object != 0) {
+		VERIFY(zap_remove(spa->spa_meta_objset,
+		    spa->spa_pool_props_object,
+		    zpool_prop_to_name(ZPOOL_PROP_BOOTFS), tx) == 0);
+		spa->spa_bootfs = 0;
+	}
+}
+
+/*
+ * ==========================================================================
+ * SPA state manipulation (open/create/destroy/import/export)
+ * ==========================================================================
+ */
+
+static int
+spa_error_entry_compare(const void *a, const void *b)
+{
+	spa_error_entry_t *sa = (spa_error_entry_t *)a;
+	spa_error_entry_t *sb = (spa_error_entry_t *)b;
+	int ret;
+
+	ret = bcmp(&sa->se_bookmark, &sb->se_bookmark,
+	    sizeof (zbookmark_t));
+
+	if (ret < 0)
+		return (-1);
+	else if (ret > 0)
+		return (1);
+	else
+		return (0);
+}
+
+/*
+ * Utility function which retrieves copies of the current logs and
+ * re-initializes them in the process.
+ */
+void
+spa_get_errlists(spa_t *spa, avl_tree_t *last, avl_tree_t *scrub)
+{
+	ASSERT(MUTEX_HELD(&spa->spa_errlist_lock));
+
+	bcopy(&spa->spa_errlist_last, last, sizeof (avl_tree_t));
+	bcopy(&spa->spa_errlist_scrub, scrub, sizeof (avl_tree_t));
+
+	avl_create(&spa->spa_errlist_scrub,
+	    spa_error_entry_compare, sizeof (spa_error_entry_t),
+	    offsetof(spa_error_entry_t, se_avl));
+	avl_create(&spa->spa_errlist_last,
+	    spa_error_entry_compare, sizeof (spa_error_entry_t),
+	    offsetof(spa_error_entry_t, se_avl));
+}
+
+/*
+ * Activate an uninitialized pool.
+ */
+static void
+spa_activate(spa_t *spa)
+{
+	ASSERT(spa->spa_state == POOL_STATE_UNINITIALIZED);
+
+	spa->spa_state = POOL_STATE_ACTIVE;
+
+	spa->spa_normal_class = metaslab_class_create();
+	spa->spa_log_class = metaslab_class_create();
+
+	for (int t = 0; t < ZIO_TYPES; t++) {
+		for (int q = 0; q < ZIO_TASKQ_TYPES; q++) {
+			spa->spa_zio_taskq[t][q] = taskq_create("spa_zio",
+			    zio_taskq_threads[t][q], maxclsyspri, 50,
+			    INT_MAX, TASKQ_PREPOPULATE);
+		}
+	}
+
+	list_create(&spa->spa_config_dirty_list, sizeof (vdev_t),
+	    offsetof(vdev_t, vdev_config_dirty_node));
+	list_create(&spa->spa_state_dirty_list, sizeof (vdev_t),
+	    offsetof(vdev_t, vdev_state_dirty_node));
+
+	txg_list_create(&spa->spa_vdev_txg_list,
+	    offsetof(struct vdev, vdev_txg_node));
+
+	avl_create(&spa->spa_errlist_scrub,
+	    spa_error_entry_compare, sizeof (spa_error_entry_t),
+	    offsetof(spa_error_entry_t, se_avl));
+	avl_create(&spa->spa_errlist_last,
+	    spa_error_entry_compare, sizeof (spa_error_entry_t),
+	    offsetof(spa_error_entry_t, se_avl));
+}
+
+/*
+ * Opposite of spa_activate().
+ */
+static void
+spa_deactivate(spa_t *spa)
+{
+	ASSERT(spa->spa_sync_on == B_FALSE);
+	ASSERT(spa->spa_dsl_pool == NULL);
+	ASSERT(spa->spa_root_vdev == NULL);
+
+	ASSERT(spa->spa_state != POOL_STATE_UNINITIALIZED);
+
+	txg_list_destroy(&spa->spa_vdev_txg_list);
+
+	list_destroy(&spa->spa_config_dirty_list);
+	list_destroy(&spa->spa_state_dirty_list);
+
+	for (int t = 0; t < ZIO_TYPES; t++) {
+		for (int q = 0; q < ZIO_TASKQ_TYPES; q++) {
+			taskq_destroy(spa->spa_zio_taskq[t][q]);
+			spa->spa_zio_taskq[t][q] = NULL;
+		}
+	}
+
+	metaslab_class_destroy(spa->spa_normal_class);
+	spa->spa_normal_class = NULL;
+
+	metaslab_class_destroy(spa->spa_log_class);
+	spa->spa_log_class = NULL;
+
+	/*
+	 * If this was part of an import or the open otherwise failed, we may
+	 * still have errors left in the queues.  Empty them just in case.
+	 */
+	spa_errlog_drain(spa);
+
+	avl_destroy(&spa->spa_errlist_scrub);
+	avl_destroy(&spa->spa_errlist_last);
+
+	spa->spa_state = POOL_STATE_UNINITIALIZED;
+}
+
+/*
+ * Verify a pool configuration, and construct the vdev tree appropriately.  This
+ * will create all the necessary vdevs in the appropriate layout, with each vdev
+ * in the CLOSED state.  This will prep the pool before open/creation/import.
+ * All vdev validation is done by the vdev_alloc() routine.
+ */
+static int
+spa_config_parse(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent,
+    uint_t id, int atype)
+{
+	nvlist_t **child;
+	uint_t c, children;
+	int error;
+
+	if ((error = vdev_alloc(spa, vdp, nv, parent, id, atype)) != 0)
+		return (error);
+
+	if ((*vdp)->vdev_ops->vdev_op_leaf)
+		return (0);
+
+	error = nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_CHILDREN,
+	    &child, &children);
+
+	if (error == ENOENT)
+		return (0);
+
+	if (error) {
+		vdev_free(*vdp);
+		*vdp = NULL;
+		return (EINVAL);
+	}
+
+	for (c = 0; c < children; c++) {
+		vdev_t *vd;
+		if ((error = spa_config_parse(spa, &vd, child[c], *vdp, c,
+		    atype)) != 0) {
+			vdev_free(*vdp);
+			*vdp = NULL;
+			return (error);
+		}
+	}
+
+	ASSERT(*vdp != NULL);
+
+	return (0);
+}
+
+/*
+ * Opposite of spa_load().
+ */
+static void
+spa_unload(spa_t *spa)
+{
+	int i;
+
+	ASSERT(MUTEX_HELD(&spa_namespace_lock));
+
+	/*
+	 * Stop async tasks.
+	 */
+	spa_async_suspend(spa);
+
+	/*
+	 * Stop syncing.
+	 */
+	if (spa->spa_sync_on) {
+		txg_sync_stop(spa->spa_dsl_pool);
+		spa->spa_sync_on = B_FALSE;
+	}
+
+	/*
+	 * Wait for any outstanding async I/O to complete.
+	 */
+	mutex_enter(&spa->spa_async_root_lock);
+	while (spa->spa_async_root_count != 0)
+		cv_wait(&spa->spa_async_root_cv, &spa->spa_async_root_lock);
+	mutex_exit(&spa->spa_async_root_lock);
+
+	/*
+	 * Drop and purge level 2 cache
+	 */
+	spa_l2cache_drop(spa);
+
+	/*
+	 * Close the dsl pool.
+	 */
+	if (spa->spa_dsl_pool) {
+		dsl_pool_close(spa->spa_dsl_pool);
+		spa->spa_dsl_pool = NULL;
+	}
+
+	/*
+	 * Close all vdevs.
+	 */
+	if (spa->spa_root_vdev)
+		vdev_free(spa->spa_root_vdev);
+	ASSERT(spa->spa_root_vdev == NULL);
+
+	for (i = 0; i < spa->spa_spares.sav_count; i++)
+		vdev_free(spa->spa_spares.sav_vdevs[i]);
+	if (spa->spa_spares.sav_vdevs) {
+		kmem_free(spa->spa_spares.sav_vdevs,
+		    spa->spa_spares.sav_count * sizeof (void *));
+		spa->spa_spares.sav_vdevs = NULL;
+	}
+	if (spa->spa_spares.sav_config) {
+		nvlist_free(spa->spa_spares.sav_config);
+		spa->spa_spares.sav_config = NULL;
+	}
+	spa->spa_spares.sav_count = 0;
+
+	for (i = 0; i < spa->spa_l2cache.sav_count; i++)
+		vdev_free(spa->spa_l2cache.sav_vdevs[i]);
+	if (spa->spa_l2cache.sav_vdevs) {
+		kmem_free(spa->spa_l2cache.sav_vdevs,
+		    spa->spa_l2cache.sav_count * sizeof (void *));
+		spa->spa_l2cache.sav_vdevs = NULL;
+	}
+	if (spa->spa_l2cache.sav_config) {
+		nvlist_free(spa->spa_l2cache.sav_config);
+		spa->spa_l2cache.sav_config = NULL;
+	}
+	spa->spa_l2cache.sav_count = 0;
+
+	spa->spa_async_suspended = 0;
+}
+
+/*
+ * Load (or re-load) the current list of vdevs describing the active spares for
+ * this pool.  When this is called, we have some form of basic information in
+ * 'spa_spares.sav_config'.  We parse this into vdevs, try to open them, and
+ * then re-generate a more complete list including status information.
+ */
+static void
+spa_load_spares(spa_t *spa)
+{
+	nvlist_t **spares;
+	uint_t nspares;
+	int i;
+	vdev_t *vd, *tvd;
+
+	ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
+
+	/*
+	 * First, close and free any existing spare vdevs.
+	 */
+	for (i = 0; i < spa->spa_spares.sav_count; i++) {
+		vd = spa->spa_spares.sav_vdevs[i];
+
+		/* Undo the call to spa_activate() below */
+		if ((tvd = spa_lookup_by_guid(spa, vd->vdev_guid,
+		    B_FALSE)) != NULL && tvd->vdev_isspare)
+			spa_spare_remove(tvd);
+		vdev_close(vd);
+		vdev_free(vd);
+	}
+
+	if (spa->spa_spares.sav_vdevs)
+		kmem_free(spa->spa_spares.sav_vdevs,
+		    spa->spa_spares.sav_count * sizeof (void *));
+
+	if (spa->spa_spares.sav_config == NULL)
+		nspares = 0;
+	else
+		VERIFY(nvlist_lookup_nvlist_array(spa->spa_spares.sav_config,
+		    ZPOOL_CONFIG_SPARES, &spares, &nspares) == 0);
+
+	spa->spa_spares.sav_count = (int)nspares;
+	spa->spa_spares.sav_vdevs = NULL;
+
+	if (nspares == 0)
+		return;
+
+	/*
+	 * Construct the array of vdevs, opening them to get status in the
+	 * process.   For each spare, there is potentially two different vdev_t
+	 * structures associated with it: one in the list of spares (used only
+	 * for basic validation purposes) and one in the active vdev
+	 * configuration (if it's spared in).  During this phase we open and
+	 * validate each vdev on the spare list.  If the vdev also exists in the
+	 * active configuration, then we also mark this vdev as an active spare.
+	 */
+	spa->spa_spares.sav_vdevs = kmem_alloc(nspares * sizeof (void *),
+	    KM_SLEEP);
+	for (i = 0; i < spa->spa_spares.sav_count; i++) {
+		VERIFY(spa_config_parse(spa, &vd, spares[i], NULL, 0,
+		    VDEV_ALLOC_SPARE) == 0);
+		ASSERT(vd != NULL);
+
+		spa->spa_spares.sav_vdevs[i] = vd;
+
+		if ((tvd = spa_lookup_by_guid(spa, vd->vdev_guid,
+		    B_FALSE)) != NULL) {
+			if (!tvd->vdev_isspare)
+				spa_spare_add(tvd);
+
+			/*
+			 * We only mark the spare active if we were successfully
+			 * able to load the vdev.  Otherwise, importing a pool
+			 * with a bad active spare would result in strange
+			 * behavior, because multiple pool would think the spare
+			 * is actively in use.
+			 *
+			 * There is a vulnerability here to an equally bizarre
+			 * circumstance, where a dead active spare is later
+			 * brought back to life (onlined or otherwise).  Given
+			 * the rarity of this scenario, and the extra complexity
+			 * it adds, we ignore the possibility.
+			 */
+			if (!vdev_is_dead(tvd))
+				spa_spare_activate(tvd);
+		}
+
+		vd->vdev_top = vd;
+
+		if (vdev_open(vd) != 0)
+			continue;
+
+		if (vdev_validate_aux(vd) == 0)
+			spa_spare_add(vd);
+	}
+
+	/*
+	 * Recompute the stashed list of spares, with status information
+	 * this time.
+	 */
+	VERIFY(nvlist_remove(spa->spa_spares.sav_config, ZPOOL_CONFIG_SPARES,
+	    DATA_TYPE_NVLIST_ARRAY) == 0);
+
+	spares = kmem_alloc(spa->spa_spares.sav_count * sizeof (void *),
+	    KM_SLEEP);
+	for (i = 0; i < spa->spa_spares.sav_count; i++)
+		spares[i] = vdev_config_generate(spa,
+		    spa->spa_spares.sav_vdevs[i], B_TRUE, B_TRUE, B_FALSE);
+	VERIFY(nvlist_add_nvlist_array(spa->spa_spares.sav_config,
+	    ZPOOL_CONFIG_SPARES, spares, spa->spa_spares.sav_count) == 0);
+	for (i = 0; i < spa->spa_spares.sav_count; i++)
+		nvlist_free(spares[i]);
+	kmem_free(spares, spa->spa_spares.sav_count * sizeof (void *));
+}
+
+/*
+ * Load (or re-load) the current list of vdevs describing the active l2cache for
+ * this pool.  When this is called, we have some form of basic information in
+ * 'spa_l2cache.sav_config'.  We parse this into vdevs, try to open them, and
+ * then re-generate a more complete list including status information.
+ * Devices which are already active have their details maintained, and are
+ * not re-opened.
+ */
+static void
+spa_load_l2cache(spa_t *spa)
+{
+	nvlist_t **l2cache;
+	uint_t nl2cache;
+	int i, j, oldnvdevs;
+	uint64_t guid, size;
+	vdev_t *vd, **oldvdevs, **newvdevs;
+	spa_aux_vdev_t *sav = &spa->spa_l2cache;
+
+	ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
+
+	if (sav->sav_config != NULL) {
+		VERIFY(nvlist_lookup_nvlist_array(sav->sav_config,
+		    ZPOOL_CONFIG_L2CACHE, &l2cache, &nl2cache) == 0);
+		newvdevs = kmem_alloc(nl2cache * sizeof (void *), KM_SLEEP);
+	} else {
+		nl2cache = 0;
+	}
+
+	oldvdevs = sav->sav_vdevs;
+	oldnvdevs = sav->sav_count;
+	sav->sav_vdevs = NULL;
+	sav->sav_count = 0;
+
+	/*
+	 * Process new nvlist of vdevs.
+	 */
+	for (i = 0; i < nl2cache; i++) {
+		VERIFY(nvlist_lookup_uint64(l2cache[i], ZPOOL_CONFIG_GUID,
+		    &guid) == 0);
+
+		newvdevs[i] = NULL;
+		for (j = 0; j < oldnvdevs; j++) {
+			vd = oldvdevs[j];
+			if (vd != NULL && guid == vd->vdev_guid) {
+				/*
+				 * Retain previous vdev for add/remove ops.
+				 */
+				newvdevs[i] = vd;
+				oldvdevs[j] = NULL;
+				break;
+			}
+		}
+
+		if (newvdevs[i] == NULL) {
+			/*
+			 * Create new vdev
+			 */
+			VERIFY(spa_config_parse(spa, &vd, l2cache[i], NULL, 0,
+			    VDEV_ALLOC_L2CACHE) == 0);
+			ASSERT(vd != NULL);
+			newvdevs[i] = vd;
+
+			/*
+			 * Commit this vdev as an l2cache device,
+			 * even if it fails to open.
+			 */
+			spa_l2cache_add(vd);
+
+			vd->vdev_top = vd;
+			vd->vdev_aux = sav;
+
+			spa_l2cache_activate(vd);
+
+			if (vdev_open(vd) != 0)
+				continue;
+
+			(void) vdev_validate_aux(vd);
+
+			if (!vdev_is_dead(vd)) {
+				size = vdev_get_rsize(vd);
+				l2arc_add_vdev(spa, vd,
+				    VDEV_LABEL_START_SIZE,
+				    size - VDEV_LABEL_START_SIZE);
+			}
+		}
+	}
+
+	/*
+	 * Purge vdevs that were dropped
+	 */
+	for (i = 0; i < oldnvdevs; i++) {
+		uint64_t pool;
+
+		vd = oldvdevs[i];
+		if (vd != NULL) {
+			if ((spa_mode & FWRITE) &&
+			    spa_l2cache_exists(vd->vdev_guid, &pool) &&
+			    pool != 0ULL &&
+			    l2arc_vdev_present(vd)) {
+				l2arc_remove_vdev(vd);
+			}
+			(void) vdev_close(vd);
+			spa_l2cache_remove(vd);
+		}
+	}
+
+	if (oldvdevs)
+		kmem_free(oldvdevs, oldnvdevs * sizeof (void *));
+
+	if (sav->sav_config == NULL)
+		goto out;
+
+	sav->sav_vdevs = newvdevs;
+	sav->sav_count = (int)nl2cache;
+
+	/*
+	 * Recompute the stashed list of l2cache devices, with status
+	 * information this time.
+	 */
+	VERIFY(nvlist_remove(sav->sav_config, ZPOOL_CONFIG_L2CACHE,
+	    DATA_TYPE_NVLIST_ARRAY) == 0);
+
+	l2cache = kmem_alloc(sav->sav_count * sizeof (void *), KM_SLEEP);
+	for (i = 0; i < sav->sav_count; i++)
+		l2cache[i] = vdev_config_generate(spa,
+		    sav->sav_vdevs[i], B_TRUE, B_FALSE, B_TRUE);
+	VERIFY(nvlist_add_nvlist_array(sav->sav_config,
+	    ZPOOL_CONFIG_L2CACHE, l2cache, sav->sav_count) == 0);
+out:
+	for (i = 0; i < sav->sav_count; i++)
+		nvlist_free(l2cache[i]);
+	if (sav->sav_count)
+		kmem_free(l2cache, sav->sav_count * sizeof (void *));
+}
+
+static int
+load_nvlist(spa_t *spa, uint64_t obj, nvlist_t **value)
+{
+	dmu_buf_t *db;
+	char *packed = NULL;
+	size_t nvsize = 0;
+	int error;
+	*value = NULL;
+
+	VERIFY(0 == dmu_bonus_hold(spa->spa_meta_objset, obj, FTAG, &db));
+	nvsize = *(uint64_t *)db->db_data;
+	dmu_buf_rele(db, FTAG);
+
+	packed = kmem_alloc(nvsize, KM_SLEEP);
+	error = dmu_read(spa->spa_meta_objset, obj, 0, nvsize, packed);
+	if (error == 0)
+		error = nvlist_unpack(packed, nvsize, value, 0);
+	kmem_free(packed, nvsize);
+
+	return (error);
+}
+
+/*
+ * Checks to see if the given vdev could not be opened, in which case we post a
+ * sysevent to notify the autoreplace code that the device has been removed.
+ */
+static void
+spa_check_removed(vdev_t *vd)
+{
+	int c;
+
+	for (c = 0; c < vd->vdev_children; c++)
+		spa_check_removed(vd->vdev_child[c]);
+
+	if (vd->vdev_ops->vdev_op_leaf && vdev_is_dead(vd)) {
+		zfs_post_autoreplace(vd->vdev_spa, vd);
+		spa_event_notify(vd->vdev_spa, vd, ESC_ZFS_VDEV_CHECK);
+	}
+}
+
+/*
+ * Check for missing log devices
+ */
+int
+spa_check_logs(spa_t *spa)
+{
+	switch (spa->spa_log_state) {
+	case SPA_LOG_MISSING:
+		/* need to recheck in case slog has been restored */
+	case SPA_LOG_UNKNOWN:
+		if (dmu_objset_find(spa->spa_name, zil_check_log_chain, NULL,
+		    DS_FIND_CHILDREN)) {
+			spa->spa_log_state = SPA_LOG_MISSING;
+			return (1);
+		}
+		break;
+
+	case SPA_LOG_CLEAR:
+		(void) dmu_objset_find(spa->spa_name, zil_clear_log_chain, NULL,
+		    DS_FIND_CHILDREN);
+		break;
+	}
+	spa->spa_log_state = SPA_LOG_GOOD;
+	return (0);
+}
+
+/*
+ * Load an existing storage pool, using the pool's builtin spa_config as a
+ * source of configuration information.
+ */
+static int
+spa_load(spa_t *spa, nvlist_t *config, spa_load_state_t state, int mosconfig)
+{
+	int error = 0;
+	nvlist_t *nvroot = NULL;
+	vdev_t *rvd;
+	uberblock_t *ub = &spa->spa_uberblock;
+	uint64_t config_cache_txg = spa->spa_config_txg;
+	uint64_t pool_guid;
+	uint64_t version;
+	uint64_t autoreplace = 0;
+	char *ereport = FM_EREPORT_ZFS_POOL;
+
+	ASSERT(MUTEX_HELD(&spa_namespace_lock));
+
+	spa->spa_load_state = state;
+
+	if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, &nvroot) ||
+	    nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_GUID, &pool_guid)) {
+		error = EINVAL;
+		goto out;
+	}
+
+	/*
+	 * Versioning wasn't explicitly added to the label until later, so if
+	 * it's not present treat it as the initial version.
+	 */
+	if (nvlist_lookup_uint64(config, ZPOOL_CONFIG_VERSION, &version) != 0)
+		version = SPA_VERSION_INITIAL;
+
+	(void) nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_TXG,
+	    &spa->spa_config_txg);
+
+	if ((state == SPA_LOAD_IMPORT || state == SPA_LOAD_TRYIMPORT) &&
+	    spa_guid_exists(pool_guid, 0)) {
+		error = EEXIST;
+		goto out;
+	}
+
+	spa->spa_load_guid = pool_guid;
+
+	/*
+	 * Parse the configuration into a vdev tree.  We explicitly set the
+	 * value that will be returned by spa_version() since parsing the
+	 * configuration requires knowing the version number.
+	 */
+	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+	spa->spa_ubsync.ub_version = version;
+	error = spa_config_parse(spa, &rvd, nvroot, NULL, 0, VDEV_ALLOC_LOAD);
+	spa_config_exit(spa, SCL_ALL, FTAG);
+
+	if (error != 0)
+		goto out;
+
+	ASSERT(spa->spa_root_vdev == rvd);
+	ASSERT(spa_guid(spa) == pool_guid);
+
+	/*
+	 * Try to open all vdevs, loading each label in the process.
+	 */
+	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+	error = vdev_open(rvd);
+	spa_config_exit(spa, SCL_ALL, FTAG);
+	if (error != 0)
+		goto out;
+
+	/*
+	 * Validate the labels for all leaf vdevs.  We need to grab the config
+	 * lock because all label I/O is done with ZIO_FLAG_CONFIG_WRITER.
+	 */
+	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+	error = vdev_validate(rvd);
+	spa_config_exit(spa, SCL_ALL, FTAG);
+
+	if (error != 0)
+		goto out;
+
+	if (rvd->vdev_state <= VDEV_STATE_CANT_OPEN) {
+		error = ENXIO;
+		goto out;
+	}
+
+	/*
+	 * Find the best uberblock.
+	 */
+	vdev_uberblock_load(NULL, rvd, ub);
+
+	/*
+	 * If we weren't able to find a single valid uberblock, return failure.
+	 */
+	if (ub->ub_txg == 0) {
+		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_CORRUPT_DATA);
+		error = ENXIO;
+		goto out;
+	}
+
+	/*
+	 * If the pool is newer than the code, we can't open it.
+	 */
+	if (ub->ub_version > SPA_VERSION) {
+		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_VERSION_NEWER);
+		error = ENOTSUP;
+		goto out;
+	}
+
+	/*
+	 * If the vdev guid sum doesn't match the uberblock, we have an
+	 * incomplete configuration.
+	 */
+	if (rvd->vdev_guid_sum != ub->ub_guid_sum && mosconfig) {
+		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_BAD_GUID_SUM);
+		error = ENXIO;
+		goto out;
+	}
+
+	/*
+	 * Initialize internal SPA structures.
+	 */
+	spa->spa_state = POOL_STATE_ACTIVE;
+	spa->spa_ubsync = spa->spa_uberblock;
+	spa->spa_first_txg = spa_last_synced_txg(spa) + 1;
+	error = dsl_pool_open(spa, spa->spa_first_txg, &spa->spa_dsl_pool);
+	if (error) {
+		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_CORRUPT_DATA);
+		goto out;
+	}
+	spa->spa_meta_objset = spa->spa_dsl_pool->dp_meta_objset;
+
+	if (zap_lookup(spa->spa_meta_objset,
+	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_CONFIG,
+	    sizeof (uint64_t), 1, &spa->spa_config_object) != 0) {
+		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_CORRUPT_DATA);
+		error = EIO;
+		goto out;
+	}
+
+	if (!mosconfig) {
+		nvlist_t *newconfig;
+		uint64_t hostid;
+
+		if (load_nvlist(spa, spa->spa_config_object, &newconfig) != 0) {
+			vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+			    VDEV_AUX_CORRUPT_DATA);
+			error = EIO;
+			goto out;
+		}
+
+		if (!spa_is_root(spa) && nvlist_lookup_uint64(newconfig,
+		    ZPOOL_CONFIG_HOSTID, &hostid) == 0) {
+			char *hostname;
+			unsigned long myhostid = 0;
+
+			VERIFY(nvlist_lookup_string(newconfig,
+			    ZPOOL_CONFIG_HOSTNAME, &hostname) == 0);
+
+			(void) ddi_strtoul(hw_serial, NULL, 10, &myhostid);
+			if (hostid != 0 && myhostid != 0 &&
+			    (unsigned long)hostid != myhostid) {
+				cmn_err(CE_WARN, "pool '%s' could not be "
+				    "loaded as it was last accessed by "
+				    "another system (host: %s hostid: 0x%lx). "
+				    "See: http://www.sun.com/msg/ZFS-8000-EY",
+				    spa_name(spa), hostname,
+				    (unsigned long)hostid);
+				error = EBADF;
+				goto out;
+			}
+		}
+
+		spa_config_set(spa, newconfig);
+		spa_unload(spa);
+		spa_deactivate(spa);
+		spa_activate(spa);
+
+		return (spa_load(spa, newconfig, state, B_TRUE));
+	}
+
+	if (zap_lookup(spa->spa_meta_objset,
+	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_SYNC_BPLIST,
+	    sizeof (uint64_t), 1, &spa->spa_sync_bplist_obj) != 0) {
+		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_CORRUPT_DATA);
+		error = EIO;
+		goto out;
+	}
+
+	/*
+	 * Load the bit that tells us to use the new accounting function
+	 * (raid-z deflation).  If we have an older pool, this will not
+	 * be present.
+	 */
+	error = zap_lookup(spa->spa_meta_objset,
+	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_DEFLATE,
+	    sizeof (uint64_t), 1, &spa->spa_deflate);
+	if (error != 0 && error != ENOENT) {
+		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_CORRUPT_DATA);
+		error = EIO;
+		goto out;
+	}
+
+	/*
+	 * Load the persistent error log.  If we have an older pool, this will
+	 * not be present.
+	 */
+	error = zap_lookup(spa->spa_meta_objset,
+	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_ERRLOG_LAST,
+	    sizeof (uint64_t), 1, &spa->spa_errlog_last);
+	if (error != 0 && error != ENOENT) {
+		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_CORRUPT_DATA);
+		error = EIO;
+		goto out;
+	}
+
+	error = zap_lookup(spa->spa_meta_objset,
+	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_ERRLOG_SCRUB,
+	    sizeof (uint64_t), 1, &spa->spa_errlog_scrub);
+	if (error != 0 && error != ENOENT) {
+		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_CORRUPT_DATA);
+		error = EIO;
+		goto out;
+	}
+
+	/*
+	 * Load the history object.  If we have an older pool, this
+	 * will not be present.
+	 */
+	error = zap_lookup(spa->spa_meta_objset,
+	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_HISTORY,
+	    sizeof (uint64_t), 1, &spa->spa_history);
+	if (error != 0 && error != ENOENT) {
+		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_CORRUPT_DATA);
+		error = EIO;
+		goto out;
+	}
+
+	/*
+	 * Load any hot spares for this pool.
+	 */
+	error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
+	    DMU_POOL_SPARES, sizeof (uint64_t), 1, &spa->spa_spares.sav_object);
+	if (error != 0 && error != ENOENT) {
+		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_CORRUPT_DATA);
+		error = EIO;
+		goto out;
+	}
+	if (error == 0) {
+		ASSERT(spa_version(spa) >= SPA_VERSION_SPARES);
+		if (load_nvlist(spa, spa->spa_spares.sav_object,
+		    &spa->spa_spares.sav_config) != 0) {
+			vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+			    VDEV_AUX_CORRUPT_DATA);
+			error = EIO;
+			goto out;
+		}
+
+		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+		spa_load_spares(spa);
+		spa_config_exit(spa, SCL_ALL, FTAG);
+	}
+
+	/*
+	 * Load any level 2 ARC devices for this pool.
+	 */
+	error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
+	    DMU_POOL_L2CACHE, sizeof (uint64_t), 1,
+	    &spa->spa_l2cache.sav_object);
+	if (error != 0 && error != ENOENT) {
+		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_CORRUPT_DATA);
+		error = EIO;
+		goto out;
+	}
+	if (error == 0) {
+		ASSERT(spa_version(spa) >= SPA_VERSION_L2CACHE);
+		if (load_nvlist(spa, spa->spa_l2cache.sav_object,
+		    &spa->spa_l2cache.sav_config) != 0) {
+			vdev_set_state(rvd, B_TRUE,
+			    VDEV_STATE_CANT_OPEN,
+			    VDEV_AUX_CORRUPT_DATA);
+			error = EIO;
+			goto out;
+		}
+
+		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+		spa_load_l2cache(spa);
+		spa_config_exit(spa, SCL_ALL, FTAG);
+	}
+
+	if (spa_check_logs(spa)) {
+		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_BAD_LOG);
+		error = ENXIO;
+		ereport = FM_EREPORT_ZFS_LOG_REPLAY;
+		goto out;
+	}
+
+
+	spa->spa_delegation = zpool_prop_default_numeric(ZPOOL_PROP_DELEGATION);
+
+	error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
+	    DMU_POOL_PROPS, sizeof (uint64_t), 1, &spa->spa_pool_props_object);
+
+	if (error && error != ENOENT) {
+		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_CORRUPT_DATA);
+		error = EIO;
+		goto out;
+	}
+
+	if (error == 0) {
+		(void) zap_lookup(spa->spa_meta_objset,
+		    spa->spa_pool_props_object,
+		    zpool_prop_to_name(ZPOOL_PROP_BOOTFS),
+		    sizeof (uint64_t), 1, &spa->spa_bootfs);
+		(void) zap_lookup(spa->spa_meta_objset,
+		    spa->spa_pool_props_object,
+		    zpool_prop_to_name(ZPOOL_PROP_AUTOREPLACE),
+		    sizeof (uint64_t), 1, &autoreplace);
+		(void) zap_lookup(spa->spa_meta_objset,
+		    spa->spa_pool_props_object,
+		    zpool_prop_to_name(ZPOOL_PROP_DELEGATION),
+		    sizeof (uint64_t), 1, &spa->spa_delegation);
+		(void) zap_lookup(spa->spa_meta_objset,
+		    spa->spa_pool_props_object,
+		    zpool_prop_to_name(ZPOOL_PROP_FAILUREMODE),
+		    sizeof (uint64_t), 1, &spa->spa_failmode);
+	}
+
+	/*
+	 * If the 'autoreplace' property is set, then post a resource notifying
+	 * the ZFS DE that it should not issue any faults for unopenable
+	 * devices.  We also iterate over the vdevs, and post a sysevent for any
+	 * unopenable vdevs so that the normal autoreplace handler can take
+	 * over.
+	 */
+	if (autoreplace && state != SPA_LOAD_TRYIMPORT)
+		spa_check_removed(spa->spa_root_vdev);
+
+	/*
+	 * Load the vdev state for all toplevel vdevs.
+	 */
+	vdev_load(rvd);
+
+	/*
+	 * Propagate the leaf DTLs we just loaded all the way up the tree.
+	 */
+	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+	vdev_dtl_reassess(rvd, 0, 0, B_FALSE);
+	spa_config_exit(spa, SCL_ALL, FTAG);
+
+	/*
+	 * Check the state of the root vdev.  If it can't be opened, it
+	 * indicates one or more toplevel vdevs are faulted.
+	 */
+	if (rvd->vdev_state <= VDEV_STATE_CANT_OPEN) {
+		error = ENXIO;
+		goto out;
+	}
+
+	if ((spa_mode & FWRITE) && state != SPA_LOAD_TRYIMPORT) {
+		dmu_tx_t *tx;
+		int need_update = B_FALSE;
+		int c;
+
+		/*
+		 * Claim log blocks that haven't been committed yet.
+		 * This must all happen in a single txg.
+		 */
+		tx = dmu_tx_create_assigned(spa_get_dsl(spa),
+		    spa_first_txg(spa));
+		(void) dmu_objset_find(spa_name(spa),
+		    zil_claim, tx, DS_FIND_CHILDREN);
+		dmu_tx_commit(tx);
+
+		spa->spa_sync_on = B_TRUE;
+		txg_sync_start(spa->spa_dsl_pool);
+
+		/*
+		 * Wait for all claims to sync.
+		 */
+		txg_wait_synced(spa->spa_dsl_pool, 0);
+
+		/*
+		 * If the config cache is stale, or we have uninitialized
+		 * metaslabs (see spa_vdev_add()), then update the config.
+		 */
+		if (config_cache_txg != spa->spa_config_txg ||
+		    state == SPA_LOAD_IMPORT)
+			need_update = B_TRUE;
+
+		for (c = 0; c < rvd->vdev_children; c++)
+			if (rvd->vdev_child[c]->vdev_ms_array == 0)
+				need_update = B_TRUE;
+
+		/*
+		 * Update the config cache asychronously in case we're the
+		 * root pool, in which case the config cache isn't writable yet.
+		 */
+		if (need_update)
+			spa_async_request(spa, SPA_ASYNC_CONFIG_UPDATE);
+	}
+
+	error = 0;
+out:
+	spa->spa_minref = refcount_count(&spa->spa_refcount);
+	if (error && error != EBADF)
+		zfs_ereport_post(ereport, spa, NULL, NULL, 0, 0);
+	spa->spa_load_state = SPA_LOAD_NONE;
+	spa->spa_ena = 0;
+
+	return (error);
+}
+
+/*
+ * Pool Open/Import
+ *
+ * The import case is identical to an open except that the configuration is sent
+ * down from userland, instead of grabbed from the configuration cache.  For the
+ * case of an open, the pool configuration will exist in the
+ * POOL_STATE_UNINITIALIZED state.
+ *
+ * The stats information (gen/count/ustats) is used to gather vdev statistics at
+ * the same time open the pool, without having to keep around the spa_t in some
+ * ambiguous state.
+ */
+static int
+spa_open_common(const char *pool, spa_t **spapp, void *tag, nvlist_t **config)
+{
+	spa_t *spa;
+	int error;
+	int locked = B_FALSE;
+
+	*spapp = NULL;
+
+	/*
+	 * As disgusting as this is, we need to support recursive calls to this
+	 * function because dsl_dir_open() is called during spa_load(), and ends
+	 * up calling spa_open() again.  The real fix is to figure out how to
+	 * avoid dsl_dir_open() calling this in the first place.
+	 */
+	if (mutex_owner(&spa_namespace_lock) != curthread) {
+		mutex_enter(&spa_namespace_lock);
+		locked = B_TRUE;
+	}
+
+	if ((spa = spa_lookup(pool)) == NULL) {
+		if (locked)
+			mutex_exit(&spa_namespace_lock);
+		return (ENOENT);
+	}
+	if (spa->spa_state == POOL_STATE_UNINITIALIZED) {
+
+		spa_activate(spa);
+
+		error = spa_load(spa, spa->spa_config, SPA_LOAD_OPEN, B_FALSE);
+
+		if (error == EBADF) {
+			/*
+			 * If vdev_validate() returns failure (indicated by
+			 * EBADF), it indicates that one of the vdevs indicates
+			 * that the pool has been exported or destroyed.  If
+			 * this is the case, the config cache is out of sync and
+			 * we should remove the pool from the namespace.
+			 */
+			spa_unload(spa);
+			spa_deactivate(spa);
+			spa_config_sync(spa, B_TRUE, B_TRUE);
+			spa_remove(spa);
+			if (locked)
+				mutex_exit(&spa_namespace_lock);
+			return (ENOENT);
+		}
+
+		if (error) {
+			/*
+			 * We can't open the pool, but we still have useful
+			 * information: the state of each vdev after the
+			 * attempted vdev_open().  Return this to the user.
+			 */
+			if (config != NULL && spa->spa_root_vdev != NULL)
+				*config = spa_config_generate(spa, NULL, -1ULL,
+				    B_TRUE);
+			spa_unload(spa);
+			spa_deactivate(spa);
+			spa->spa_last_open_failed = B_TRUE;
+			if (locked)
+				mutex_exit(&spa_namespace_lock);
+			*spapp = NULL;
+			return (error);
+		} else {
+			spa->spa_last_open_failed = B_FALSE;
+		}
+	}
+
+	spa_open_ref(spa, tag);
+
+	if (locked)
+		mutex_exit(&spa_namespace_lock);
+
+	*spapp = spa;
+
+	if (config != NULL)
+		*config = spa_config_generate(spa, NULL, -1ULL, B_TRUE);
+
+	return (0);
+}
+
+int
+spa_open(const char *name, spa_t **spapp, void *tag)
+{
+	return (spa_open_common(name, spapp, tag, NULL));
+}
+
+/*
+ * Lookup the given spa_t, incrementing the inject count in the process,
+ * preventing it from being exported or destroyed.
+ */
+spa_t *
+spa_inject_addref(char *name)
+{
+	spa_t *spa;
+
+	mutex_enter(&spa_namespace_lock);
+	if ((spa = spa_lookup(name)) == NULL) {
+		mutex_exit(&spa_namespace_lock);
+		return (NULL);
+	}
+	spa->spa_inject_ref++;
+	mutex_exit(&spa_namespace_lock);
+
+	return (spa);
+}
+
+void
+spa_inject_delref(spa_t *spa)
+{
+	mutex_enter(&spa_namespace_lock);
+	spa->spa_inject_ref--;
+	mutex_exit(&spa_namespace_lock);
+}
+
+/*
+ * Add spares device information to the nvlist.
+ */
+static void
+spa_add_spares(spa_t *spa, nvlist_t *config)
+{
+	nvlist_t **spares;
+	uint_t i, nspares;
+	nvlist_t *nvroot;
+	uint64_t guid;
+	vdev_stat_t *vs;
+	uint_t vsc;
+	uint64_t pool;
+
+	if (spa->spa_spares.sav_count == 0)
+		return;
+
+	VERIFY(nvlist_lookup_nvlist(config,
+	    ZPOOL_CONFIG_VDEV_TREE, &nvroot) == 0);
+	VERIFY(nvlist_lookup_nvlist_array(spa->spa_spares.sav_config,
+	    ZPOOL_CONFIG_SPARES, &spares, &nspares) == 0);
+	if (nspares != 0) {
+		VERIFY(nvlist_add_nvlist_array(nvroot,
+		    ZPOOL_CONFIG_SPARES, spares, nspares) == 0);
+		VERIFY(nvlist_lookup_nvlist_array(nvroot,
+		    ZPOOL_CONFIG_SPARES, &spares, &nspares) == 0);
+
+		/*
+		 * Go through and find any spares which have since been
+		 * repurposed as an active spare.  If this is the case, update
+		 * their status appropriately.
+		 */
+		for (i = 0; i < nspares; i++) {
+			VERIFY(nvlist_lookup_uint64(spares[i],
+			    ZPOOL_CONFIG_GUID, &guid) == 0);
+			if (spa_spare_exists(guid, &pool, NULL) &&
+			    pool != 0ULL) {
+				VERIFY(nvlist_lookup_uint64_array(
+				    spares[i], ZPOOL_CONFIG_STATS,
+				    (uint64_t **)&vs, &vsc) == 0);
+				vs->vs_state = VDEV_STATE_CANT_OPEN;
+				vs->vs_aux = VDEV_AUX_SPARED;
+			}
+		}
+	}
+}
+
+/*
+ * Add l2cache device information to the nvlist, including vdev stats.
+ */
+static void
+spa_add_l2cache(spa_t *spa, nvlist_t *config)
+{
+	nvlist_t **l2cache;
+	uint_t i, j, nl2cache;
+	nvlist_t *nvroot;
+	uint64_t guid;
+	vdev_t *vd;
+	vdev_stat_t *vs;
+	uint_t vsc;
+
+	if (spa->spa_l2cache.sav_count == 0)
+		return;
+
+	spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
+
+	VERIFY(nvlist_lookup_nvlist(config,
+	    ZPOOL_CONFIG_VDEV_TREE, &nvroot) == 0);
+	VERIFY(nvlist_lookup_nvlist_array(spa->spa_l2cache.sav_config,
+	    ZPOOL_CONFIG_L2CACHE, &l2cache, &nl2cache) == 0);
+	if (nl2cache != 0) {
+		VERIFY(nvlist_add_nvlist_array(nvroot,
+		    ZPOOL_CONFIG_L2CACHE, l2cache, nl2cache) == 0);
+		VERIFY(nvlist_lookup_nvlist_array(nvroot,
+		    ZPOOL_CONFIG_L2CACHE, &l2cache, &nl2cache) == 0);
+
+		/*
+		 * Update level 2 cache device stats.
+		 */
+
+		for (i = 0; i < nl2cache; i++) {
+			VERIFY(nvlist_lookup_uint64(l2cache[i],
+			    ZPOOL_CONFIG_GUID, &guid) == 0);
+
+			vd = NULL;
+			for (j = 0; j < spa->spa_l2cache.sav_count; j++) {
+				if (guid ==
+				    spa->spa_l2cache.sav_vdevs[j]->vdev_guid) {
+					vd = spa->spa_l2cache.sav_vdevs[j];
+					break;
+				}
+			}
+			ASSERT(vd != NULL);
+
+			VERIFY(nvlist_lookup_uint64_array(l2cache[i],
+			    ZPOOL_CONFIG_STATS, (uint64_t **)&vs, &vsc) == 0);
+			vdev_get_stats(vd, vs);
+		}
+	}
+
+	spa_config_exit(spa, SCL_CONFIG, FTAG);
+}
+
+int
+spa_get_stats(const char *name, nvlist_t **config, char *altroot, size_t buflen)
+{
+	int error;
+	spa_t *spa;
+
+	*config = NULL;
+	error = spa_open_common(name, &spa, FTAG, config);
+
+	if (spa && *config != NULL) {
+		VERIFY(nvlist_add_uint64(*config, ZPOOL_CONFIG_ERRCOUNT,
+		    spa_get_errlog_size(spa)) == 0);
+
+		if (spa_suspended(spa))
+			VERIFY(nvlist_add_uint64(*config,
+			    ZPOOL_CONFIG_SUSPENDED, spa->spa_failmode) == 0);
+
+		spa_add_spares(spa, *config);
+		spa_add_l2cache(spa, *config);
+	}
+
+	/*
+	 * We want to get the alternate root even for faulted pools, so we cheat
+	 * and call spa_lookup() directly.
+	 */
+	if (altroot) {
+		if (spa == NULL) {
+			mutex_enter(&spa_namespace_lock);
+			spa = spa_lookup(name);
+			if (spa)
+				spa_altroot(spa, altroot, buflen);
+			else
+				altroot[0] = '\0';
+			spa = NULL;
+			mutex_exit(&spa_namespace_lock);
+		} else {
+			spa_altroot(spa, altroot, buflen);
+		}
+	}
+
+	if (spa != NULL)
+		spa_close(spa, FTAG);
+
+	return (error);
+}
+
+/*
+ * Validate that the auxiliary device array is well formed.  We must have an
+ * array of nvlists, each which describes a valid leaf vdev.  If this is an
+ * import (mode is VDEV_ALLOC_SPARE), then we allow corrupted spares to be
+ * specified, as long as they are well-formed.
+ */
+static int
+spa_validate_aux_devs(spa_t *spa, nvlist_t *nvroot, uint64_t crtxg, int mode,
+    spa_aux_vdev_t *sav, const char *config, uint64_t version,
+    vdev_labeltype_t label)
+{
+	nvlist_t **dev;
+	uint_t i, ndev;
+	vdev_t *vd;
+	int error;
+
+	ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
+
+	/*
+	 * It's acceptable to have no devs specified.
+	 */
+	if (nvlist_lookup_nvlist_array(nvroot, config, &dev, &ndev) != 0)
+		return (0);
+
+	if (ndev == 0)
+		return (EINVAL);
+
+	/*
+	 * Make sure the pool is formatted with a version that supports this
+	 * device type.
+	 */
+	if (spa_version(spa) < version)
+		return (ENOTSUP);
+
+	/*
+	 * Set the pending device list so we correctly handle device in-use
+	 * checking.
+	 */
+	sav->sav_pending = dev;
+	sav->sav_npending = ndev;
+
+	for (i = 0; i < ndev; i++) {
+		if ((error = spa_config_parse(spa, &vd, dev[i], NULL, 0,
+		    mode)) != 0)
+			goto out;
+
+		if (!vd->vdev_ops->vdev_op_leaf) {
+			vdev_free(vd);
+			error = EINVAL;
+			goto out;
+		}
+
+		/*
+		 * The L2ARC currently only supports disk devices in
+		 * kernel context.  For user-level testing, we allow it.
+		 */
+#ifdef _KERNEL
+		if ((strcmp(config, ZPOOL_CONFIG_L2CACHE) == 0) &&
+		    strcmp(vd->vdev_ops->vdev_op_type, VDEV_TYPE_DISK) != 0) {
+			error = ENOTBLK;
+			goto out;
+		}
+#endif
+		vd->vdev_top = vd;
+
+		if ((error = vdev_open(vd)) == 0 &&
+		    (error = vdev_label_init(vd, crtxg, label)) == 0) {
+			VERIFY(nvlist_add_uint64(dev[i], ZPOOL_CONFIG_GUID,
+			    vd->vdev_guid) == 0);
+		}
+
+		vdev_free(vd);
+
+		if (error &&
+		    (mode != VDEV_ALLOC_SPARE && mode != VDEV_ALLOC_L2CACHE))
+			goto out;
+		else
+			error = 0;
+	}
+
+out:
+	sav->sav_pending = NULL;
+	sav->sav_npending = 0;
+	return (error);
+}
+
+static int
+spa_validate_aux(spa_t *spa, nvlist_t *nvroot, uint64_t crtxg, int mode)
+{
+	int error;
+
+	ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
+
+	if ((error = spa_validate_aux_devs(spa, nvroot, crtxg, mode,
+	    &spa->spa_spares, ZPOOL_CONFIG_SPARES, SPA_VERSION_SPARES,
+	    VDEV_LABEL_SPARE)) != 0) {
+		return (error);
+	}
+
+	return (spa_validate_aux_devs(spa, nvroot, crtxg, mode,
+	    &spa->spa_l2cache, ZPOOL_CONFIG_L2CACHE, SPA_VERSION_L2CACHE,
+	    VDEV_LABEL_L2CACHE));
+}
+
+static void
+spa_set_aux_vdevs(spa_aux_vdev_t *sav, nvlist_t **devs, int ndevs,
+    const char *config)
+{
+	int i;
+
+	if (sav->sav_config != NULL) {
+		nvlist_t **olddevs;
+		uint_t oldndevs;
+		nvlist_t **newdevs;
+
+		/*
+		 * Generate new dev list by concatentating with the
+		 * current dev list.
+		 */
+		VERIFY(nvlist_lookup_nvlist_array(sav->sav_config, config,
+		    &olddevs, &oldndevs) == 0);
+
+		newdevs = kmem_alloc(sizeof (void *) *
+		    (ndevs + oldndevs), KM_SLEEP);
+		for (i = 0; i < oldndevs; i++)
+			VERIFY(nvlist_dup(olddevs[i], &newdevs[i],
+			    KM_SLEEP) == 0);
+		for (i = 0; i < ndevs; i++)
+			VERIFY(nvlist_dup(devs[i], &newdevs[i + oldndevs],
+			    KM_SLEEP) == 0);
+
+		VERIFY(nvlist_remove(sav->sav_config, config,
+		    DATA_TYPE_NVLIST_ARRAY) == 0);
+
+		VERIFY(nvlist_add_nvlist_array(sav->sav_config,
+		    config, newdevs, ndevs + oldndevs) == 0);
+		for (i = 0; i < oldndevs + ndevs; i++)
+			nvlist_free(newdevs[i]);
+		kmem_free(newdevs, (oldndevs + ndevs) * sizeof (void *));
+	} else {
+		/*
+		 * Generate a new dev list.
+		 */
+		VERIFY(nvlist_alloc(&sav->sav_config, NV_UNIQUE_NAME,
+		    KM_SLEEP) == 0);
+		VERIFY(nvlist_add_nvlist_array(sav->sav_config, config,
+		    devs, ndevs) == 0);
+	}
+}
+
+/*
+ * Stop and drop level 2 ARC devices
+ */
+void
+spa_l2cache_drop(spa_t *spa)
+{
+	vdev_t *vd;
+	int i;
+	spa_aux_vdev_t *sav = &spa->spa_l2cache;
+
+	for (i = 0; i < sav->sav_count; i++) {
+		uint64_t pool;
+
+		vd = sav->sav_vdevs[i];
+		ASSERT(vd != NULL);
+
+		if ((spa_mode & FWRITE) &&
+		    spa_l2cache_exists(vd->vdev_guid, &pool) && pool != 0ULL &&
+		    l2arc_vdev_present(vd)) {
+			l2arc_remove_vdev(vd);
+		}
+		if (vd->vdev_isl2cache)
+			spa_l2cache_remove(vd);
+		vdev_clear_stats(vd);
+		(void) vdev_close(vd);
+	}
+}
+
+/*
+ * Pool Creation
+ */
+int
+spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
+    const char *history_str, nvlist_t *zplprops)
+{
+	spa_t *spa;
+	char *altroot = NULL;
+	vdev_t *rvd;
+	dsl_pool_t *dp;
+	dmu_tx_t *tx;
+	int c, error = 0;
+	uint64_t txg = TXG_INITIAL;
+	nvlist_t **spares, **l2cache;
+	uint_t nspares, nl2cache;
+	uint64_t version;
+
+	/*
+	 * If this pool already exists, return failure.
+	 */
+	mutex_enter(&spa_namespace_lock);
+	if (spa_lookup(pool) != NULL) {
+		mutex_exit(&spa_namespace_lock);
+		return (EEXIST);
+	}
+
+	/*
+	 * Allocate a new spa_t structure.
+	 */
+	(void) nvlist_lookup_string(props,
+	    zpool_prop_to_name(ZPOOL_PROP_ALTROOT), &altroot);
+	spa = spa_add(pool, altroot);
+	spa_activate(spa);
+
+	spa->spa_uberblock.ub_txg = txg - 1;
+
+	if (props && (error = spa_prop_validate(spa, props))) {
+		spa_unload(spa);
+		spa_deactivate(spa);
+		spa_remove(spa);
+		mutex_exit(&spa_namespace_lock);
+		return (error);
+	}
+
+	if (nvlist_lookup_uint64(props, zpool_prop_to_name(ZPOOL_PROP_VERSION),
+	    &version) != 0)
+		version = SPA_VERSION;
+	ASSERT(version <= SPA_VERSION);
+	spa->spa_uberblock.ub_version = version;
+	spa->spa_ubsync = spa->spa_uberblock;
+
+	/*
+	 * Create the root vdev.
+	 */
+	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+
+	error = spa_config_parse(spa, &rvd, nvroot, NULL, 0, VDEV_ALLOC_ADD);
+
+	ASSERT(error != 0 || rvd != NULL);
+	ASSERT(error != 0 || spa->spa_root_vdev == rvd);
+
+	if (error == 0 && !zfs_allocatable_devs(nvroot))
+		error = EINVAL;
+
+	if (error == 0 &&
+	    (error = vdev_create(rvd, txg, B_FALSE)) == 0 &&
+	    (error = spa_validate_aux(spa, nvroot, txg,
+	    VDEV_ALLOC_ADD)) == 0) {
+		for (c = 0; c < rvd->vdev_children; c++)
+			vdev_init(rvd->vdev_child[c], txg);
+		vdev_config_dirty(rvd);
+	}
+
+	spa_config_exit(spa, SCL_ALL, FTAG);
+
+	if (error != 0) {
+		spa_unload(spa);
+		spa_deactivate(spa);
+		spa_remove(spa);
+		mutex_exit(&spa_namespace_lock);
+		return (error);
+	}
+
+	/*
+	 * Get the list of spares, if specified.
+	 */
+	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
+	    &spares, &nspares) == 0) {
+		VERIFY(nvlist_alloc(&spa->spa_spares.sav_config, NV_UNIQUE_NAME,
+		    KM_SLEEP) == 0);
+		VERIFY(nvlist_add_nvlist_array(spa->spa_spares.sav_config,
+		    ZPOOL_CONFIG_SPARES, spares, nspares) == 0);
+		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+		spa_load_spares(spa);
+		spa_config_exit(spa, SCL_ALL, FTAG);
+		spa->spa_spares.sav_sync = B_TRUE;
+	}
+
+	/*
+	 * Get the list of level 2 cache devices, if specified.
+	 */
+	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_L2CACHE,
+	    &l2cache, &nl2cache) == 0) {
+		VERIFY(nvlist_alloc(&spa->spa_l2cache.sav_config,
+		    NV_UNIQUE_NAME, KM_SLEEP) == 0);
+		VERIFY(nvlist_add_nvlist_array(spa->spa_l2cache.sav_config,
+		    ZPOOL_CONFIG_L2CACHE, l2cache, nl2cache) == 0);
+		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+		spa_load_l2cache(spa);
+		spa_config_exit(spa, SCL_ALL, FTAG);
+		spa->spa_l2cache.sav_sync = B_TRUE;
+	}
+
+	spa->spa_dsl_pool = dp = dsl_pool_create(spa, zplprops, txg);
+	spa->spa_meta_objset = dp->dp_meta_objset;
+
+	tx = dmu_tx_create_assigned(dp, txg);
+
+	/*
+	 * Create the pool config object.
+	 */
+	spa->spa_config_object = dmu_object_alloc(spa->spa_meta_objset,
+	    DMU_OT_PACKED_NVLIST, SPA_CONFIG_BLOCKSIZE,
+	    DMU_OT_PACKED_NVLIST_SIZE, sizeof (uint64_t), tx);
+
+	if (zap_add(spa->spa_meta_objset,
+	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_CONFIG,
+	    sizeof (uint64_t), 1, &spa->spa_config_object, tx) != 0) {
+		cmn_err(CE_PANIC, "failed to add pool config");
+	}
+
+	/* Newly created pools with the right version are always deflated. */
+	if (version >= SPA_VERSION_RAIDZ_DEFLATE) {
+		spa->spa_deflate = TRUE;
+		if (zap_add(spa->spa_meta_objset,
+		    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_DEFLATE,
+		    sizeof (uint64_t), 1, &spa->spa_deflate, tx) != 0) {
+			cmn_err(CE_PANIC, "failed to add deflate");
+		}
+	}
+
+	/*
+	 * Create the deferred-free bplist object.  Turn off compression
+	 * because sync-to-convergence takes longer if the blocksize
+	 * keeps changing.
+	 */
+	spa->spa_sync_bplist_obj = bplist_create(spa->spa_meta_objset,
+	    1 << 14, tx);
+	dmu_object_set_compress(spa->spa_meta_objset, spa->spa_sync_bplist_obj,
+	    ZIO_COMPRESS_OFF, tx);
+
+	if (zap_add(spa->spa_meta_objset,
+	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_SYNC_BPLIST,
+	    sizeof (uint64_t), 1, &spa->spa_sync_bplist_obj, tx) != 0) {
+		cmn_err(CE_PANIC, "failed to add bplist");
+	}
+
+	/*
+	 * Create the pool's history object.
+	 */
+	if (version >= SPA_VERSION_ZPOOL_HISTORY)
+		spa_history_create_obj(spa, tx);
+
+	/*
+	 * Set pool properties.
+	 */
+	spa->spa_bootfs = zpool_prop_default_numeric(ZPOOL_PROP_BOOTFS);
+	spa->spa_delegation = zpool_prop_default_numeric(ZPOOL_PROP_DELEGATION);
+	spa->spa_failmode = zpool_prop_default_numeric(ZPOOL_PROP_FAILUREMODE);
+	if (props)
+		spa_sync_props(spa, props, CRED(), tx);
+
+	dmu_tx_commit(tx);
+
+	spa->spa_sync_on = B_TRUE;
+	txg_sync_start(spa->spa_dsl_pool);
+
+	/*
+	 * We explicitly wait for the first transaction to complete so that our
+	 * bean counters are appropriately updated.
+	 */
+	txg_wait_synced(spa->spa_dsl_pool, txg);
+
+	spa_config_sync(spa, B_FALSE, B_TRUE);
+
+	if (version >= SPA_VERSION_ZPOOL_HISTORY && history_str != NULL)
+		(void) spa_history_log(spa, history_str, LOG_CMD_POOL_CREATE);
+
+	mutex_exit(&spa_namespace_lock);
+
+	spa->spa_minref = refcount_count(&spa->spa_refcount);
+
+	return (0);
+}
+
+/*
+ * Import the given pool into the system.  We set up the necessary spa_t and
+ * then call spa_load() to do the dirty work.
+ */
+static int
+spa_import_common(const char *pool, nvlist_t *config, nvlist_t *props,
+    boolean_t isroot, boolean_t allowfaulted)
+{
+	spa_t *spa;
+	char *altroot = NULL;
+	int error, loaderr;
+	nvlist_t *nvroot;
+	nvlist_t **spares, **l2cache;
+	uint_t nspares, nl2cache;
+
+	/*
+	 * If a pool with this name exists, return failure.
+	 */
+	mutex_enter(&spa_namespace_lock);
+	if ((spa = spa_lookup(pool)) != NULL) {
+		if (isroot) {
+			/*
+			 * Remove the existing root pool from the
+			 * namespace so that we can replace it with
+			 * the correct config we just read in.
+			 */
+			ASSERT(spa->spa_state == POOL_STATE_UNINITIALIZED);
+			spa_remove(spa);
+		} else {
+			mutex_exit(&spa_namespace_lock);
+			return (EEXIST);
+		}
+	}
+
+	/*
+	 * Create and initialize the spa structure.
+	 */
+	(void) nvlist_lookup_string(props,
+	    zpool_prop_to_name(ZPOOL_PROP_ALTROOT), &altroot);
+	spa = spa_add(pool, altroot);
+	spa_activate(spa);
+
+	if (allowfaulted)
+		spa->spa_import_faulted = B_TRUE;
+	spa->spa_is_root = isroot;
+
+	/*
+	 * Pass off the heavy lifting to spa_load().
+	 * Pass TRUE for mosconfig (unless this is a root pool) because
+	 * the user-supplied config is actually the one to trust when
+	 * doing an import.
+	 */
+	loaderr = error = spa_load(spa, config, SPA_LOAD_IMPORT, !isroot);
+
+	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+	/*
+	 * Toss any existing sparelist, as it doesn't have any validity anymore,
+	 * and conflicts with spa_has_spare().
+	 */
+	if (!isroot && spa->spa_spares.sav_config) {
+		nvlist_free(spa->spa_spares.sav_config);
+		spa->spa_spares.sav_config = NULL;
+		spa_load_spares(spa);
+	}
+	if (!isroot && spa->spa_l2cache.sav_config) {
+		nvlist_free(spa->spa_l2cache.sav_config);
+		spa->spa_l2cache.sav_config = NULL;
+		spa_load_l2cache(spa);
+	}
+
+	VERIFY(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE,
+	    &nvroot) == 0);
+	if (error == 0)
+		error = spa_validate_aux(spa, nvroot, -1ULL, VDEV_ALLOC_SPARE);
+	if (error == 0)
+		error = spa_validate_aux(spa, nvroot, -1ULL,
+		    VDEV_ALLOC_L2CACHE);
+	spa_config_exit(spa, SCL_ALL, FTAG);
+
+	if (error != 0 || (props && (error = spa_prop_set(spa, props)))) {
+		if (loaderr != 0 && loaderr != EINVAL && allowfaulted) {
+			/*
+			 * If we failed to load the pool, but 'allowfaulted' is
+			 * set, then manually set the config as if the config
+			 * passed in was specified in the cache file.
+			 */
+			error = 0;
+			spa->spa_import_faulted = B_FALSE;
+			if (spa->spa_config == NULL)
+				spa->spa_config = spa_config_generate(spa,
+				    NULL, -1ULL, B_TRUE);
+			spa_unload(spa);
+			spa_deactivate(spa);
+			spa_config_sync(spa, B_FALSE, B_TRUE);
+		} else {
+			spa_unload(spa);
+			spa_deactivate(spa);
+			spa_remove(spa);
+		}
+		mutex_exit(&spa_namespace_lock);
+		return (error);
+	}
+
+	/*
+	 * Override any spares and level 2 cache devices as specified by
+	 * the user, as these may have correct device names/devids, etc.
+	 */
+	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES,
+	    &spares, &nspares) == 0) {
+		if (spa->spa_spares.sav_config)
+			VERIFY(nvlist_remove(spa->spa_spares.sav_config,
+			    ZPOOL_CONFIG_SPARES, DATA_TYPE_NVLIST_ARRAY) == 0);
+		else
+			VERIFY(nvlist_alloc(&spa->spa_spares.sav_config,
+			    NV_UNIQUE_NAME, KM_SLEEP) == 0);
+		VERIFY(nvlist_add_nvlist_array(spa->spa_spares.sav_config,
+		    ZPOOL_CONFIG_SPARES, spares, nspares) == 0);
+		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+		spa_load_spares(spa);
+		spa_config_exit(spa, SCL_ALL, FTAG);
+		spa->spa_spares.sav_sync = B_TRUE;
+	}
+	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_L2CACHE,
+	    &l2cache, &nl2cache) == 0) {
+		if (spa->spa_l2cache.sav_config)
+			VERIFY(nvlist_remove(spa->spa_l2cache.sav_config,
+			    ZPOOL_CONFIG_L2CACHE, DATA_TYPE_NVLIST_ARRAY) == 0);
+		else
+			VERIFY(nvlist_alloc(&spa->spa_l2cache.sav_config,
+			    NV_UNIQUE_NAME, KM_SLEEP) == 0);
+		VERIFY(nvlist_add_nvlist_array(spa->spa_l2cache.sav_config,
+		    ZPOOL_CONFIG_L2CACHE, l2cache, nl2cache) == 0);
+		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+		spa_load_l2cache(spa);
+		spa_config_exit(spa, SCL_ALL, FTAG);
+		spa->spa_l2cache.sav_sync = B_TRUE;
+	}
+
+	if (spa_mode & FWRITE) {
+		/*
+		 * Update the config cache to include the newly-imported pool.
+		 */
+		spa_config_update_common(spa, SPA_CONFIG_UPDATE_POOL, isroot);
+	}
+
+	spa->spa_import_faulted = B_FALSE;
+	mutex_exit(&spa_namespace_lock);
+
+	return (0);
+}
+
+#ifdef _KERNEL
+/*
+ * Build a "root" vdev for a top level vdev read in from a rootpool
+ * device label.
+ */
+static void
+spa_build_rootpool_config(nvlist_t *config)
+{
+	nvlist_t *nvtop, *nvroot;
+	uint64_t pgid;
+
+	/*
+	 * Add this top-level vdev to the child array.
+	 */
+	VERIFY(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, &nvtop)
+	    == 0);
+	VERIFY(nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_GUID, &pgid)
+	    == 0);
+
+	/*
+	 * Put this pool's top-level vdevs into a root vdev.
+	 */
+	VERIFY(nvlist_alloc(&nvroot, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+	VERIFY(nvlist_add_string(nvroot, ZPOOL_CONFIG_TYPE, VDEV_TYPE_ROOT)
+	    == 0);
+	VERIFY(nvlist_add_uint64(nvroot, ZPOOL_CONFIG_ID, 0ULL) == 0);
+	VERIFY(nvlist_add_uint64(nvroot, ZPOOL_CONFIG_GUID, pgid) == 0);
+	VERIFY(nvlist_add_nvlist_array(nvroot, ZPOOL_CONFIG_CHILDREN,
+	    &nvtop, 1) == 0);
+
+	/*
+	 * Replace the existing vdev_tree with the new root vdev in
+	 * this pool's configuration (remove the old, add the new).
+	 */
+	VERIFY(nvlist_add_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, nvroot) == 0);
+	nvlist_free(nvroot);
+}
+
+/*
+ * Get the root pool information from the root disk, then import the root pool
+ * during the system boot up time.
+ */
+extern int vdev_disk_read_rootlabel(char *, char *, nvlist_t **);
+
+int
+spa_check_rootconf(char *devpath, char *devid, nvlist_t **bestconf,
+    uint64_t *besttxg)
+{
+	nvlist_t *config;
+	uint64_t txg;
+	int error;
+
+	if (error = vdev_disk_read_rootlabel(devpath, devid, &config))
+		return (error);
+
+	VERIFY(nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_TXG, &txg) == 0);
+
+	if (bestconf != NULL)
+		*bestconf = config;
+	else
+		nvlist_free(config);
+	*besttxg = txg;
+	return (0);
+}
+
+boolean_t
+spa_rootdev_validate(nvlist_t *nv)
+{
+	uint64_t ival;
+
+	if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_OFFLINE, &ival) == 0 ||
+	    nvlist_lookup_uint64(nv, ZPOOL_CONFIG_FAULTED, &ival) == 0 ||
+	    nvlist_lookup_uint64(nv, ZPOOL_CONFIG_REMOVED, &ival) == 0)
+		return (B_FALSE);
+
+	return (B_TRUE);
+}
+
+
+/*
+ * Given the boot device's physical path or devid, check if the device
+ * is in a valid state.  If so, return the configuration from the vdev
+ * label.
+ */
+int
+spa_get_rootconf(char *devpath, char *devid, nvlist_t **bestconf)
+{
+	nvlist_t *conf = NULL;
+	uint64_t txg = 0;
+	nvlist_t *nvtop, **child;
+	char *type;
+	char *bootpath = NULL;
+	uint_t children, c;
+	char *tmp;
+	int error;
+
+	if (devpath && ((tmp = strchr(devpath, ' ')) != NULL))
+		*tmp = '\0';
+	if (error = spa_check_rootconf(devpath, devid, &conf, &txg)) {
+		cmn_err(CE_NOTE, "error reading device label");
+		return (error);
+	}
+	if (txg == 0) {
+		cmn_err(CE_NOTE, "this device is detached");
+		nvlist_free(conf);
+		return (EINVAL);
+	}
+
+	VERIFY(nvlist_lookup_nvlist(conf, ZPOOL_CONFIG_VDEV_TREE,
+	    &nvtop) == 0);
+	VERIFY(nvlist_lookup_string(nvtop, ZPOOL_CONFIG_TYPE, &type) == 0);
+
+	if (strcmp(type, VDEV_TYPE_DISK) == 0) {
+		if (spa_rootdev_validate(nvtop)) {
+			goto out;
+		} else {
+			nvlist_free(conf);
+			return (EINVAL);
+		}
+	}
+
+	ASSERT(strcmp(type, VDEV_TYPE_MIRROR) == 0);
+
+	VERIFY(nvlist_lookup_nvlist_array(nvtop, ZPOOL_CONFIG_CHILDREN,
+	    &child, &children) == 0);
+
+	/*
+	 * Go thru vdevs in the mirror to see if the given device
+	 * has the most recent txg. Only the device with the most
+	 * recent txg has valid information and should be booted.
+	 */
+	for (c = 0; c < children; c++) {
+		char *cdevid, *cpath;
+		uint64_t tmptxg;
+
+		if (nvlist_lookup_string(child[c], ZPOOL_CONFIG_PHYS_PATH,
+		    &cpath) != 0)
+			return (EINVAL);
+		if (nvlist_lookup_string(child[c], ZPOOL_CONFIG_DEVID,
+		    &cdevid) != 0)
+			return (EINVAL);
+		if ((spa_check_rootconf(cpath, cdevid, NULL,
+		    &tmptxg) == 0) && (tmptxg > txg)) {
+			txg = tmptxg;
+			VERIFY(nvlist_lookup_string(child[c],
+			    ZPOOL_CONFIG_PATH, &bootpath) == 0);
+		}
+	}
+
+	/* Does the best device match the one we've booted from? */
+	if (bootpath) {
+		cmn_err(CE_NOTE, "try booting from '%s'", bootpath);
+		return (EINVAL);
+	}
+out:
+	*bestconf = conf;
+	return (0);
+}
+
+/*
+ * Import a root pool.
+ *
+ * For x86. devpath_list will consist of devid and/or physpath name of
+ * the vdev (e.g. "id1,sd@SSEAGATE..." or "/pci@1f,0/ide@d/disk@0,0:a").
+ * The GRUB "findroot" command will return the vdev we should boot.
+ *
+ * For Sparc, devpath_list consists the physpath name of the booting device
+ * no matter the rootpool is a single device pool or a mirrored pool.
+ * e.g.
+ *	"/pci@1f,0/ide@d/disk@0,0:a"
+ */
+int
+spa_import_rootpool(char *devpath, char *devid)
+{
+	nvlist_t *conf = NULL;
+	char *pname;
+	int error;
+
+	/*
+	 * Get the vdev pathname and configuation from the most
+	 * recently updated vdev (highest txg).
+	 */
+	if (error = spa_get_rootconf(devpath, devid, &conf))
+		goto msg_out;
+
+	/*
+	 * Add type "root" vdev to the config.
+	 */
+	spa_build_rootpool_config(conf);
+
+	VERIFY(nvlist_lookup_string(conf, ZPOOL_CONFIG_POOL_NAME, &pname) == 0);
+
+	/*
+	 * We specify 'allowfaulted' for this to be treated like spa_open()
+	 * instead of spa_import().  This prevents us from marking vdevs as
+	 * persistently unavailable, and generates FMA ereports as if it were a
+	 * pool open, not import.
+	 */
+	error = spa_import_common(pname, conf, NULL, B_TRUE, B_TRUE);
+	ASSERT(error != EEXIST);
+
+	nvlist_free(conf);
+	return (error);
+
+msg_out:
+	cmn_err(CE_NOTE, "\n"
+	    "  ***************************************************  \n"
+	    "  *  This device is not bootable!                   *  \n"
+	    "  *  It is either offlined or detached or faulted.  *  \n"
+	    "  *  Please try to boot from a different device.    *  \n"
+	    "  ***************************************************  ");
+
+	return (error);
+}
+#endif
+
+/*
+ * Import a non-root pool into the system.
+ */
+int
+spa_import(const char *pool, nvlist_t *config, nvlist_t *props)
+{
+	return (spa_import_common(pool, config, props, B_FALSE, B_FALSE));
+}
+
+int
+spa_import_faulted(const char *pool, nvlist_t *config, nvlist_t *props)
+{
+	return (spa_import_common(pool, config, props, B_FALSE, B_TRUE));
+}
+
+
+/*
+ * This (illegal) pool name is used when temporarily importing a spa_t in order
+ * to get the vdev stats associated with the imported devices.
+ */
+#define	TRYIMPORT_NAME	"$import"
+
+nvlist_t *
+spa_tryimport(nvlist_t *tryconfig)
+{
+	nvlist_t *config = NULL;
+	char *poolname;
+	spa_t *spa;
+	uint64_t state;
+
+	if (nvlist_lookup_string(tryconfig, ZPOOL_CONFIG_POOL_NAME, &poolname))
+		return (NULL);
+
+	if (nvlist_lookup_uint64(tryconfig, ZPOOL_CONFIG_POOL_STATE, &state))
+		return (NULL);
+
+	/*
+	 * Create and initialize the spa structure.
+	 */
+	mutex_enter(&spa_namespace_lock);
+	spa = spa_add(TRYIMPORT_NAME, NULL);
+	spa_activate(spa);
+
+	/*
+	 * Pass off the heavy lifting to spa_load().
+	 * Pass TRUE for mosconfig because the user-supplied config
+	 * is actually the one to trust when doing an import.
+	 */
+	(void) spa_load(spa, tryconfig, SPA_LOAD_TRYIMPORT, B_TRUE);
+
+	/*
+	 * If 'tryconfig' was at least parsable, return the current config.
+	 */
+	if (spa->spa_root_vdev != NULL) {
+		config = spa_config_generate(spa, NULL, -1ULL, B_TRUE);
+		VERIFY(nvlist_add_string(config, ZPOOL_CONFIG_POOL_NAME,
+		    poolname) == 0);
+		VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_POOL_STATE,
+		    state) == 0);
+		VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_TIMESTAMP,
+		    spa->spa_uberblock.ub_timestamp) == 0);
+
+		/*
+		 * If the bootfs property exists on this pool then we
+		 * copy it out so that external consumers can tell which
+		 * pools are bootable.
+		 */
+		if (spa->spa_bootfs) {
+			char *tmpname = kmem_alloc(MAXPATHLEN, KM_SLEEP);
+
+			/*
+			 * We have to play games with the name since the
+			 * pool was opened as TRYIMPORT_NAME.
+			 */
+			if (dsl_dsobj_to_dsname(spa_name(spa),
+			    spa->spa_bootfs, tmpname) == 0) {
+				char *cp;
+				char *dsname = kmem_alloc(MAXPATHLEN, KM_SLEEP);
+
+				cp = strchr(tmpname, '/');
+				if (cp == NULL) {
+					(void) strlcpy(dsname, tmpname,
+					    MAXPATHLEN);
+				} else {
+					(void) snprintf(dsname, MAXPATHLEN,
+					    "%s/%s", poolname, ++cp);
+				}
+				VERIFY(nvlist_add_string(config,
+				    ZPOOL_CONFIG_BOOTFS, dsname) == 0);
+				kmem_free(dsname, MAXPATHLEN);
+			}
+			kmem_free(tmpname, MAXPATHLEN);
+		}
+
+		/*
+		 * Add the list of hot spares and level 2 cache devices.
+		 */
+		spa_add_spares(spa, config);
+		spa_add_l2cache(spa, config);
+	}
+
+	spa_unload(spa);
+	spa_deactivate(spa);
+	spa_remove(spa);
+	mutex_exit(&spa_namespace_lock);
+
+	return (config);
+}
+
+/*
+ * Pool export/destroy
+ *
+ * The act of destroying or exporting a pool is very simple.  We make sure there
+ * is no more pending I/O and any references to the pool are gone.  Then, we
+ * update the pool state and sync all the labels to disk, removing the
+ * configuration from the cache afterwards.
+ */
+static int
+spa_export_common(char *pool, int new_state, nvlist_t **oldconfig,
+    boolean_t force)
+{
+	spa_t *spa;
+
+	if (oldconfig)
+		*oldconfig = NULL;
+
+	if (!(spa_mode & FWRITE))
+		return (EROFS);
+
+	mutex_enter(&spa_namespace_lock);
+	if ((spa = spa_lookup(pool)) == NULL) {
+		mutex_exit(&spa_namespace_lock);
+		return (ENOENT);
+	}
+
+	/*
+	 * Put a hold on the pool, drop the namespace lock, stop async tasks,
+	 * reacquire the namespace lock, and see if we can export.
+	 */
+	spa_open_ref(spa, FTAG);
+	mutex_exit(&spa_namespace_lock);
+	spa_async_suspend(spa);
+	mutex_enter(&spa_namespace_lock);
+	spa_close(spa, FTAG);
+
+	/*
+	 * The pool will be in core if it's openable,
+	 * in which case we can modify its state.
+	 */
+	if (spa->spa_state != POOL_STATE_UNINITIALIZED && spa->spa_sync_on) {
+		/*
+		 * Objsets may be open only because they're dirty, so we
+		 * have to force it to sync before checking spa_refcnt.
+		 */
+		txg_wait_synced(spa->spa_dsl_pool, 0);
+
+		/*
+		 * A pool cannot be exported or destroyed if there are active
+		 * references.  If we are resetting a pool, allow references by
+		 * fault injection handlers.
+		 */
+		if (!spa_refcount_zero(spa) ||
+		    (spa->spa_inject_ref != 0 &&
+		    new_state != POOL_STATE_UNINITIALIZED)) {
+			spa_async_resume(spa);
+			mutex_exit(&spa_namespace_lock);
+			return (EBUSY);
+		}
+
+		/*
+		 * A pool cannot be exported if it has an active shared spare.
+		 * This is to prevent other pools stealing the active spare
+		 * from an exported pool. At user's own will, such pool can
+		 * be forcedly exported.
+		 */
+		if (!force && new_state == POOL_STATE_EXPORTED &&
+		    spa_has_active_shared_spare(spa)) {
+			spa_async_resume(spa);
+			mutex_exit(&spa_namespace_lock);
+			return (EXDEV);
+		}
+
+		/*
+		 * We want this to be reflected on every label,
+		 * so mark them all dirty.  spa_unload() will do the
+		 * final sync that pushes these changes out.
+		 */
+		if (new_state != POOL_STATE_UNINITIALIZED) {
+			spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+			spa->spa_state = new_state;
+			spa->spa_final_txg = spa_last_synced_txg(spa) + 1;
+			vdev_config_dirty(spa->spa_root_vdev);
+			spa_config_exit(spa, SCL_ALL, FTAG);
+		}
+	}
+
+	spa_event_notify(spa, NULL, ESC_ZFS_POOL_DESTROY);
+
+	if (spa->spa_state != POOL_STATE_UNINITIALIZED) {
+		spa_unload(spa);
+		spa_deactivate(spa);
+	}
+
+	if (oldconfig && spa->spa_config)
+		VERIFY(nvlist_dup(spa->spa_config, oldconfig, 0) == 0);
+
+	if (new_state != POOL_STATE_UNINITIALIZED) {
+		spa_config_sync(spa, B_TRUE, B_TRUE);
+		spa_remove(spa);
+	}
+	mutex_exit(&spa_namespace_lock);
+
+	return (0);
+}
+
+/*
+ * Destroy a storage pool.
+ */
+int
+spa_destroy(char *pool)
+{
+	return (spa_export_common(pool, POOL_STATE_DESTROYED, NULL, B_FALSE));
+}
+
+/*
+ * Export a storage pool.
+ */
+int
+spa_export(char *pool, nvlist_t **oldconfig, boolean_t force)
+{
+	return (spa_export_common(pool, POOL_STATE_EXPORTED, oldconfig, force));
+}
+
+/*
+ * Similar to spa_export(), this unloads the spa_t without actually removing it
+ * from the namespace in any way.
+ */
+int
+spa_reset(char *pool)
+{
+	return (spa_export_common(pool, POOL_STATE_UNINITIALIZED, NULL,
+	    B_FALSE));
+}
+
+/*
+ * ==========================================================================
+ * Device manipulation
+ * ==========================================================================
+ */
+
+/*
+ * Add a device to a storage pool.
+ */
+int
+spa_vdev_add(spa_t *spa, nvlist_t *nvroot)
+{
+	uint64_t txg;
+	int c, error;
+	vdev_t *rvd = spa->spa_root_vdev;
+	vdev_t *vd, *tvd;
+	nvlist_t **spares, **l2cache;
+	uint_t nspares, nl2cache;
+
+	txg = spa_vdev_enter(spa);
+
+	if ((error = spa_config_parse(spa, &vd, nvroot, NULL, 0,
+	    VDEV_ALLOC_ADD)) != 0)
+		return (spa_vdev_exit(spa, NULL, txg, error));
+
+	spa->spa_pending_vdev = vd;	/* spa_vdev_exit() will clear this */
+
+	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_SPARES, &spares,
+	    &nspares) != 0)
+		nspares = 0;
+
+	if (nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_L2CACHE, &l2cache,
+	    &nl2cache) != 0)
+		nl2cache = 0;
+
+	if (vd->vdev_children == 0 && nspares == 0 && nl2cache == 0)
+		return (spa_vdev_exit(spa, vd, txg, EINVAL));
+
+	if (vd->vdev_children != 0 &&
+	    (error = vdev_create(vd, txg, B_FALSE)) != 0)
+		return (spa_vdev_exit(spa, vd, txg, error));
+
+	/*
+	 * We must validate the spares and l2cache devices after checking the
+	 * children.  Otherwise, vdev_inuse() will blindly overwrite the spare.
+	 */
+	if ((error = spa_validate_aux(spa, nvroot, txg, VDEV_ALLOC_ADD)) != 0)
+		return (spa_vdev_exit(spa, vd, txg, error));
+
+	/*
+	 * Transfer each new top-level vdev from vd to rvd.
+	 */
+	for (c = 0; c < vd->vdev_children; c++) {
+		tvd = vd->vdev_child[c];
+		vdev_remove_child(vd, tvd);
+		tvd->vdev_id = rvd->vdev_children;
+		vdev_add_child(rvd, tvd);
+		vdev_config_dirty(tvd);
+	}
+
+	if (nspares != 0) {
+		spa_set_aux_vdevs(&spa->spa_spares, spares, nspares,
+		    ZPOOL_CONFIG_SPARES);
+		spa_load_spares(spa);
+		spa->spa_spares.sav_sync = B_TRUE;
+	}
+
+	if (nl2cache != 0) {
+		spa_set_aux_vdevs(&spa->spa_l2cache, l2cache, nl2cache,
+		    ZPOOL_CONFIG_L2CACHE);
+		spa_load_l2cache(spa);
+		spa->spa_l2cache.sav_sync = B_TRUE;
+	}
+
+	/*
+	 * We have to be careful when adding new vdevs to an existing pool.
+	 * If other threads start allocating from these vdevs before we
+	 * sync the config cache, and we lose power, then upon reboot we may
+	 * fail to open the pool because there are DVAs that the config cache
+	 * can't translate.  Therefore, we first add the vdevs without
+	 * initializing metaslabs; sync the config cache (via spa_vdev_exit());
+	 * and then let spa_config_update() initialize the new metaslabs.
+	 *
+	 * spa_load() checks for added-but-not-initialized vdevs, so that
+	 * if we lose power at any point in this sequence, the remaining
+	 * steps will be completed the next time we load the pool.
+	 */
+	(void) spa_vdev_exit(spa, vd, txg, 0);
+
+	mutex_enter(&spa_namespace_lock);
+	spa_config_update(spa, SPA_CONFIG_UPDATE_POOL);
+	mutex_exit(&spa_namespace_lock);
+
+	return (0);
+}
+
+/*
+ * Attach a device to a mirror.  The arguments are the path to any device
+ * in the mirror, and the nvroot for the new device.  If the path specifies
+ * a device that is not mirrored, we automatically insert the mirror vdev.
+ *
+ * If 'replacing' is specified, the new device is intended to replace the
+ * existing device; in this case the two devices are made into their own
+ * mirror using the 'replacing' vdev, which is functionally identical to
+ * the mirror vdev (it actually reuses all the same ops) but has a few
+ * extra rules: you can't attach to it after it's been created, and upon
+ * completion of resilvering, the first disk (the one being replaced)
+ * is automatically detached.
+ */
+int
+spa_vdev_attach(spa_t *spa, uint64_t guid, nvlist_t *nvroot, int replacing)
+{
+	uint64_t txg, open_txg;
+	vdev_t *rvd = spa->spa_root_vdev;
+	vdev_t *oldvd, *newvd, *newrootvd, *pvd, *tvd;
+	vdev_ops_t *pvops;
+	dmu_tx_t *tx;
+	char *oldvdpath, *newvdpath;
+	int newvd_isspare;
+	int error;
+
+	txg = spa_vdev_enter(spa);
+
+	oldvd = spa_lookup_by_guid(spa, guid, B_FALSE);
+
+	if (oldvd == NULL)
+		return (spa_vdev_exit(spa, NULL, txg, ENODEV));
+
+	if (!oldvd->vdev_ops->vdev_op_leaf)
+		return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
+
+	pvd = oldvd->vdev_parent;
+
+	if ((error = spa_config_parse(spa, &newrootvd, nvroot, NULL, 0,
+	    VDEV_ALLOC_ADD)) != 0)
+		return (spa_vdev_exit(spa, NULL, txg, EINVAL));
+
+	if (newrootvd->vdev_children != 1)
+		return (spa_vdev_exit(spa, newrootvd, txg, EINVAL));
+
+	newvd = newrootvd->vdev_child[0];
+
+	if (!newvd->vdev_ops->vdev_op_leaf)
+		return (spa_vdev_exit(spa, newrootvd, txg, EINVAL));
+
+	if ((error = vdev_create(newrootvd, txg, replacing)) != 0)
+		return (spa_vdev_exit(spa, newrootvd, txg, error));
+
+	/*
+	 * Spares can't replace logs
+	 */
+	if (oldvd->vdev_top->vdev_islog && newvd->vdev_isspare)
+		return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
+
+	if (!replacing) {
+		/*
+		 * For attach, the only allowable parent is a mirror or the root
+		 * vdev.
+		 */
+		if (pvd->vdev_ops != &vdev_mirror_ops &&
+		    pvd->vdev_ops != &vdev_root_ops)
+			return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
+
+		pvops = &vdev_mirror_ops;
+	} else {
+		/*
+		 * Active hot spares can only be replaced by inactive hot
+		 * spares.
+		 */
+		if (pvd->vdev_ops == &vdev_spare_ops &&
+		    pvd->vdev_child[1] == oldvd &&
+		    !spa_has_spare(spa, newvd->vdev_guid))
+			return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
+
+		/*
+		 * If the source is a hot spare, and the parent isn't already a
+		 * spare, then we want to create a new hot spare.  Otherwise, we
+		 * want to create a replacing vdev.  The user is not allowed to
+		 * attach to a spared vdev child unless the 'isspare' state is
+		 * the same (spare replaces spare, non-spare replaces
+		 * non-spare).
+		 */
+		if (pvd->vdev_ops == &vdev_replacing_ops)
+			return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
+		else if (pvd->vdev_ops == &vdev_spare_ops &&
+		    newvd->vdev_isspare != oldvd->vdev_isspare)
+			return (spa_vdev_exit(spa, newrootvd, txg, ENOTSUP));
+		else if (pvd->vdev_ops != &vdev_spare_ops &&
+		    newvd->vdev_isspare)
+			pvops = &vdev_spare_ops;
+		else
+			pvops = &vdev_replacing_ops;
+	}
+
+	/*
+	 * Compare the new device size with the replaceable/attachable
+	 * device size.
+	 */
+	if (newvd->vdev_psize < vdev_get_rsize(oldvd))
+		return (spa_vdev_exit(spa, newrootvd, txg, EOVERFLOW));
+
+	/*
+	 * The new device cannot have a higher alignment requirement
+	 * than the top-level vdev.
+	 */
+	if (newvd->vdev_ashift > oldvd->vdev_top->vdev_ashift)
+		return (spa_vdev_exit(spa, newrootvd, txg, EDOM));
+
+	/*
+	 * If this is an in-place replacement, update oldvd's path and devid
+	 * to make it distinguishable from newvd, and unopenable from now on.
+	 */
+	if (strcmp(oldvd->vdev_path, newvd->vdev_path) == 0) {
+		spa_strfree(oldvd->vdev_path);
+		oldvd->vdev_path = kmem_alloc(strlen(newvd->vdev_path) + 5,
+		    KM_SLEEP);
+		(void) sprintf(oldvd->vdev_path, "%s/%s",
+		    newvd->vdev_path, "old");
+		if (oldvd->vdev_devid != NULL) {
+			spa_strfree(oldvd->vdev_devid);
+			oldvd->vdev_devid = NULL;
+		}
+	}
+
+	/*
+	 * If the parent is not a mirror, or if we're replacing, insert the new
+	 * mirror/replacing/spare vdev above oldvd.
+	 */
+	if (pvd->vdev_ops != pvops)
+		pvd = vdev_add_parent(oldvd, pvops);
+
+	ASSERT(pvd->vdev_top->vdev_parent == rvd);
+	ASSERT(pvd->vdev_ops == pvops);
+	ASSERT(oldvd->vdev_parent == pvd);
+
+	/*
+	 * Extract the new device from its root and add it to pvd.
+	 */
+	vdev_remove_child(newrootvd, newvd);
+	newvd->vdev_id = pvd->vdev_children;
+	vdev_add_child(pvd, newvd);
+
+	/*
+	 * If newvd is smaller than oldvd, but larger than its rsize,
+	 * the addition of newvd may have decreased our parent's asize.
+	 */
+	pvd->vdev_asize = MIN(pvd->vdev_asize, newvd->vdev_asize);
+
+	tvd = newvd->vdev_top;
+	ASSERT(pvd->vdev_top == tvd);
+	ASSERT(tvd->vdev_parent == rvd);
+
+	vdev_config_dirty(tvd);
+
+	/*
+	 * Set newvd's DTL to [TXG_INITIAL, open_txg].  It will propagate
+	 * upward when spa_vdev_exit() calls vdev_dtl_reassess().
+	 */
+	open_txg = txg + TXG_CONCURRENT_STATES - 1;
+
+	mutex_enter(&newvd->vdev_dtl_lock);
+	space_map_add(&newvd->vdev_dtl_map, TXG_INITIAL,
+	    open_txg - TXG_INITIAL + 1);
+	mutex_exit(&newvd->vdev_dtl_lock);
+
+	if (newvd->vdev_isspare)
+		spa_spare_activate(newvd);
+	oldvdpath = spa_strdup(oldvd->vdev_path);
+	newvdpath = spa_strdup(newvd->vdev_path);
+	newvd_isspare = newvd->vdev_isspare;
+
+	/*
+	 * Mark newvd's DTL dirty in this txg.
+	 */
+	vdev_dirty(tvd, VDD_DTL, newvd, txg);
+
+	(void) spa_vdev_exit(spa, newrootvd, open_txg, 0);
+
+	tx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir);
+	if (dmu_tx_assign(tx, TXG_WAIT) == 0) {
+		spa_history_internal_log(LOG_POOL_VDEV_ATTACH, spa, tx,
+		    CRED(),  "%s vdev=%s %s vdev=%s",
+		    replacing && newvd_isspare ? "spare in" :
+		    replacing ? "replace" : "attach", newvdpath,
+		    replacing ? "for" : "to", oldvdpath);
+		dmu_tx_commit(tx);
+	} else {
+		dmu_tx_abort(tx);
+	}
+
+	spa_strfree(oldvdpath);
+	spa_strfree(newvdpath);
+
+	/*
+	 * Kick off a resilver to update newvd.
+	 */
+	VERIFY3U(spa_scrub(spa, POOL_SCRUB_RESILVER), ==, 0);
+
+	return (0);
+}
+
+/*
+ * Detach a device from a mirror or replacing vdev.
+ * If 'replace_done' is specified, only detach if the parent
+ * is a replacing vdev.
+ */
+int
+spa_vdev_detach(spa_t *spa, uint64_t guid, int replace_done)
+{
+	uint64_t txg;
+	int c, t, error;
+	vdev_t *rvd = spa->spa_root_vdev;
+	vdev_t *vd, *pvd, *cvd, *tvd;
+	boolean_t unspare = B_FALSE;
+	uint64_t unspare_guid;
+	size_t len;
+
+	txg = spa_vdev_enter(spa);
+
+	vd = spa_lookup_by_guid(spa, guid, B_FALSE);
+
+	if (vd == NULL)
+		return (spa_vdev_exit(spa, NULL, txg, ENODEV));
+
+	if (!vd->vdev_ops->vdev_op_leaf)
+		return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
+
+	pvd = vd->vdev_parent;
+
+	/*
+	 * If replace_done is specified, only remove this device if it's
+	 * the first child of a replacing vdev.  For the 'spare' vdev, either
+	 * disk can be removed.
+	 */
+	if (replace_done) {
+		if (pvd->vdev_ops == &vdev_replacing_ops) {
+			if (vd->vdev_id != 0)
+				return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
+		} else if (pvd->vdev_ops != &vdev_spare_ops) {
+			return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
+		}
+	}
+
+	ASSERT(pvd->vdev_ops != &vdev_spare_ops ||
+	    spa_version(spa) >= SPA_VERSION_SPARES);
+
+	/*
+	 * Only mirror, replacing, and spare vdevs support detach.
+	 */
+	if (pvd->vdev_ops != &vdev_replacing_ops &&
+	    pvd->vdev_ops != &vdev_mirror_ops &&
+	    pvd->vdev_ops != &vdev_spare_ops)
+		return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
+
+	/*
+	 * If there's only one replica, you can't detach it.
+	 */
+	if (pvd->vdev_children <= 1)
+		return (spa_vdev_exit(spa, NULL, txg, EBUSY));
+
+	/*
+	 * If all siblings have non-empty DTLs, this device may have the only
+	 * valid copy of the data, which means we cannot safely detach it.
+	 *
+	 * XXX -- as in the vdev_offline() case, we really want a more
+	 * precise DTL check.
+	 */
+	for (c = 0; c < pvd->vdev_children; c++) {
+		uint64_t dirty;
+
+		cvd = pvd->vdev_child[c];
+		if (cvd == vd)
+			continue;
+		if (vdev_is_dead(cvd))
+			continue;
+		mutex_enter(&cvd->vdev_dtl_lock);
+		dirty = cvd->vdev_dtl_map.sm_space |
+		    cvd->vdev_dtl_scrub.sm_space;
+		mutex_exit(&cvd->vdev_dtl_lock);
+		if (!dirty)
+			break;
+	}
+
+	if (c == pvd->vdev_children)
+		return (spa_vdev_exit(spa, NULL, txg, EBUSY));
+
+	/*
+	 * If we are detaching the second disk from a replacing vdev, then
+	 * check to see if we changed the original vdev's path to have "/old"
+	 * at the end in spa_vdev_attach().  If so, undo that change now.
+	 */
+	if (pvd->vdev_ops == &vdev_replacing_ops && vd->vdev_id == 1 &&
+	    pvd->vdev_child[0]->vdev_path != NULL &&
+	    pvd->vdev_child[1]->vdev_path != NULL) {
+		ASSERT(pvd->vdev_child[1] == vd);
+		cvd = pvd->vdev_child[0];
+		len = strlen(vd->vdev_path);
+		if (strncmp(cvd->vdev_path, vd->vdev_path, len) == 0 &&
+		    strcmp(cvd->vdev_path + len, "/old") == 0) {
+			spa_strfree(cvd->vdev_path);
+			cvd->vdev_path = spa_strdup(vd->vdev_path);
+		}
+	}
+
+	/*
+	 * If we are detaching the original disk from a spare, then it implies
+	 * that the spare should become a real disk, and be removed from the
+	 * active spare list for the pool.
+	 */
+	if (pvd->vdev_ops == &vdev_spare_ops &&
+	    vd->vdev_id == 0)
+		unspare = B_TRUE;
+
+	/*
+	 * Erase the disk labels so the disk can be used for other things.
+	 * This must be done after all other error cases are handled,
+	 * but before we disembowel vd (so we can still do I/O to it).
+	 * But if we can't do it, don't treat the error as fatal --
+	 * it may be that the unwritability of the disk is the reason
+	 * it's being detached!
+	 */
+	error = vdev_label_init(vd, 0, VDEV_LABEL_REMOVE);
+
+	/*
+	 * Remove vd from its parent and compact the parent's children.
+	 */
+	vdev_remove_child(pvd, vd);
+	vdev_compact_children(pvd);
+
+	/*
+	 * Remember one of the remaining children so we can get tvd below.
+	 */
+	cvd = pvd->vdev_child[0];
+
+	/*
+	 * If we need to remove the remaining child from the list of hot spares,
+	 * do it now, marking the vdev as no longer a spare in the process.  We
+	 * must do this before vdev_remove_parent(), because that can change the
+	 * GUID if it creates a new toplevel GUID.
+	 */
+	if (unspare) {
+		ASSERT(cvd->vdev_isspare);
+		spa_spare_remove(cvd);
+		unspare_guid = cvd->vdev_guid;
+	}
+
+	/*
+	 * If the parent mirror/replacing vdev only has one child,
+	 * the parent is no longer needed.  Remove it from the tree.
+	 */
+	if (pvd->vdev_children == 1)
+		vdev_remove_parent(cvd);
+
+	/*
+	 * We don't set tvd until now because the parent we just removed
+	 * may have been the previous top-level vdev.
+	 */
+	tvd = cvd->vdev_top;
+	ASSERT(tvd->vdev_parent == rvd);
+
+	/*
+	 * Reevaluate the parent vdev state.
+	 */
+	vdev_propagate_state(cvd);
+
+	/*
+	 * If the device we just detached was smaller than the others, it may be
+	 * possible to add metaslabs (i.e. grow the pool).  vdev_metaslab_init()
+	 * can't fail because the existing metaslabs are already in core, so
+	 * there's nothing to read from disk.
+	 */
+	VERIFY(vdev_metaslab_init(tvd, txg) == 0);
+
+	vdev_config_dirty(tvd);
+
+	/*
+	 * Mark vd's DTL as dirty in this txg.  vdev_dtl_sync() will see that
+	 * vd->vdev_detached is set and free vd's DTL object in syncing context.
+	 * But first make sure we're not on any *other* txg's DTL list, to
+	 * prevent vd from being accessed after it's freed.
+	 */
+	for (t = 0; t < TXG_SIZE; t++)
+		(void) txg_list_remove_this(&tvd->vdev_dtl_list, vd, t);
+	vd->vdev_detached = B_TRUE;
+	vdev_dirty(tvd, VDD_DTL, vd, txg);
+
+	spa_event_notify(spa, vd, ESC_ZFS_VDEV_REMOVE);
+
+	error = spa_vdev_exit(spa, vd, txg, 0);
+
+	/*
+	 * If this was the removal of the original device in a hot spare vdev,
+	 * then we want to go through and remove the device from the hot spare
+	 * list of every other pool.
+	 */
+	if (unspare) {
+		spa = NULL;
+		mutex_enter(&spa_namespace_lock);
+		while ((spa = spa_next(spa)) != NULL) {
+			if (spa->spa_state != POOL_STATE_ACTIVE)
+				continue;
+			spa_open_ref(spa, FTAG);
+			mutex_exit(&spa_namespace_lock);
+			(void) spa_vdev_remove(spa, unspare_guid, B_TRUE);
+			mutex_enter(&spa_namespace_lock);
+			spa_close(spa, FTAG);
+		}
+		mutex_exit(&spa_namespace_lock);
+	}
+
+	return (error);
+}
+
+static nvlist_t *
+spa_nvlist_lookup_by_guid(nvlist_t **nvpp, int count, uint64_t target_guid)
+{
+	for (int i = 0; i < count; i++) {
+		uint64_t guid;
+
+		VERIFY(nvlist_lookup_uint64(nvpp[i], ZPOOL_CONFIG_GUID,
+		    &guid) == 0);
+
+		if (guid == target_guid)
+			return (nvpp[i]);
+	}
+
+	return (NULL);
+}
+
+static void
+spa_vdev_remove_aux(nvlist_t *config, char *name, nvlist_t **dev, int count,
+	nvlist_t *dev_to_remove)
+{
+	nvlist_t **newdev = NULL;
+
+	if (count > 1)
+		newdev = kmem_alloc((count - 1) * sizeof (void *), KM_SLEEP);
+
+	for (int i = 0, j = 0; i < count; i++) {
+		if (dev[i] == dev_to_remove)
+			continue;
+		VERIFY(nvlist_dup(dev[i], &newdev[j++], KM_SLEEP) == 0);
+	}
+
+	VERIFY(nvlist_remove(config, name, DATA_TYPE_NVLIST_ARRAY) == 0);
+	VERIFY(nvlist_add_nvlist_array(config, name, newdev, count - 1) == 0);
+
+	for (int i = 0; i < count - 1; i++)
+		nvlist_free(newdev[i]);
+
+	if (count > 1)
+		kmem_free(newdev, (count - 1) * sizeof (void *));
+}
+
+/*
+ * Remove a device from the pool.  Currently, this supports removing only hot
+ * spares and level 2 ARC devices.
+ */
+int
+spa_vdev_remove(spa_t *spa, uint64_t guid, boolean_t unspare)
+{
+	vdev_t *vd;
+	nvlist_t **spares, **l2cache, *nv;
+	uint_t nspares, nl2cache;
+	uint64_t txg;
+	int error = 0;
+
+	txg = spa_vdev_enter(spa);
+
+	vd = spa_lookup_by_guid(spa, guid, B_FALSE);
+
+	if (spa->spa_spares.sav_vdevs != NULL &&
+	    nvlist_lookup_nvlist_array(spa->spa_spares.sav_config,
+	    ZPOOL_CONFIG_SPARES, &spares, &nspares) == 0 &&
+	    (nv = spa_nvlist_lookup_by_guid(spares, nspares, guid)) != NULL) {
+		/*
+		 * Only remove the hot spare if it's not currently in use
+		 * in this pool.
+		 */
+		if (vd == NULL || unspare) {
+			spa_vdev_remove_aux(spa->spa_spares.sav_config,
+			    ZPOOL_CONFIG_SPARES, spares, nspares, nv);
+			spa_load_spares(spa);
+			spa->spa_spares.sav_sync = B_TRUE;
+		} else {
+			error = EBUSY;
+		}
+	} else if (spa->spa_l2cache.sav_vdevs != NULL &&
+	    nvlist_lookup_nvlist_array(spa->spa_l2cache.sav_config,
+	    ZPOOL_CONFIG_L2CACHE, &l2cache, &nl2cache) == 0 &&
+	    (nv = spa_nvlist_lookup_by_guid(l2cache, nl2cache, guid)) != NULL) {
+		/*
+		 * Cache devices can always be removed.
+		 */
+		spa_vdev_remove_aux(spa->spa_l2cache.sav_config,
+		    ZPOOL_CONFIG_L2CACHE, l2cache, nl2cache, nv);
+		spa_load_l2cache(spa);
+		spa->spa_l2cache.sav_sync = B_TRUE;
+	} else if (vd != NULL) {
+		/*
+		 * Normal vdevs cannot be removed (yet).
+		 */
+		error = ENOTSUP;
+	} else {
+		/*
+		 * There is no vdev of any kind with the specified guid.
+		 */
+		error = ENOENT;
+	}
+
+	return (spa_vdev_exit(spa, NULL, txg, error));
+}
+
+/*
+ * Find any device that's done replacing, or a vdev marked 'unspare' that's
+ * current spared, so we can detach it.
+ */
+static vdev_t *
+spa_vdev_resilver_done_hunt(vdev_t *vd)
+{
+	vdev_t *newvd, *oldvd;
+	int c;
+
+	for (c = 0; c < vd->vdev_children; c++) {
+		oldvd = spa_vdev_resilver_done_hunt(vd->vdev_child[c]);
+		if (oldvd != NULL)
+			return (oldvd);
+	}
+
+	/*
+	 * Check for a completed replacement.
+	 */
+	if (vd->vdev_ops == &vdev_replacing_ops && vd->vdev_children == 2) {
+		oldvd = vd->vdev_child[0];
+		newvd = vd->vdev_child[1];
+
+		mutex_enter(&newvd->vdev_dtl_lock);
+		if (newvd->vdev_dtl_map.sm_space == 0 &&
+		    newvd->vdev_dtl_scrub.sm_space == 0) {
+			mutex_exit(&newvd->vdev_dtl_lock);
+			return (oldvd);
+		}
+		mutex_exit(&newvd->vdev_dtl_lock);
+	}
+
+	/*
+	 * Check for a completed resilver with the 'unspare' flag set.
+	 */
+	if (vd->vdev_ops == &vdev_spare_ops && vd->vdev_children == 2) {
+		newvd = vd->vdev_child[0];
+		oldvd = vd->vdev_child[1];
+
+		mutex_enter(&newvd->vdev_dtl_lock);
+		if (newvd->vdev_unspare &&
+		    newvd->vdev_dtl_map.sm_space == 0 &&
+		    newvd->vdev_dtl_scrub.sm_space == 0) {
+			newvd->vdev_unspare = 0;
+			mutex_exit(&newvd->vdev_dtl_lock);
+			return (oldvd);
+		}
+		mutex_exit(&newvd->vdev_dtl_lock);
+	}
+
+	return (NULL);
+}
+
+static void
+spa_vdev_resilver_done(spa_t *spa)
+{
+	vdev_t *vd;
+	vdev_t *pvd;
+	uint64_t guid;
+	uint64_t pguid = 0;
+
+	spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
+
+	while ((vd = spa_vdev_resilver_done_hunt(spa->spa_root_vdev)) != NULL) {
+		guid = vd->vdev_guid;
+		/*
+		 * If we have just finished replacing a hot spared device, then
+		 * we need to detach the parent's first child (the original hot
+		 * spare) as well.
+		 */
+		pvd = vd->vdev_parent;
+		if (pvd->vdev_parent->vdev_ops == &vdev_spare_ops &&
+		    pvd->vdev_id == 0) {
+			ASSERT(pvd->vdev_ops == &vdev_replacing_ops);
+			ASSERT(pvd->vdev_parent->vdev_children == 2);
+			pguid = pvd->vdev_parent->vdev_child[1]->vdev_guid;
+		}
+		spa_config_exit(spa, SCL_CONFIG, FTAG);
+		if (spa_vdev_detach(spa, guid, B_TRUE) != 0)
+			return;
+		if (pguid != 0 && spa_vdev_detach(spa, pguid, B_TRUE) != 0)
+			return;
+		spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
+	}
+
+	spa_config_exit(spa, SCL_CONFIG, FTAG);
+}
+
+/*
+ * Update the stored path for this vdev.  Dirty the vdev configuration, relying
+ * on spa_vdev_enter/exit() to synchronize the labels and cache.
+ */
+int
+spa_vdev_setpath(spa_t *spa, uint64_t guid, const char *newpath)
+{
+	vdev_t *vd;
+	uint64_t txg;
+
+	txg = spa_vdev_enter(spa);
+
+	if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL) {
+		/*
+		 * Determine if this is a reference to a hot spare device.  If
+		 * it is, update the path manually as there is no associated
+		 * vdev_t that can be synced to disk.
+		 */
+		nvlist_t **spares;
+		uint_t i, nspares;
+
+		if (spa->spa_spares.sav_config != NULL) {
+			VERIFY(nvlist_lookup_nvlist_array(
+			    spa->spa_spares.sav_config, ZPOOL_CONFIG_SPARES,
+			    &spares, &nspares) == 0);
+			for (i = 0; i < nspares; i++) {
+				uint64_t theguid;
+				VERIFY(nvlist_lookup_uint64(spares[i],
+				    ZPOOL_CONFIG_GUID, &theguid) == 0);
+				if (theguid == guid) {
+					VERIFY(nvlist_add_string(spares[i],
+					    ZPOOL_CONFIG_PATH, newpath) == 0);
+					spa_load_spares(spa);
+					spa->spa_spares.sav_sync = B_TRUE;
+					return (spa_vdev_exit(spa, NULL, txg,
+					    0));
+				}
+			}
+		}
+
+		return (spa_vdev_exit(spa, NULL, txg, ENOENT));
+	}
+
+	if (!vd->vdev_ops->vdev_op_leaf)
+		return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
+
+	spa_strfree(vd->vdev_path);
+	vd->vdev_path = spa_strdup(newpath);
+
+	vdev_config_dirty(vd->vdev_top);
+
+	return (spa_vdev_exit(spa, NULL, txg, 0));
+}
+
+/*
+ * ==========================================================================
+ * SPA Scrubbing
+ * ==========================================================================
+ */
+
+int
+spa_scrub(spa_t *spa, pool_scrub_type_t type)
+{
+	ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == 0);
+
+	if ((uint_t)type >= POOL_SCRUB_TYPES)
+		return (ENOTSUP);
+
+	/*
+	 * If a resilver was requested, but there is no DTL on a
+	 * writeable leaf device, we have nothing to do.
+	 */
+	if (type == POOL_SCRUB_RESILVER &&
+	    !vdev_resilver_needed(spa->spa_root_vdev, NULL, NULL)) {
+		spa_async_request(spa, SPA_ASYNC_RESILVER_DONE);
+		return (0);
+	}
+
+	if (type == POOL_SCRUB_EVERYTHING &&
+	    spa->spa_dsl_pool->dp_scrub_func != SCRUB_FUNC_NONE &&
+	    spa->spa_dsl_pool->dp_scrub_isresilver)
+		return (EBUSY);
+
+	if (type == POOL_SCRUB_EVERYTHING || type == POOL_SCRUB_RESILVER) {
+		return (dsl_pool_scrub_clean(spa->spa_dsl_pool));
+	} else if (type == POOL_SCRUB_NONE) {
+		return (dsl_pool_scrub_cancel(spa->spa_dsl_pool));
+	} else {
+		return (EINVAL);
+	}
+}
+
+/*
+ * ==========================================================================
+ * SPA async task processing
+ * ==========================================================================
+ */
+
+static void
+spa_async_remove(spa_t *spa, vdev_t *vd)
+{
+	if (vd->vdev_remove_wanted) {
+		vd->vdev_remove_wanted = 0;
+		vdev_set_state(vd, B_FALSE, VDEV_STATE_REMOVED, VDEV_AUX_NONE);
+		vdev_clear(spa, vd);
+		vdev_state_dirty(vd->vdev_top);
+	}
+
+	for (int c = 0; c < vd->vdev_children; c++)
+		spa_async_remove(spa, vd->vdev_child[c]);
+}
+
+static void
+spa_async_probe(spa_t *spa, vdev_t *vd)
+{
+	if (vd->vdev_probe_wanted) {
+		vd->vdev_probe_wanted = 0;
+		vdev_reopen(vd);	/* vdev_open() does the actual probe */
+	}
+
+	for (int c = 0; c < vd->vdev_children; c++)
+		spa_async_probe(spa, vd->vdev_child[c]);
+}
+
+static void
+spa_async_thread(spa_t *spa)
+{
+	int tasks;
+
+	ASSERT(spa->spa_sync_on);
+
+	mutex_enter(&spa->spa_async_lock);
+	tasks = spa->spa_async_tasks;
+	spa->spa_async_tasks = 0;
+	mutex_exit(&spa->spa_async_lock);
+
+	/*
+	 * See if the config needs to be updated.
+	 */
+	if (tasks & SPA_ASYNC_CONFIG_UPDATE) {
+		mutex_enter(&spa_namespace_lock);
+		spa_config_update(spa, SPA_CONFIG_UPDATE_POOL);
+		mutex_exit(&spa_namespace_lock);
+	}
+
+	/*
+	 * See if any devices need to be marked REMOVED.
+	 */
+	if (tasks & SPA_ASYNC_REMOVE) {
+		spa_vdev_state_enter(spa);
+		spa_async_remove(spa, spa->spa_root_vdev);
+		for (int i = 0; i < spa->spa_l2cache.sav_count; i++)
+			spa_async_remove(spa, spa->spa_l2cache.sav_vdevs[i]);
+		for (int i = 0; i < spa->spa_spares.sav_count; i++)
+			spa_async_remove(spa, spa->spa_spares.sav_vdevs[i]);
+		(void) spa_vdev_state_exit(spa, NULL, 0);
+	}
+
+	/*
+	 * See if any devices need to be probed.
+	 */
+	if (tasks & SPA_ASYNC_PROBE) {
+		spa_vdev_state_enter(spa);
+		spa_async_probe(spa, spa->spa_root_vdev);
+		(void) spa_vdev_state_exit(spa, NULL, 0);
+	}
+
+	/*
+	 * If any devices are done replacing, detach them.
+	 */
+	if (tasks & SPA_ASYNC_RESILVER_DONE)
+		spa_vdev_resilver_done(spa);
+
+	/*
+	 * Kick off a resilver.
+	 */
+	if (tasks & SPA_ASYNC_RESILVER)
+		VERIFY(spa_scrub(spa, POOL_SCRUB_RESILVER) == 0);
+
+	/*
+	 * Let the world know that we're done.
+	 */
+	mutex_enter(&spa->spa_async_lock);
+	spa->spa_async_thread = NULL;
+	cv_broadcast(&spa->spa_async_cv);
+	mutex_exit(&spa->spa_async_lock);
+	thread_exit();
+}
+
+void
+spa_async_suspend(spa_t *spa)
+{
+	mutex_enter(&spa->spa_async_lock);
+	spa->spa_async_suspended++;
+	while (spa->spa_async_thread != NULL)
+		cv_wait(&spa->spa_async_cv, &spa->spa_async_lock);
+	mutex_exit(&spa->spa_async_lock);
+}
+
+void
+spa_async_resume(spa_t *spa)
+{
+	mutex_enter(&spa->spa_async_lock);
+	ASSERT(spa->spa_async_suspended != 0);
+	spa->spa_async_suspended--;
+	mutex_exit(&spa->spa_async_lock);
+}
+
+static void
+spa_async_dispatch(spa_t *spa)
+{
+	mutex_enter(&spa->spa_async_lock);
+	if (spa->spa_async_tasks && !spa->spa_async_suspended &&
+	    spa->spa_async_thread == NULL &&
+	    rootdir != NULL && !vn_is_readonly(rootdir))
+		spa->spa_async_thread = thread_create(NULL, 0,
+		    spa_async_thread, spa, 0, &p0, TS_RUN, maxclsyspri);
+	mutex_exit(&spa->spa_async_lock);
+}
+
+void
+spa_async_request(spa_t *spa, int task)
+{
+	mutex_enter(&spa->spa_async_lock);
+	spa->spa_async_tasks |= task;
+	mutex_exit(&spa->spa_async_lock);
+}
+
+/*
+ * ==========================================================================
+ * SPA syncing routines
+ * ==========================================================================
+ */
+
+static void
+spa_sync_deferred_frees(spa_t *spa, uint64_t txg)
+{
+	bplist_t *bpl = &spa->spa_sync_bplist;
+	dmu_tx_t *tx;
+	blkptr_t blk;
+	uint64_t itor = 0;
+	zio_t *zio;
+	int error;
+	uint8_t c = 1;
+
+	zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
+
+	while (bplist_iterate(bpl, &itor, &blk) == 0) {
+		ASSERT(blk.blk_birth < txg);
+		zio_nowait(zio_free(zio, spa, txg, &blk, NULL, NULL,
+		    ZIO_FLAG_MUSTSUCCEED));
+	}
+
+	error = zio_wait(zio);
+	ASSERT3U(error, ==, 0);
+
+	tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
+	bplist_vacate(bpl, tx);
+
+	/*
+	 * Pre-dirty the first block so we sync to convergence faster.
+	 * (Usually only the first block is needed.)
+	 */
+	dmu_write(spa->spa_meta_objset, spa->spa_sync_bplist_obj, 0, 1, &c, tx);
+	dmu_tx_commit(tx);
+}
+
+static void
+spa_sync_nvlist(spa_t *spa, uint64_t obj, nvlist_t *nv, dmu_tx_t *tx)
+{
+	char *packed = NULL;
+	size_t bufsize;
+	size_t nvsize = 0;
+	dmu_buf_t *db;
+
+	VERIFY(nvlist_size(nv, &nvsize, NV_ENCODE_XDR) == 0);
+
+	/*
+	 * Write full (SPA_CONFIG_BLOCKSIZE) blocks of configuration
+	 * information.  This avoids the dbuf_will_dirty() path and
+	 * saves us a pre-read to get data we don't actually care about.
+	 */
+	bufsize = P2ROUNDUP(nvsize, SPA_CONFIG_BLOCKSIZE);
+	packed = kmem_alloc(bufsize, KM_SLEEP);
+
+	VERIFY(nvlist_pack(nv, &packed, &nvsize, NV_ENCODE_XDR,
+	    KM_SLEEP) == 0);
+	bzero(packed + nvsize, bufsize - nvsize);
+
+	dmu_write(spa->spa_meta_objset, obj, 0, bufsize, packed, tx);
+
+	kmem_free(packed, bufsize);
+
+	VERIFY(0 == dmu_bonus_hold(spa->spa_meta_objset, obj, FTAG, &db));
+	dmu_buf_will_dirty(db, tx);
+	*(uint64_t *)db->db_data = nvsize;
+	dmu_buf_rele(db, FTAG);
+}
+
+static void
+spa_sync_aux_dev(spa_t *spa, spa_aux_vdev_t *sav, dmu_tx_t *tx,
+    const char *config, const char *entry)
+{
+	nvlist_t *nvroot;
+	nvlist_t **list;
+	int i;
+
+	if (!sav->sav_sync)
+		return;
+
+	/*
+	 * Update the MOS nvlist describing the list of available devices.
+	 * spa_validate_aux() will have already made sure this nvlist is
+	 * valid and the vdevs are labeled appropriately.
+	 */
+	if (sav->sav_object == 0) {
+		sav->sav_object = dmu_object_alloc(spa->spa_meta_objset,
+		    DMU_OT_PACKED_NVLIST, 1 << 14, DMU_OT_PACKED_NVLIST_SIZE,
+		    sizeof (uint64_t), tx);
+		VERIFY(zap_update(spa->spa_meta_objset,
+		    DMU_POOL_DIRECTORY_OBJECT, entry, sizeof (uint64_t), 1,
+		    &sav->sav_object, tx) == 0);
+	}
+
+	VERIFY(nvlist_alloc(&nvroot, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+	if (sav->sav_count == 0) {
+		VERIFY(nvlist_add_nvlist_array(nvroot, config, NULL, 0) == 0);
+	} else {
+		list = kmem_alloc(sav->sav_count * sizeof (void *), KM_SLEEP);
+		for (i = 0; i < sav->sav_count; i++)
+			list[i] = vdev_config_generate(spa, sav->sav_vdevs[i],
+			    B_FALSE, B_FALSE, B_TRUE);
+		VERIFY(nvlist_add_nvlist_array(nvroot, config, list,
+		    sav->sav_count) == 0);
+		for (i = 0; i < sav->sav_count; i++)
+			nvlist_free(list[i]);
+		kmem_free(list, sav->sav_count * sizeof (void *));
+	}
+
+	spa_sync_nvlist(spa, sav->sav_object, nvroot, tx);
+	nvlist_free(nvroot);
+
+	sav->sav_sync = B_FALSE;
+}
+
+static void
+spa_sync_config_object(spa_t *spa, dmu_tx_t *tx)
+{
+	nvlist_t *config;
+
+	if (list_is_empty(&spa->spa_config_dirty_list))
+		return;
+
+	spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
+
+	config = spa_config_generate(spa, spa->spa_root_vdev,
+	    dmu_tx_get_txg(tx), B_FALSE);
+
+	spa_config_exit(spa, SCL_STATE, FTAG);
+
+	if (spa->spa_config_syncing)
+		nvlist_free(spa->spa_config_syncing);
+	spa->spa_config_syncing = config;
+
+	spa_sync_nvlist(spa, spa->spa_config_object, config, tx);
+}
+
+/*
+ * Set zpool properties.
+ */
+static void
+spa_sync_props(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
+{
+	spa_t *spa = arg1;
+	objset_t *mos = spa->spa_meta_objset;
+	nvlist_t *nvp = arg2;
+	nvpair_t *elem;
+	uint64_t intval;
+	char *strval;
+	zpool_prop_t prop;
+	const char *propname;
+	zprop_type_t proptype;
+	spa_config_dirent_t *dp;
+
+	mutex_enter(&spa->spa_props_lock);
+
+	elem = NULL;
+	while ((elem = nvlist_next_nvpair(nvp, elem))) {
+		switch (prop = zpool_name_to_prop(nvpair_name(elem))) {
+		case ZPOOL_PROP_VERSION:
+			/*
+			 * Only set version for non-zpool-creation cases
+			 * (set/import). spa_create() needs special care
+			 * for version setting.
+			 */
+			if (tx->tx_txg != TXG_INITIAL) {
+				VERIFY(nvpair_value_uint64(elem,
+				    &intval) == 0);
+				ASSERT(intval <= SPA_VERSION);
+				ASSERT(intval >= spa_version(spa));
+				spa->spa_uberblock.ub_version = intval;
+				vdev_config_dirty(spa->spa_root_vdev);
+			}
+			break;
+
+		case ZPOOL_PROP_ALTROOT:
+			/*
+			 * 'altroot' is a non-persistent property. It should
+			 * have been set temporarily at creation or import time.
+			 */
+			ASSERT(spa->spa_root != NULL);
+			break;
+
+		case ZPOOL_PROP_CACHEFILE:
+			/*
+			 * 'cachefile' is a non-persistent property, but note
+			 * an async request that the config cache needs to be
+			 * udpated.
+			 */
+			VERIFY(nvpair_value_string(elem, &strval) == 0);
+
+			dp = kmem_alloc(sizeof (spa_config_dirent_t), KM_SLEEP);
+
+			if (strval[0] == '\0')
+				dp->scd_path = spa_strdup(spa_config_path);
+			else if (strcmp(strval, "none") == 0)
+				dp->scd_path = NULL;
+			else
+				dp->scd_path = spa_strdup(strval);
+
+			list_insert_head(&spa->spa_config_list, dp);
+			spa_async_request(spa, SPA_ASYNC_CONFIG_UPDATE);
+			break;
+		default:
+			/*
+			 * Set pool property values in the poolprops mos object.
+			 */
+			if (spa->spa_pool_props_object == 0) {
+				objset_t *mos = spa->spa_meta_objset;
+
+				VERIFY((spa->spa_pool_props_object =
+				    zap_create(mos, DMU_OT_POOL_PROPS,
+				    DMU_OT_NONE, 0, tx)) > 0);
+
+				VERIFY(zap_update(mos,
+				    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_PROPS,
+				    8, 1, &spa->spa_pool_props_object, tx)
+				    == 0);
+			}
+
+			/* normalize the property name */
+			propname = zpool_prop_to_name(prop);
+			proptype = zpool_prop_get_type(prop);
+
+			if (nvpair_type(elem) == DATA_TYPE_STRING) {
+				ASSERT(proptype == PROP_TYPE_STRING);
+				VERIFY(nvpair_value_string(elem, &strval) == 0);
+				VERIFY(zap_update(mos,
+				    spa->spa_pool_props_object, propname,
+				    1, strlen(strval) + 1, strval, tx) == 0);
+
+			} else if (nvpair_type(elem) == DATA_TYPE_UINT64) {
+				VERIFY(nvpair_value_uint64(elem, &intval) == 0);
+
+				if (proptype == PROP_TYPE_INDEX) {
+					const char *unused;
+					VERIFY(zpool_prop_index_to_string(
+					    prop, intval, &unused) == 0);
+				}
+				VERIFY(zap_update(mos,
+				    spa->spa_pool_props_object, propname,
+				    8, 1, &intval, tx) == 0);
+			} else {
+				ASSERT(0); /* not allowed */
+			}
+
+			switch (prop) {
+			case ZPOOL_PROP_DELEGATION:
+				spa->spa_delegation = intval;
+				break;
+			case ZPOOL_PROP_BOOTFS:
+				spa->spa_bootfs = intval;
+				break;
+			case ZPOOL_PROP_FAILUREMODE:
+				spa->spa_failmode = intval;
+				break;
+			default:
+				break;
+			}
+		}
+
+		/* log internal history if this is not a zpool create */
+		if (spa_version(spa) >= SPA_VERSION_ZPOOL_HISTORY &&
+		    tx->tx_txg != TXG_INITIAL) {
+			spa_history_internal_log(LOG_POOL_PROPSET,
+			    spa, tx, cr, "%s %lld %s",
+			    nvpair_name(elem), intval, spa_name(spa));
+		}
+	}
+
+	mutex_exit(&spa->spa_props_lock);
+}
+
+/*
+ * Sync the specified transaction group.  New blocks may be dirtied as
+ * part of the process, so we iterate until it converges.
+ */
+void
+spa_sync(spa_t *spa, uint64_t txg)
+{
+	dsl_pool_t *dp = spa->spa_dsl_pool;
+	objset_t *mos = spa->spa_meta_objset;
+	bplist_t *bpl = &spa->spa_sync_bplist;
+	vdev_t *rvd = spa->spa_root_vdev;
+	vdev_t *vd;
+	dmu_tx_t *tx;
+	int dirty_vdevs;
+	int error;
+
+	/*
+	 * Lock out configuration changes.
+	 */
+	spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
+
+	spa->spa_syncing_txg = txg;
+	spa->spa_sync_pass = 0;
+
+	/*
+	 * If there are any pending vdev state changes, convert them
+	 * into config changes that go out with this transaction group.
+	 */
+	spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
+	while ((vd = list_head(&spa->spa_state_dirty_list)) != NULL) {
+		vdev_state_clean(vd);
+		vdev_config_dirty(vd);
+	}
+	spa_config_exit(spa, SCL_STATE, FTAG);
+
+	VERIFY(0 == bplist_open(bpl, mos, spa->spa_sync_bplist_obj));
+
+	tx = dmu_tx_create_assigned(dp, txg);
+
+	/*
+	 * If we are upgrading to SPA_VERSION_RAIDZ_DEFLATE this txg,
+	 * set spa_deflate if we have no raid-z vdevs.
+	 */
+	if (spa->spa_ubsync.ub_version < SPA_VERSION_RAIDZ_DEFLATE &&
+	    spa->spa_uberblock.ub_version >= SPA_VERSION_RAIDZ_DEFLATE) {
+		int i;
+
+		for (i = 0; i < rvd->vdev_children; i++) {
+			vd = rvd->vdev_child[i];
+			if (vd->vdev_deflate_ratio != SPA_MINBLOCKSIZE)
+				break;
+		}
+		if (i == rvd->vdev_children) {
+			spa->spa_deflate = TRUE;
+			VERIFY(0 == zap_add(spa->spa_meta_objset,
+			    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_DEFLATE,
+			    sizeof (uint64_t), 1, &spa->spa_deflate, tx));
+		}
+	}
+
+	if (spa->spa_ubsync.ub_version < SPA_VERSION_ORIGIN &&
+	    spa->spa_uberblock.ub_version >= SPA_VERSION_ORIGIN) {
+		dsl_pool_create_origin(dp, tx);
+
+		/* Keeping the origin open increases spa_minref */
+		spa->spa_minref += 3;
+	}
+
+	if (spa->spa_ubsync.ub_version < SPA_VERSION_NEXT_CLONES &&
+	    spa->spa_uberblock.ub_version >= SPA_VERSION_NEXT_CLONES) {
+		dsl_pool_upgrade_clones(dp, tx);
+	}
+
+	/*
+	 * If anything has changed in this txg, push the deferred frees
+	 * from the previous txg.  If not, leave them alone so that we
+	 * don't generate work on an otherwise idle system.
+	 */
+	if (!txg_list_empty(&dp->dp_dirty_datasets, txg) ||
+	    !txg_list_empty(&dp->dp_dirty_dirs, txg) ||
+	    !txg_list_empty(&dp->dp_sync_tasks, txg))
+		spa_sync_deferred_frees(spa, txg);
+
+	/*
+	 * Iterate to convergence.
+	 */
+	do {
+		spa->spa_sync_pass++;
+
+		spa_sync_config_object(spa, tx);
+		spa_sync_aux_dev(spa, &spa->spa_spares, tx,
+		    ZPOOL_CONFIG_SPARES, DMU_POOL_SPARES);
+		spa_sync_aux_dev(spa, &spa->spa_l2cache, tx,
+		    ZPOOL_CONFIG_L2CACHE, DMU_POOL_L2CACHE);
+		spa_errlog_sync(spa, txg);
+		dsl_pool_sync(dp, txg);
+
+		dirty_vdevs = 0;
+		while (vd = txg_list_remove(&spa->spa_vdev_txg_list, txg)) {
+			vdev_sync(vd, txg);
+			dirty_vdevs++;
+		}
+
+		bplist_sync(bpl, tx);
+	} while (dirty_vdevs);
+
+	bplist_close(bpl);
+
+	dprintf("txg %llu passes %d\n", txg, spa->spa_sync_pass);
+
+	/*
+	 * Rewrite the vdev configuration (which includes the uberblock)
+	 * to commit the transaction group.
+	 *
+	 * If there are no dirty vdevs, we sync the uberblock to a few
+	 * random top-level vdevs that are known to be visible in the
+	 * config cache (see spa_vdev_add() for a complete description).
+	 * If there *are* dirty vdevs, sync the uberblock to all vdevs.
+	 */
+	for (;;) {
+		/*
+		 * We hold SCL_STATE to prevent vdev open/close/etc.
+		 * while we're attempting to write the vdev labels.
+		 */
+		spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
+
+		if (list_is_empty(&spa->spa_config_dirty_list)) {
+			vdev_t *svd[SPA_DVAS_PER_BP];
+			int svdcount = 0;
+			int children = rvd->vdev_children;
+			int c0 = spa_get_random(children);
+			int c;
+
+			for (c = 0; c < children; c++) {
+				vd = rvd->vdev_child[(c0 + c) % children];
+				if (vd->vdev_ms_array == 0 || vd->vdev_islog)
+					continue;
+				svd[svdcount++] = vd;
+				if (svdcount == SPA_DVAS_PER_BP)
+					break;
+			}
+			error = vdev_config_sync(svd, svdcount, txg);
+		} else {
+			error = vdev_config_sync(rvd->vdev_child,
+			    rvd->vdev_children, txg);
+		}
+
+		spa_config_exit(spa, SCL_STATE, FTAG);
+
+		if (error == 0)
+			break;
+		zio_suspend(spa, NULL);
+		zio_resume_wait(spa);
+	}
+	dmu_tx_commit(tx);
+
+	/*
+	 * Clear the dirty config list.
+	 */
+	while ((vd = list_head(&spa->spa_config_dirty_list)) != NULL)
+		vdev_config_clean(vd);
+
+	/*
+	 * Now that the new config has synced transactionally,
+	 * let it become visible to the config cache.
+	 */
+	if (spa->spa_config_syncing != NULL) {
+		spa_config_set(spa, spa->spa_config_syncing);
+		spa->spa_config_txg = txg;
+		spa->spa_config_syncing = NULL;
+	}
+
+	spa->spa_ubsync = spa->spa_uberblock;
+
+	/*
+	 * Clean up the ZIL records for the synced txg.
+	 */
+	dsl_pool_zil_clean(dp);
+
+	/*
+	 * Update usable space statistics.
+	 */
+	while (vd = txg_list_remove(&spa->spa_vdev_txg_list, TXG_CLEAN(txg)))
+		vdev_sync_done(vd, txg);
+
+	/*
+	 * It had better be the case that we didn't dirty anything
+	 * since vdev_config_sync().
+	 */
+	ASSERT(txg_list_empty(&dp->dp_dirty_datasets, txg));
+	ASSERT(txg_list_empty(&dp->dp_dirty_dirs, txg));
+	ASSERT(txg_list_empty(&spa->spa_vdev_txg_list, txg));
+	ASSERT(bpl->bpl_queue == NULL);
+
+	spa_config_exit(spa, SCL_CONFIG, FTAG);
+
+	/*
+	 * If any async tasks have been requested, kick them off.
+	 */
+	spa_async_dispatch(spa);
+}
+
+/*
+ * Sync all pools.  We don't want to hold the namespace lock across these
+ * operations, so we take a reference on the spa_t and drop the lock during the
+ * sync.
+ */
+void
+spa_sync_allpools(void)
+{
+	spa_t *spa = NULL;
+	mutex_enter(&spa_namespace_lock);
+	while ((spa = spa_next(spa)) != NULL) {
+		if (spa_state(spa) != POOL_STATE_ACTIVE || spa_suspended(spa))
+			continue;
+		spa_open_ref(spa, FTAG);
+		mutex_exit(&spa_namespace_lock);
+		txg_wait_synced(spa_get_dsl(spa), 0);
+		mutex_enter(&spa_namespace_lock);
+		spa_close(spa, FTAG);
+	}
+	mutex_exit(&spa_namespace_lock);
+}
+
+/*
+ * ==========================================================================
+ * Miscellaneous routines
+ * ==========================================================================
+ */
+
+/*
+ * Remove all pools in the system.
+ */
+void
+spa_evict_all(void)
+{
+	spa_t *spa;
+
+	/*
+	 * Remove all cached state.  All pools should be closed now,
+	 * so every spa in the AVL tree should be unreferenced.
+	 */
+	mutex_enter(&spa_namespace_lock);
+	while ((spa = spa_next(NULL)) != NULL) {
+		/*
+		 * Stop async tasks.  The async thread may need to detach
+		 * a device that's been replaced, which requires grabbing
+		 * spa_namespace_lock, so we must drop it here.
+		 */
+		spa_open_ref(spa, FTAG);
+		mutex_exit(&spa_namespace_lock);
+		spa_async_suspend(spa);
+		mutex_enter(&spa_namespace_lock);
+		spa_close(spa, FTAG);
+
+		if (spa->spa_state != POOL_STATE_UNINITIALIZED) {
+			spa_unload(spa);
+			spa_deactivate(spa);
+		}
+		spa_remove(spa);
+	}
+	mutex_exit(&spa_namespace_lock);
+}
+
+vdev_t *
+spa_lookup_by_guid(spa_t *spa, uint64_t guid, boolean_t l2cache)
+{
+	vdev_t *vd;
+	int i;
+
+	if ((vd = vdev_lookup_by_guid(spa->spa_root_vdev, guid)) != NULL)
+		return (vd);
+
+	if (l2cache) {
+		for (i = 0; i < spa->spa_l2cache.sav_count; i++) {
+			vd = spa->spa_l2cache.sav_vdevs[i];
+			if (vd->vdev_guid == guid)
+				return (vd);
+		}
+	}
+
+	return (NULL);
+}
+
+void
+spa_upgrade(spa_t *spa, uint64_t version)
+{
+	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+
+	/*
+	 * This should only be called for a non-faulted pool, and since a
+	 * future version would result in an unopenable pool, this shouldn't be
+	 * possible.
+	 */
+	ASSERT(spa->spa_uberblock.ub_version <= SPA_VERSION);
+	ASSERT(version >= spa->spa_uberblock.ub_version);
+
+	spa->spa_uberblock.ub_version = version;
+	vdev_config_dirty(spa->spa_root_vdev);
+
+	spa_config_exit(spa, SCL_ALL, FTAG);
+
+	txg_wait_synced(spa_get_dsl(spa), 0);
+}
+
+boolean_t
+spa_has_spare(spa_t *spa, uint64_t guid)
+{
+	int i;
+	uint64_t spareguid;
+	spa_aux_vdev_t *sav = &spa->spa_spares;
+
+	for (i = 0; i < sav->sav_count; i++)
+		if (sav->sav_vdevs[i]->vdev_guid == guid)
+			return (B_TRUE);
+
+	for (i = 0; i < sav->sav_npending; i++) {
+		if (nvlist_lookup_uint64(sav->sav_pending[i], ZPOOL_CONFIG_GUID,
+		    &spareguid) == 0 && spareguid == guid)
+			return (B_TRUE);
+	}
+
+	return (B_FALSE);
+}
+
+/*
+ * Check if a pool has an active shared spare device.
+ * Note: reference count of an active spare is 2, as a spare and as a replace
+ */
+static boolean_t
+spa_has_active_shared_spare(spa_t *spa)
+{
+	int i, refcnt;
+	uint64_t pool;
+	spa_aux_vdev_t *sav = &spa->spa_spares;
+
+	for (i = 0; i < sav->sav_count; i++) {
+		if (spa_spare_exists(sav->sav_vdevs[i]->vdev_guid, &pool,
+		    &refcnt) && pool != 0ULL && pool == spa_guid(spa) &&
+		    refcnt > 2)
+			return (B_TRUE);
+	}
+
+	return (B_FALSE);
+}
+
+/*
+ * Post a sysevent corresponding to the given event.  The 'name' must be one of
+ * the event definitions in sys/sysevent/eventdefs.h.  The payload will be
+ * filled in from the spa and (optionally) the vdev.  This doesn't do anything
+ * in the userland libzpool, as we don't want consumers to misinterpret ztest
+ * or zdb as real changes.
+ */
+void
+spa_event_notify(spa_t *spa, vdev_t *vd, const char *name)
+{
+#ifdef _KERNEL
+	sysevent_t		*ev;
+	sysevent_attr_list_t	*attr = NULL;
+	sysevent_value_t	value;
+	sysevent_id_t		eid;
+
+	ev = sysevent_alloc(EC_ZFS, (char *)name, SUNW_KERN_PUB "zfs",
+	    SE_SLEEP);
+
+	value.value_type = SE_DATA_TYPE_STRING;
+	value.value.sv_string = spa_name(spa);
+	if (sysevent_add_attr(&attr, ZFS_EV_POOL_NAME, &value, SE_SLEEP) != 0)
+		goto done;
+
+	value.value_type = SE_DATA_TYPE_UINT64;
+	value.value.sv_uint64 = spa_guid(spa);
+	if (sysevent_add_attr(&attr, ZFS_EV_POOL_GUID, &value, SE_SLEEP) != 0)
+		goto done;
+
+	if (vd) {
+		value.value_type = SE_DATA_TYPE_UINT64;
+		value.value.sv_uint64 = vd->vdev_guid;
+		if (sysevent_add_attr(&attr, ZFS_EV_VDEV_GUID, &value,
+		    SE_SLEEP) != 0)
+			goto done;
+
+		if (vd->vdev_path) {
+			value.value_type = SE_DATA_TYPE_STRING;
+			value.value.sv_string = vd->vdev_path;
+			if (sysevent_add_attr(&attr, ZFS_EV_VDEV_PATH,
+			    &value, SE_SLEEP) != 0)
+				goto done;
+		}
+	}
+
+	if (sysevent_attach_attributes(ev, attr) != 0)
+		goto done;
+	attr = NULL;
+
+	(void) log_sysevent(ev, SE_SLEEP, &eid);
+
+done:
+	if (attr)
+		sysevent_free_attr(attr);
+	sysevent_free(ev);
+#endif
+}