]> git.proxmox.com Git - mirror_zfs.git/blobdiff - module/zfs/spa.c
OpenZFS 8962 - zdb should work on non-idle pools
[mirror_zfs.git] / module / zfs / spa.c
index b5e024c3f2911b069b3c1b46bb5e16f13662576c..80f0c6f368f3f92022ce9c37f58884c1a3d3e6df 100644 (file)
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2017 by Delphix. All rights reserved.
+ * Copyright (c) 2015, Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2013, 2014, Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
+ * Copyright 2013 Saso Kiselkov. All rights reserved.
+ * Copyright (c) 2014 Integros [integros.com]
+ * Copyright 2016 Toomas Soome <tsoome@me.com>
+ * Copyright (c) 2016 Actifio, Inc. All rights reserved.
+ * Copyright (c) 2017 Datto Inc.
+ * Copyright 2017 Joyent, Inc.
  */
 
 /*
 #include <sys/zil.h>
 #include <sys/ddt.h>
 #include <sys/vdev_impl.h>
+#include <sys/vdev_removal.h>
+#include <sys/vdev_indirect_mapping.h>
+#include <sys/vdev_indirect_births.h>
 #include <sys/vdev_disk.h>
 #include <sys/metaslab.h>
 #include <sys/metaslab_impl.h>
+#include <sys/mmp.h>
 #include <sys/uberblock_impl.h>
 #include <sys/txg.h>
 #include <sys/avl.h>
+#include <sys/bpobj.h>
 #include <sys/dmu_traverse.h>
 #include <sys/dmu_objset.h>
 #include <sys/unique.h>
@@ -71,6 +83,8 @@
 #include <sys/zvol.h>
 
 #ifdef _KERNEL
+#include <sys/fm/protocol.h>
+#include <sys/fm/util.h>
 #include <sys/bootprops.h>
 #include <sys/callb.h>
 #include <sys/cpupart.h>
 #include "zfs_prop.h"
 #include "zfs_comutil.h"
 
+/*
+ * The interval, in seconds, at which failed configuration cache file writes
+ * should be retried.
+ */
+int zfs_ccw_retry_interval = 300;
+
 typedef enum zti_modes {
        ZTI_MODE_FIXED,                 /* value is # of threads (min 1) */
        ZTI_MODE_BATCH,                 /* cpu-intensive; value is ignored */
@@ -138,7 +158,7 @@ static void spa_sync_version(void *arg, dmu_tx_t *tx);
 static void spa_sync_props(void *arg, dmu_tx_t *tx);
 static boolean_t spa_has_active_shared_spare(spa_t *spa);
 static inline int spa_load_impl(spa_t *spa, uint64_t, nvlist_t *config,
-    spa_load_state_t state, spa_import_type_t type, boolean_t mosconfig,
+    spa_load_state_t state, spa_import_type_t type, boolean_t trust_config,
     char **ereport);
 static void spa_vdev_resilver_done(spa_t *spa);
 
@@ -149,6 +169,12 @@ uint_t             zio_taskq_basedc = 80;          /* base duty cycle */
 
 boolean_t      spa_create_process = B_TRUE;    /* no process ==> no sysdc */
 
+/*
+ * Report any spa_load_verify errors found, but do not fail spa_load.
+ * This is used by zdb to analyze non-idle pools.
+ */
+boolean_t      spa_load_verify_dryrun = B_FALSE;
+
 /*
  * This (illegal) pool name is used when temporarily importing a spa_t in order
  * to get the vdev stats associated with the imported devices.
@@ -192,7 +218,7 @@ spa_prop_get_config(spa_t *spa, nvlist_t **nvp)
        vdev_t *rvd = spa->spa_root_vdev;
        dsl_pool_t *pool = spa->spa_dsl_pool;
        uint64_t size, alloc, cap, version;
-       zprop_source_t src = ZPROP_SRC_NONE;
+       const zprop_source_t src = ZPROP_SRC_NONE;
        spa_config_dirent_t *dp;
        metaslab_class_t *mc = spa_normal_class(spa);
 
@@ -224,11 +250,13 @@ spa_prop_get_config(spa_t *spa, nvlist_t **nvp)
                    rvd->vdev_state, src);
 
                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 (version == zpool_prop_default_numeric(ZPOOL_PROP_VERSION)) {
+                       spa_prop_add_list(*nvp, ZPOOL_PROP_VERSION, NULL,
+                           version, ZPROP_SRC_DEFAULT);
+               } else {
+                       spa_prop_add_list(*nvp, ZPOOL_PROP_VERSION, NULL,
+                           version, ZPROP_SRC_LOCAL);
+               }
        }
 
        if (pool != NULL) {
@@ -274,6 +302,14 @@ spa_prop_get_config(spa_t *spa, nvlist_t **nvp)
                    SPA_OLD_MAXBLOCKSIZE, ZPROP_SRC_NONE);
        }
 
+       if (spa_feature_is_enabled(spa, SPA_FEATURE_LARGE_DNODE)) {
+               spa_prop_add_list(*nvp, ZPOOL_PROP_MAXDNODESIZE, NULL,
+                   DNODE_MAX_SIZE, ZPROP_SRC_NONE);
+       } else {
+               spa_prop_add_list(*nvp, ZPOOL_PROP_MAXDNODESIZE, NULL,
+                   DNODE_MIN_SIZE, ZPROP_SRC_NONE);
+       }
+
        if ((dp = list_head(&spa->spa_config_list)) != NULL) {
                if (dp->scd_path == NULL) {
                        spa_prop_add_list(*nvp, ZPOOL_PROP_CACHEFILE,
@@ -324,7 +360,7 @@ spa_prop_get(spa_t *spa, nvlist_t **nvp)
                zprop_source_t src = ZPROP_SRC_DEFAULT;
                zpool_prop_t prop;
 
-               if ((prop = zpool_name_to_prop(za.za_name)) == ZPROP_INVAL)
+               if ((prop = zpool_name_to_prop(za.za_name)) == ZPOOL_PROP_INVAL)
                        continue;
 
                switch (za.za_integer_length) {
@@ -346,8 +382,7 @@ spa_prop_get(spa_t *spa, nvlist_t **nvp)
                                        break;
                                }
 
-                               strval = kmem_alloc(
-                                   MAXNAMELEN + strlen(MOS_DIR_NAME) + 1,
+                               strval = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN,
                                    KM_SLEEP);
                                dsl_dataset_name(ds, strval);
                                dsl_dataset_rele(ds, FTAG);
@@ -360,8 +395,7 @@ spa_prop_get(spa_t *spa, nvlist_t **nvp)
                        spa_prop_add_list(*nvp, prop, strval, intval, src);
 
                        if (strval != NULL)
-                               kmem_free(strval,
-                                   MAXNAMELEN + strlen(MOS_DIR_NAME) + 1);
+                               kmem_free(strval, ZFS_MAX_DATASET_NAME_LEN);
 
                        break;
 
@@ -413,8 +447,8 @@ spa_prop_validate(spa_t *spa, nvlist_t *props)
                const char *propname = nvpair_name(elem);
                zpool_prop_t prop = zpool_name_to_prop(propname);
 
-               switch ((int)prop) {
-               case ZPROP_INVAL:
+               switch (prop) {
+               case ZPOOL_PROP_INVAL:
                        if (!zpool_prop_feature(propname)) {
                                error = SET_ERROR(EINVAL);
                                break;
@@ -465,6 +499,16 @@ spa_prop_validate(spa_t *spa, nvlist_t *props)
                                error = SET_ERROR(EINVAL);
                        break;
 
+               case ZPOOL_PROP_MULTIHOST:
+                       error = nvpair_value_uint64(elem, &intval);
+                       if (!error && intval > 1)
+                               error = SET_ERROR(EINVAL);
+
+                       if (!error && !spa_get_hostid())
+                               error = SET_ERROR(ENOTSUP);
+
+                       break;
+
                case ZPOOL_PROP_BOOTFS:
                        /*
                         * If the pool version is less than SPA_VERSION_BOOTFS,
@@ -505,7 +549,8 @@ spa_prop_validate(spa_t *spa, nvlist_t *props)
                                /*
                                 * Must be ZPL, and its property settings
                                 * must be supported by GRUB (compression
-                                * is not gzip, and large blocks are not used).
+                                * is not gzip, and large blocks or large
+                                * dnodes are not used).
                                 */
 
                                if (dmu_objset_type(os) != DMU_OST_ZFS) {
@@ -518,9 +563,9 @@ spa_prop_validate(spa_t *spa, nvlist_t *props)
                                        error = SET_ERROR(ENOTSUP);
                                } else if ((error =
                                    dsl_prop_get_int_ds(dmu_objset_ds(os),
-                                   zfs_prop_to_name(ZFS_PROP_RECORDSIZE),
+                                   zfs_prop_to_name(ZFS_PROP_DNODESIZE),
                                    &propval)) == 0 &&
-                                   propval > SPA_OLD_MAXBLOCKSIZE) {
+                                   propval != ZFS_DNSIZE_LEGACY) {
                                        error = SET_ERROR(ENOTSUP);
                                } else {
                                        objnum = dmu_objset_id(os);
@@ -531,8 +576,7 @@ spa_prop_validate(spa_t *spa, nvlist_t *props)
 
                case ZPOOL_PROP_FAILUREMODE:
                        error = nvpair_value_uint64(elem, &intval);
-                       if (!error && (intval < ZIO_FAILURE_MODE_WAIT ||
-                           intval > ZIO_FAILURE_MODE_PANIC))
+                       if (!error && intval > ZIO_FAILURE_MODE_PANIC)
                                error = SET_ERROR(EINVAL);
 
                        /*
@@ -582,7 +626,6 @@ spa_prop_validate(spa_t *spa, nvlist_t *props)
                                        error = SET_ERROR(EINVAL);
                                        break;
                                }
-                               check++;
                        }
                        if (strlen(strval) > ZPROP_MAX_COMMENT)
                                error = SET_ERROR(E2BIG);
@@ -662,7 +705,7 @@ spa_prop_set(spa_t *spa, nvlist_t *nvp)
                    prop == ZPOOL_PROP_READONLY)
                        continue;
 
-               if (prop == ZPOOL_PROP_VERSION || prop == ZPROP_INVAL) {
+               if (prop == ZPOOL_PROP_VERSION || prop == ZPOOL_PROP_INVAL) {
                        uint64_t ver;
 
                        if (prop == ZPOOL_PROP_VERSION) {
@@ -721,10 +764,10 @@ spa_prop_clear_bootfs(spa_t *spa, uint64_t dsobj, dmu_tx_t *tx)
 static int
 spa_change_guid_check(void *arg, dmu_tx_t *tx)
 {
+       ASSERTV(uint64_t *newguid = arg);
        spa_t *spa = dmu_tx_pool(tx)->dp_spa;
        vdev_t *rvd = spa->spa_root_vdev;
        uint64_t vdev_state;
-       ASSERTV(uint64_t *newguid = arg);
 
        spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
        vdev_state = rvd->vdev_state;
@@ -781,8 +824,8 @@ spa_change_guid(spa_t *spa)
            spa_change_guid_sync, &guid, 5, ZFS_SPACE_CHECK_RESERVED);
 
        if (error == 0) {
-               spa_config_sync(spa, B_FALSE, B_TRUE);
-               spa_event_notify(spa, NULL, FM_EREPORT_ZFS_POOL_REGUID);
+               spa_write_cachefile(spa, B_FALSE, B_TRUE);
+               spa_event_notify(spa, NULL, NULL, ESC_ZFS_POOL_REGUID);
        }
 
        mutex_exit(&spa_namespace_lock);
@@ -800,19 +843,14 @@ spa_change_guid(spa_t *spa)
 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;
+       const spa_error_entry_t *sa = (const spa_error_entry_t *)a;
+       const spa_error_entry_t *sb = (const spa_error_entry_t *)b;
        int ret;
 
-       ret = bcmp(&sa->se_bookmark, &sb->se_bookmark,
+       ret = memcmp(&sa->se_bookmark, &sb->se_bookmark,
            sizeof (zbookmark_phys_t));
 
-       if (ret < 0)
-               return (-1);
-       else if (ret > 0)
-               return (1);
-       else
-               return (0);
+       return (AVL_ISIGN(ret));
 }
 
 /*
@@ -844,7 +882,7 @@ spa_taskqs_init(spa_t *spa, zio_type_t t, zio_taskq_type_t q)
        uint_t count = ztip->zti_count;
        spa_taskqs_t *tqs = &spa->spa_zio_taskq[t][q];
        char name[32];
-       uint_t i, flags = TASKQ_DYNAMIC;
+       uint_t flags = 0;
        boolean_t batch = B_FALSE;
 
        if (mode == ZTI_MODE_NULL) {
@@ -862,12 +900,13 @@ spa_taskqs_init(spa_t *spa, zio_type_t t, zio_taskq_type_t q)
        case ZTI_MODE_FIXED:
                ASSERT3U(value, >=, 1);
                value = MAX(value, 1);
+               flags |= TASKQ_DYNAMIC;
                break;
 
        case ZTI_MODE_BATCH:
                batch = B_TRUE;
                flags |= TASKQ_THREADS_CPU_PCT;
-               value = zio_taskq_batch_pct;
+               value = MIN(zio_taskq_batch_pct, 100);
                break;
 
        default:
@@ -877,7 +916,7 @@ spa_taskqs_init(spa_t *spa, zio_type_t t, zio_taskq_type_t q)
                break;
        }
 
-       for (i = 0; i < count; i++) {
+       for (uint_t i = 0; i < count; i++) {
                taskq_t *tq;
 
                if (count > 1) {
@@ -898,11 +937,13 @@ spa_taskqs_init(spa_t *spa, zio_type_t t, zio_taskq_type_t q)
                        pri_t pri = maxclsyspri;
                        /*
                         * The write issue taskq can be extremely CPU
-                        * intensive.  Run it at slightly lower priority
-                        * than the other taskqs.
+                        * intensive.  Run it at slightly less important
+                        * priority than the other taskqs.  Under Linux this
+                        * means incrementing the priority value on platforms
+                        * like illumos it should be decremented.
                         */
                        if (t == ZIO_TYPE_WRITE && q == ZIO_TASKQ_ISSUE)
-                               pri--;
+                               pri++;
 
                        tq = taskq_create_proc(name, value, pri, 50,
                            INT_MAX, spa->spa_proc, flags);
@@ -916,14 +957,13 @@ static void
 spa_taskqs_fini(spa_t *spa, zio_type_t t, zio_taskq_type_t q)
 {
        spa_taskqs_t *tqs = &spa->spa_zio_taskq[t][q];
-       uint_t i;
 
        if (tqs->stqs_taskq == NULL) {
                ASSERT3U(tqs->stqs_count, ==, 0);
                return;
        }
 
-       for (i = 0; i < tqs->stqs_count; i++) {
+       for (uint_t i = 0; i < tqs->stqs_count; i++) {
                ASSERT3P(tqs->stqs_taskq[i], !=, NULL);
                taskq_destroy(tqs->stqs_taskq[i]);
        }
@@ -985,15 +1025,18 @@ spa_taskq_dispatch_sync(spa_t *spa, zio_type_t t, zio_taskq_type_t q,
 static void
 spa_create_zio_taskqs(spa_t *spa)
 {
-       int t, q;
-
-       for (t = 0; t < ZIO_TYPES; t++) {
-               for (q = 0; q < ZIO_TASKQ_TYPES; q++) {
+       for (int t = 0; t < ZIO_TYPES; t++) {
+               for (int q = 0; q < ZIO_TASKQ_TYPES; q++) {
                        spa_taskqs_init(spa, t, q);
                }
        }
 }
 
+/*
+ * Disabled until spa_thread() can be adapted for Linux.
+ */
+#undef HAVE_SPA_THREAD
+
 #if defined(_KERNEL) && defined(HAVE_SPA_THREAD)
 static void
 spa_thread(void *arg)
@@ -1113,6 +1156,9 @@ spa_activate(spa_t *spa, int mode)
                spa_create_zio_taskqs(spa);
        }
 
+       for (size_t i = 0; i < TXG_SIZE; i++)
+               spa->spa_txg_zio[i] = zio_root(spa, NULL, NULL, 0);
+
        list_create(&spa->spa_config_dirty_list, sizeof (vdev_t),
            offsetof(vdev_t, vdev_config_dirty_node));
        list_create(&spa->spa_evicting_os_list, sizeof (objset_t),
@@ -1120,7 +1166,7 @@ spa_activate(spa_t *spa, int mode)
        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,
+       txg_list_create(&spa->spa_vdev_txg_list, spa,
            offsetof(struct vdev, vdev_txg_node));
 
        avl_create(&spa->spa_errlist_scrub,
@@ -1129,6 +1175,41 @@ spa_activate(spa_t *spa, int mode)
        avl_create(&spa->spa_errlist_last,
            spa_error_entry_compare, sizeof (spa_error_entry_t),
            offsetof(spa_error_entry_t, se_avl));
+
+       spa_keystore_init(&spa->spa_keystore);
+
+       /*
+        * This taskq is used to perform zvol-minor-related tasks
+        * asynchronously. This has several advantages, including easy
+        * resolution of various deadlocks (zfsonlinux bug #3681).
+        *
+        * The taskq must be single threaded to ensure tasks are always
+        * processed in the order in which they were dispatched.
+        *
+        * A taskq per pool allows one to keep the pools independent.
+        * This way if one pool is suspended, it will not impact another.
+        *
+        * The preferred location to dispatch a zvol minor task is a sync
+        * task. In this context, there is easy access to the spa_t and minimal
+        * error handling is required because the sync task must succeed.
+        */
+       spa->spa_zvol_taskq = taskq_create("z_zvol", 1, defclsyspri,
+           1, INT_MAX, 0);
+
+       /*
+        * Taskq dedicated to prefetcher threads: this is used to prevent the
+        * pool traverse code from monopolizing the global (and limited)
+        * system_taskq by inappropriately scheduling long running tasks on it.
+        */
+       spa->spa_prefetch_taskq = taskq_create("z_prefetch", boot_ncpus,
+           defclsyspri, 1, INT_MAX, TASKQ_DYNAMIC);
+
+       /*
+        * The taskq to upgrade datasets in this pool. Currently used by
+        * feature SPA_FEATURE_USEROBJ_ACCOUNTING/SPA_FEATURE_PROJECT_QUOTA.
+        */
+       spa->spa_upgrade_taskq = taskq_create("z_upgrade", boot_ncpus,
+           defclsyspri, 1, INT_MAX, TASKQ_DYNAMIC);
 }
 
 /*
@@ -1137,8 +1218,6 @@ spa_activate(spa_t *spa, int mode)
 static void
 spa_deactivate(spa_t *spa)
 {
-       int t, q;
-
        ASSERT(spa->spa_sync_on == B_FALSE);
        ASSERT(spa->spa_dsl_pool == NULL);
        ASSERT(spa->spa_root_vdev == NULL);
@@ -1147,20 +1226,41 @@ spa_deactivate(spa_t *spa)
 
        spa_evicting_os_wait(spa);
 
+       if (spa->spa_zvol_taskq) {
+               taskq_destroy(spa->spa_zvol_taskq);
+               spa->spa_zvol_taskq = NULL;
+       }
+
+       if (spa->spa_prefetch_taskq) {
+               taskq_destroy(spa->spa_prefetch_taskq);
+               spa->spa_prefetch_taskq = NULL;
+       }
+
+       if (spa->spa_upgrade_taskq) {
+               taskq_destroy(spa->spa_upgrade_taskq);
+               spa->spa_upgrade_taskq = NULL;
+       }
+
        txg_list_destroy(&spa->spa_vdev_txg_list);
 
        list_destroy(&spa->spa_config_dirty_list);
        list_destroy(&spa->spa_evicting_os_list);
        list_destroy(&spa->spa_state_dirty_list);
 
-       taskq_cancel_id(system_taskq, spa->spa_deadman_tqid);
+       taskq_cancel_id(system_delay_taskq, spa->spa_deadman_tqid);
 
-       for (t = 0; t < ZIO_TYPES; t++) {
-               for (q = 0; q < ZIO_TASKQ_TYPES; q++) {
+       for (int t = 0; t < ZIO_TYPES; t++) {
+               for (int q = 0; q < ZIO_TASKQ_TYPES; q++) {
                        spa_taskqs_fini(spa, t, q);
                }
        }
 
+       for (size_t i = 0; i < TXG_SIZE; i++) {
+               ASSERT3P(spa->spa_txg_zio[i], !=, NULL);
+               VERIFY0(zio_wait(spa->spa_txg_zio[i]));
+               spa->spa_txg_zio[i] = NULL;
+       }
+
        metaslab_class_destroy(spa->spa_normal_class);
        spa->spa_normal_class = NULL;
 
@@ -1172,10 +1272,11 @@ spa_deactivate(spa_t *spa)
         * 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_keystore_fini(&spa->spa_keystore);
+
        spa->spa_state = POOL_STATE_UNINITIALIZED;
 
        mutex_enter(&spa->spa_proc_lock);
@@ -1217,7 +1318,6 @@ spa_config_parse(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent,
        nvlist_t **child;
        uint_t children;
        int error;
-       int c;
 
        if ((error = vdev_alloc(spa, vdp, nv, parent, id, atype)) != 0)
                return (error);
@@ -1237,7 +1337,7 @@ spa_config_parse(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent,
                return (SET_ERROR(EINVAL));
        }
 
-       for (c = 0; c < children; c++) {
+       for (int c = 0; c < children; c++) {
                vdev_t *vd;
                if ((error = spa_config_parse(spa, &vd, child[c], *vdp, c,
                    atype)) != 0) {
@@ -1262,6 +1362,8 @@ spa_unload(spa_t *spa)
 
        ASSERT(MUTEX_HELD(&spa_namespace_lock));
 
+       spa_load_note(spa, "UNLOADING");
+
        /*
         * Stop async tasks.
         */
@@ -1275,16 +1377,45 @@ spa_unload(spa_t *spa)
                spa->spa_sync_on = B_FALSE;
        }
 
+       /*
+        * Even though vdev_free() also calls vdev_metaslab_fini, we need
+        * to call it earlier, before we wait for async i/o to complete.
+        * This ensures that there is no async metaslab prefetching, by
+        * calling taskq_wait(mg_taskq).
+        */
+       if (spa->spa_root_vdev != NULL) {
+               spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+               for (int c = 0; c < spa->spa_root_vdev->vdev_children; c++)
+                       vdev_metaslab_fini(spa->spa_root_vdev->vdev_child[c]);
+               spa_config_exit(spa, SCL_ALL, FTAG);
+       }
+
+       if (spa->spa_mmp.mmp_thread)
+               mmp_thread_stop(spa);
+
        /*
         * Wait for any outstanding async I/O to complete.
         */
        if (spa->spa_async_zio_root != NULL) {
-               for (i = 0; i < max_ncpus; i++)
+               for (int i = 0; i < max_ncpus; i++)
                        (void) zio_wait(spa->spa_async_zio_root[i]);
                kmem_free(spa->spa_async_zio_root, max_ncpus * sizeof (void *));
                spa->spa_async_zio_root = NULL;
        }
 
+       if (spa->spa_vdev_removal != NULL) {
+               spa_vdev_removal_destroy(spa->spa_vdev_removal);
+               spa->spa_vdev_removal = NULL;
+       }
+
+       if (spa->spa_condense_zthr != NULL) {
+               ASSERT(!zthr_isrunning(spa->spa_condense_zthr));
+               zthr_destroy(spa->spa_condense_zthr);
+               spa->spa_condense_zthr = NULL;
+       }
+
+       spa_condense_fini(spa);
+
        bpobj_close(&spa->spa_deferred_bpobj);
 
        spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
@@ -1307,7 +1438,6 @@ spa_unload(spa_t *spa)
 
        ddt_unload(spa);
 
-
        /*
         * Drop and purge level 2 cache
         */
@@ -1343,6 +1473,8 @@ spa_unload(spa_t *spa)
 
        spa->spa_async_suspended = 0;
 
+       spa->spa_indirect_vdevs_loaded = B_FALSE;
+
        if (spa->spa_comment != NULL) {
                spa_strfree(spa->spa_comment);
                spa->spa_comment = NULL;
@@ -1357,7 +1489,7 @@ spa_unload(spa_t *spa)
  * '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
+void
 spa_load_spares(spa_t *spa)
 {
        nvlist_t **spares;
@@ -1474,10 +1606,10 @@ spa_load_spares(spa_t *spa)
  * Devices which are already active have their details maintained, and are
  * not re-opened.
  */
-static void
+void
 spa_load_l2cache(spa_t *spa)
 {
-       nvlist_t **l2cache;
+       nvlist_t **l2cache = NULL;
        uint_t nl2cache;
        int i, j, oldnvdevs;
        uint64_t guid;
@@ -1486,20 +1618,21 @@ spa_load_l2cache(spa_t *spa)
 
        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;
-               newvdevs = NULL;
-       }
-
        oldvdevs = sav->sav_vdevs;
        oldnvdevs = sav->sav_count;
        sav->sav_vdevs = NULL;
        sav->sav_count = 0;
 
+       if (sav->sav_config == NULL) {
+               nl2cache = 0;
+               newvdevs = NULL;
+               goto out;
+       }
+
+       VERIFY(nvlist_lookup_nvlist_array(sav->sav_config,
+           ZPOOL_CONFIG_L2CACHE, &l2cache, &nl2cache) == 0);
+       newvdevs = kmem_alloc(nl2cache * sizeof (void *), KM_SLEEP);
+
        /*
         * Process new nvlist of vdevs.
         */
@@ -1550,6 +1683,26 @@ spa_load_l2cache(spa_t *spa)
                }
        }
 
+       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);
+
+       if (sav->sav_count > 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, VDEV_CONFIG_L2CACHE);
+       VERIFY(nvlist_add_nvlist_array(sav->sav_config,
+           ZPOOL_CONFIG_L2CACHE, l2cache, sav->sav_count) == 0);
+
+out:
        /*
         * Purge vdevs that were dropped
         */
@@ -1571,26 +1724,6 @@ spa_load_l2cache(spa_t *spa)
        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, VDEV_CONFIG_L2CACHE);
-       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)
@@ -1630,16 +1763,26 @@ load_nvlist(spa_t *spa, uint64_t obj, nvlist_t **value)
 static void
 spa_check_removed(vdev_t *vd)
 {
-       int c;
-
-       for (c = 0; c < vd->vdev_children; c++)
+       for (int 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) &&
-           !vd->vdev_ishole) {
-               zfs_ereport_post(FM_EREPORT_RESOURCE_AUTOREPLACE,
-                   vd->vdev_spa, vd, NULL, 0, 0);
-               spa_event_notify(vd->vdev_spa, vd, FM_EREPORT_ZFS_DEVICE_CHECK);
+           vdev_is_concrete(vd)) {
+               zfs_post_autoreplace(vd->vdev_spa, vd);
+               spa_event_notify(vd->vdev_spa, vd, NULL, ESC_ZFS_VDEV_CHECK);
+       }
+}
+
+static void
+spa_config_valid_zaps(vdev_t *vd, vdev_t *mvd)
+{
+       ASSERT3U(vd->vdev_children, ==, mvd->vdev_children);
+
+       vd->vdev_top_zap = mvd->vdev_top_zap;
+       vd->vdev_leaf_zap = mvd->vdev_leaf_zap;
+
+       for (uint64_t i = 0; i < vd->vdev_children; i++) {
+               spa_config_valid_zaps(vd->vdev_child[i], mvd->vdev_child[i]);
        }
 }
 
@@ -1651,7 +1794,6 @@ spa_config_valid(spa_t *spa, nvlist_t *config)
 {
        vdev_t *mrvd, *rvd = spa->spa_root_vdev;
        nvlist_t *nv;
-       int c, i;
 
        VERIFY(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, &nv) == 0);
 
@@ -1669,11 +1811,11 @@ spa_config_valid(spa_t *spa, nvlist_t *config)
                nvlist_t **child, *nv;
                uint64_t idx = 0;
 
-               child = kmem_alloc(rvd->vdev_children * sizeof (nvlist_t **),
+               child = kmem_alloc(rvd->vdev_children * sizeof (nvlist_t *),
                    KM_SLEEP);
                VERIFY(nvlist_alloc(&nv, NV_UNIQUE_NAME, KM_SLEEP) == 0);
 
-               for (c = 0; c < rvd->vdev_children; c++) {
+               for (int c = 0; c < rvd->vdev_children; c++) {
                        vdev_t *tvd = rvd->vdev_child[c];
                        vdev_t *mtvd  = mrvd->vdev_child[c];
 
@@ -1690,7 +1832,7 @@ spa_config_valid(spa_t *spa, nvlist_t *config)
                        VERIFY(nvlist_add_nvlist(spa->spa_load_info,
                            ZPOOL_CONFIG_MISSING_DEVICES, nv) == 0);
 
-                       for (i = 0; i < idx; i++)
+                       for (int i = 0; i < idx; i++)
                                nvlist_free(child[i]);
                }
                nvlist_free(nv);
@@ -1702,33 +1844,32 @@ spa_config_valid(spa_t *spa, nvlist_t *config)
         * from the MOS config (mrvd). Check each top-level vdev
         * with the corresponding MOS config top-level (mtvd).
         */
-       for (c = 0; c < rvd->vdev_children; c++) {
+       for (int c = 0; c < rvd->vdev_children; c++) {
                vdev_t *tvd = rvd->vdev_child[c];
                vdev_t *mtvd  = mrvd->vdev_child[c];
 
                /*
                 * Resolve any "missing" vdevs in the current configuration.
+                * Also trust the MOS config about any "indirect" vdevs.
                 * If we find that the MOS config has more accurate information
                 * about the top-level vdev then use that vdev instead.
                 */
-               if (tvd->vdev_ops == &vdev_missing_ops &&
-                   mtvd->vdev_ops != &vdev_missing_ops) {
-
-                       if (!(spa->spa_import_flags & ZFS_IMPORT_MISSING_LOG))
-                               continue;
+               if ((tvd->vdev_ops == &vdev_missing_ops &&
+                   mtvd->vdev_ops != &vdev_missing_ops) ||
+                   (mtvd->vdev_ops == &vdev_indirect_ops &&
+                   tvd->vdev_ops != &vdev_indirect_ops)) {
 
                        /*
                         * Device specific actions.
                         */
                        if (mtvd->vdev_islog) {
+                               if (!(spa->spa_import_flags &
+                                   ZFS_IMPORT_MISSING_LOG)) {
+                                       continue;
+                               }
+
                                spa_set_log_state(spa, SPA_LOG_CLEAR);
-                       } else {
-                               /*
-                                * XXX - once we have 'readonly' pool
-                                * support we should be able to handle
-                                * missing data devices by transitioning
-                                * the pool to readonly.
-                                */
+                       } else if (mtvd->vdev_ops != &vdev_indirect_ops) {
                                continue;
                        }
 
@@ -1742,21 +1883,34 @@ spa_config_valid(spa_t *spa, nvlist_t *config)
                        vdev_add_child(rvd, mtvd);
                        vdev_add_child(mrvd, tvd);
 
-                       spa_config_exit(spa, SCL_ALL, FTAG);
-                       vdev_load(mtvd);
-                       spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
-
                        vdev_reopen(rvd);
-               } else if (mtvd->vdev_islog) {
+               } else {
+                       if (mtvd->vdev_islog) {
+                               /*
+                                * Load the slog device's state from the MOS
+                                * config since it's possible that the label
+                                * does not contain the most up-to-date
+                                * information.
+                                */
+                               vdev_load_log_state(tvd, mtvd);
+                               vdev_reopen(tvd);
+                       }
+
                        /*
-                        * Load the slog device's state from the MOS config
-                        * since it's possible that the label does not
-                        * contain the most up-to-date information.
+                        * Per-vdev ZAP info is stored exclusively in the MOS.
                         */
-                       vdev_load_log_state(tvd, mtvd);
-                       vdev_reopen(tvd);
+                       spa_config_valid_zaps(tvd, mtvd);
                }
+
+               /*
+                * Never trust this info from userland; always use what's
+                * in the MOS.  This prevents it from getting out of sync
+                * with the rest of the info in the MOS.
+                */
+               tvd->vdev_removing = mtvd->vdev_removing;
+               tvd->vdev_indirect_config = mtvd->vdev_indirect_config;
        }
+
        vdev_free(mrvd);
        spa_config_exit(spa, SCL_ALL, FTAG);
 
@@ -1795,14 +1949,13 @@ spa_passivate_log(spa_t *spa)
 {
        vdev_t *rvd = spa->spa_root_vdev;
        boolean_t slog_found = B_FALSE;
-       int c;
 
        ASSERT(spa_config_held(spa, SCL_ALLOC, RW_WRITER));
 
        if (!spa_has_slogs(spa))
                return (B_FALSE);
 
-       for (c = 0; c < rvd->vdev_children; c++) {
+       for (int c = 0; c < rvd->vdev_children; c++) {
                vdev_t *tvd = rvd->vdev_child[c];
                metaslab_group_t *mg = tvd->vdev_mg;
 
@@ -1819,11 +1972,10 @@ static void
 spa_activate_log(spa_t *spa)
 {
        vdev_t *rvd = spa->spa_root_vdev;
-       int c;
 
        ASSERT(spa_config_held(spa, SCL_ALLOC, RW_WRITER));
 
-       for (c = 0; c < rvd->vdev_children; c++) {
+       for (int c = 0; c < rvd->vdev_children; c++) {
                vdev_t *tvd = rvd->vdev_child[c];
                metaslab_group_t *mg = tvd->vdev_mg;
 
@@ -1833,11 +1985,11 @@ spa_activate_log(spa_t *spa)
 }
 
 int
-spa_offline_log(spa_t *spa)
+spa_reset_logs(spa_t *spa)
 {
        int error;
 
-       error = dmu_objset_find(spa_name(spa), zil_vdev_offline,
+       error = dmu_objset_find(spa_name(spa), zil_reset,
            NULL, DS_FIND_CHILDREN);
        if (error == 0) {
                /*
@@ -1853,9 +2005,7 @@ spa_offline_log(spa_t *spa)
 static void
 spa_aux_check_removed(spa_aux_vdev_t *sav)
 {
-       int i;
-
-       for (i = 0; i < sav->sav_count; i++)
+       for (int i = 0; i < sav->sav_count; i++)
                spa_check_removed(sav->sav_vdevs[i]);
 }
 
@@ -1887,17 +2037,17 @@ spa_load_verify_done(zio_t *zio)
        int error = zio->io_error;
        spa_t *spa = zio->io_spa;
 
+       abd_free(zio->io_abd);
        if (error) {
                if ((BP_GET_LEVEL(bp) != 0 || DMU_OT_IS_METADATA(type)) &&
                    type != DMU_OT_INTENT_LOG)
-                       atomic_add_64(&sle->sle_meta_count, 1);
+                       atomic_inc_64(&sle->sle_meta_count);
                else
-                       atomic_add_64(&sle->sle_data_count, 1);
+                       atomic_inc_64(&sle->sle_data_count);
        }
-       zio_data_buf_free(zio->io_data, zio->io_size);
 
        mutex_enter(&spa->spa_scrub_lock);
-       spa->spa_scrub_inflight--;
+       spa->spa_load_verify_ios--;
        cv_broadcast(&spa->spa_scrub_io_cv);
        mutex_exit(&spa->spa_scrub_lock);
 }
@@ -1915,11 +2065,7 @@ static int
 spa_load_verify_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
     const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
 {
-       zio_t *rio;
-       size_t size;
-       void *data;
-
-       if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp))
+       if (bp == NULL || BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp))
                return (0);
        /*
         * Note: normally this routine will not be called if
@@ -1928,26 +2074,35 @@ spa_load_verify_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
         */
        if (!spa_load_verify_metadata)
                return (0);
-       if (BP_GET_BUFC_TYPE(bp) == ARC_BUFC_DATA && !spa_load_verify_data)
+       if (!BP_IS_METADATA(bp) && !spa_load_verify_data)
                return (0);
 
-       rio = arg;
-       size = BP_GET_PSIZE(bp);
-       data = zio_data_buf_alloc(size);
+       zio_t *rio = arg;
+       size_t size = BP_GET_PSIZE(bp);
 
        mutex_enter(&spa->spa_scrub_lock);
-       while (spa->spa_scrub_inflight >= spa_load_verify_maxinflight)
+       while (spa->spa_load_verify_ios >= spa_load_verify_maxinflight)
                cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
-       spa->spa_scrub_inflight++;
+       spa->spa_load_verify_ios++;
        mutex_exit(&spa->spa_scrub_lock);
 
-       zio_nowait(zio_read(rio, spa, bp, data, size,
+       zio_nowait(zio_read(rio, spa, bp, abd_alloc_for_io(size, B_FALSE), size,
            spa_load_verify_done, rio->io_private, ZIO_PRIORITY_SCRUB,
            ZIO_FLAG_SPECULATIVE | ZIO_FLAG_CANFAIL |
            ZIO_FLAG_SCRUB | ZIO_FLAG_RAW, zb));
        return (0);
 }
 
+/* ARGSUSED */
+int
+verify_dataset_name_len(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
+{
+       if (dsl_dataset_namelen(ds) >= ZFS_MAX_DATASET_NAME_LEN)
+               return (SET_ERROR(ENAMETOOLONG));
+
+       return (0);
+}
+
 static int
 spa_load_verify(spa_t *spa)
 {
@@ -1962,13 +2117,28 @@ spa_load_verify(spa_t *spa)
        if (policy.zrp_request & ZPOOL_NEVER_REWIND)
                return (0);
 
+       dsl_pool_config_enter(spa->spa_dsl_pool, FTAG);
+       error = dmu_objset_find_dp(spa->spa_dsl_pool,
+           spa->spa_dsl_pool->dp_root_dir_obj, verify_dataset_name_len, NULL,
+           DS_FIND_CHILDREN);
+       dsl_pool_config_exit(spa->spa_dsl_pool, FTAG);
+       if (error != 0)
+               return (error);
+
        rio = zio_root(spa, NULL, &sle,
            ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE);
 
        if (spa_load_verify_metadata) {
+               if (spa->spa_extreme_rewind) {
+                       spa_load_note(spa, "performing a complete scan of the "
+                           "pool since extreme rewind is on. This may take "
+                           "a very long time.\n  (spa_load_verify_data=%u, "
+                           "spa_load_verify_metadata=%u)",
+                           spa_load_verify_data, spa_load_verify_metadata);
+               }
                error = traverse_pool(spa, spa->spa_verify_min_txg,
-                   TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA,
-                   spa_load_verify_cb, rio);
+                   TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA |
+                   TRAVERSE_NO_DECRYPT, spa_load_verify_cb, rio);
        }
 
        (void) zio_wait(rio);
@@ -1976,8 +2146,15 @@ spa_load_verify(spa_t *spa)
        spa->spa_load_meta_errors = sle.sle_meta_count;
        spa->spa_load_data_errors = sle.sle_data_count;
 
-       if (!error && sle.sle_meta_count <= policy.zrp_maxmeta &&
-           sle.sle_data_count <= policy.zrp_maxdata) {
+       if (sle.sle_meta_count != 0 || sle.sle_data_count != 0) {
+               spa_load_note(spa, "spa_load_verify found %llu metadata errors "
+                   "and %llu data errors", (u_longlong_t)sle.sle_meta_count,
+                   (u_longlong_t)sle.sle_data_count);
+       }
+
+       if (spa_load_verify_dryrun ||
+           (!error && sle.sle_meta_count <= policy.zrp_maxmeta &&
+           sle.sle_data_count <= policy.zrp_maxdata)) {
                int64_t loss = 0;
 
                verify_ok = B_TRUE;
@@ -1995,6 +2172,9 @@ spa_load_verify(spa_t *spa)
                spa->spa_load_max_txg = spa->spa_uberblock.ub_txg;
        }
 
+       if (spa_load_verify_dryrun)
+               return (0);
+
        if (error) {
                if (error != ENXIO && error != EIO)
                        error = SET_ERROR(EIO);
@@ -2018,17 +2198,34 @@ spa_prop_find(spa_t *spa, zpool_prop_t prop, uint64_t *val)
  * Find a value in the pool directory object.
  */
 static int
-spa_dir_prop(spa_t *spa, const char *name, uint64_t *val)
+spa_dir_prop(spa_t *spa, const char *name, uint64_t *val, boolean_t log_enoent)
 {
-       return (zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
-           name, sizeof (uint64_t), 1, val));
+       int error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
+           name, sizeof (uint64_t), 1, val);
+
+       if (error != 0 && (error != ENOENT || log_enoent)) {
+               spa_load_failed(spa, "couldn't get '%s' value in MOS directory "
+                   "[error=%d]", name, error);
+       }
+
+       return (error);
 }
 
 static int
 spa_vdev_err(vdev_t *vdev, vdev_aux_t aux, int err)
 {
        vdev_set_state(vdev, B_TRUE, VDEV_STATE_CANT_OPEN, aux);
-       return (err);
+       return (SET_ERROR(err));
+}
+
+static void
+spa_spawn_aux_threads(spa_t *spa)
+{
+       ASSERT(spa_writeable(spa));
+
+       ASSERT(MUTEX_HELD(&spa_namespace_lock));
+
+       spa_start_indirect_condensing_thread(spa);
 }
 
 /*
@@ -2115,7 +2312,7 @@ spa_try_repair(spa_t *spa, nvlist_t *config)
 
 static int
 spa_load(spa_t *spa, spa_load_state_t state, spa_import_type_t type,
-    boolean_t mosconfig)
+    boolean_t trust_config)
 {
        nvlist_t *config = spa->spa_config;
        char *ereport = FM_EREPORT_ZFS_POOL;
@@ -2159,7 +2356,7 @@ spa_load(spa_t *spa, spa_load_state_t state, spa_import_type_t type,
 
                gethrestime(&spa->spa_loaded_ts);
                error = spa_load_impl(spa, pool_guid, config, state, type,
-                   mosconfig, &ereport);
+                   trust_config, &ereport);
        }
 
        /*
@@ -2174,7 +2371,7 @@ spa_load(spa_t *spa, spa_load_state_t state, spa_import_type_t type,
                        spa->spa_loaded_ts.tv_nsec = 0;
                }
                if (error != EBADF) {
-                       zfs_ereport_post(ereport, spa, NULL, NULL, 0, 0);
+                       zfs_ereport_post(ereport, spa, NULL, NULL, NULL, 0, 0);
                }
        }
        spa->spa_load_state = error ? SPA_LOAD_ERROR : SPA_LOAD_NONE;
@@ -2183,109 +2380,358 @@ spa_load(spa_t *spa, spa_load_state_t state, spa_import_type_t type,
        return (error);
 }
 
+#ifdef ZFS_DEBUG
 /*
- * Load an existing storage pool, using the pool's builtin spa_config as a
- * source of configuration information.
+ * Count the number of per-vdev ZAPs associated with all of the vdevs in the
+ * vdev tree rooted in the given vd, and ensure that each ZAP is present in the
+ * spa's per-vdev ZAP list.
  */
-__attribute__((always_inline))
-static inline int
-spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
-    spa_load_state_t state, spa_import_type_t type, boolean_t mosconfig,
-    char **ereport)
+static uint64_t
+vdev_count_verify_zaps(vdev_t *vd)
 {
-       int error = 0;
-       nvlist_t *nvroot = NULL;
-       nvlist_t *label;
-       vdev_t *rvd;
-       uberblock_t *ub = &spa->spa_uberblock;
-       uint64_t children, config_cache_txg = spa->spa_config_txg;
-       int orig_mode = spa->spa_mode;
-       int parse, i;
-       uint64_t obj;
-       boolean_t missing_feat_write = B_FALSE;
+       spa_t *spa = vd->vdev_spa;
+       uint64_t total = 0;
 
-       /*
-        * If this is an untrusted config, access the pool in read-only mode.
-        * This prevents things like resilvering recently removed devices.
-        */
-       if (!mosconfig)
-               spa->spa_mode = FREAD;
+       if (vd->vdev_top_zap != 0) {
+               total++;
+               ASSERT0(zap_lookup_int(spa->spa_meta_objset,
+                   spa->spa_all_vdev_zaps, vd->vdev_top_zap));
+       }
+       if (vd->vdev_leaf_zap != 0) {
+               total++;
+               ASSERT0(zap_lookup_int(spa->spa_meta_objset,
+                   spa->spa_all_vdev_zaps, vd->vdev_leaf_zap));
+       }
 
-       ASSERT(MUTEX_HELD(&spa_namespace_lock));
+       for (uint64_t i = 0; i < vd->vdev_children; i++) {
+               total += vdev_count_verify_zaps(vd->vdev_child[i]);
+       }
 
-       spa->spa_load_state = state;
+       return (total);
+}
+#endif
 
-       if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, &nvroot))
-               return (SET_ERROR(EINVAL));
+/*
+ * Determine whether the activity check is required.
+ */
+static boolean_t
+spa_activity_check_required(spa_t *spa, uberblock_t *ub, nvlist_t *label,
+    nvlist_t *config)
+{
+       uint64_t state = 0;
+       uint64_t hostid = 0;
+       uint64_t tryconfig_txg = 0;
+       uint64_t tryconfig_timestamp = 0;
+       nvlist_t *nvinfo;
 
-       parse = (type == SPA_IMPORT_EXISTING ?
-           VDEV_ALLOC_LOAD : VDEV_ALLOC_SPLIT);
+       if (nvlist_exists(config, ZPOOL_CONFIG_LOAD_INFO)) {
+               nvinfo = fnvlist_lookup_nvlist(config, ZPOOL_CONFIG_LOAD_INFO);
+               (void) nvlist_lookup_uint64(nvinfo, ZPOOL_CONFIG_MMP_TXG,
+                   &tryconfig_txg);
+               (void) nvlist_lookup_uint64(config, ZPOOL_CONFIG_TIMESTAMP,
+                   &tryconfig_timestamp);
+       }
+
+       (void) nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_STATE, &state);
 
        /*
-        * Create "The Godfather" zio to hold all async IOs
+        * Disable the MMP activity check - This is used by zdb which
+        * is intended to be used on potentially active pools.
         */
-       spa->spa_async_zio_root = kmem_alloc(max_ncpus * sizeof (void *),
-           KM_SLEEP);
-       for (i = 0; i < max_ncpus; i++) {
-               spa->spa_async_zio_root[i] = zio_root(spa, NULL, NULL,
-                   ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE |
-                   ZIO_FLAG_GODFATHER);
-       }
+       if (spa->spa_import_flags & ZFS_IMPORT_SKIP_MMP)
+               return (B_FALSE);
 
        /*
-        * 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.
+        * Skip the activity check when the MMP feature is disabled.
         */
-       spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
-       error = spa_config_parse(spa, &rvd, nvroot, NULL, 0, parse);
-       spa_config_exit(spa, SCL_ALL, FTAG);
-
-       if (error != 0)
-               return (error);
-
-       ASSERT(spa->spa_root_vdev == rvd);
-       ASSERT3U(spa->spa_min_ashift, >=, SPA_MINBLOCKSHIFT);
-       ASSERT3U(spa->spa_max_ashift, <=, SPA_MAXBLOCKSHIFT);
-
-       if (type != SPA_IMPORT_ASSEMBLE) {
-               ASSERT(spa_guid(spa) == pool_guid);
-       }
-
+       if (ub->ub_mmp_magic == MMP_MAGIC && ub->ub_mmp_delay == 0)
+               return (B_FALSE);
        /*
-        * Try to open all vdevs, loading each label in the process.
+        * If the tryconfig_* values are nonzero, they are the results of an
+        * earlier tryimport.  If they match the uberblock we just found, then
+        * the pool has not changed and we return false so we do not test a
+        * second time.
         */
-       spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
-       error = vdev_open(rvd);
-       spa_config_exit(spa, SCL_ALL, FTAG);
-       if (error != 0)
-               return (error);
+       if (tryconfig_txg && tryconfig_txg == ub->ub_txg &&
+           tryconfig_timestamp && tryconfig_timestamp == ub->ub_timestamp)
+               return (B_FALSE);
 
        /*
-        * We need to validate the vdev labels against the configuration that
-        * we have in hand, which is dependent on the setting of mosconfig. If
-        * mosconfig is true then we're validating the vdev labels based on
-        * that config.  Otherwise, we're validating against the cached config
-        * (zpool.cache) that was read when we loaded the zfs module, and then
-        * later we will recursively call spa_load() and validate against
-        * the vdev config.
-        *
-        * If we're assembling a new pool that's been split off from an
-        * existing pool, the labels haven't yet been updated so we skip
-        * validation for now.
+        * Allow the activity check to be skipped when importing the pool
+        * on the same host which last imported it.  Since the hostid from
+        * configuration may be stale use the one read from the label.
         */
-       if (type != SPA_IMPORT_ASSEMBLE) {
-               spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
-               error = vdev_validate(rvd, mosconfig);
-               spa_config_exit(spa, SCL_ALL, FTAG);
+       if (nvlist_exists(label, ZPOOL_CONFIG_HOSTID))
+               hostid = fnvlist_lookup_uint64(label, ZPOOL_CONFIG_HOSTID);
 
-               if (error != 0)
+       if (hostid == spa_get_hostid())
+               return (B_FALSE);
+
+       /*
+        * Skip the activity test when the pool was cleanly exported.
+        */
+       if (state != POOL_STATE_ACTIVE)
+               return (B_FALSE);
+
+       return (B_TRUE);
+}
+
+/*
+ * Perform the import activity check.  If the user canceled the import or
+ * we detected activity then fail.
+ */
+static int
+spa_activity_check(spa_t *spa, uberblock_t *ub, nvlist_t *config)
+{
+       uint64_t import_intervals = MAX(zfs_multihost_import_intervals, 1);
+       uint64_t txg = ub->ub_txg;
+       uint64_t timestamp = ub->ub_timestamp;
+       uint64_t import_delay = NANOSEC;
+       hrtime_t import_expire;
+       nvlist_t *mmp_label = NULL;
+       vdev_t *rvd = spa->spa_root_vdev;
+       kcondvar_t cv;
+       kmutex_t mtx;
+       int error = 0;
+
+       cv_init(&cv, NULL, CV_DEFAULT, NULL);
+       mutex_init(&mtx, NULL, MUTEX_DEFAULT, NULL);
+       mutex_enter(&mtx);
+
+       /*
+        * If ZPOOL_CONFIG_MMP_TXG is present an activity check was performed
+        * during the earlier tryimport.  If the txg recorded there is 0 then
+        * the pool is known to be active on another host.
+        *
+        * Otherwise, the pool might be in use on another node.  Check for
+        * changes in the uberblocks on disk if necessary.
+        */
+       if (nvlist_exists(config, ZPOOL_CONFIG_LOAD_INFO)) {
+               nvlist_t *nvinfo = fnvlist_lookup_nvlist(config,
+                   ZPOOL_CONFIG_LOAD_INFO);
+
+               if (nvlist_exists(nvinfo, ZPOOL_CONFIG_MMP_TXG) &&
+                   fnvlist_lookup_uint64(nvinfo, ZPOOL_CONFIG_MMP_TXG) == 0) {
+                       vdev_uberblock_load(rvd, ub, &mmp_label);
+                       error = SET_ERROR(EREMOTEIO);
+                       goto out;
+               }
+       }
+
+       /*
+        * Preferentially use the zfs_multihost_interval from the node which
+        * last imported the pool.  This value is stored in an MMP uberblock as.
+        *
+        * ub_mmp_delay * vdev_count_leaves() == zfs_multihost_interval
+        */
+       if (ub->ub_mmp_magic == MMP_MAGIC && ub->ub_mmp_delay)
+               import_delay = MAX(import_delay, import_intervals *
+                   ub->ub_mmp_delay * MAX(vdev_count_leaves(spa), 1));
+
+       /* Apply a floor using the local default values. */
+       import_delay = MAX(import_delay, import_intervals *
+           MSEC2NSEC(MAX(zfs_multihost_interval, MMP_MIN_INTERVAL)));
+
+       zfs_dbgmsg("import_delay=%llu ub_mmp_delay=%llu import_intervals=%u "
+           "leaves=%u", import_delay, ub->ub_mmp_delay, import_intervals,
+           vdev_count_leaves(spa));
+
+       /* Add a small random factor in case of simultaneous imports (0-25%) */
+       import_expire = gethrtime() + import_delay +
+           (import_delay * spa_get_random(250) / 1000);
+
+       while (gethrtime() < import_expire) {
+               vdev_uberblock_load(rvd, ub, &mmp_label);
+
+               if (txg != ub->ub_txg || timestamp != ub->ub_timestamp) {
+                       error = SET_ERROR(EREMOTEIO);
+                       break;
+               }
+
+               if (mmp_label) {
+                       nvlist_free(mmp_label);
+                       mmp_label = NULL;
+               }
+
+               error = cv_timedwait_sig(&cv, &mtx, ddi_get_lbolt() + hz);
+               if (error != -1) {
+                       error = SET_ERROR(EINTR);
+                       break;
+               }
+               error = 0;
+       }
+
+out:
+       mutex_exit(&mtx);
+       mutex_destroy(&mtx);
+       cv_destroy(&cv);
+
+       /*
+        * If the pool is determined to be active store the status in the
+        * spa->spa_load_info nvlist.  If the remote hostname or hostid are
+        * available from configuration read from disk store them as well.
+        * This allows 'zpool import' to generate a more useful message.
+        *
+        * ZPOOL_CONFIG_MMP_STATE    - observed pool status (mandatory)
+        * ZPOOL_CONFIG_MMP_HOSTNAME - hostname from the active pool
+        * ZPOOL_CONFIG_MMP_HOSTID   - hostid from the active pool
+        */
+       if (error == EREMOTEIO) {
+               char *hostname = "<unknown>";
+               uint64_t hostid = 0;
+
+               if (mmp_label) {
+                       if (nvlist_exists(mmp_label, ZPOOL_CONFIG_HOSTNAME)) {
+                               hostname = fnvlist_lookup_string(mmp_label,
+                                   ZPOOL_CONFIG_HOSTNAME);
+                               fnvlist_add_string(spa->spa_load_info,
+                                   ZPOOL_CONFIG_MMP_HOSTNAME, hostname);
+                       }
+
+                       if (nvlist_exists(mmp_label, ZPOOL_CONFIG_HOSTID)) {
+                               hostid = fnvlist_lookup_uint64(mmp_label,
+                                   ZPOOL_CONFIG_HOSTID);
+                               fnvlist_add_uint64(spa->spa_load_info,
+                                   ZPOOL_CONFIG_MMP_HOSTID, hostid);
+                       }
+               }
+
+               fnvlist_add_uint64(spa->spa_load_info,
+                   ZPOOL_CONFIG_MMP_STATE, MMP_STATE_ACTIVE);
+               fnvlist_add_uint64(spa->spa_load_info,
+                   ZPOOL_CONFIG_MMP_TXG, 0);
+
+               error = spa_vdev_err(rvd, VDEV_AUX_ACTIVE, EREMOTEIO);
+       }
+
+       if (mmp_label)
+               nvlist_free(mmp_label);
+
+       return (error);
+}
+
+static int
+spa_ld_parse_config(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
+    spa_import_type_t type)
+{
+       int error = 0;
+       nvlist_t *nvtree = NULL;
+       int parse;
+       vdev_t *rvd;
+
+       if (nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, &nvtree)) {
+               spa_load_failed(spa, "invalid config provided: '%s' missing",
+                   ZPOOL_CONFIG_VDEV_TREE);
+               return (SET_ERROR(EINVAL));
+       }
+
+       parse = (type == SPA_IMPORT_EXISTING ?
+           VDEV_ALLOC_LOAD : VDEV_ALLOC_SPLIT);
+
+       /*
+        * Create "The Godfather" zio to hold all async IOs
+        */
+       spa->spa_async_zio_root = kmem_alloc(max_ncpus * sizeof (void *),
+           KM_SLEEP);
+       for (int i = 0; i < max_ncpus; i++) {
+               spa->spa_async_zio_root[i] = zio_root(spa, NULL, NULL,
+                   ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE |
+                   ZIO_FLAG_GODFATHER);
+       }
+
+       /*
+        * 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);
+       error = spa_config_parse(spa, &rvd, nvtree, NULL, 0, parse);
+       spa_config_exit(spa, SCL_ALL, FTAG);
+
+       if (error != 0) {
+               spa_load_failed(spa, "unable to parse config [error=%d]",
+                   error);
+               return (error);
+       }
+
+       ASSERT(spa->spa_root_vdev == rvd);
+       ASSERT3U(spa->spa_min_ashift, >=, SPA_MINBLOCKSHIFT);
+       ASSERT3U(spa->spa_max_ashift, <=, SPA_MAXBLOCKSHIFT);
+
+       if (type != SPA_IMPORT_ASSEMBLE) {
+               ASSERT(spa_guid(spa) == pool_guid);
+       }
+
+       return (0);
+}
+
+static int
+spa_ld_open_vdevs(spa_t *spa)
+{
+       int error = 0;
+
+       spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+       error = vdev_open(spa->spa_root_vdev);
+       spa_config_exit(spa, SCL_ALL, FTAG);
+       if (error != 0) {
+               spa_load_failed(spa, "unable to open vdev tree [error=%d]",
+                   error);
+       }
+
+       return (error);
+}
+
+static int
+spa_ld_validate_vdevs(spa_t *spa, spa_import_type_t type,
+    boolean_t trust_config)
+{
+       int error = 0;
+       vdev_t *rvd = spa->spa_root_vdev;
+
+       /*
+        * We need to validate the vdev labels against the configuration that
+        * we have in hand, which is dependent on the setting of trust_config.
+        * If trust_config is true then we're validating the vdev labels based
+        * on that config.  Otherwise, we're validating against the cached
+        * config (zpool.cache) that was read when we loaded the zfs module, and
+        * then later we will recursively call spa_load() and validate against
+        * the vdev config.
+        *
+        * If we're assembling a new pool that's been split off from an
+        * existing pool, the labels haven't yet been updated so we skip
+        * validation for now.
+        */
+       if (type != SPA_IMPORT_ASSEMBLE) {
+               spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+               error = vdev_validate(rvd, trust_config);
+               spa_config_exit(spa, SCL_ALL, FTAG);
+
+               if (error != 0) {
+                       spa_load_failed(spa, "vdev_validate failed [error=%d]",
+                           error);
                        return (error);
+               }
 
-               if (rvd->vdev_state <= VDEV_STATE_CANT_OPEN)
+               if (rvd->vdev_state <= VDEV_STATE_CANT_OPEN) {
+                       spa_load_failed(spa, "cannot open vdev tree after "
+                           "invalidating some vdevs");
                        return (SET_ERROR(ENXIO));
+               }
        }
 
+       return (0);
+}
+
+static int
+spa_ld_select_uberblock(spa_t *spa, nvlist_t *config, spa_import_type_t type,
+    boolean_t trust_config)
+{
+       vdev_t *rvd = spa->spa_root_vdev;
+       nvlist_t *label;
+       uberblock_t *ub = &spa->spa_uberblock;
+       uint64_t children;
+       boolean_t activity_check = B_FALSE;
+
        /*
         * Find the best uberblock.
         */
@@ -2296,14 +2742,48 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
         */
        if (ub->ub_txg == 0) {
                nvlist_free(label);
+               spa_load_failed(spa, "no valid uberblock found");
                return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, ENXIO));
        }
 
+       spa_load_note(spa, "using uberblock with txg=%llu",
+           (u_longlong_t)ub->ub_txg);
+
+
+       /*
+        * For pools which have the multihost property on determine if the
+        * pool is truly inactive and can be safely imported.  Prevent
+        * hosts which don't have a hostid set from importing the pool.
+        */
+       activity_check = spa_activity_check_required(spa, ub, label, config);
+       if (activity_check) {
+               if (ub->ub_mmp_magic == MMP_MAGIC && ub->ub_mmp_delay &&
+                   spa_get_hostid() == 0) {
+                       nvlist_free(label);
+                       fnvlist_add_uint64(spa->spa_load_info,
+                           ZPOOL_CONFIG_MMP_STATE, MMP_STATE_NO_HOSTID);
+                       return (spa_vdev_err(rvd, VDEV_AUX_ACTIVE, EREMOTEIO));
+               }
+
+               int error = spa_activity_check(spa, ub, config);
+               if (error) {
+                       nvlist_free(label);
+                       return (error);
+               }
+
+               fnvlist_add_uint64(spa->spa_load_info,
+                   ZPOOL_CONFIG_MMP_STATE, MMP_STATE_INACTIVE);
+               fnvlist_add_uint64(spa->spa_load_info,
+                   ZPOOL_CONFIG_MMP_TXG, ub->ub_txg);
+       }
+
        /*
         * If the pool has an unsupported version we can't open it.
         */
        if (!SPA_VERSION_IS_SUPPORTED(ub->ub_version)) {
                nvlist_free(label);
+               spa_load_failed(spa, "version %llu is not supported",
+                   (u_longlong_t)ub->ub_version);
                return (spa_vdev_err(rvd, VDEV_AUX_VERSION_NEWER, ENOTSUP));
        }
 
@@ -2314,9 +2794,17 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
                 * If we weren't able to find what's necessary for reading the
                 * MOS in the label, return failure.
                 */
-               if (label == NULL || nvlist_lookup_nvlist(label,
-                   ZPOOL_CONFIG_FEATURES_FOR_READ, &features) != 0) {
+               if (label == NULL) {
+                       spa_load_failed(spa, "label config unavailable");
+                       return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA,
+                           ENXIO));
+               }
+
+               if (nvlist_lookup_nvlist(label, ZPOOL_CONFIG_FEATURES_FOR_READ,
+                   &features) != 0) {
                        nvlist_free(label);
+                       spa_load_failed(spa, "invalid label: '%s' missing",
+                           ZPOOL_CONFIG_FEATURES_FOR_READ);
                        return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA,
                            ENXIO));
                }
@@ -2338,13 +2826,12 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
         */
        if (ub->ub_version >= SPA_VERSION_FEATURES) {
                nvlist_t *unsup_feat;
-               nvpair_t *nvp;
 
                VERIFY(nvlist_alloc(&unsup_feat, NV_UNIQUE_NAME, KM_SLEEP) ==
                    0);
 
-               for (nvp = nvlist_next_nvpair(spa->spa_label_features, NULL);
-                   nvp != NULL;
+               for (nvpair_t *nvp = nvlist_next_nvpair(spa->spa_label_features,
+                   NULL); nvp != NULL;
                    nvp = nvlist_next_nvpair(spa->spa_label_features, nvp)) {
                        if (!zfeature_is_supported(nvpair_name(nvp))) {
                                VERIFY(nvlist_add_string(unsup_feat,
@@ -2356,6 +2843,7 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
                        VERIFY(nvlist_add_nvlist(spa->spa_load_info,
                            ZPOOL_CONFIG_UNSUP_FEAT, unsup_feat) == 0);
                        nvlist_free(unsup_feat);
+                       spa_load_failed(spa, "some features are unsupported");
                        return (spa_vdev_err(rvd, VDEV_AUX_UNSUP_FEAT,
                            ENOTSUP));
                }
@@ -2371,9 +2859,14 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
         * can handle missing vdevs.
         */
        if (nvlist_lookup_uint64(config, ZPOOL_CONFIG_VDEV_CHILDREN,
-           &children) != 0 && mosconfig && type != SPA_IMPORT_ASSEMBLE &&
-           rvd->vdev_guid_sum != ub->ub_guid_sum)
+           &children) != 0 && trust_config && type != SPA_IMPORT_ASSEMBLE &&
+           rvd->vdev_guid_sum != ub->ub_guid_sum) {
+               spa_load_failed(spa, "guid sum in config doesn't match guid "
+                   "sum in uberblock (%llu != %llu)",
+                   (u_longlong_t)rvd->vdev_guid_sum,
+                   (u_longlong_t)ub->ub_guid_sum);
                return (spa_vdev_err(rvd, VDEV_AUX_BAD_GUID_SUM, ENXIO));
+       }
 
        if (type != SPA_IMPORT_ASSEMBLE && spa->spa_config_splitting) {
                spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
@@ -2395,31 +2888,125 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
        spa->spa_claim_max_txg = spa->spa_first_txg;
        spa->spa_prev_software_version = ub->ub_software_version;
 
+       return (0);
+}
+
+static int
+spa_ld_open_rootbp(spa_t *spa)
+{
+       int error = 0;
+       vdev_t *rvd = spa->spa_root_vdev;
+
        error = dsl_pool_init(spa, spa->spa_first_txg, &spa->spa_dsl_pool);
-       if (error)
+       if (error != 0) {
+               spa_load_failed(spa, "unable to open rootbp in dsl_pool_init "
+                   "[error=%d]", error);
                return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+       }
        spa->spa_meta_objset = spa->spa_dsl_pool->dp_meta_objset;
 
-       if (spa_dir_prop(spa, DMU_POOL_CONFIG, &spa->spa_config_object) != 0)
+       return (0);
+}
+
+static int
+spa_ld_validate_config(spa_t *spa, spa_import_type_t type)
+{
+       vdev_t *rvd = spa->spa_root_vdev;
+
+       if (spa_dir_prop(spa, DMU_POOL_CONFIG, &spa->spa_config_object, B_TRUE)
+           != 0)
+               return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+
+       /*
+        * Validate the config, using the MOS config to fill in any
+        * information which might be missing.  If we fail to validate
+        * the config then declare the pool unfit for use. If we're
+        * assembling a pool from a split, the log is not transferred
+        * over.
+        */
+       if (type != SPA_IMPORT_ASSEMBLE) {
+               nvlist_t *mos_config;
+               if (load_nvlist(spa, spa->spa_config_object, &mos_config)
+                   != 0) {
+                       spa_load_failed(spa, "unable to retrieve MOS config");
+                       return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+               }
+
+               if (!spa_config_valid(spa, mos_config)) {
+                       nvlist_free(mos_config);
+                       spa_load_failed(spa, "mismatch between config provided "
+                           "and config stored in MOS");
+                       return (spa_vdev_err(rvd, VDEV_AUX_BAD_GUID_SUM,
+                           ENXIO));
+               }
+               nvlist_free(mos_config);
+
+               /*
+                * Now that we've validated the config, 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) {
+                       spa_load_failed(spa, "some top vdevs are unavailable");
+                       return (SET_ERROR(ENXIO));
+               }
+       }
+
+       return (0);
+}
+
+static int
+spa_ld_open_indirect_vdev_metadata(spa_t *spa)
+{
+       int error = 0;
+       vdev_t *rvd = spa->spa_root_vdev;
+
+       /*
+        * Everything that we read before spa_remove_init() must be stored
+        * on concreted vdevs.  Therefore we do this as early as possible.
+        */
+       error = spa_remove_init(spa);
+       if (error != 0) {
+               spa_load_failed(spa, "spa_remove_init failed [error=%d]",
+                   error);
                return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+       }
+
+       /*
+        * Retrieve information needed to condense indirect vdev mappings.
+        */
+       error = spa_condense_init(spa);
+       if (error != 0) {
+               spa_load_failed(spa, "spa_condense_init failed [error=%d]",
+                   error);
+               return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, error));
+       }
+
+       return (0);
+}
+
+static int
+spa_ld_check_features(spa_t *spa, boolean_t *missing_feat_writep)
+{
+       int error = 0;
+       vdev_t *rvd = spa->spa_root_vdev;
 
        if (spa_version(spa) >= SPA_VERSION_FEATURES) {
                boolean_t missing_feat_read = B_FALSE;
                nvlist_t *unsup_feat, *enabled_feat;
-               spa_feature_t i;
 
                if (spa_dir_prop(spa, DMU_POOL_FEATURES_FOR_READ,
-                   &spa->spa_feat_for_read_obj) != 0) {
+                   &spa->spa_feat_for_read_obj, B_TRUE) != 0) {
                        return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
                }
 
                if (spa_dir_prop(spa, DMU_POOL_FEATURES_FOR_WRITE,
-                   &spa->spa_feat_for_write_obj) != 0) {
+                   &spa->spa_feat_for_write_obj, B_TRUE) != 0) {
                        return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
                }
 
                if (spa_dir_prop(spa, DMU_POOL_FEATURE_DESCRIPTIONS,
-                   &spa->spa_feat_desc_obj) != 0) {
+                   &spa->spa_feat_desc_obj, B_TRUE) != 0) {
                        return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
                }
 
@@ -2430,10 +3017,11 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
                    unsup_feat, enabled_feat))
                        missing_feat_read = B_TRUE;
 
-               if (spa_writeable(spa) || state == SPA_LOAD_TRYIMPORT) {
+               if (spa_writeable(spa) ||
+                   spa->spa_load_state == SPA_LOAD_TRYIMPORT) {
                        if (!spa_features_check(spa, B_TRUE,
                            unsup_feat, enabled_feat)) {
-                               missing_feat_write = B_TRUE;
+                               *missing_feat_writep = B_TRUE;
                        }
                }
 
@@ -2472,8 +3060,9 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
                 * userland in order to know whether to display the
                 * abovementioned note.
                 */
-               if (missing_feat_read || (missing_feat_write &&
+               if (missing_feat_read || (*missing_feat_writep &&
                    spa_writeable(spa))) {
+                       spa_load_failed(spa, "pool uses unsupported features");
                        return (spa_vdev_err(rvd, VDEV_AUX_UNSUP_FEAT,
                            ENOTSUP));
                }
@@ -2482,7 +3071,7 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
                 * Load refcounts for ZFS features from disk into an in-memory
                 * cache during SPA initialization.
                 */
-               for (i = 0; i < SPA_FEATURES; i++) {
+               for (spa_feature_t i = 0; i < SPA_FEATURES; i++) {
                        uint64_t refcount;
 
                        error = feature_get_refcount_from_disk(spa,
@@ -2493,6 +3082,9 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
                                spa->spa_feat_refcount_cache[i] =
                                    SPA_FEATURE_DISABLED;
                        } else {
+                               spa_load_failed(spa, "error getting refcount "
+                                   "for feature %s [error=%d]",
+                                   spa_feature_table[i].fi_guid, error);
                                return (spa_vdev_err(rvd,
                                    VDEV_AUX_CORRUPT_DATA, EIO));
                        }
@@ -2501,82 +3093,113 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
 
        if (spa_feature_is_active(spa, SPA_FEATURE_ENABLED_TXG)) {
                if (spa_dir_prop(spa, DMU_POOL_FEATURE_ENABLED_TXG,
-                   &spa->spa_feat_enabled_txg_obj) != 0)
+                   &spa->spa_feat_enabled_txg_obj, B_TRUE) != 0)
                        return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
        }
 
+       return (0);
+}
+
+static int
+spa_ld_load_special_directories(spa_t *spa)
+{
+       int error = 0;
+       vdev_t *rvd = spa->spa_root_vdev;
+
        spa->spa_is_initializing = B_TRUE;
        error = dsl_pool_open(spa->spa_dsl_pool);
        spa->spa_is_initializing = B_FALSE;
-       if (error != 0)
+       if (error != 0) {
+               spa_load_failed(spa, "dsl_pool_open failed [error=%d]", error);
                return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+       }
 
-       if (!mosconfig) {
-               uint64_t hostid;
-               nvlist_t *policy = NULL, *nvconfig;
+       return (0);
+}
 
-               if (load_nvlist(spa, spa->spa_config_object, &nvconfig) != 0)
-                       return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+static int
+spa_ld_prepare_for_reload(spa_t *spa, int orig_mode)
+{
+       vdev_t *rvd = spa->spa_root_vdev;
 
-               if (!spa_is_root(spa) && nvlist_lookup_uint64(nvconfig,
-                   ZPOOL_CONFIG_HOSTID, &hostid) == 0) {
-                       char *hostname;
-                       unsigned long myhostid = 0;
+       uint64_t hostid;
+       nvlist_t *policy = NULL;
+       nvlist_t *mos_config;
 
-                       VERIFY(nvlist_lookup_string(nvconfig,
-                           ZPOOL_CONFIG_HOSTNAME, &hostname) == 0);
+       if (load_nvlist(spa, spa->spa_config_object, &mos_config) != 0) {
+               spa_load_failed(spa, "unable to retrieve MOS config");
+               return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+       }
 
-#ifdef _KERNEL
-                       myhostid = zone_get_hostid(NULL);
-#else  /* _KERNEL */
-                       /*
-                        * We're emulating the system's hostid in userland, so
-                        * we can't use zone_get_hostid().
-                        */
-                       (void) ddi_strtoul(hw_serial, NULL, 10, &myhostid);
-#endif /* _KERNEL */
-                       if (hostid != 0 && myhostid != 0 &&
-                           hostid != myhostid) {
-                               nvlist_free(nvconfig);
-                               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://zfsonlinux.org/msg/ZFS-8000-EY",
-                                   spa_name(spa), hostname,
-                                   (unsigned long)hostid);
-                               return (SET_ERROR(EBADF));
-                       }
+       if (!spa_is_root(spa) && nvlist_lookup_uint64(mos_config,
+           ZPOOL_CONFIG_HOSTID, &hostid) == 0) {
+               char *hostname;
+               unsigned long myhostid = 0;
+
+               VERIFY(nvlist_lookup_string(mos_config,
+                   ZPOOL_CONFIG_HOSTNAME, &hostname) == 0);
+
+               myhostid = spa_get_hostid();
+               if (hostid && myhostid && hostid != myhostid) {
+                       nvlist_free(mos_config);
+                       return (SET_ERROR(EBADF));
                }
-               if (nvlist_lookup_nvlist(spa->spa_config,
-                   ZPOOL_REWIND_POLICY, &policy) == 0)
-                       VERIFY(nvlist_add_nvlist(nvconfig,
-                           ZPOOL_REWIND_POLICY, policy) == 0);
+       }
+       if (nvlist_lookup_nvlist(spa->spa_config,
+           ZPOOL_REWIND_POLICY, &policy) == 0)
+               VERIFY(nvlist_add_nvlist(mos_config,
+                   ZPOOL_REWIND_POLICY, policy) == 0);
 
-               spa_config_set(spa, nvconfig);
-               spa_unload(spa);
-               spa_deactivate(spa);
-               spa_activate(spa, orig_mode);
+       spa_config_set(spa, mos_config);
+       spa_unload(spa);
+       spa_deactivate(spa);
+       spa_activate(spa, orig_mode);
 
-               return (spa_load(spa, state, SPA_IMPORT_EXISTING, B_TRUE));
+       return (0);
+}
+
+static int
+spa_ld_get_props(spa_t *spa)
+{
+       int error = 0;
+       uint64_t obj;
+       vdev_t *rvd = spa->spa_root_vdev;
+
+       /* Grab the checksum salt from the MOS. */
+       error = zap_lookup(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
+           DMU_POOL_CHECKSUM_SALT, 1,
+           sizeof (spa->spa_cksum_salt.zcs_bytes),
+           spa->spa_cksum_salt.zcs_bytes);
+       if (error == ENOENT) {
+               /* Generate a new salt for subsequent use */
+               (void) random_get_pseudo_bytes(spa->spa_cksum_salt.zcs_bytes,
+                   sizeof (spa->spa_cksum_salt.zcs_bytes));
+       } else if (error != 0) {
+               spa_load_failed(spa, "unable to retrieve checksum salt from "
+                   "MOS [error=%d]", error);
+               return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
        }
 
-       if (spa_dir_prop(spa, DMU_POOL_SYNC_BPOBJ, &obj) != 0)
+       if (spa_dir_prop(spa, DMU_POOL_SYNC_BPOBJ, &obj, B_TRUE) != 0)
                return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
        error = bpobj_open(&spa->spa_deferred_bpobj, spa->spa_meta_objset, obj);
-       if (error != 0)
+       if (error != 0) {
+               spa_load_failed(spa, "error opening deferred-frees bpobj "
+                   "[error=%d]", error);
                return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+       }
 
        /*
         * 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 = spa_dir_prop(spa, DMU_POOL_DEFLATE, &spa->spa_deflate);
+       error = spa_dir_prop(spa, DMU_POOL_DEFLATE, &spa->spa_deflate, B_FALSE);
        if (error != 0 && error != ENOENT)
                return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
 
        error = spa_dir_prop(spa, DMU_POOL_CREATION_VERSION,
-           &spa->spa_creation_version);
+           &spa->spa_creation_version, B_FALSE);
        if (error != 0 && error != ENOENT)
                return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
 
@@ -2584,12 +3207,13 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
         * Load the persistent error log.  If we have an older pool, this will
         * not be present.
         */
-       error = spa_dir_prop(spa, DMU_POOL_ERRLOG_LAST, &spa->spa_errlog_last);
+       error = spa_dir_prop(spa, DMU_POOL_ERRLOG_LAST, &spa->spa_errlog_last,
+           B_FALSE);
        if (error != 0 && error != ENOENT)
                return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
 
        error = spa_dir_prop(spa, DMU_POOL_ERRLOG_SCRUB,
-           &spa->spa_errlog_scrub);
+           &spa->spa_errlog_scrub, B_FALSE);
        if (error != 0 && error != ENOENT)
                return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
 
@@ -2597,10 +3221,80 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
         * Load the history object.  If we have an older pool, this
         * will not be present.
         */
-       error = spa_dir_prop(spa, DMU_POOL_HISTORY, &spa->spa_history);
+       error = spa_dir_prop(spa, DMU_POOL_HISTORY, &spa->spa_history, B_FALSE);
        if (error != 0 && error != ENOENT)
                return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
 
+       /*
+        * Load the per-vdev ZAP map. If we have an older pool, this will not
+        * be present; in this case, defer its creation to a later time to
+        * avoid dirtying the MOS this early / out of sync context. See
+        * spa_sync_config_object.
+        */
+
+       /* The sentinel is only available in the MOS config. */
+       nvlist_t *mos_config;
+       if (load_nvlist(spa, spa->spa_config_object, &mos_config) != 0) {
+               spa_load_failed(spa, "unable to retrieve MOS config");
+               return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+       }
+
+       error = spa_dir_prop(spa, DMU_POOL_VDEV_ZAP_MAP,
+           &spa->spa_all_vdev_zaps, B_FALSE);
+
+       if (error == ENOENT) {
+               VERIFY(!nvlist_exists(mos_config,
+                   ZPOOL_CONFIG_HAS_PER_VDEV_ZAPS));
+               spa->spa_avz_action = AVZ_ACTION_INITIALIZE;
+               ASSERT0(vdev_count_verify_zaps(spa->spa_root_vdev));
+       } else if (error != 0) {
+               return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+       } else if (!nvlist_exists(mos_config, ZPOOL_CONFIG_HAS_PER_VDEV_ZAPS)) {
+               /*
+                * An older version of ZFS overwrote the sentinel value, so
+                * we have orphaned per-vdev ZAPs in the MOS. Defer their
+                * destruction to later; see spa_sync_config_object.
+                */
+               spa->spa_avz_action = AVZ_ACTION_DESTROY;
+               /*
+                * We're assuming that no vdevs have had their ZAPs created
+                * before this. Better be sure of it.
+                */
+               ASSERT0(vdev_count_verify_zaps(spa->spa_root_vdev));
+       }
+       nvlist_free(mos_config);
+
+       spa->spa_delegation = zpool_prop_default_numeric(ZPOOL_PROP_DELEGATION);
+
+       error = spa_dir_prop(spa, DMU_POOL_PROPS, &spa->spa_pool_props_object,
+           B_FALSE);
+       if (error && error != ENOENT)
+               return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+
+       if (error == 0) {
+               uint64_t autoreplace;
+
+               spa_prop_find(spa, ZPOOL_PROP_BOOTFS, &spa->spa_bootfs);
+               spa_prop_find(spa, ZPOOL_PROP_AUTOREPLACE, &autoreplace);
+               spa_prop_find(spa, ZPOOL_PROP_DELEGATION, &spa->spa_delegation);
+               spa_prop_find(spa, ZPOOL_PROP_FAILUREMODE, &spa->spa_failmode);
+               spa_prop_find(spa, ZPOOL_PROP_AUTOEXPAND, &spa->spa_autoexpand);
+               spa_prop_find(spa, ZPOOL_PROP_MULTIHOST, &spa->spa_multihost);
+               spa_prop_find(spa, ZPOOL_PROP_DEDUPDITTO,
+                   &spa->spa_dedup_ditto);
+
+               spa->spa_autoreplace = (autoreplace != 0);
+       }
+
+       return (0);
+}
+
+static int
+spa_ld_open_aux_vdevs(spa_t *spa, spa_import_type_t type)
+{
+       int error = 0;
+       vdev_t *rvd = spa->spa_root_vdev;
+
        /*
         * If we're assembling the pool from the split-off vdevs of
         * an existing pool, we don't want to attach the spares & cache
@@ -2610,14 +3304,17 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
        /*
         * Load any hot spares for this pool.
         */
-       error = spa_dir_prop(spa, DMU_POOL_SPARES, &spa->spa_spares.sav_object);
+       error = spa_dir_prop(spa, DMU_POOL_SPARES, &spa->spa_spares.sav_object,
+           B_FALSE);
        if (error != 0 && error != ENOENT)
                return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
        if (error == 0 && type != SPA_IMPORT_ASSEMBLE) {
                ASSERT(spa_version(spa) >= SPA_VERSION_SPARES);
                if (load_nvlist(spa, spa->spa_spares.sav_object,
-                   &spa->spa_spares.sav_config) != 0)
+                   &spa->spa_spares.sav_config) != 0) {
+                       spa_load_failed(spa, "error loading spares nvlist");
                        return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+               }
 
                spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
                spa_load_spares(spa);
@@ -2630,14 +3327,16 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
         * Load any level 2 ARC devices for this pool.
         */
        error = spa_dir_prop(spa, DMU_POOL_L2CACHE,
-           &spa->spa_l2cache.sav_object);
+           &spa->spa_l2cache.sav_object, B_FALSE);
        if (error != 0 && error != ENOENT)
                return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
        if (error == 0 && type != SPA_IMPORT_ASSEMBLE) {
                ASSERT(spa_version(spa) >= SPA_VERSION_L2CACHE);
                if (load_nvlist(spa, spa->spa_l2cache.sav_object,
-                   &spa->spa_l2cache.sav_config) != 0)
+                   &spa->spa_l2cache.sav_config) != 0) {
+                       spa_load_failed(spa, "error loading l2cache nvlist");
                        return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+               }
 
                spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
                spa_load_l2cache(spa);
@@ -2646,100 +3345,336 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
                spa->spa_l2cache.sav_sync = B_TRUE;
        }
 
-       spa->spa_delegation = zpool_prop_default_numeric(ZPOOL_PROP_DELEGATION);
+       return (0);
+}
 
-       error = spa_dir_prop(spa, DMU_POOL_PROPS, &spa->spa_pool_props_object);
-       if (error && error != ENOENT)
+static int
+spa_ld_load_vdev_metadata(spa_t *spa)
+{
+       int error = 0;
+       vdev_t *rvd = spa->spa_root_vdev;
+
+       /*
+        * If the 'multihost' property is set, then never allow a pool to
+        * be imported when the system hostid is zero.  The exception to
+        * this rule is zdb which is always allowed to access pools.
+        */
+       if (spa_multihost(spa) && spa_get_hostid() == 0 &&
+           (spa->spa_import_flags & ZFS_IMPORT_SKIP_MMP) == 0) {
+               fnvlist_add_uint64(spa->spa_load_info,
+                   ZPOOL_CONFIG_MMP_STATE, MMP_STATE_NO_HOSTID);
+               return (spa_vdev_err(rvd, VDEV_AUX_ACTIVE, EREMOTEIO));
+       }
+
+       /*
+        * 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 (spa->spa_autoreplace && spa->spa_load_state != SPA_LOAD_TRYIMPORT) {
+               spa_check_removed(spa->spa_root_vdev);
+               /*
+                * For the import case, this is done in spa_import(), because
+                * at this point we're using the spare definitions from
+                * the MOS config, not necessarily from the userland config.
+                */
+               if (spa->spa_load_state != SPA_LOAD_IMPORT) {
+                       spa_aux_check_removed(&spa->spa_spares);
+                       spa_aux_check_removed(&spa->spa_l2cache);
+               }
+       }
+
+       /*
+        * Load the vdev metadata such as metaslabs, DTLs, spacemap object, etc.
+        */
+       error = vdev_load(rvd);
+       if (error != 0) {
+               spa_load_failed(spa, "vdev_load failed [error=%d]", error);
+               return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, error));
+       }
+
+       /*
+        * Propagate the leaf DTLs we just loaded all the way up the vdev 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);
+
+       return (0);
+}
+
+static int
+spa_ld_load_dedup_tables(spa_t *spa)
+{
+       int error = 0;
+       vdev_t *rvd = spa->spa_root_vdev;
+
+       error = ddt_load(spa);
+       if (error != 0) {
+               spa_load_failed(spa, "ddt_load failed [error=%d]", error);
                return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+       }
 
-       if (error == 0) {
-               uint64_t autoreplace = 0;
+       return (0);
+}
 
-               spa_prop_find(spa, ZPOOL_PROP_BOOTFS, &spa->spa_bootfs);
-               spa_prop_find(spa, ZPOOL_PROP_AUTOREPLACE, &autoreplace);
-               spa_prop_find(spa, ZPOOL_PROP_DELEGATION, &spa->spa_delegation);
-               spa_prop_find(spa, ZPOOL_PROP_FAILUREMODE, &spa->spa_failmode);
-               spa_prop_find(spa, ZPOOL_PROP_AUTOEXPAND, &spa->spa_autoexpand);
-               spa_prop_find(spa, ZPOOL_PROP_DEDUPDITTO,
-                   &spa->spa_dedup_ditto);
+static int
+spa_ld_verify_logs(spa_t *spa, spa_import_type_t type, char **ereport)
+{
+       vdev_t *rvd = spa->spa_root_vdev;
 
-               spa->spa_autoreplace = (autoreplace != 0);
+       if (type != SPA_IMPORT_ASSEMBLE && spa_writeable(spa)) {
+               boolean_t missing = spa_check_logs(spa);
+               if (missing) {
+                       *ereport = FM_EREPORT_ZFS_LOG_REPLAY;
+                       spa_load_failed(spa, "spa_check_logs failed");
+                       return (spa_vdev_err(rvd, VDEV_AUX_BAD_LOG, ENXIO));
+               }
        }
 
+       return (0);
+}
+
+static int
+spa_ld_verify_pool_data(spa_t *spa)
+{
+       int error = 0;
+       vdev_t *rvd = spa->spa_root_vdev;
+
+       /*
+        * We've successfully opened the pool, verify that we're ready
+        * to start pushing transactions.
+        */
+       if (spa->spa_load_state != SPA_LOAD_TRYIMPORT) {
+               error = spa_load_verify(spa);
+               if (error != 0) {
+                       spa_load_failed(spa, "spa_load_verify failed "
+                           "[error=%d]", error);
+                       return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA,
+                           error));
+               }
+       }
+
+       return (0);
+}
+
+static void
+spa_ld_claim_log_blocks(spa_t *spa)
+{
+       dmu_tx_t *tx;
+       dsl_pool_t *dp = spa_get_dsl(spa);
+
+       /*
+        * Claim log blocks that haven't been committed yet.
+        * This must all happen in a single txg.
+        * Note: spa_claim_max_txg is updated by spa_claim_notify(),
+        * invoked from zil_claim_log_block()'s i/o done callback.
+        * Price of rollback is that we abandon the log.
+        */
+       spa->spa_claiming = B_TRUE;
+
+       tx = dmu_tx_create_assigned(dp, spa_first_txg(spa));
+       (void) dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
+           zil_claim, tx, DS_FIND_CHILDREN);
+       dmu_tx_commit(tx);
+
+       spa->spa_claiming = B_FALSE;
+
+       spa_set_log_state(spa, SPA_LOG_GOOD);
+}
+
+static void
+spa_ld_check_for_config_update(spa_t *spa, uint64_t config_cache_txg)
+{
+       vdev_t *rvd = spa->spa_root_vdev;
+       int need_update = B_FALSE;
+
+       /*
+        * If the config cache is stale, or we have uninitialized
+        * metaslabs (see spa_vdev_add()), then update the config.
+        *
+        * If this is a verbatim import, trust the current
+        * in-core spa_config and update the disk labels.
+        */
+       if (config_cache_txg != spa->spa_config_txg ||
+           spa->spa_load_state == SPA_LOAD_IMPORT ||
+           spa->spa_load_state == SPA_LOAD_RECOVER ||
+           (spa->spa_import_flags & ZFS_IMPORT_VERBATIM))
+               need_update = B_TRUE;
+
+       for (int 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);
+}
+
+/*
+ * Load an existing storage pool, using the config provided. This config
+ * describes which vdevs are part of the pool and is later validated against
+ * partial configs present in each vdev's label and an entire copy of the
+ * config stored in the MOS.
+ */
+static int
+spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
+    spa_load_state_t state, spa_import_type_t type, boolean_t trust_config,
+    char **ereport)
+{
+       int error = 0;
+       uint64_t config_cache_txg = spa->spa_config_txg;
+       int orig_mode = spa->spa_mode;
+       boolean_t missing_feat_write = B_FALSE;
+
+       ASSERT(MUTEX_HELD(&spa_namespace_lock));
+
+       spa->spa_load_state = state;
+       spa_load_note(spa, "LOADING");
+
+       /*
+        * If this is an untrusted config, first access the pool in read-only
+        * mode. We will then retrieve a trusted copy of the config from the MOS
+        * and use it to reopen the pool in read-write mode.
+        */
+       if (!trust_config)
+               spa->spa_mode = FREAD;
+
+       /*
+        * Parse the config provided to create a vdev tree.
+        */
+       error = spa_ld_parse_config(spa, pool_guid, config, type);
+       if (error != 0)
+               return (error);
+
+       /*
+        * Now that we have the vdev tree, try to open each vdev. This involves
+        * opening the underlying physical device, retrieving its geometry and
+        * probing the vdev with a dummy I/O. The state of each vdev will be set
+        * based on the success of those operations. After this we'll be ready
+        * to read from the vdevs.
+        */
+       error = spa_ld_open_vdevs(spa);
+       if (error != 0)
+               return (error);
+
+       /*
+        * Read the label of each vdev and make sure that the GUIDs stored
+        * there match the GUIDs in the config provided.
+        */
+       error = spa_ld_validate_vdevs(spa, type, trust_config);
+       if (error != 0)
+               return (error);
+
+       /*
+        * Read vdev labels to find the best uberblock (i.e. latest, unless
+        * spa_load_max_txg is set) and store it in spa_uberblock. We get the
+        * list of features required to read blkptrs in the MOS from the vdev
+        * label with the best uberblock and verify that our version of zfs
+        * supports them all.
+        */
+       error = spa_ld_select_uberblock(spa, config, type, trust_config);
+       if (error != 0)
+               return (error);
+
+       /*
+        * Pass that uberblock to the dsl_pool layer which will open the root
+        * blkptr. This blkptr points to the latest version of the MOS and will
+        * allow us to read its contents.
+        */
+       error = spa_ld_open_rootbp(spa);
+       if (error != 0)
+               return (error);
+
+       /*
+        * Retrieve the config stored in the MOS and use it to validate the
+        * config provided. Also extract some information from the MOS config
+        * to update our vdev tree.
+        */
+       error = spa_ld_validate_config(spa, type);
+       if (error != 0)
+               return (error);
+
+       /*
+        * Retrieve the mapping of indirect vdevs. Those vdevs were removed
+        * from the pool and their contents were re-mapped to other vdevs. Note
+        * that everything that we read before this step must have been
+        * rewritten on concrete vdevs after the last device removal was
+        * initiated. Otherwise we could be reading from indirect vdevs before
+        * we have loaded their mappings.
+        */
+       error = spa_ld_open_indirect_vdev_metadata(spa);
+       if (error != 0)
+               return (error);
+
        /*
-        * 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.
+        * Retrieve the full list of active features from the MOS and check if
+        * they are all supported.
         */
-       if (spa->spa_autoreplace && state != SPA_LOAD_TRYIMPORT) {
-               spa_check_removed(spa->spa_root_vdev);
-               /*
-                * For the import case, this is done in spa_import(), because
-                * at this point we're using the spare definitions from
-                * the MOS config, not necessarily from the userland config.
-                */
-               if (state != SPA_LOAD_IMPORT) {
-                       spa_aux_check_removed(&spa->spa_spares);
-                       spa_aux_check_removed(&spa->spa_l2cache);
-               }
-       }
+       error = spa_ld_check_features(spa, &missing_feat_write);
+       if (error != 0)
+               return (error);
 
        /*
-        * Load the vdev state for all toplevel vdevs.
+        * Load several special directories from the MOS needed by the dsl_pool
+        * layer.
         */
-       vdev_load(rvd);
+       error = spa_ld_load_special_directories(spa);
+       if (error != 0)
+               return (error);
 
        /*
-        * Propagate the leaf DTLs we just loaded all the way up the tree.
+        * If the config provided is not trusted, discard it and use the config
+        * from the MOS to reload the pool.
         */
-       spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
-       vdev_dtl_reassess(rvd, 0, 0, B_FALSE);
-       spa_config_exit(spa, SCL_ALL, FTAG);
+       if (!trust_config) {
+               error = spa_ld_prepare_for_reload(spa, orig_mode);
+               if (error != 0)
+                       return (error);
+
+               spa_load_note(spa, "RELOADING");
+               return (spa_load(spa, state, SPA_IMPORT_EXISTING, B_TRUE));
+       }
 
        /*
-        * Load the DDTs (dedup tables).
+        * Retrieve pool properties from the MOS.
         */
-       error = ddt_load(spa);
+       error = spa_ld_get_props(spa);
        if (error != 0)
-               return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
-
-       spa_update_dspace(spa);
+               return (error);
 
        /*
-        * Validate the config, using the MOS config to fill in any
-        * information which might be missing.  If we fail to validate
-        * the config then declare the pool unfit for use. If we're
-        * assembling a pool from a split, the log is not transferred
-        * over.
+        * Retrieve the list of auxiliary devices - cache devices and spares -
+        * and open them.
         */
-       if (type != SPA_IMPORT_ASSEMBLE) {
-               nvlist_t *nvconfig;
-
-               if (load_nvlist(spa, spa->spa_config_object, &nvconfig) != 0)
-                       return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA, EIO));
+       error = spa_ld_open_aux_vdevs(spa, type);
+       if (error != 0)
+               return (error);
 
-               if (!spa_config_valid(spa, nvconfig)) {
-                       nvlist_free(nvconfig);
-                       return (spa_vdev_err(rvd, VDEV_AUX_BAD_GUID_SUM,
-                           ENXIO));
-               }
-               nvlist_free(nvconfig);
+       /*
+        * Load the metadata for all vdevs. Also check if unopenable devices
+        * should be autoreplaced.
+        */
+       error = spa_ld_load_vdev_metadata(spa);
+       if (error != 0)
+               return (error);
 
-               /*
-                * Now that we've validated the config, 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)
-                       return (SET_ERROR(ENXIO));
+       error = spa_ld_load_dedup_tables(spa);
+       if (error != 0)
+               return (error);
 
-               if (spa_writeable(spa) && spa_check_logs(spa)) {
-                       *ereport = FM_EREPORT_ZFS_LOG_REPLAY;
-                       return (spa_vdev_err(rvd, VDEV_AUX_BAD_LOG, ENXIO));
-               }
-       }
+       /*
+        * Verify the logs now to make sure we don't have any unexpected errors
+        * when we claim log blocks later.
+        */
+       error = spa_ld_verify_logs(spa, type, ereport);
+       if (error != 0)
+               return (error);
 
        if (missing_feat_write) {
                ASSERT(state == SPA_LOAD_TRYIMPORT);
@@ -2749,93 +3684,75 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
                 * read-only mode but not read-write mode. We now have enough
                 * information and can return to userland.
                 */
-               return (spa_vdev_err(rvd, VDEV_AUX_UNSUP_FEAT, ENOTSUP));
+               return (spa_vdev_err(spa->spa_root_vdev, VDEV_AUX_UNSUP_FEAT,
+                   ENOTSUP));
        }
 
        /*
-        * We've successfully opened the pool, verify that we're ready
-        * to start pushing transactions.
+        * Traverse the last txgs to make sure the pool was left off in a safe
+        * state. When performing an extreme rewind, we verify the whole pool,
+        * which can take a very long time.
         */
-       if (state != SPA_LOAD_TRYIMPORT) {
-               if ((error = spa_load_verify(spa)))
-                       return (spa_vdev_err(rvd, VDEV_AUX_CORRUPT_DATA,
-                           error));
-       }
+       error = spa_ld_verify_pool_data(spa);
+       if (error != 0)
+               return (error);
 
+       /*
+        * Calculate the deflated space for the pool. This must be done before
+        * we write anything to the pool because we'd need to update the space
+        * accounting using the deflated sizes.
+        */
+       spa_update_dspace(spa);
+
+       /*
+        * We have now retrieved all the information we needed to open the
+        * pool. If we are importing the pool in read-write mode, a few
+        * additional steps must be performed to finish the import.
+        */
        if (spa_writeable(spa) && (state == SPA_LOAD_RECOVER ||
            spa->spa_load_max_txg == UINT64_MAX)) {
-               dmu_tx_t *tx;
-               int need_update = B_FALSE;
-               dsl_pool_t *dp = spa_get_dsl(spa);
-               int c;
-
                ASSERT(state != SPA_LOAD_TRYIMPORT);
 
                /*
-                * Claim log blocks that haven't been committed yet.
-                * This must all happen in a single txg.
-                * Note: spa_claim_max_txg is updated by spa_claim_notify(),
-                * invoked from zil_claim_log_block()'s i/o done callback.
-                * Price of rollback is that we abandon the log.
+                * Traverse the ZIL and claim all blocks.
                 */
-               spa->spa_claiming = B_TRUE;
-
-               tx = dmu_tx_create_assigned(dp, spa_first_txg(spa));
-               (void) dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
-                   zil_claim, tx, DS_FIND_CHILDREN);
-               dmu_tx_commit(tx);
-
-               spa->spa_claiming = B_FALSE;
+               spa_ld_claim_log_blocks(spa);
 
-               spa_set_log_state(spa, SPA_LOG_GOOD);
+               /*
+                * Kick-off the syncing thread.
+                */
                spa->spa_sync_on = B_TRUE;
                txg_sync_start(spa->spa_dsl_pool);
+               mmp_thread_start(spa);
 
                /*
                 * Wait for all claims to sync.  We sync up to the highest
                 * claimed log block birth time so that claimed log blocks
                 * don't appear to be from the future.  spa_claim_max_txg
-                * will have been set for us by either zil_check_log_chain()
-                * (invoked from spa_check_logs()) or zil_claim() above.
+                * will have been set for us by ZIL traversal operations
+                * performed above.
                 */
                txg_wait_synced(spa->spa_dsl_pool, spa->spa_claim_max_txg);
 
                /*
-                * If the config cache is stale, or we have uninitialized
-                * metaslabs (see spa_vdev_add()), then update the config.
-                *
-                * If this is a verbatim import, trust the current
-                * in-core spa_config and update the disk labels.
-                */
-               if (config_cache_txg != spa->spa_config_txg ||
-                   state == SPA_LOAD_IMPORT ||
-                   state == SPA_LOAD_RECOVER ||
-                   (spa->spa_import_flags & ZFS_IMPORT_VERBATIM))
-                       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.
+                * Check if we need to request an update of the config. On the
+                * next sync, we would update the config stored in vdev labels
+                * and the cachefile (by default /etc/zfs/zpool.cache).
                 */
-               if (need_update)
-                       spa_async_request(spa, SPA_ASYNC_CONFIG_UPDATE);
+               spa_ld_check_for_config_update(spa, config_cache_txg);
 
                /*
                 * Check all DTLs to see if anything needs resilvering.
                 */
                if (!dsl_scan_resilvering(spa->spa_dsl_pool) &&
-                   vdev_resilver_needed(rvd, NULL, NULL))
+                   vdev_resilver_needed(spa->spa_root_vdev, NULL, NULL))
                        spa_async_request(spa, SPA_ASYNC_RESILVER);
 
                /*
                 * Log the fact that we booted up (so that we can detect if
                 * we rebooted in the middle of an operation).
                 */
-               spa_history_log_version(spa, "open");
+               spa_history_log_version(spa, "open", NULL);
 
                /*
                 * Delete any inconsistent datasets.
@@ -2847,13 +3764,19 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
                 * Clean up any stale temporary dataset userrefs.
                 */
                dsl_pool_clean_tmp_userrefs(spa->spa_dsl_pool);
+
+               spa_restart_removal(spa);
+
+               spa_spawn_aux_threads(spa);
        }
 
+       spa_load_note(spa, "LOADED");
+
        return (0);
 }
 
 static int
-spa_load_retry(spa_t *spa, spa_load_state_t state, int mosconfig)
+spa_load_retry(spa_t *spa, spa_load_state_t state, int trust_config)
 {
        int mode = spa->spa_mode;
 
@@ -2865,7 +3788,10 @@ spa_load_retry(spa_t *spa, spa_load_state_t state, int mosconfig)
        spa_activate(spa, mode);
        spa_async_suspend(spa);
 
-       return (spa_load(spa, state, SPA_IMPORT_EXISTING, mosconfig));
+       spa_load_note(spa, "spa_load_retry: rewind, max txg: %llu",
+           (u_longlong_t)spa->spa_load_max_txg);
+
+       return (spa_load(spa, state, SPA_IMPORT_EXISTING, trust_config));
 }
 
 /*
@@ -2876,7 +3802,7 @@ spa_load_retry(spa_t *spa, spa_load_state_t state, int mosconfig)
  * spa_load().
  */
 static int
-spa_load_best(spa_t *spa, spa_load_state_t state, int mosconfig,
+spa_load_best(spa_t *spa, spa_load_state_t state, int trust_config,
     uint64_t max_request, int rewind_flags)
 {
        nvlist_t *loadinfo = NULL;
@@ -2895,7 +3821,7 @@ spa_load_best(spa_t *spa, spa_load_state_t state, int mosconfig,
        }
 
        load_error = rewind_error = spa_load(spa, state, SPA_IMPORT_EXISTING,
-           mosconfig);
+           trust_config);
        if (load_error == 0)
                return (0);
 
@@ -2936,7 +3862,7 @@ spa_load_best(spa_t *spa, spa_load_state_t state, int mosconfig,
            spa->spa_uberblock.ub_txg <= spa->spa_load_max_txg) {
                if (spa->spa_load_max_txg < safe_rewind_txg)
                        spa->spa_extreme_rewind = B_TRUE;
-               rewind_error = spa_load_retry(spa, state, mosconfig);
+               rewind_error = spa_load_retry(spa, state, trust_config);
        }
 
        spa->spa_extreme_rewind = B_FALSE;
@@ -2944,6 +3870,8 @@ spa_load_best(spa_t *spa, spa_load_state_t state, int mosconfig,
 
        if (config && (rewind_error || state != SPA_LOAD_RECOVER))
                spa_config_set(spa, config);
+       else
+               nvlist_free(config);
 
        if (state == SPA_LOAD_RECOVER) {
                ASSERT3P(loadinfo, ==, NULL);
@@ -2991,7 +3919,7 @@ spa_open_common(const char *pool, spa_t **spapp, void *tag, nvlist_t *nvpolicy,
         * 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) {
+       if (MUTEX_NOT_HELD(&spa_namespace_lock)) {
                mutex_enter(&spa_namespace_lock);
                locked = B_TRUE;
        }
@@ -3017,6 +3945,7 @@ spa_open_common(const char *pool, spa_t **spapp, void *tag, nvlist_t *nvpolicy,
                if (state != SPA_LOAD_RECOVER)
                        spa->spa_last_ubsync_txg = spa->spa_load_txg = 0;
 
+               zfs_dbgmsg("spa_open_common: opening %s", pool);
                error = spa_load_best(spa, state, B_FALSE, policy.zrp_txg,
                    policy.zrp_request);
 
@@ -3030,7 +3959,7 @@ spa_open_common(const char *pool, spa_t **spapp, void *tag, nvlist_t *nvpolicy,
                         */
                        spa_unload(spa);
                        spa_deactivate(spa);
-                       spa_config_sync(spa, B_TRUE, B_TRUE);
+                       spa_write_cachefile(spa, B_TRUE, B_TRUE);
                        spa_remove(spa);
                        if (locked)
                                mutex_exit(&spa_namespace_lock);
@@ -3081,10 +4010,8 @@ spa_open_common(const char *pool, spa_t **spapp, void *tag, nvlist_t *nvpolicy,
                mutex_exit(&spa_namespace_lock);
        }
 
-#ifdef _KERNEL
        if (firstopen)
-               zvol_create_minors(spa->spa_name);
-#endif
+               zvol_create_minors(spa, spa_name(spa), B_TRUE);
 
        *spapp = spa;
 
@@ -3232,6 +4159,8 @@ spa_add_l2cache(spa_t *spa, nvlist_t *config)
                            ZPOOL_CONFIG_VDEV_STATS, (uint64_t **)&vs, &vsc)
                            == 0);
                        vdev_get_stats(vd, vs);
+                       vdev_config_generate_stats(vd, l2cache[i]);
+
                }
        }
 }
@@ -3350,10 +4279,14 @@ spa_get_stats(const char *name, nvlist_t **config,
                            ZPOOL_CONFIG_ERRCOUNT,
                            spa_get_errlog_size(spa)) == 0);
 
-                       if (spa_suspended(spa))
+                       if (spa_suspended(spa)) {
                                VERIFY(nvlist_add_uint64(*config,
                                    ZPOOL_CONFIG_SUSPENDED,
                                    spa->spa_failmode) == 0);
+                               VERIFY(nvlist_add_uint64(*config,
+                                   ZPOOL_CONFIG_SUSPENDED_REASON,
+                                   spa->spa_suspended) == 0);
+                       }
 
                        spa_add_spares(spa, *config);
                        spa_add_l2cache(spa, *config);
@@ -3440,18 +4373,6 @@ spa_validate_aux_devs(spa_t *spa, nvlist_t *nvroot, uint64_t crtxg, int mode,
                        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 = SET_ERROR(ENOTBLK);
-                       vdev_free(vd);
-                       goto out;
-               }
-#endif
                vd->vdev_top = vd;
 
                if ((error = vdev_open(vd)) == 0 &&
@@ -3505,7 +4426,7 @@ spa_set_aux_vdevs(spa_aux_vdev_t *sav, nvlist_t **devs, int ndevs,
                nvlist_t **newdevs;
 
                /*
-                * Generate new dev list by concatentating with the
+                * Generate new dev list by concatenating with the
                 * current dev list.
                 */
                VERIFY(nvlist_lookup_nvlist_array(sav->sav_config, config,
@@ -3561,12 +4482,28 @@ spa_l2cache_drop(spa_t *spa)
        }
 }
 
+/*
+ * Verify encryption parameters for spa creation. If we are encrypting, we must
+ * have the encryption feature flag enabled.
+ */
+static int
+spa_create_check_encryption_params(dsl_crypto_params_t *dcp,
+    boolean_t has_encryption)
+{
+       if (dcp->cp_crypt != ZIO_CRYPT_OFF &&
+           dcp->cp_crypt != ZIO_CRYPT_INHERIT &&
+           !has_encryption)
+               return (SET_ERROR(ENOTSUP));
+
+       return (dmu_objset_create_crypt_check(NULL, dcp));
+}
+
 /*
  * Pool Creation
  */
 int
 spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
-    nvlist_t *zplprops)
+    nvlist_t *zplprops, dsl_crypto_params_t *dcp)
 {
        spa_t *spa;
        char *altroot = NULL;
@@ -3577,10 +4514,11 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
        uint64_t txg = TXG_INITIAL;
        nvlist_t **spares, **l2cache;
        uint_t nspares, nl2cache;
-       uint64_t version, obj;
+       uint64_t version, obj, root_dsobj = 0;
        boolean_t has_features;
-       nvpair_t *elem;
-       int c, i;
+       boolean_t has_encryption;
+       spa_feature_t feat;
+       char *feat_name;
        char *poolname;
        nvlist_t *nvl;
 
@@ -3621,10 +4559,28 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
                spa->spa_import_flags |= ZFS_IMPORT_TEMP_NAME;
 
        has_features = B_FALSE;
-       for (elem = nvlist_next_nvpair(props, NULL);
+       has_encryption = B_FALSE;
+       for (nvpair_t *elem = nvlist_next_nvpair(props, NULL);
            elem != NULL; elem = nvlist_next_nvpair(props, elem)) {
-               if (zpool_prop_feature(nvpair_name(elem)))
+               if (zpool_prop_feature(nvpair_name(elem))) {
                        has_features = B_TRUE;
+
+                       feat_name = strchr(nvpair_name(elem), '@') + 1;
+                       VERIFY0(zfeature_lookup_name(feat_name, &feat));
+                       if (feat == SPA_FEATURE_ENCRYPTION)
+                               has_encryption = B_TRUE;
+               }
+       }
+
+       /* verify encryption params, if they were provided */
+       if (dcp != NULL) {
+               error = spa_create_check_encryption_params(dcp, has_encryption);
+               if (error != 0) {
+                       spa_deactivate(spa);
+                       spa_remove(spa);
+                       mutex_exit(&spa_namespace_lock);
+                       return (error);
+               }
        }
 
        if (has_features || nvlist_lookup_uint64(props,
@@ -3637,13 +4593,17 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
        spa->spa_uberblock.ub_txg = txg - 1;
        spa->spa_uberblock.ub_version = version;
        spa->spa_ubsync = spa->spa_uberblock;
+       spa->spa_load_state = SPA_LOAD_CREATE;
+       spa->spa_removing_phys.sr_state = DSS_NONE;
+       spa->spa_removing_phys.sr_removing_vdev = -1;
+       spa->spa_removing_phys.sr_prev_indirect_vdev = -1;
 
        /*
         * Create "The Godfather" zio to hold all async IOs
         */
        spa->spa_async_zio_root = kmem_alloc(max_ncpus * sizeof (void *),
            KM_SLEEP);
-       for (i = 0; i < max_ncpus; i++) {
+       for (int i = 0; i < max_ncpus; i++) {
                spa->spa_async_zio_root[i] = zio_root(spa, NULL, NULL,
                    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE |
                    ZIO_FLAG_GODFATHER);
@@ -3666,7 +4626,7 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
            (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++) {
+               for (int c = 0; c < rvd->vdev_children; c++) {
                        vdev_metaslab_set_size(rvd->vdev_child[c]);
                        vdev_expand(rvd->vdev_child[c], txg);
                }
@@ -3713,8 +4673,7 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
        }
 
        spa->spa_is_initializing = B_TRUE;
-       spa->spa_dsl_pool = dp = dsl_pool_create(spa, zplprops, txg);
-       spa->spa_meta_objset = dp->dp_meta_objset;
+       spa->spa_dsl_pool = dp = dsl_pool_create(spa, zplprops, dcp, txg);
        spa->spa_is_initializing = B_FALSE;
 
        /*
@@ -3726,6 +4685,15 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
 
        tx = dmu_tx_create_assigned(dp, txg);
 
+       /*
+        * Create the pool's history object.
+        */
+       if (version >= SPA_VERSION_ZPOOL_HISTORY && !spa->spa_history)
+               spa_history_create_obj(spa, tx);
+
+       spa_event_notify(spa, NULL, NULL, ESC_ZFS_POOL_CREATE);
+       spa_history_log_version(spa, "create", tx);
+
        /*
         * Create the pool config object.
         */
@@ -3739,9 +4707,6 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
                cmn_err(CE_PANIC, "failed to add pool config");
        }
 
-       if (spa_version(spa) >= SPA_VERSION_FEATURES)
-               spa_feature_create_zap_objects(spa, tx);
-
        if (zap_add(spa->spa_meta_objset,
            DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_CREATION_VERSION,
            sizeof (uint64_t), 1, &version, tx) != 0) {
@@ -3752,279 +4717,88 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
        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 bpobj.  Turn off compression
-        * because sync-to-convergence takes longer if the blocksize
-        * keeps changing.
-        */
-       obj = bpobj_alloc(spa->spa_meta_objset, 1 << 14, tx);
-       dmu_object_set_compress(spa->spa_meta_objset, obj,
-           ZIO_COMPRESS_OFF, tx);
-       if (zap_add(spa->spa_meta_objset,
-           DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_SYNC_BPOBJ,
-           sizeof (uint64_t), 1, &obj, tx) != 0) {
-               cmn_err(CE_PANIC, "failed to add bpobj");
-       }
-       VERIFY3U(0, ==, bpobj_open(&spa->spa_deferred_bpobj,
-           spa->spa_meta_objset, obj));
-
-       /*
-        * 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);
-       spa->spa_autoexpand = zpool_prop_default_numeric(ZPOOL_PROP_AUTOEXPAND);
-
-       if (props != NULL) {
-               spa_configfile_set(spa, props, B_FALSE);
-               spa_sync_props(props, 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);
-
-       spa_history_log_version(spa, "create");
-
-       /*
-        * Don't count references from objsets that are already closed
-        * and are making their way through the eviction process.
-        */
-       spa_evicting_os_wait(spa);
-       spa->spa_minref = refcount_count(&spa->spa_refcount);
-
-       mutex_exit(&spa_namespace_lock);
-
-       return (0);
-}
-
-#ifdef _KERNEL
-/*
- * 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 **);
-
-static nvlist_t *
-spa_generate_rootconf(char *devpath, char *devid, uint64_t *guid)
-{
-       nvlist_t *config;
-       nvlist_t *nvtop, *nvroot;
-       uint64_t pgid;
-
-       if (vdev_disk_read_rootlabel(devpath, devid, &config) != 0)
-               return (NULL);
-
-       /*
-        * 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);
-       VERIFY(nvlist_lookup_uint64(config, ZPOOL_CONFIG_GUID, guid) == 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);
-       return (config);
-}
-
-/*
- * Walk the vdev tree and see if we can find a device with "better"
- * configuration. A configuration is "better" if the label on that
- * device has a more recent txg.
- */
-static void
-spa_alt_rootvdev(vdev_t *vd, vdev_t **avd, uint64_t *txg)
-{
-       int c;
-
-       for (c = 0; c < vd->vdev_children; c++)
-               spa_alt_rootvdev(vd->vdev_child[c], avd, txg);
-
-       if (vd->vdev_ops->vdev_op_leaf) {
-               nvlist_t *label;
-               uint64_t label_txg;
-
-               if (vdev_disk_read_rootlabel(vd->vdev_physpath, vd->vdev_devid,
-                   &label) != 0)
-                       return;
-
-               VERIFY(nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_TXG,
-                   &label_txg) == 0);
-
-               /*
-                * Do we have a better boot device?
-                */
-               if (label_txg > *txg) {
-                       *txg = label_txg;
-                       *avd = vd;
-               }
-               nvlist_free(label);
-       }
-}
-
-/*
- * 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)
-{
-       spa_t *spa;
-       vdev_t *rvd, *bvd, *avd = NULL;
-       nvlist_t *config, *nvtop;
-       uint64_t guid, txg;
-       char *pname;
-       int error;
-
-       /*
-        * Read the label from the boot device and generate a configuration.
-        */
-       config = spa_generate_rootconf(devpath, devid, &guid);
-#if defined(_OBP) && defined(_KERNEL)
-       if (config == NULL) {
-               if (strstr(devpath, "/iscsi/ssd") != NULL) {
-                       /* iscsi boot */
-                       get_iscsi_bootpath_phy(devpath);
-                       config = spa_generate_rootconf(devpath, devid, &guid);
-               }
-       }
-#endif
-       if (config == NULL) {
-               cmn_err(CE_NOTE, "Cannot read the pool label from '%s'",
-                   devpath);
-               return (SET_ERROR(EIO));
-       }
-
-       VERIFY(nvlist_lookup_string(config, ZPOOL_CONFIG_POOL_NAME,
-           &pname) == 0);
-       VERIFY(nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_TXG, &txg) == 0);
-
-       mutex_enter(&spa_namespace_lock);
-       if ((spa = spa_lookup(pname)) != NULL) {
-               /*
-                * Remove the existing root pool from the namespace so that we
-                * can replace it with the correct config we just read in.
-                */
-               spa_remove(spa);
+                   DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_DEFLATE,
+                   sizeof (uint64_t), 1, &spa->spa_deflate, tx) != 0) {
+                       cmn_err(CE_PANIC, "failed to add deflate");
+               }
        }
 
-       spa = spa_add(pname, config, NULL);
-       spa->spa_is_root = B_TRUE;
-       spa->spa_import_flags = ZFS_IMPORT_VERBATIM;
-
        /*
-        * Build up a vdev tree based on the boot device's label config.
+        * Create the deferred-free bpobj.  Turn off compression
+        * because sync-to-convergence takes longer if the blocksize
+        * keeps changing.
         */
-       VERIFY(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE,
-           &nvtop) == 0);
-       spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
-       error = spa_config_parse(spa, &rvd, nvtop, NULL, 0,
-           VDEV_ALLOC_ROOTPOOL);
-       spa_config_exit(spa, SCL_ALL, FTAG);
-       if (error) {
-               mutex_exit(&spa_namespace_lock);
-               nvlist_free(config);
-               cmn_err(CE_NOTE, "Can not parse the config for pool '%s'",
-                   pname);
-               return (error);
+       obj = bpobj_alloc(spa->spa_meta_objset, 1 << 14, tx);
+       dmu_object_set_compress(spa->spa_meta_objset, obj,
+           ZIO_COMPRESS_OFF, tx);
+       if (zap_add(spa->spa_meta_objset,
+           DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_SYNC_BPOBJ,
+           sizeof (uint64_t), 1, &obj, tx) != 0) {
+               cmn_err(CE_PANIC, "failed to add bpobj");
        }
+       VERIFY3U(0, ==, bpobj_open(&spa->spa_deferred_bpobj,
+           spa->spa_meta_objset, obj));
 
        /*
-        * Get the boot vdev.
+        * Generate some random noise for salted checksums to operate on.
         */
-       if ((bvd = vdev_lookup_by_guid(rvd, guid)) == NULL) {
-               cmn_err(CE_NOTE, "Can not find the boot vdev for guid %llu",
-                   (u_longlong_t)guid);
-               error = SET_ERROR(ENOENT);
-               goto out;
-       }
+       (void) random_get_pseudo_bytes(spa->spa_cksum_salt.zcs_bytes,
+           sizeof (spa->spa_cksum_salt.zcs_bytes));
 
        /*
-        * Determine if there is a better boot device.
+        * Set pool properties.
         */
-       avd = bvd;
-       spa_alt_rootvdev(rvd, &avd, &txg);
-       if (avd != bvd) {
-               cmn_err(CE_NOTE, "The boot device is 'degraded'. Please "
-                   "try booting from '%s'", avd->vdev_path);
-               error = SET_ERROR(EINVAL);
-               goto out;
+       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);
+       spa->spa_autoexpand = zpool_prop_default_numeric(ZPOOL_PROP_AUTOEXPAND);
+       spa->spa_multihost = zpool_prop_default_numeric(ZPOOL_PROP_MULTIHOST);
+
+       if (props != NULL) {
+               spa_configfile_set(spa, props, B_FALSE);
+               spa_sync_props(props, tx);
        }
 
+       dmu_tx_commit(tx);
+
        /*
-        * If the boot device is part of a spare vdev then ensure that
-        * we're booting off the active spare.
+        * If the root dataset is encrypted we will need to create key mappings
+        * for the zio layer before we start to write any data to disk and hold
+        * them until after the first txg has been synced. Waiting for the first
+        * transaction to complete also ensures that our bean counters are
+        * appropriately updated.
         */
-       if (bvd->vdev_parent->vdev_ops == &vdev_spare_ops &&
-           !bvd->vdev_isspare) {
-               cmn_err(CE_NOTE, "The boot device is currently spared. Please "
-                   "try booting from '%s'",
-                   bvd->vdev_parent->
-                   vdev_child[bvd->vdev_parent->vdev_children - 1]->vdev_path);
-               error = SET_ERROR(EINVAL);
-               goto out;
+       if (dp->dp_root_dir->dd_crypto_obj != 0) {
+               root_dsobj = dsl_dir_phys(dp->dp_root_dir)->dd_head_dataset_obj;
+               VERIFY0(spa_keystore_create_mapping_impl(spa, root_dsobj,
+                   dp->dp_root_dir, FTAG));
        }
 
-       error = 0;
-out:
-       spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
-       vdev_free(rvd);
-       spa_config_exit(spa, SCL_ALL, FTAG);
+       spa->spa_sync_on = B_TRUE;
+       txg_sync_start(dp);
+       mmp_thread_start(spa);
+       txg_wait_synced(dp, txg);
+
+       if (dp->dp_root_dir->dd_crypto_obj != 0)
+               VERIFY0(spa_keystore_remove_mapping(spa, root_dsobj, FTAG));
+
+       spa_spawn_aux_threads(spa);
+
+       spa_write_cachefile(spa, B_FALSE, B_TRUE);
+
+       /*
+        * Don't count references from objsets that are already closed
+        * and are making their way through the eviction process.
+        */
+       spa_evicting_os_wait(spa);
+       spa->spa_minref = refcount_count(&spa->spa_refcount);
+       spa->spa_load_state = SPA_LOAD_NONE;
+
        mutex_exit(&spa_namespace_lock);
 
-       nvlist_free(config);
-       return (error);
+       return (0);
 }
 
-#endif
-
 /*
  * Import a non-root pool into the system.
  */
@@ -4071,8 +4845,9 @@ spa_import(char *pool, nvlist_t *config, nvlist_t *props, uint64_t flags)
                if (props != NULL)
                        spa_configfile_set(spa, props, B_FALSE);
 
-               spa_config_sync(spa, B_FALSE, B_TRUE);
-
+               spa_write_cachefile(spa, B_FALSE, B_TRUE);
+               spa_event_notify(spa, NULL, NULL, ESC_ZFS_POOL_IMPORT);
+               zfs_dbgmsg("spa_import: verbatim import of %s", pool);
                mutex_exit(&spa_namespace_lock);
                return (0);
        }
@@ -4089,13 +4864,15 @@ spa_import(char *pool, nvlist_t *config, nvlist_t *props, uint64_t flags)
                state = SPA_LOAD_RECOVER;
 
        /*
-        * Pass off the heavy lifting to spa_load().  Pass TRUE for mosconfig
+        * Pass off the heavy lifting to spa_load().  Pass TRUE for trust_config
         * because the user-supplied config is actually the one to trust when
         * doing an import.
         */
        if (state != SPA_LOAD_RECOVER)
                spa->spa_last_ubsync_txg = spa->spa_load_txg = 0;
 
+       zfs_dbgmsg("spa_import: importing %s%s", pool,
+           (state == SPA_LOAD_RECOVER) ? " (RECOVERY MODE)" : "");
        error = spa_load_best(spa, state, B_TRUE, policy.zrp_txg,
            policy.zrp_request);
 
@@ -4124,12 +4901,6 @@ spa_import(char *pool, nvlist_t *config, nvlist_t *props, uint64_t flags)
 
        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 (props != NULL)
@@ -4202,12 +4973,13 @@ spa_import(char *pool, nvlist_t *config, nvlist_t *props, uint64_t flags)
         */
        spa_async_request(spa, SPA_ASYNC_AUTOEXPAND);
 
-       mutex_exit(&spa_namespace_lock);
-       spa_history_log_version(spa, "import");
+       spa_history_log_version(spa, "import", NULL);
 
-#ifdef _KERNEL
-       zvol_create_minors(pool);
-#endif
+       spa_event_notify(spa, NULL, NULL, ESC_ZFS_POOL_IMPORT);
+
+       zvol_create_minors(spa, pool, B_TRUE);
+
+       mutex_exit(&spa_namespace_lock);
 
        return (0);
 }
@@ -4234,9 +5006,11 @@ spa_tryimport(nvlist_t *tryconfig)
        spa = spa_add(TRYIMPORT_NAME, tryconfig, NULL);
        spa_activate(spa, FREAD);
 
+       zfs_dbgmsg("spa_tryimport: importing %s", poolname);
+
        /*
         * Pass off the heavy lifting to spa_load().
-        * Pass TRUE for mosconfig because the user-supplied config
+        * Pass TRUE for trust_config because the user-supplied config
         * is actually the one to trust when doing an import.
         */
        error = spa_load(spa, SPA_LOAD_TRYIMPORT, SPA_IMPORT_EXISTING, B_TRUE);
@@ -4342,6 +5116,10 @@ spa_export_common(char *pool, int new_state, nvlist_t **oldconfig,
        spa_open_ref(spa, FTAG);
        mutex_exit(&spa_namespace_lock);
        spa_async_suspend(spa);
+       if (spa->spa_zvol_taskq) {
+               zvol_remove_minors(spa, spa_name(spa), B_TRUE);
+               taskq_wait(spa->spa_zvol_taskq);
+       }
        mutex_enter(&spa_namespace_lock);
        spa_close(spa, FTAG);
 
@@ -4400,7 +5178,10 @@ spa_export_common(char *pool, int new_state, nvlist_t **oldconfig,
        }
 
 export_spa:
-       spa_event_notify(spa, NULL, FM_EREPORT_ZFS_POOL_DESTROY);
+       if (new_state == POOL_STATE_DESTROYED)
+               spa_event_notify(spa, NULL, NULL, ESC_ZFS_POOL_DESTROY);
+       else if (new_state == POOL_STATE_EXPORTED)
+               spa_event_notify(spa, NULL, NULL, ESC_ZFS_POOL_EXPORT);
 
        if (spa->spa_state != POOL_STATE_UNINITIALIZED) {
                spa_unload(spa);
@@ -4412,7 +5193,7 @@ export_spa:
 
        if (new_state != POOL_STATE_UNINITIALIZED) {
                if (!hardforce)
-                       spa_config_sync(spa, B_TRUE, B_TRUE);
+                       spa_write_cachefile(spa, B_TRUE, B_TRUE);
                spa_remove(spa);
        }
        mutex_exit(&spa_namespace_lock);
@@ -4470,7 +5251,6 @@ spa_vdev_add(spa_t *spa, nvlist_t *nvroot)
        vdev_t *vd, *tvd;
        nvlist_t **spares, **l2cache;
        uint_t nspares, nl2cache;
-       int c;
 
        ASSERT(spa_writeable(spa));
 
@@ -4505,9 +5285,41 @@ spa_vdev_add(spa_t *spa, nvlist_t *nvroot)
                return (spa_vdev_exit(spa, vd, txg, error));
 
        /*
-        * Transfer each new top-level vdev from vd to rvd.
+        * If we are in the middle of a device removal, we can only add
+        * devices which match the existing devices in the pool.
+        * If we are in the middle of a removal, or have some indirect
+        * vdevs, we can not add raidz toplevels.
         */
-       for (c = 0; c < vd->vdev_children; c++) {
+       if (spa->spa_vdev_removal != NULL ||
+           spa->spa_removing_phys.sr_prev_indirect_vdev != -1) {
+               for (int c = 0; c < vd->vdev_children; c++) {
+                       tvd = vd->vdev_child[c];
+                       if (spa->spa_vdev_removal != NULL &&
+                           tvd->vdev_ashift != spa->spa_max_ashift) {
+                               return (spa_vdev_exit(spa, vd, txg, EINVAL));
+                       }
+                       /* Fail if top level vdev is raidz */
+                       if (tvd->vdev_ops == &vdev_raidz_ops) {
+                               return (spa_vdev_exit(spa, vd, txg, EINVAL));
+                       }
+                       /*
+                        * Need the top level mirror to be
+                        * a mirror of leaf vdevs only
+                        */
+                       if (tvd->vdev_ops == &vdev_mirror_ops) {
+                               for (uint64_t cid = 0;
+                                   cid < tvd->vdev_children; cid++) {
+                                       vdev_t *cvd = tvd->vdev_child[cid];
+                                       if (!cvd->vdev_ops->vdev_op_leaf) {
+                                               return (spa_vdev_exit(spa, vd,
+                                                   txg, EINVAL));
+                                       }
+                               }
+                       }
+               }
+       }
+
+       for (int c = 0; c < vd->vdev_children; c++) {
 
                /*
                 * Set the vdev id to the first hole, if one exists.
@@ -4556,6 +5368,7 @@ spa_vdev_add(spa_t *spa, nvlist_t *nvroot)
 
        mutex_enter(&spa_namespace_lock);
        spa_config_update(spa, SPA_CONFIG_UPDATE_POOL);
+       spa_event_notify(spa, NULL, NULL, ESC_ZFS_VDEV_ADD);
        mutex_exit(&spa_namespace_lock);
 
        return (0);
@@ -4578,12 +5391,12 @@ int
 spa_vdev_attach(spa_t *spa, uint64_t guid, nvlist_t *nvroot, int replacing)
 {
        uint64_t txg, dtl_max_txg;
+       ASSERTV(vdev_t *rvd = spa->spa_root_vdev);
        vdev_t *oldvd, *newvd, *newrootvd, *pvd, *tvd;
        vdev_ops_t *pvops;
        char *oldvdpath, *newvdpath;
        int newvd_isspare;
        int error;
-       ASSERTV(vdev_t *rvd = spa->spa_root_vdev);
 
        ASSERT(spa_writeable(spa));
 
@@ -4591,6 +5404,9 @@ spa_vdev_attach(spa_t *spa, uint64_t guid, nvlist_t *nvroot, int replacing)
 
        oldvd = spa_lookup_by_guid(spa, guid, B_FALSE);
 
+       if (spa->spa_vdev_removal != NULL)
+               return (spa_vdev_exit(spa, NULL, txg, EBUSY));
+
        if (oldvd == NULL)
                return (spa_vdev_exit(spa, NULL, txg, ENODEV));
 
@@ -4713,6 +5529,11 @@ spa_vdev_attach(spa_t *spa, uint64_t guid, nvlist_t *nvroot, int replacing)
        newvd->vdev_crtxg = oldvd->vdev_crtxg;
        vdev_add_child(pvd, newvd);
 
+       /*
+        * Reevaluate the parent vdev state.
+        */
+       vdev_propagate_state(pvd);
+
        tvd = newvd->vdev_top;
        ASSERT(pvd->vdev_top == tvd);
        ASSERT(tvd->vdev_parent == rvd);
@@ -4731,7 +5552,7 @@ spa_vdev_attach(spa_t *spa, uint64_t guid, nvlist_t *nvroot, int replacing)
 
        if (newvd->vdev_isspare) {
                spa_spare_activate(newvd);
-               spa_event_notify(spa, newvd, FM_EREPORT_ZFS_DEVICE_SPARE);
+               spa_event_notify(spa, newvd, NULL, ESC_ZFS_VDEV_SPARE);
        }
 
        oldvdpath = spa_strdup(oldvd->vdev_path);
@@ -4750,6 +5571,11 @@ spa_vdev_attach(spa_t *spa, uint64_t guid, nvlist_t *nvroot, int replacing)
         */
        dsl_resilver_restart(spa->spa_dsl_pool, dtl_max_txg);
 
+       if (spa->spa_bootfs)
+               spa_event_notify(spa, newvd, NULL, ESC_ZFS_BOOTFS_VDEV_ATTACH);
+
+       spa_event_notify(spa, newvd, NULL, ESC_ZFS_VDEV_ATTACH);
+
        /*
         * Commit the config
         */
@@ -4764,9 +5590,6 @@ spa_vdev_attach(spa_t *spa, uint64_t guid, nvlist_t *nvroot, int replacing)
        spa_strfree(oldvdpath);
        spa_strfree(newvdpath);
 
-       if (spa->spa_bootfs)
-               spa_event_notify(spa, newvd, FM_EREPORT_ZFS_BOOTFS_VDEV_ATTACH);
-
        return (0);
 }
 
@@ -4781,12 +5604,12 @@ spa_vdev_detach(spa_t *spa, uint64_t guid, uint64_t pguid, int replace_done)
 {
        uint64_t txg;
        int error;
+       ASSERTV(vdev_t *rvd = spa->spa_root_vdev);
        vdev_t *vd, *pvd, *cvd, *tvd;
        boolean_t unspare = B_FALSE;
        uint64_t unspare_guid = 0;
        char *vdpath;
-       int c, t;
-       ASSERTV(vdev_t *rvd = spa->spa_root_vdev);
+
        ASSERT(spa_writeable(spa));
 
        txg = spa_vdev_enter(spa);
@@ -4853,7 +5676,7 @@ spa_vdev_detach(spa_t *spa, uint64_t guid, uint64_t pguid, int replace_done)
            vd->vdev_path != NULL) {
                size_t len = strlen(vd->vdev_path);
 
-               for (c = 0; c < pvd->vdev_children; c++) {
+               for (int c = 0; c < pvd->vdev_children; c++) {
                        cvd = pvd->vdev_child[c];
 
                        if (cvd == vd || cvd->vdev_path == NULL)
@@ -4959,13 +5782,13 @@ spa_vdev_detach(spa_t *spa, uint64_t guid, uint64_t pguid, int replace_done)
         * But first make sure we're not on any *other* txg's DTL list, to
         * prevent vd from being accessed after it's freed.
         */
-       vdpath = spa_strdup(vd->vdev_path);
-       for (t = 0; t < TXG_SIZE; t++)
+       vdpath = spa_strdup(vd->vdev_path ? vd->vdev_path : "none");
+       for (int 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, FM_EREPORT_ZFS_DEVICE_REMOVE);
+       spa_event_notify(spa, vd, NULL, ESC_ZFS_VDEV_REMOVE);
 
        /* hang on to the spa before we release the lock */
        spa_open_ref(spa, FTAG);
@@ -5034,7 +5857,7 @@ spa_vdev_split_mirror(spa_t *spa, char *newname, nvlist_t *config,
        /* clear the log and flush everything up to now */
        activate_slog = spa_passivate_log(spa);
        (void) spa_vdev_config_exit(spa, NULL, txg, 0, FTAG);
-       error = spa_offline_log(spa);
+       error = spa_reset_logs(spa);
        txg = spa_vdev_config_enter(spa);
 
        if (activate_slog)
@@ -5062,7 +5885,7 @@ spa_vdev_split_mirror(spa_t *spa, char *newname, nvlist_t *config,
                vdev_t *vd = rvd->vdev_child[c];
 
                /* don't count the holes & logs as children */
-               if (vd->vdev_islog || vd->vdev_ishole) {
+               if (vd->vdev_islog || !vdev_is_concrete(vd)) {
                        if (lastlog == 0)
                                lastlog = c;
                        continue;
@@ -5115,7 +5938,7 @@ spa_vdev_split_mirror(spa_t *spa, char *newname, nvlist_t *config,
                /* make sure there's nothing stopping the split */
                if (vml[c]->vdev_parent->vdev_ops != &vdev_mirror_ops ||
                    vml[c]->vdev_islog ||
-                   vml[c]->vdev_ishole ||
+                   !vdev_is_concrete(vml[c]) ||
                    vml[c]->vdev_isspare ||
                    vml[c]->vdev_isl2cache ||
                    !vdev_writeable(vml[c]) ||
@@ -5140,6 +5963,16 @@ spa_vdev_split_mirror(spa_t *spa, char *newname, nvlist_t *config,
                    vml[c]->vdev_top->vdev_asize) == 0);
                VERIFY(nvlist_add_uint64(child[c], ZPOOL_CONFIG_ASHIFT,
                    vml[c]->vdev_top->vdev_ashift) == 0);
+
+               /* transfer per-vdev ZAPs */
+               ASSERT3U(vml[c]->vdev_leaf_zap, !=, 0);
+               VERIFY0(nvlist_add_uint64(child[c],
+                   ZPOOL_CONFIG_VDEV_LEAF_ZAP, vml[c]->vdev_leaf_zap));
+
+               ASSERT3U(vml[c]->vdev_top->vdev_top_zap, !=, 0);
+               VERIFY0(nvlist_add_uint64(child[c],
+                   ZPOOL_CONFIG_VDEV_TOP_ZAP,
+                   vml[c]->vdev_parent->vdev_top_zap));
        }
 
        if (error != 0) {
@@ -5181,11 +6014,13 @@ spa_vdev_split_mirror(spa_t *spa, char *newname, nvlist_t *config,
            spa->spa_config_txg) == 0);
        VERIFY(nvlist_add_uint64(config, ZPOOL_CONFIG_POOL_GUID,
            spa_generate_guid(NULL)) == 0);
+       VERIFY0(nvlist_add_boolean(config, ZPOOL_CONFIG_HAS_PER_VDEV_ZAPS));
        (void) nvlist_lookup_string(props,
            zpool_prop_to_name(ZPOOL_PROP_ALTROOT), &altroot);
 
        /* add the new pool to the namespace */
        newspa = spa_add(newname, config, altroot);
+       newspa->spa_avz_action = AVZ_ACTION_REBUILD;
        newspa->spa_config_txg = spa->spa_config_txg;
        spa_set_log_state(newspa, SPA_LOG_CLEAR);
 
@@ -5195,342 +6030,101 @@ spa_vdev_split_mirror(spa_t *spa, char *newname, nvlist_t *config,
        if (zio_injection_enabled)
                zio_handle_panic_injection(spa, FTAG, 1);
 
-       spa_activate(newspa, spa_mode_global);
-       spa_async_suspend(newspa);
-
-       /* create the new pool from the disks of the original pool */
-       error = spa_load(newspa, SPA_LOAD_IMPORT, SPA_IMPORT_ASSEMBLE, B_TRUE);
-       if (error)
-               goto out;
-
-       /* if that worked, generate a real config for the new pool */
-       if (newspa->spa_root_vdev != NULL) {
-               VERIFY(nvlist_alloc(&newspa->spa_config_splitting,
-                   NV_UNIQUE_NAME, KM_SLEEP) == 0);
-               VERIFY(nvlist_add_uint64(newspa->spa_config_splitting,
-                   ZPOOL_CONFIG_SPLIT_GUID, spa_guid(spa)) == 0);
-               spa_config_set(newspa, spa_config_generate(newspa, NULL, -1ULL,
-                   B_TRUE));
-       }
-
-       /* set the props */
-       if (props != NULL) {
-               spa_configfile_set(newspa, props, B_FALSE);
-               error = spa_prop_set(newspa, props);
-               if (error)
-                       goto out;
-       }
-
-       /* flush everything */
-       txg = spa_vdev_config_enter(newspa);
-       vdev_config_dirty(newspa->spa_root_vdev);
-       (void) spa_vdev_config_exit(newspa, NULL, txg, 0, FTAG);
-
-       if (zio_injection_enabled)
-               zio_handle_panic_injection(spa, FTAG, 2);
-
-       spa_async_resume(newspa);
-
-       /* finally, update the original pool's config */
-       txg = spa_vdev_config_enter(spa);
-       tx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir);
-       error = dmu_tx_assign(tx, TXG_WAIT);
-       if (error != 0)
-               dmu_tx_abort(tx);
-       for (c = 0; c < children; c++) {
-               if (vml[c] != NULL) {
-                       vdev_split(vml[c]);
-                       if (error == 0)
-                               spa_history_log_internal(spa, "detach", tx,
-                                   "vdev=%s", vml[c]->vdev_path);
-                       vdev_free(vml[c]);
-               }
-       }
-       vdev_config_dirty(spa->spa_root_vdev);
-       spa->spa_config_splitting = NULL;
-       nvlist_free(nvl);
-       if (error == 0)
-               dmu_tx_commit(tx);
-       (void) spa_vdev_exit(spa, NULL, txg, 0);
-
-       if (zio_injection_enabled)
-               zio_handle_panic_injection(spa, FTAG, 3);
-
-       /* split is complete; log a history record */
-       spa_history_log_internal(newspa, "split", NULL,
-           "from pool %s", spa_name(spa));
-
-       kmem_free(vml, children * sizeof (vdev_t *));
-
-       /* if we're not going to mount the filesystems in userland, export */
-       if (exp)
-               error = spa_export_common(newname, POOL_STATE_EXPORTED, NULL,
-                   B_FALSE, B_FALSE);
-
-       return (error);
-
-out:
-       spa_unload(newspa);
-       spa_deactivate(newspa);
-       spa_remove(newspa);
-
-       txg = spa_vdev_config_enter(spa);
-
-       /* re-online all offlined disks */
-       for (c = 0; c < children; c++) {
-               if (vml[c] != NULL)
-                       vml[c]->vdev_offline = B_FALSE;
-       }
-       vdev_reopen(spa->spa_root_vdev);
-
-       nvlist_free(spa->spa_config_splitting);
-       spa->spa_config_splitting = NULL;
-       (void) spa_vdev_exit(spa, NULL, txg, error);
-
-       kmem_free(vml, children * sizeof (vdev_t *));
-       return (error);
-}
-
-static nvlist_t *
-spa_nvlist_lookup_by_guid(nvlist_t **nvpp, int count, uint64_t target_guid)
-{
-       int i;
-
-       for (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;
-       int i, j;
-
-       if (count > 1)
-               newdev = kmem_alloc((count - 1) * sizeof (void *), KM_SLEEP);
-
-       for (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 (i = 0; i < count - 1; i++)
-               nvlist_free(newdev[i]);
-
-       if (count > 1)
-               kmem_free(newdev, (count - 1) * sizeof (void *));
-}
-
-/*
- * Evacuate the device.
- */
-static int
-spa_vdev_remove_evacuate(spa_t *spa, vdev_t *vd)
-{
-       uint64_t txg;
-       int error = 0;
-
-       ASSERT(MUTEX_HELD(&spa_namespace_lock));
-       ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == 0);
-       ASSERT(vd == vd->vdev_top);
-
-       /*
-        * Evacuate the device.  We don't hold the config lock as writer
-        * since we need to do I/O but we do keep the
-        * spa_namespace_lock held.  Once this completes the device
-        * should no longer have any blocks allocated on it.
-        */
-       if (vd->vdev_islog) {
-               if (vd->vdev_stat.vs_alloc != 0)
-                       error = spa_offline_log(spa);
-       } else {
-               error = SET_ERROR(ENOTSUP);
-       }
-
-       if (error)
-               return (error);
-
-       /*
-        * The evacuation succeeded.  Remove any remaining MOS metadata
-        * associated with this vdev, and wait for these changes to sync.
-        */
-       ASSERT0(vd->vdev_stat.vs_alloc);
-       txg = spa_vdev_config_enter(spa);
-       vd->vdev_removing = B_TRUE;
-       vdev_dirty_leaves(vd, VDD_DTL, txg);
-       vdev_config_dirty(vd);
-       spa_vdev_config_exit(spa, NULL, txg, 0, FTAG);
-
-       return (0);
-}
-
-/*
- * Complete the removal by cleaning up the namespace.
- */
-static void
-spa_vdev_remove_from_namespace(spa_t *spa, vdev_t *vd)
-{
-       vdev_t *rvd = spa->spa_root_vdev;
-       uint64_t id = vd->vdev_id;
-       boolean_t last_vdev = (id == (rvd->vdev_children - 1));
-
-       ASSERT(MUTEX_HELD(&spa_namespace_lock));
-       ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
-       ASSERT(vd == vd->vdev_top);
-
-       /*
-        * Only remove any devices which are empty.
-        */
-       if (vd->vdev_stat.vs_alloc != 0)
-               return;
-
-       (void) vdev_label_init(vd, 0, VDEV_LABEL_REMOVE);
-
-       if (list_link_active(&vd->vdev_state_dirty_node))
-               vdev_state_clean(vd);
-       if (list_link_active(&vd->vdev_config_dirty_node))
-               vdev_config_clean(vd);
+       spa_activate(newspa, spa_mode_global);
+       spa_async_suspend(newspa);
 
-       vdev_free(vd);
+       /* create the new pool from the disks of the original pool */
+       error = spa_load(newspa, SPA_LOAD_IMPORT, SPA_IMPORT_ASSEMBLE, B_TRUE);
+       if (error)
+               goto out;
 
-       if (last_vdev) {
-               vdev_compact_children(rvd);
-       } else {
-               vd = vdev_alloc_common(spa, id, 0, &vdev_hole_ops);
-               vdev_add_child(rvd, vd);
+       /* if that worked, generate a real config for the new pool */
+       if (newspa->spa_root_vdev != NULL) {
+               VERIFY(nvlist_alloc(&newspa->spa_config_splitting,
+                   NV_UNIQUE_NAME, KM_SLEEP) == 0);
+               VERIFY(nvlist_add_uint64(newspa->spa_config_splitting,
+                   ZPOOL_CONFIG_SPLIT_GUID, spa_guid(spa)) == 0);
+               spa_config_set(newspa, spa_config_generate(newspa, NULL, -1ULL,
+                   B_TRUE));
        }
-       vdev_config_dirty(rvd);
 
-       /*
-        * Reassess the health of our root vdev.
-        */
-       vdev_reopen(rvd);
-}
+       /* set the props */
+       if (props != NULL) {
+               spa_configfile_set(newspa, props, B_FALSE);
+               error = spa_prop_set(newspa, props);
+               if (error)
+                       goto out;
+       }
 
-/*
- * Remove a device from the pool -
- *
- * Removing a device from the vdev namespace requires several steps
- * and can take a significant amount of time.  As a result we use
- * the spa_vdev_config_[enter/exit] functions which allow us to
- * grab and release the spa_config_lock while still holding the namespace
- * lock.  During each step the configuration is synced out.
- *
- * Currently, this supports removing only hot spares, slogs, and level 2 ARC
- * devices.
- */
-int
-spa_vdev_remove(spa_t *spa, uint64_t guid, boolean_t unspare)
-{
-       vdev_t *vd;
-       metaslab_group_t *mg;
-       nvlist_t **spares, **l2cache, *nv;
-       uint64_t txg = 0;
-       uint_t nspares, nl2cache;
-       int error = 0;
-       boolean_t locked = MUTEX_HELD(&spa_namespace_lock);
+       /* flush everything */
+       txg = spa_vdev_config_enter(newspa);
+       vdev_config_dirty(newspa->spa_root_vdev);
+       (void) spa_vdev_config_exit(newspa, NULL, txg, 0, FTAG);
 
-       ASSERT(spa_writeable(spa));
+       if (zio_injection_enabled)
+               zio_handle_panic_injection(spa, FTAG, 2);
 
-       if (!locked)
-               txg = spa_vdev_enter(spa);
+       spa_async_resume(newspa);
 
-       vd = spa_lookup_by_guid(spa, guid, B_FALSE);
+       /* finally, update the original pool's config */
+       txg = spa_vdev_config_enter(spa);
+       tx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir);
+       error = dmu_tx_assign(tx, TXG_WAIT);
+       if (error != 0)
+               dmu_tx_abort(tx);
+       for (c = 0; c < children; c++) {
+               if (vml[c] != NULL) {
+                       vdev_split(vml[c]);
+                       if (error == 0)
+                               spa_history_log_internal(spa, "detach", tx,
+                                   "vdev=%s", vml[c]->vdev_path);
 
-       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 = SET_ERROR(EBUSY);
+                       vdev_free(vml[c]);
                }
-       } 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 && vd->vdev_islog) {
-               ASSERT(!locked);
-               ASSERT(vd == vd->vdev_top);
+       }
+       spa->spa_avz_action = AVZ_ACTION_REBUILD;
+       vdev_config_dirty(spa->spa_root_vdev);
+       spa->spa_config_splitting = NULL;
+       nvlist_free(nvl);
+       if (error == 0)
+               dmu_tx_commit(tx);
+       (void) spa_vdev_exit(spa, NULL, txg, 0);
 
-               mg = vd->vdev_mg;
+       if (zio_injection_enabled)
+               zio_handle_panic_injection(spa, FTAG, 3);
 
-               /*
-                * Stop allocating from this vdev.
-                */
-               metaslab_group_passivate(mg);
+       /* split is complete; log a history record */
+       spa_history_log_internal(newspa, "split", NULL,
+           "from pool %s", spa_name(spa));
 
-               /*
-                * Wait for the youngest allocations and frees to sync,
-                * and then wait for the deferral of those frees to finish.
-                */
-               spa_vdev_config_exit(spa, NULL,
-                   txg + TXG_CONCURRENT_STATES + TXG_DEFER_SIZE, 0, FTAG);
+       kmem_free(vml, children * sizeof (vdev_t *));
 
-               /*
-                * Attempt to evacuate the vdev.
-                */
-               error = spa_vdev_remove_evacuate(spa, vd);
+       /* if we're not going to mount the filesystems in userland, export */
+       if (exp)
+               error = spa_export_common(newname, POOL_STATE_EXPORTED, NULL,
+                   B_FALSE, B_FALSE);
 
-               txg = spa_vdev_config_enter(spa);
+       return (error);
 
-               /*
-                * If we couldn't evacuate the vdev, unwind.
-                */
-               if (error) {
-                       metaslab_group_activate(mg);
-                       return (spa_vdev_exit(spa, NULL, txg, error));
-               }
+out:
+       spa_unload(newspa);
+       spa_deactivate(newspa);
+       spa_remove(newspa);
 
-               /*
-                * Clean up the vdev namespace.
-                */
-               spa_vdev_remove_from_namespace(spa, vd);
+       txg = spa_vdev_config_enter(spa);
 
-       } else if (vd != NULL) {
-               /*
-                * Normal vdevs cannot be removed (yet).
-                */
-               error = SET_ERROR(ENOTSUP);
-       } else {
-               /*
-                * There is no vdev of any kind with the specified guid.
-                */
-               error = SET_ERROR(ENOENT);
+       /* re-online all offlined disks */
+       for (c = 0; c < children; c++) {
+               if (vml[c] != NULL)
+                       vml[c]->vdev_offline = B_FALSE;
        }
+       vdev_reopen(spa->spa_root_vdev);
 
-       if (!locked)
-               return (spa_vdev_exit(spa, NULL, txg, error));
+       nvlist_free(spa->spa_config_splitting);
+       spa->spa_config_splitting = NULL;
+       (void) spa_vdev_exit(spa, NULL, txg, error);
 
+       kmem_free(vml, children * sizeof (vdev_t *));
        return (error);
 }
 
@@ -5542,9 +6136,8 @@ 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++) {
+       for (int c = 0; c < vd->vdev_children; c++) {
                oldvd = spa_vdev_resilver_done_hunt(vd->vdev_child[c]);
                if (oldvd != NULL)
                        return (oldvd);
@@ -5709,6 +6302,16 @@ spa_vdev_setfru(spa_t *spa, uint64_t guid, const char *newfru)
  * SPA Scanning
  * ==========================================================================
  */
+int
+spa_scrub_pause_resume(spa_t *spa, pool_scrub_cmd_t cmd)
+{
+       ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == 0);
+
+       if (dsl_scan_resilvering(spa->spa_dsl_pool))
+               return (SET_ERROR(EBUSY));
+
+       return (dsl_scrub_set_pause_resume(spa->spa_dsl_pool, cmd));
+}
 
 int
 spa_scan_stop(spa_t *spa)
@@ -5749,8 +6352,6 @@ spa_scan(spa_t *spa, pool_scan_func_t func)
 static void
 spa_async_remove(spa_t *spa, vdev_t *vd)
 {
-       int c;
-
        if (vd->vdev_remove_wanted) {
                vd->vdev_remove_wanted = B_FALSE;
                vd->vdev_delayed_close = B_FALSE;
@@ -5769,33 +6370,29 @@ spa_async_remove(spa_t *spa, vdev_t *vd)
                vdev_state_dirty(vd->vdev_top);
        }
 
-       for (c = 0; c < vd->vdev_children; c++)
+       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)
 {
-       int c;
-
        if (vd->vdev_probe_wanted) {
                vd->vdev_probe_wanted = B_FALSE;
                vdev_reopen(vd);        /* vdev_open() does the actual probe */
        }
 
-       for (c = 0; c < vd->vdev_children; c++)
+       for (int c = 0; c < vd->vdev_children; c++)
                spa_async_probe(spa, vd->vdev_child[c]);
 }
 
 static void
 spa_async_autoexpand(spa_t *spa, vdev_t *vd)
 {
-       int c;
-
        if (!spa->spa_autoexpand)
                return;
 
-       for (c = 0; c < vd->vdev_children; c++) {
+       for (int c = 0; c < vd->vdev_children; c++) {
                vdev_t *cvd = vd->vdev_child[c];
                spa_async_autoexpand(spa, cvd);
        }
@@ -5803,13 +6400,14 @@ spa_async_autoexpand(spa_t *spa, vdev_t *vd)
        if (!vd->vdev_ops->vdev_op_leaf || vd->vdev_physpath == NULL)
                return;
 
-       spa_event_notify(vd->vdev_spa, vd, FM_EREPORT_ZFS_DEVICE_AUTOEXPAND);
+       spa_event_notify(vd->vdev_spa, vd, NULL, ESC_ZFS_VDEV_AUTOEXPAND);
 }
 
 static void
-spa_async_thread(spa_t *spa)
+spa_async_thread(void *arg)
 {
-       int tasks, i;
+       spa_t *spa = (spa_t *)arg;
+       int tasks;
 
        ASSERT(spa->spa_sync_on);
 
@@ -5847,9 +6445,9 @@ spa_async_thread(spa_t *spa)
        if (tasks & SPA_ASYNC_REMOVE) {
                spa_vdev_state_enter(spa, SCL_NONE);
                spa_async_remove(spa, spa->spa_root_vdev);
-               for (i = 0; i < spa->spa_l2cache.sav_count; i++)
+               for (int i = 0; i < spa->spa_l2cache.sav_count; i++)
                        spa_async_remove(spa, spa->spa_l2cache.sav_vdevs[i]);
-               for (i = 0; i < spa->spa_spares.sav_count; 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);
        }
@@ -5899,6 +6497,12 @@ spa_async_suspend(spa_t *spa)
        while (spa->spa_async_thread != NULL)
                cv_wait(&spa->spa_async_cv, &spa->spa_async_lock);
        mutex_exit(&spa->spa_async_lock);
+
+       spa_vdev_remove_suspend(spa);
+
+       zthr_t *condense_thread = spa->spa_condense_zthr;
+       if (condense_thread != NULL && zthr_isrunning(condense_thread))
+               VERIFY0(zthr_cancel(condense_thread));
 }
 
 void
@@ -5908,15 +6512,41 @@ spa_async_resume(spa_t *spa)
        ASSERT(spa->spa_async_suspended != 0);
        spa->spa_async_suspended--;
        mutex_exit(&spa->spa_async_lock);
+       spa_restart_removal(spa);
+
+       zthr_t *condense_thread = spa->spa_condense_zthr;
+       if (condense_thread != NULL && !zthr_isrunning(condense_thread))
+               zthr_resume(condense_thread);
+}
+
+static boolean_t
+spa_async_tasks_pending(spa_t *spa)
+{
+       uint_t non_config_tasks;
+       uint_t config_task;
+       boolean_t config_task_suspended;
+
+       non_config_tasks = spa->spa_async_tasks & ~SPA_ASYNC_CONFIG_UPDATE;
+       config_task = spa->spa_async_tasks & SPA_ASYNC_CONFIG_UPDATE;
+       if (spa->spa_ccw_fail_time == 0) {
+               config_task_suspended = B_FALSE;
+       } else {
+               config_task_suspended =
+                   (gethrtime() - spa->spa_ccw_fail_time) <
+                   ((hrtime_t)zfs_ccw_retry_interval * NANOSEC);
+       }
+
+       return (non_config_tasks || (config_task && !config_task_suspended));
 }
 
 static void
 spa_async_dispatch(spa_t *spa)
 {
        mutex_enter(&spa->spa_async_lock);
-       if (spa->spa_async_tasks && !spa->spa_async_suspended &&
+       if (spa_async_tasks_pending(spa) &&
+           !spa->spa_async_suspended &&
            spa->spa_async_thread == NULL &&
-           rootdir != NULL && !vn_is_readonly(rootdir))
+           rootdir != NULL)
                spa->spa_async_thread = thread_create(NULL, 0,
                    spa_async_thread, spa, 0, &p0, TS_RUN, maxclsyspri);
        mutex_exit(&spa->spa_async_lock);
@@ -6058,16 +6688,120 @@ spa_sync_aux_dev(spa_t *spa, spa_aux_vdev_t *sav, dmu_tx_t *tx,
        sav->sav_sync = B_FALSE;
 }
 
+/*
+ * Rebuild spa's all-vdev ZAP from the vdev ZAPs indicated in each vdev_t.
+ * The all-vdev ZAP must be empty.
+ */
+static void
+spa_avz_build(vdev_t *vd, uint64_t avz, dmu_tx_t *tx)
+{
+       spa_t *spa = vd->vdev_spa;
+
+       if (vd->vdev_top_zap != 0) {
+               VERIFY0(zap_add_int(spa->spa_meta_objset, avz,
+                   vd->vdev_top_zap, tx));
+       }
+       if (vd->vdev_leaf_zap != 0) {
+               VERIFY0(zap_add_int(spa->spa_meta_objset, avz,
+                   vd->vdev_leaf_zap, tx));
+       }
+       for (uint64_t i = 0; i < vd->vdev_children; i++) {
+               spa_avz_build(vd->vdev_child[i], avz, tx);
+       }
+}
+
 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))
+       /*
+        * If the pool is being imported from a pre-per-vdev-ZAP version of ZFS,
+        * its config may not be dirty but we still need to build per-vdev ZAPs.
+        * Similarly, if the pool is being assembled (e.g. after a split), we
+        * need to rebuild the AVZ although the config may not be dirty.
+        */
+       if (list_is_empty(&spa->spa_config_dirty_list) &&
+           spa->spa_avz_action == AVZ_ACTION_NONE)
                return;
 
        spa_config_enter(spa, SCL_STATE, FTAG, RW_READER);
 
+       ASSERT(spa->spa_avz_action == AVZ_ACTION_NONE ||
+           spa->spa_avz_action == AVZ_ACTION_INITIALIZE ||
+           spa->spa_all_vdev_zaps != 0);
+
+       if (spa->spa_avz_action == AVZ_ACTION_REBUILD) {
+               /* Make and build the new AVZ */
+               uint64_t new_avz = zap_create(spa->spa_meta_objset,
+                   DMU_OTN_ZAP_METADATA, DMU_OT_NONE, 0, tx);
+               spa_avz_build(spa->spa_root_vdev, new_avz, tx);
+
+               /* Diff old AVZ with new one */
+               zap_cursor_t zc;
+               zap_attribute_t za;
+
+               for (zap_cursor_init(&zc, spa->spa_meta_objset,
+                   spa->spa_all_vdev_zaps);
+                   zap_cursor_retrieve(&zc, &za) == 0;
+                   zap_cursor_advance(&zc)) {
+                       uint64_t vdzap = za.za_first_integer;
+                       if (zap_lookup_int(spa->spa_meta_objset, new_avz,
+                           vdzap) == ENOENT) {
+                               /*
+                                * ZAP is listed in old AVZ but not in new one;
+                                * destroy it
+                                */
+                               VERIFY0(zap_destroy(spa->spa_meta_objset, vdzap,
+                                   tx));
+                       }
+               }
+
+               zap_cursor_fini(&zc);
+
+               /* Destroy the old AVZ */
+               VERIFY0(zap_destroy(spa->spa_meta_objset,
+                   spa->spa_all_vdev_zaps, tx));
+
+               /* Replace the old AVZ in the dir obj with the new one */
+               VERIFY0(zap_update(spa->spa_meta_objset,
+                   DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_VDEV_ZAP_MAP,
+                   sizeof (new_avz), 1, &new_avz, tx));
+
+               spa->spa_all_vdev_zaps = new_avz;
+       } else if (spa->spa_avz_action == AVZ_ACTION_DESTROY) {
+               zap_cursor_t zc;
+               zap_attribute_t za;
+
+               /* Walk through the AVZ and destroy all listed ZAPs */
+               for (zap_cursor_init(&zc, spa->spa_meta_objset,
+                   spa->spa_all_vdev_zaps);
+                   zap_cursor_retrieve(&zc, &za) == 0;
+                   zap_cursor_advance(&zc)) {
+                       uint64_t zap = za.za_first_integer;
+                       VERIFY0(zap_destroy(spa->spa_meta_objset, zap, tx));
+               }
+
+               zap_cursor_fini(&zc);
+
+               /* Destroy and unlink the AVZ itself */
+               VERIFY0(zap_destroy(spa->spa_meta_objset,
+                   spa->spa_all_vdev_zaps, tx));
+               VERIFY0(zap_remove(spa->spa_meta_objset,
+                   DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_VDEV_ZAP_MAP, tx));
+               spa->spa_all_vdev_zaps = 0;
+       }
+
+       if (spa->spa_all_vdev_zaps == 0) {
+               spa->spa_all_vdev_zaps = zap_create_link(spa->spa_meta_objset,
+                   DMU_OTN_ZAP_METADATA, DMU_POOL_DIRECTORY_OBJECT,
+                   DMU_POOL_VDEV_ZAP_MAP, tx);
+       }
+       spa->spa_avz_action = AVZ_ACTION_NONE;
+
+       /* Create ZAPs for vdevs that don't have them. */
+       vdev_construct_zaps(spa->spa_root_vdev, tx);
+
        config = spa_config_generate(spa, spa->spa_root_vdev,
            dmu_tx_get_txg(tx), B_FALSE);
 
@@ -6081,8 +6815,7 @@ spa_sync_config_object(spa_t *spa, dmu_tx_t *tx)
 
        spa_config_exit(spa, SCL_STATE, FTAG);
 
-       if (spa->spa_config_syncing)
-               nvlist_free(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);
@@ -6129,9 +6862,8 @@ spa_sync_props(void *arg, dmu_tx_t *tx)
                zprop_type_t proptype;
                spa_feature_t fid;
 
-               prop = zpool_name_to_prop(nvpair_name(elem));
-               switch ((int)prop) {
-               case ZPROP_INVAL:
+               switch (prop = zpool_name_to_prop(nvpair_name(elem))) {
+               case ZPOOL_PROP_INVAL:
                        /*
                         * We checked this earlier in spa_prop_validate().
                         */
@@ -6148,7 +6880,7 @@ spa_sync_props(void *arg, dmu_tx_t *tx)
                case ZPOOL_PROP_VERSION:
                        intval = fnvpair_value_uint64(elem);
                        /*
-                        * The version is synced seperatly before other
+                        * The version is synced separately before other
                         * properties and should be correct by now.
                         */
                        ASSERT3U(spa_version(spa), >=, intval);
@@ -6178,7 +6910,7 @@ spa_sync_props(void *arg, dmu_tx_t *tx)
                         * We need to dirty the configuration on all the vdevs
                         * so that their labels get updated.  It's unnecessary
                         * to do this for pool creation since the vdev's
-                        * configuratoin has already been dirtied.
+                        * configuration has already been dirtied.
                         */
                        if (tx->tx_txg != TXG_INITIAL)
                                vdev_config_dirty(spa->spa_root_vdev);
@@ -6241,6 +6973,9 @@ spa_sync_props(void *arg, dmu_tx_t *tx)
                                        spa_async_request(spa,
                                            SPA_ASYNC_AUTOEXPAND);
                                break;
+                       case ZPOOL_PROP_MULTIHOST:
+                               spa->spa_multihost = intval;
+                               break;
                        case ZPOOL_PROP_DEDUPDITTO:
                                spa->spa_dedup_ditto = intval;
                                break;
@@ -6311,9 +7046,56 @@ spa_sync_upgrades(spa_t *spa, dmu_tx_t *tx)
                if (lz4_en && !lz4_ac)
                        spa_feature_incr(spa, SPA_FEATURE_LZ4_COMPRESS, tx);
        }
+
+       /*
+        * If we haven't written the salt, do so now.  Note that the
+        * feature may not be activated yet, but that's fine since
+        * the presence of this ZAP entry is backwards compatible.
+        */
+       if (zap_contains(spa->spa_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
+           DMU_POOL_CHECKSUM_SALT) == ENOENT) {
+               VERIFY0(zap_add(spa->spa_meta_objset,
+                   DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_CHECKSUM_SALT, 1,
+                   sizeof (spa->spa_cksum_salt.zcs_bytes),
+                   spa->spa_cksum_salt.zcs_bytes, tx));
+       }
+
        rrw_exit(&dp->dp_config_rwlock, FTAG);
 }
 
+static void
+vdev_indirect_state_sync_verify(vdev_t *vd)
+{
+       ASSERTV(vdev_indirect_mapping_t *vim = vd->vdev_indirect_mapping);
+       ASSERTV(vdev_indirect_births_t *vib = vd->vdev_indirect_births);
+
+       if (vd->vdev_ops == &vdev_indirect_ops) {
+               ASSERT(vim != NULL);
+               ASSERT(vib != NULL);
+       }
+
+       if (vdev_obsolete_sm_object(vd) != 0) {
+               ASSERT(vd->vdev_obsolete_sm != NULL);
+               ASSERT(vd->vdev_removing ||
+                   vd->vdev_ops == &vdev_indirect_ops);
+               ASSERT(vdev_indirect_mapping_num_entries(vim) > 0);
+               ASSERT(vdev_indirect_mapping_bytes_mapped(vim) > 0);
+
+               ASSERT3U(vdev_obsolete_sm_object(vd), ==,
+                   space_map_object(vd->vdev_obsolete_sm));
+               ASSERT3U(vdev_indirect_mapping_bytes_mapped(vim), >=,
+                   space_map_allocated(vd->vdev_obsolete_sm));
+       }
+       ASSERT(vd->vdev_obsolete_segments != NULL);
+
+       /*
+        * Since frees / remaps to an indirect vdev can only
+        * happen in syncing context, the obsolete segments
+        * tree must be empty when we start syncing.
+        */
+       ASSERT0(range_tree_space(vd->vdev_obsolete_segments));
+}
+
 /*
  * Sync the specified transaction group.  New blocks may be dirtied as
  * part of the process, so we iterate until it converges.
@@ -6328,10 +7110,18 @@ spa_sync(spa_t *spa, uint64_t txg)
        vdev_t *vd;
        dmu_tx_t *tx;
        int error;
-       int c;
+       uint32_t max_queue_depth = zfs_vdev_async_write_max_active *
+           zfs_vdev_queue_depth_pct / 100;
 
        VERIFY(spa_writeable(spa));
 
+       /*
+        * Wait for i/os issued in open context that need to complete
+        * before this txg syncs.
+        */
+       VERIFY0(zio_wait(spa->spa_txg_zio[txg & TXG_MASK]));
+       spa->spa_txg_zio[txg & TXG_MASK] = zio_root(spa, NULL, NULL, 0);
+
        /*
         * Lock out configuration changes.
         */
@@ -6340,6 +7130,10 @@ spa_sync(spa_t *spa, uint64_t txg)
        spa->spa_syncing_txg = txg;
        spa->spa_sync_pass = 0;
 
+       mutex_enter(&spa->spa_alloc_lock);
+       VERIFY0(avl_numnodes(&spa->spa_alloc_tree));
+       mutex_exit(&spa->spa_alloc_lock);
+
        /*
         * If there are any pending vdev state changes, convert them
         * into config changes that go out with this transaction group.
@@ -6367,8 +7161,8 @@ spa_sync(spa_t *spa, uint64_t txg)
        tx = dmu_tx_create_assigned(dp, txg);
 
        spa->spa_sync_starttime = gethrtime();
-       taskq_cancel_id(system_taskq, spa->spa_deadman_tqid);
-       spa->spa_deadman_tqid = taskq_dispatch_delay(system_taskq,
+       taskq_cancel_id(system_delay_taskq, spa->spa_deadman_tqid);
+       spa->spa_deadman_tqid = taskq_dispatch_delay(system_delay_taskq,
            spa_deadman, spa, TQ_SLEEP, ddi_get_lbolt() +
            NSEC_TO_TICK(spa->spa_deadman_synctime));
 
@@ -6394,18 +7188,45 @@ spa_sync(spa_t *spa, uint64_t txg)
        }
 
        /*
-        * If anything has changed in this txg, or if someone is waiting
-        * for this txg to sync (eg, spa_vdev_remove()), 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.
+        * Set the top-level vdev's max queue depth. Evaluate each
+        * top-level's async write queue depth in case it changed.
+        * The max queue depth will not change in the middle of syncing
+        * out this txg.
         */
-       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) ||
-           ((dsl_scan_active(dp->dp_scan) ||
-           txg_sync_waiting(dp)) && !spa_shutting_down(spa))) {
-               spa_sync_deferred_frees(spa, tx);
+       uint64_t queue_depth_total = 0;
+       for (int c = 0; c < rvd->vdev_children; c++) {
+               vdev_t *tvd = rvd->vdev_child[c];
+               metaslab_group_t *mg = tvd->vdev_mg;
+
+               if (mg == NULL || mg->mg_class != spa_normal_class(spa) ||
+                   !metaslab_group_initialized(mg))
+                       continue;
+
+               /*
+                * It is safe to do a lock-free check here because only async
+                * allocations look at mg_max_alloc_queue_depth, and async
+                * allocations all happen from spa_sync().
+                */
+               ASSERT0(refcount_count(&mg->mg_alloc_queue_depth));
+               mg->mg_max_alloc_queue_depth = max_queue_depth;
+               queue_depth_total += mg->mg_max_alloc_queue_depth;
+       }
+       metaslab_class_t *mc = spa_normal_class(spa);
+       ASSERT0(refcount_count(&mc->mc_alloc_slots));
+       mc->mc_alloc_max_slots = queue_depth_total;
+       mc->mc_alloc_throttle_enabled = zio_dva_throttle_enabled;
+
+       ASSERT3U(mc->mc_alloc_max_slots, <=,
+           max_queue_depth * rvd->vdev_children);
+
+       for (int c = 0; c < rvd->vdev_children; c++) {
+               vdev_t *vd = rvd->vdev_child[c];
+               vdev_indirect_state_sync_verify(vd);
+
+               if (vdev_indirect_should_condense(vd)) {
+                       spa_condense_indirect_start_sync(vd, tx);
+                       break;
+               }
        }
 
        /*
@@ -6425,6 +7246,11 @@ spa_sync(spa_t *spa, uint64_t txg)
                if (pass < zfs_sync_pass_deferred_free) {
                        spa_sync_frees(spa, free_bpl, tx);
                } else {
+                       /*
+                        * We can not defer frees in pass 1, because
+                        * we sync the deferred frees later in pass 1.
+                        */
+                       ASSERT3U(pass, >, 1);
                        bplist_iterate(free_bpl, bpobj_enqueue_cb,
                            &spa->spa_deferred_bpobj, tx);
                }
@@ -6432,14 +7258,68 @@ spa_sync(spa_t *spa, uint64_t txg)
                ddt_sync(spa, txg);
                dsl_scan_sync(dp, tx);
 
-               while ((vd = txg_list_remove(&spa->spa_vdev_txg_list, txg)))
+               if (spa->spa_vdev_removal != NULL)
+                       svr_sync(spa, tx);
+
+               while ((vd = txg_list_remove(&spa->spa_vdev_txg_list, txg))
+                   != NULL)
                        vdev_sync(vd, txg);
 
-               if (pass == 1)
+               if (pass == 1) {
                        spa_sync_upgrades(spa, tx);
+                       ASSERT3U(txg, >=,
+                           spa->spa_uberblock.ub_rootbp.blk_birth);
+                       /*
+                        * Note: We need to check if the MOS is dirty
+                        * because we could have marked the MOS dirty
+                        * without updating the uberblock (e.g. if we
+                        * have sync tasks but no dirty user data).  We
+                        * need to check the uberblock's rootbp because
+                        * it is updated if we have synced out dirty
+                        * data (though in this case the MOS will most
+                        * likely also be dirty due to second order
+                        * effects, we don't want to rely on that here).
+                        */
+                       if (spa->spa_uberblock.ub_rootbp.blk_birth < txg &&
+                           !dmu_objset_is_dirty(mos, txg)) {
+                               /*
+                                * Nothing changed on the first pass,
+                                * therefore this TXG is a no-op.  Avoid
+                                * syncing deferred frees, so that we
+                                * can keep this TXG as a no-op.
+                                */
+                               ASSERT(txg_list_empty(&dp->dp_dirty_datasets,
+                                   txg));
+                               ASSERT(txg_list_empty(&dp->dp_dirty_dirs, txg));
+                               ASSERT(txg_list_empty(&dp->dp_sync_tasks, txg));
+                               break;
+                       }
+                       spa_sync_deferred_frees(spa, tx);
+               }
 
        } while (dmu_objset_is_dirty(mos, txg));
 
+#ifdef ZFS_DEBUG
+       if (!list_is_empty(&spa->spa_config_dirty_list)) {
+               /*
+                * Make sure that the number of ZAPs for all the vdevs matches
+                * the number of ZAPs in the per-vdev ZAP list. This only gets
+                * called if the config is dirty; otherwise there may be
+                * outstanding AVZ operations that weren't completed in
+                * spa_sync_config_object.
+                */
+               uint64_t all_vdev_zap_entry_count;
+               ASSERT0(zap_count(spa->spa_meta_objset,
+                   spa->spa_all_vdev_zaps, &all_vdev_zap_entry_count));
+               ASSERT3U(vdev_count_verify_zaps(spa->spa_root_vdev), ==,
+                   all_vdev_zap_entry_count);
+       }
+#endif
+
+       if (spa->spa_vdev_removal != NULL) {
+               ASSERT0(spa->spa_vdev_removal->svr_bytes_done[txg & TXG_MASK]);
+       }
+
        /*
         * Rewrite the vdev configuration (which includes the uberblock)
         * to commit the transaction group.
@@ -6462,24 +7342,19 @@ spa_sync(spa_t *spa, uint64_t txg)
                        int children = rvd->vdev_children;
                        int c0 = spa_get_random(children);
 
-                       for (c = 0; c < children; c++) {
+                       for (int c = 0; c < children; c++) {
                                vd = rvd->vdev_child[(c0 + c) % children];
-                               if (vd->vdev_ms_array == 0 || vd->vdev_islog)
+                               if (vd->vdev_ms_array == 0 || vd->vdev_islog ||
+                                   !vdev_is_concrete(vd))
                                        continue;
                                svd[svdcount++] = vd;
                                if (svdcount == SPA_DVAS_PER_BP)
                                        break;
                        }
-                       error = vdev_config_sync(svd, svdcount, txg, B_FALSE);
-                       if (error != 0)
-                               error = vdev_config_sync(svd, svdcount, txg,
-                                   B_TRUE);
+                       error = vdev_config_sync(svd, svdcount, txg);
                } else {
                        error = vdev_config_sync(rvd->vdev_child,
-                           rvd->vdev_children, txg, B_FALSE);
-                       if (error != 0)
-                               error = vdev_config_sync(rvd->vdev_child,
-                                   rvd->vdev_children, txg, B_TRUE);
+                           rvd->vdev_children, txg);
                }
 
                if (error == 0)
@@ -6489,12 +7364,12 @@ spa_sync(spa_t *spa, uint64_t txg)
 
                if (error == 0)
                        break;
-               zio_suspend(spa, NULL);
+               zio_suspend(spa, NULL, ZIO_SUSPEND_IOERR);
                zio_resume_wait(spa);
        }
        dmu_tx_commit(tx);
 
-       taskq_cancel_id(system_taskq, spa->spa_deadman_tqid);
+       taskq_cancel_id(system_delay_taskq, spa->spa_deadman_tqid);
        spa->spa_deadman_tqid = 0;
 
        /*
@@ -6513,10 +7388,12 @@ spa_sync(spa_t *spa, uint64_t txg)
                spa->spa_config_syncing = NULL;
        }
 
-       spa->spa_ubsync = spa->spa_uberblock;
-
        dsl_pool_sync_done(dp, txg);
 
+       mutex_enter(&spa->spa_alloc_lock);
+       VERIFY0(avl_numnodes(&spa->spa_alloc_tree));
+       mutex_exit(&spa->spa_alloc_lock);
+
        /*
         * Update usable space statistics.
         */
@@ -6535,6 +7412,13 @@ spa_sync(spa_t *spa, uint64_t txg)
 
        spa->spa_sync_pass = 0;
 
+       /*
+        * Update the last synced uberblock here. We want to do this at
+        * the end of spa_sync() so that consumers of spa_last_synced_txg()
+        * will be guaranteed that all the processing associated with
+        * that txg has been completed.
+        */
+       spa->spa_ubsync = spa->spa_uberblock;
        spa_config_exit(spa, SCL_CONFIG, FTAG);
 
        spa_handle_ignored_writes(spa);
@@ -6698,18 +7582,44 @@ spa_has_active_shared_spare(spa_t *spa)
        return (B_FALSE);
 }
 
+sysevent_t *
+spa_event_create(spa_t *spa, vdev_t *vd, nvlist_t *hist_nvl, const char *name)
+{
+       sysevent_t *ev = NULL;
+#ifdef _KERNEL
+       nvlist_t *resource;
+
+       resource = zfs_event_create(spa, vd, FM_SYSEVENT_CLASS, name, hist_nvl);
+       if (resource) {
+               ev = kmem_alloc(sizeof (sysevent_t), KM_SLEEP);
+               ev->resource = resource;
+       }
+#endif
+       return (ev);
+}
+
+void
+spa_event_post(sysevent_t *ev)
+{
+#ifdef _KERNEL
+       if (ev) {
+               zfs_zevent_post(ev->resource, NULL, zfs_zevent_post_cb);
+               kmem_free(ev, sizeof (*ev));
+       }
+#endif
+}
+
 /*
- * Post a FM_EREPORT_ZFS_* event from sys/fm/fs/zfs.h.  The payload will be
+ * Post a zevent corresponding to the given sysevent.   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)
+spa_event_notify(spa_t *spa, vdev_t *vd, nvlist_t *hist_nvl, const char *name)
 {
-#ifdef _KERNEL
-       zfs_ereport_post(name, spa, vd, NULL, 0, 0);
-#endif
+       spa_event_post(spa_event_create(spa, vd, hist_nvl, name));
 }
 
 #if defined(_KERNEL) && defined(HAVE_SPL)
@@ -6718,7 +7628,6 @@ EXPORT_SYMBOL(spa_open);
 EXPORT_SYMBOL(spa_open_rewind);
 EXPORT_SYMBOL(spa_get_stats);
 EXPORT_SYMBOL(spa_create);
-EXPORT_SYMBOL(spa_import_rootpool);
 EXPORT_SYMBOL(spa_import);
 EXPORT_SYMBOL(spa_tryimport);
 EXPORT_SYMBOL(spa_destroy);
@@ -6736,7 +7645,6 @@ EXPORT_SYMBOL(spa_scan_get_stats);
 EXPORT_SYMBOL(spa_vdev_add);
 EXPORT_SYMBOL(spa_vdev_attach);
 EXPORT_SYMBOL(spa_vdev_detach);
-EXPORT_SYMBOL(spa_vdev_remove);
 EXPORT_SYMBOL(spa_vdev_setpath);
 EXPORT_SYMBOL(spa_vdev_setfru);
 EXPORT_SYMBOL(spa_vdev_split_mirror);
@@ -6783,4 +7691,10 @@ MODULE_PARM_DESC(spa_load_verify_metadata,
 module_param(spa_load_verify_data, int, 0644);
 MODULE_PARM_DESC(spa_load_verify_data,
        "Set to traverse data on pool import");
+
+/* CSTYLED */
+module_param(zio_taskq_batch_pct, uint, 0444);
+MODULE_PARM_DESC(zio_taskq_batch_pct,
+       "Percentage of CPUs to run an IO worker thread");
+
 #endif