]> git.proxmox.com Git - mirror_zfs-debian.git/blobdiff - module/zfs/vdev.c
Imported Upstream version 0.6.4.2
[mirror_zfs-debian.git] / module / zfs / vdev.c
index 7751683d1396003713eca509a992290275657864..52198261e434ec74510453a3c7b7f32191407ab9 100644 (file)
@@ -22,7 +22,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
- * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
  */
 
 #include <sys/zfs_context.h>
@@ -36,6 +36,7 @@
 #include <sys/metaslab.h>
 #include <sys/metaslab_impl.h>
 #include <sys/space_map.h>
+#include <sys/space_reftree.h>
 #include <sys/zio.h>
 #include <sys/zap.h>
 #include <sys/fs/zfs.h>
 #include <sys/dsl_scan.h>
 #include <sys/zvol.h>
 
+/*
+ * When a vdev is added, it will be divided into approximately (but no
+ * more than) this number of metaslabs.
+ */
+int metaslabs_per_vdev = 200;
+
 /*
  * Virtual device management.
  */
@@ -193,7 +200,7 @@ vdev_add_child(vdev_t *pvd, vdev_t *cvd)
        pvd->vdev_children = MAX(pvd->vdev_children, id + 1);
        newsize = pvd->vdev_children * sizeof (vdev_t *);
 
-       newchild = kmem_zalloc(newsize, KM_PUSHPAGE);
+       newchild = kmem_alloc(newsize, KM_SLEEP);
        if (pvd->vdev_child != NULL) {
                bcopy(pvd->vdev_child, newchild, oldsize);
                kmem_free(pvd->vdev_child, oldsize);
@@ -263,7 +270,7 @@ vdev_compact_children(vdev_t *pvd)
                if (pvd->vdev_child[c])
                        newc++;
 
-       newchild = kmem_alloc(newc * sizeof (vdev_t *), KM_PUSHPAGE);
+       newchild = kmem_zalloc(newc * sizeof (vdev_t *), KM_SLEEP);
 
        for (c = newc = 0; c < oldc; c++) {
                if ((cvd = pvd->vdev_child[c]) != NULL) {
@@ -286,7 +293,7 @@ vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid, vdev_ops_t *ops)
        vdev_t *vd;
        int t;
 
-       vd = kmem_zalloc(sizeof (vdev_t), KM_PUSHPAGE);
+       vd = kmem_zalloc(sizeof (vdev_t), KM_SLEEP);
 
        if (spa->spa_root_vdev == NULL) {
                ASSERT(ops == &vdev_root_ops);
@@ -324,7 +331,7 @@ vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid, vdev_ops_t *ops)
        mutex_init(&vd->vdev_stat_lock, NULL, MUTEX_DEFAULT, NULL);
        mutex_init(&vd->vdev_probe_lock, NULL, MUTEX_DEFAULT, NULL);
        for (t = 0; t < DTL_TYPES; t++) {
-               space_map_create(&vd->vdev_dtl[t], 0, -1ULL, 0,
+               vd->vdev_dtl[t] = range_tree_create(NULL, NULL,
                    &vd->vdev_dtl_lock);
        }
        txg_list_create(&vd->vdev_ms_list,
@@ -510,7 +517,7 @@ vdev_alloc(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent, uint_t id,
            alloctype == VDEV_ALLOC_ROOTPOOL)) {
                if (alloctype == VDEV_ALLOC_LOAD) {
                        (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_DTL,
-                           &vd->vdev_dtl_smo.smo_object);
+                           &vd->vdev_dtl_object);
                        (void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_UNSPARE,
                            &vd->vdev_unspare);
                }
@@ -633,9 +640,10 @@ vdev_free(vdev_t *vd)
        txg_list_destroy(&vd->vdev_dtl_list);
 
        mutex_enter(&vd->vdev_dtl_lock);
+       space_map_close(vd->vdev_dtl_sm);
        for (t = 0; t < DTL_TYPES; t++) {
-               space_map_unload(&vd->vdev_dtl[t]);
-               space_map_destroy(&vd->vdev_dtl[t]);
+               range_tree_vacate(vd->vdev_dtl[t], NULL, NULL);
+               range_tree_destroy(vd->vdev_dtl[t]);
        }
        mutex_exit(&vd->vdev_dtl_lock);
 
@@ -793,6 +801,17 @@ vdev_remove_parent(vdev_t *cvd)
                cvd->vdev_orig_guid = cvd->vdev_guid;
                cvd->vdev_guid += guid_delta;
                cvd->vdev_guid_sum += guid_delta;
+
+               /*
+                * If pool not set for autoexpand, we need to also preserve
+                * mvd's asize to prevent automatic expansion of cvd.
+                * Otherwise if we are adjusting the mirror by attaching and
+                * detaching children of non-uniform sizes, the mirror could
+                * autoexpand, unexpectedly requiring larger devices to
+                * re-establish the mirror.
+                */
+               if (!cvd->vdev_spa->spa_autoexpand)
+                       cvd->vdev_asize = mvd->vdev_asize;
        }
        cvd->vdev_id = mvd->vdev_id;
        vdev_add_child(pvd, cvd);
@@ -837,7 +856,7 @@ vdev_metaslab_init(vdev_t *vd, uint64_t txg)
 
        ASSERT(oldc <= newc);
 
-       mspp = kmem_zalloc(newc * sizeof (*mspp), KM_PUSHPAGE | KM_NODEBUG);
+       mspp = kmem_zalloc(newc * sizeof (*mspp), KM_SLEEP);
 
        if (oldc != 0) {
                bcopy(vd->vdev_ms, mspp, oldc * sizeof (*mspp));
@@ -848,27 +867,20 @@ vdev_metaslab_init(vdev_t *vd, uint64_t txg)
        vd->vdev_ms_count = newc;
 
        for (m = oldc; m < newc; m++) {
-               space_map_obj_t smo = { 0, 0, 0 };
+               uint64_t object = 0;
+
                if (txg == 0) {
-                       uint64_t object = 0;
                        error = dmu_read(mos, vd->vdev_ms_array,
                            m * sizeof (uint64_t), sizeof (uint64_t), &object,
                            DMU_READ_PREFETCH);
                        if (error)
                                return (error);
-                       if (object != 0) {
-                               dmu_buf_t *db;
-                               error = dmu_bonus_hold(mos, object, FTAG, &db);
-                               if (error)
-                                       return (error);
-                               ASSERT3U(db->db_size, >=, sizeof (smo));
-                               bcopy(db->db_data, &smo, sizeof (smo));
-                               ASSERT3U(smo.smo_object, ==, object);
-                               dmu_buf_rele(db, FTAG);
-                       }
                }
-               vd->vdev_ms[m] = metaslab_init(vd->vdev_mg, &smo,
-                   m << vd->vdev_ms_shift, 1ULL << vd->vdev_ms_shift, txg);
+
+               error = metaslab_init(vd->vdev_mg, m, object, txg,
+                   &(vd->vdev_ms[m]));
+               if (error)
+                       return (error);
        }
 
        if (txg == 0)
@@ -896,9 +908,12 @@ vdev_metaslab_fini(vdev_t *vd)
 
        if (vd->vdev_ms != NULL) {
                metaslab_group_passivate(vd->vdev_mg);
-               for (m = 0; m < count; m++)
-                       if (vd->vdev_ms[m] != NULL)
-                               metaslab_fini(vd->vdev_ms[m]);
+               for (m = 0; m < count; m++) {
+                       metaslab_t *msp = vd->vdev_ms[m];
+
+                       if (msp != NULL)
+                               metaslab_fini(msp);
+               }
                kmem_free(vd->vdev_ms, count * sizeof (metaslab_t *));
                vd->vdev_ms = NULL;
        }
@@ -996,7 +1011,7 @@ vdev_probe(vdev_t *vd, zio_t *zio)
        mutex_enter(&vd->vdev_probe_lock);
 
        if ((pio = vd->vdev_probe_zio) == NULL) {
-               vps = kmem_zalloc(sizeof (*vps), KM_PUSHPAGE);
+               vps = kmem_zalloc(sizeof (*vps), KM_SLEEP);
 
                vps->vps_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_PROBE |
                    ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE |
@@ -1561,9 +1576,10 @@ vdev_create(vdev_t *vd, uint64_t txg, boolean_t isreplacing)
        }
 
        /*
-        * Recursively initialize all labels.
+        * Recursively load DTLs and initialize all labels.
         */
-       if ((error = vdev_label_init(vd, txg, isreplacing ?
+       if ((error = vdev_dtl_load(vd)) != 0 ||
+           (error = vdev_label_init(vd, txg, isreplacing ?
            VDEV_LABEL_REPLACE : VDEV_LABEL_CREATE)) != 0) {
                vdev_close(vd);
                return (error);
@@ -1576,9 +1592,9 @@ void
 vdev_metaslab_set_size(vdev_t *vd)
 {
        /*
-        * Aim for roughly 200 metaslabs per vdev.
+        * Aim for roughly metaslabs_per_vdev (default 200) metaslabs per vdev.
         */
-       vd->vdev_ms_shift = highbit(vd->vdev_asize / 200);
+       vd->vdev_ms_shift = highbit64(vd->vdev_asize / metaslabs_per_vdev);
        vd->vdev_ms_shift = MAX(vd->vdev_ms_shift, SPA_MAXBLOCKSHIFT);
 }
 
@@ -1599,6 +1615,18 @@ vdev_dirty(vdev_t *vd, int flags, void *arg, uint64_t txg)
        (void) txg_list_add(&vd->vdev_spa->spa_vdev_txg_list, vd, txg);
 }
 
+void
+vdev_dirty_leaves(vdev_t *vd, int flags, uint64_t txg)
+{
+       int c;
+
+       for (c = 0; c < vd->vdev_children; c++)
+               vdev_dirty_leaves(vd->vdev_child[c], flags, txg);
+
+       if (vd->vdev_ops->vdev_op_leaf)
+               vdev_dirty(vd->vdev_top, flags, vd, txg);
+}
+
 /*
  * DTLs.
  *
@@ -1640,31 +1668,31 @@ vdev_dirty(vdev_t *vd, int flags, void *arg, uint64_t txg)
 void
 vdev_dtl_dirty(vdev_t *vd, vdev_dtl_type_t t, uint64_t txg, uint64_t size)
 {
-       space_map_t *sm = &vd->vdev_dtl[t];
+       range_tree_t *rt = vd->vdev_dtl[t];
 
        ASSERT(t < DTL_TYPES);
        ASSERT(vd != vd->vdev_spa->spa_root_vdev);
        ASSERT(spa_writeable(vd->vdev_spa));
 
-       mutex_enter(sm->sm_lock);
-       if (!space_map_contains(sm, txg, size))
-               space_map_add(sm, txg, size);
-       mutex_exit(sm->sm_lock);
+       mutex_enter(rt->rt_lock);
+       if (!range_tree_contains(rt, txg, size))
+               range_tree_add(rt, txg, size);
+       mutex_exit(rt->rt_lock);
 }
 
 boolean_t
 vdev_dtl_contains(vdev_t *vd, vdev_dtl_type_t t, uint64_t txg, uint64_t size)
 {
-       space_map_t *sm = &vd->vdev_dtl[t];
+       range_tree_t *rt = vd->vdev_dtl[t];
        boolean_t dirty = B_FALSE;
 
        ASSERT(t < DTL_TYPES);
        ASSERT(vd != vd->vdev_spa->spa_root_vdev);
 
-       mutex_enter(sm->sm_lock);
-       if (sm->sm_space != 0)
-               dirty = space_map_contains(sm, txg, size);
-       mutex_exit(sm->sm_lock);
+       mutex_enter(rt->rt_lock);
+       if (range_tree_space(rt) != 0)
+               dirty = range_tree_contains(rt, txg, size);
+       mutex_exit(rt->rt_lock);
 
        return (dirty);
 }
@@ -1672,12 +1700,12 @@ vdev_dtl_contains(vdev_t *vd, vdev_dtl_type_t t, uint64_t txg, uint64_t size)
 boolean_t
 vdev_dtl_empty(vdev_t *vd, vdev_dtl_type_t t)
 {
-       space_map_t *sm = &vd->vdev_dtl[t];
+       range_tree_t *rt = vd->vdev_dtl[t];
        boolean_t empty;
 
-       mutex_enter(sm->sm_lock);
-       empty = (sm->sm_space == 0);
-       mutex_exit(sm->sm_lock);
+       mutex_enter(rt->rt_lock);
+       empty = (range_tree_space(rt) == 0);
+       mutex_exit(rt->rt_lock);
 
        return (empty);
 }
@@ -1688,14 +1716,14 @@ vdev_dtl_empty(vdev_t *vd, vdev_dtl_type_t t)
 static uint64_t
 vdev_dtl_min(vdev_t *vd)
 {
-       space_seg_t *ss;
+       range_seg_t *rs;
 
        ASSERT(MUTEX_HELD(&vd->vdev_dtl_lock));
-       ASSERT3U(vd->vdev_dtl[DTL_MISSING].sm_space, !=, 0);
+       ASSERT3U(range_tree_space(vd->vdev_dtl[DTL_MISSING]), !=, 0);
        ASSERT0(vd->vdev_children);
 
-       ss = avl_first(&vd->vdev_dtl[DTL_MISSING].sm_root);
-       return (ss->ss_start - 1);
+       rs = avl_first(&vd->vdev_dtl[DTL_MISSING]->rt_root);
+       return (rs->rs_start - 1);
 }
 
 /*
@@ -1704,14 +1732,14 @@ vdev_dtl_min(vdev_t *vd)
 static uint64_t
 vdev_dtl_max(vdev_t *vd)
 {
-       space_seg_t *ss;
+       range_seg_t *rs;
 
        ASSERT(MUTEX_HELD(&vd->vdev_dtl_lock));
-       ASSERT3U(vd->vdev_dtl[DTL_MISSING].sm_space, !=, 0);
+       ASSERT3U(range_tree_space(vd->vdev_dtl[DTL_MISSING]), !=, 0);
        ASSERT0(vd->vdev_children);
 
-       ss = avl_last(&vd->vdev_dtl[DTL_MISSING].sm_root);
-       return (ss->ss_end);
+       rs = avl_last(&vd->vdev_dtl[DTL_MISSING]->rt_root);
+       return (rs->rs_end);
 }
 
 /*
@@ -1732,7 +1760,7 @@ vdev_dtl_should_excise(vdev_t *vd)
        ASSERT0(vd->vdev_children);
 
        if (vd->vdev_resilver_txg == 0 ||
-           vd->vdev_dtl[DTL_MISSING].sm_space == 0)
+           range_tree_space(vd->vdev_dtl[DTL_MISSING]) == 0)
                return (B_TRUE);
 
        /*
@@ -1802,35 +1830,35 @@ vdev_dtl_reassess(vdev_t *vd, uint64_t txg, uint64_t scrub_txg, int scrub_done)
                         * positive refcnt -- either 1 or 2.  We then convert
                         * the reference tree into the new DTL_MISSING map.
                         */
-                       space_map_ref_create(&reftree);
-                       space_map_ref_add_map(&reftree,
-                           &vd->vdev_dtl[DTL_MISSING], 1);
-                       space_map_ref_add_seg(&reftree, 0, scrub_txg, -1);
-                       space_map_ref_add_map(&reftree,
-                           &vd->vdev_dtl[DTL_SCRUB], 2);
-                       space_map_ref_generate_map(&reftree,
-                           &vd->vdev_dtl[DTL_MISSING], 1);
-                       space_map_ref_destroy(&reftree);
+                       space_reftree_create(&reftree);
+                       space_reftree_add_map(&reftree,
+                           vd->vdev_dtl[DTL_MISSING], 1);
+                       space_reftree_add_seg(&reftree, 0, scrub_txg, -1);
+                       space_reftree_add_map(&reftree,
+                           vd->vdev_dtl[DTL_SCRUB], 2);
+                       space_reftree_generate_map(&reftree,
+                           vd->vdev_dtl[DTL_MISSING], 1);
+                       space_reftree_destroy(&reftree);
                }
-               space_map_vacate(&vd->vdev_dtl[DTL_PARTIAL], NULL, NULL);
-               space_map_walk(&vd->vdev_dtl[DTL_MISSING],
-                   space_map_add, &vd->vdev_dtl[DTL_PARTIAL]);
+               range_tree_vacate(vd->vdev_dtl[DTL_PARTIAL], NULL, NULL);
+               range_tree_walk(vd->vdev_dtl[DTL_MISSING],
+                   range_tree_add, vd->vdev_dtl[DTL_PARTIAL]);
                if (scrub_done)
-                       space_map_vacate(&vd->vdev_dtl[DTL_SCRUB], NULL, NULL);
-               space_map_vacate(&vd->vdev_dtl[DTL_OUTAGE], NULL, NULL);
+                       range_tree_vacate(vd->vdev_dtl[DTL_SCRUB], NULL, NULL);
+               range_tree_vacate(vd->vdev_dtl[DTL_OUTAGE], NULL, NULL);
                if (!vdev_readable(vd))
-                       space_map_add(&vd->vdev_dtl[DTL_OUTAGE], 0, -1ULL);
+                       range_tree_add(vd->vdev_dtl[DTL_OUTAGE], 0, -1ULL);
                else
-                       space_map_walk(&vd->vdev_dtl[DTL_MISSING],
-                           space_map_add, &vd->vdev_dtl[DTL_OUTAGE]);
+                       range_tree_walk(vd->vdev_dtl[DTL_MISSING],
+                           range_tree_add, vd->vdev_dtl[DTL_OUTAGE]);
 
                /*
                 * If the vdev was resilvering and no longer has any
                 * DTLs then reset its resilvering flag.
                 */
                if (vd->vdev_resilver_txg != 0 &&
-                   vd->vdev_dtl[DTL_MISSING].sm_space == 0 &&
-                   vd->vdev_dtl[DTL_OUTAGE].sm_space == 0)
+                   range_tree_space(vd->vdev_dtl[DTL_MISSING]) == 0 &&
+                   range_tree_space(vd->vdev_dtl[DTL_OUTAGE]) == 0)
                        vd->vdev_resilver_txg = 0;
 
                mutex_exit(&vd->vdev_dtl_lock);
@@ -1842,6 +1870,8 @@ vdev_dtl_reassess(vdev_t *vd, uint64_t txg, uint64_t scrub_txg, int scrub_done)
 
        mutex_enter(&vd->vdev_dtl_lock);
        for (t = 0; t < DTL_TYPES; t++) {
+               int c;
+
                /* account for child's outage in parent's missing map */
                int s = (t == DTL_MISSING) ? DTL_OUTAGE: t;
                if (t == DTL_SCRUB)
@@ -1852,46 +1882,56 @@ vdev_dtl_reassess(vdev_t *vd, uint64_t txg, uint64_t scrub_txg, int scrub_done)
                        minref = vd->vdev_nparity + 1;  /* RAID-Z */
                else
                        minref = vd->vdev_children;     /* any kind of mirror */
-               space_map_ref_create(&reftree);
+               space_reftree_create(&reftree);
                for (c = 0; c < vd->vdev_children; c++) {
                        vdev_t *cvd = vd->vdev_child[c];
                        mutex_enter(&cvd->vdev_dtl_lock);
-                       space_map_ref_add_map(&reftree, &cvd->vdev_dtl[s], 1);
+                       space_reftree_add_map(&reftree, cvd->vdev_dtl[s], 1);
                        mutex_exit(&cvd->vdev_dtl_lock);
                }
-               space_map_ref_generate_map(&reftree, &vd->vdev_dtl[t], minref);
-               space_map_ref_destroy(&reftree);
+               space_reftree_generate_map(&reftree, vd->vdev_dtl[t], minref);
+               space_reftree_destroy(&reftree);
        }
        mutex_exit(&vd->vdev_dtl_lock);
 }
 
-static int
+int
 vdev_dtl_load(vdev_t *vd)
 {
        spa_t *spa = vd->vdev_spa;
-       space_map_obj_t *smo = &vd->vdev_dtl_smo;
        objset_t *mos = spa->spa_meta_objset;
-       dmu_buf_t *db;
-       int error;
+       int error = 0;
+       int c;
 
-       ASSERT(vd->vdev_children == 0);
+       if (vd->vdev_ops->vdev_op_leaf && vd->vdev_dtl_object != 0) {
+               ASSERT(!vd->vdev_ishole);
 
-       if (smo->smo_object == 0)
-               return (0);
+               error = space_map_open(&vd->vdev_dtl_sm, mos,
+                   vd->vdev_dtl_object, 0, -1ULL, 0, &vd->vdev_dtl_lock);
+               if (error)
+                       return (error);
+               ASSERT(vd->vdev_dtl_sm != NULL);
 
-       ASSERT(!vd->vdev_ishole);
+               mutex_enter(&vd->vdev_dtl_lock);
 
-       if ((error = dmu_bonus_hold(mos, smo->smo_object, FTAG, &db)) != 0)
-               return (error);
+               /*
+                * Now that we've opened the space_map we need to update
+                * the in-core DTL.
+                */
+               space_map_update(vd->vdev_dtl_sm);
 
-       ASSERT3U(db->db_size, >=, sizeof (*smo));
-       bcopy(db->db_data, smo, sizeof (*smo));
-       dmu_buf_rele(db, FTAG);
+               error = space_map_load(vd->vdev_dtl_sm,
+                   vd->vdev_dtl[DTL_MISSING], SM_ALLOC);
+               mutex_exit(&vd->vdev_dtl_lock);
 
-       mutex_enter(&vd->vdev_dtl_lock);
-       error = space_map_load(&vd->vdev_dtl[DTL_MISSING],
-           NULL, SM_ALLOC, smo, mos);
-       mutex_exit(&vd->vdev_dtl_lock);
+               return (error);
+       }
+
+       for (c = 0; c < vd->vdev_children; c++) {
+               error = vdev_dtl_load(vd->vdev_child[c]);
+               if (error != 0)
+                       break;
+       }
 
        return (error);
 }
@@ -1900,64 +1940,74 @@ void
 vdev_dtl_sync(vdev_t *vd, uint64_t txg)
 {
        spa_t *spa = vd->vdev_spa;
-       space_map_obj_t *smo = &vd->vdev_dtl_smo;
-       space_map_t *sm = &vd->vdev_dtl[DTL_MISSING];
+       range_tree_t *rt = vd->vdev_dtl[DTL_MISSING];
        objset_t *mos = spa->spa_meta_objset;
-       space_map_t smsync;
-       kmutex_t smlock;
-       dmu_buf_t *db;
+       range_tree_t *rtsync;
+       kmutex_t rtlock;
        dmu_tx_t *tx;
+       uint64_t object = space_map_object(vd->vdev_dtl_sm);
 
        ASSERT(!vd->vdev_ishole);
+       ASSERT(vd->vdev_ops->vdev_op_leaf);
 
        tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
 
-       if (vd->vdev_detached) {
-               if (smo->smo_object != 0) {
-                       VERIFY0(dmu_object_free(mos, smo->smo_object, tx));
-                       smo->smo_object = 0;
-               }
+       if (vd->vdev_detached || vd->vdev_top->vdev_removing) {
+               mutex_enter(&vd->vdev_dtl_lock);
+               space_map_free(vd->vdev_dtl_sm, tx);
+               space_map_close(vd->vdev_dtl_sm);
+               vd->vdev_dtl_sm = NULL;
+               mutex_exit(&vd->vdev_dtl_lock);
                dmu_tx_commit(tx);
                return;
        }
 
-       if (smo->smo_object == 0) {
-               ASSERT(smo->smo_objsize == 0);
-               ASSERT(smo->smo_alloc == 0);
-               smo->smo_object = dmu_object_alloc(mos,
-                   DMU_OT_SPACE_MAP, 1 << SPACE_MAP_BLOCKSHIFT,
-                   DMU_OT_SPACE_MAP_HEADER, sizeof (*smo), tx);
-               ASSERT(smo->smo_object != 0);
-               vdev_config_dirty(vd->vdev_top);
+       if (vd->vdev_dtl_sm == NULL) {
+               uint64_t new_object;
+
+               new_object = space_map_alloc(mos, tx);
+               VERIFY3U(new_object, !=, 0);
+
+               VERIFY0(space_map_open(&vd->vdev_dtl_sm, mos, new_object,
+                   0, -1ULL, 0, &vd->vdev_dtl_lock));
+               ASSERT(vd->vdev_dtl_sm != NULL);
        }
 
-       mutex_init(&smlock, NULL, MUTEX_DEFAULT, NULL);
+       mutex_init(&rtlock, NULL, MUTEX_DEFAULT, NULL);
 
-       space_map_create(&smsync, sm->sm_start, sm->sm_size, sm->sm_shift,
-           &smlock);
+       rtsync = range_tree_create(NULL, NULL, &rtlock);
 
-       mutex_enter(&smlock);
+       mutex_enter(&rtlock);
 
        mutex_enter(&vd->vdev_dtl_lock);
-       space_map_walk(sm, space_map_add, &smsync);
+       range_tree_walk(rt, range_tree_add, rtsync);
        mutex_exit(&vd->vdev_dtl_lock);
 
-       space_map_truncate(smo, mos, tx);
-       space_map_sync(&smsync, SM_ALLOC, smo, mos, tx);
-       space_map_vacate(&smsync, NULL, NULL);
+       space_map_truncate(vd->vdev_dtl_sm, tx);
+       space_map_write(vd->vdev_dtl_sm, rtsync, SM_ALLOC, tx);
+       range_tree_vacate(rtsync, NULL, NULL);
 
-       space_map_destroy(&smsync);
+       range_tree_destroy(rtsync);
 
-       mutex_exit(&smlock);
-       mutex_destroy(&smlock);
+       mutex_exit(&rtlock);
+       mutex_destroy(&rtlock);
 
-       VERIFY(0 == dmu_bonus_hold(mos, smo->smo_object, FTAG, &db));
-       dmu_buf_will_dirty(db, tx);
-       ASSERT3U(db->db_size, >=, sizeof (*smo));
-       bcopy(smo, db->db_data, sizeof (*smo));
-       dmu_buf_rele(db, FTAG);
+       /*
+        * If the object for the space map has changed then dirty
+        * the top level so that we update the config.
+        */
+       if (object != space_map_object(vd->vdev_dtl_sm)) {
+               zfs_dbgmsg("txg %llu, spa %s, DTL old object %llu, "
+                   "new object %llu", txg, spa_name(spa), object,
+                   space_map_object(vd->vdev_dtl_sm));
+               vdev_config_dirty(vd->vdev_top);
+       }
 
        dmu_tx_commit(tx);
+
+       mutex_enter(&vd->vdev_dtl_lock);
+       space_map_update(vd->vdev_dtl_sm);
+       mutex_exit(&vd->vdev_dtl_lock);
 }
 
 /*
@@ -2007,7 +2057,7 @@ vdev_resilver_needed(vdev_t *vd, uint64_t *minp, uint64_t *maxp)
 
        if (vd->vdev_children == 0) {
                mutex_enter(&vd->vdev_dtl_lock);
-               if (vd->vdev_dtl[DTL_MISSING].sm_space != 0 &&
+               if (range_tree_space(vd->vdev_dtl[DTL_MISSING]) != 0 &&
                    vdev_writeable(vd)) {
 
                        thismin = vdev_dtl_min(vd);
@@ -2111,33 +2161,49 @@ vdev_remove(vdev_t *vd, uint64_t txg)
        spa_t *spa = vd->vdev_spa;
        objset_t *mos = spa->spa_meta_objset;
        dmu_tx_t *tx;
-       int m;
+       int m, i;
 
        tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg);
 
-       if (vd->vdev_dtl_smo.smo_object) {
-               ASSERT0(vd->vdev_dtl_smo.smo_alloc);
-               (void) dmu_object_free(mos, vd->vdev_dtl_smo.smo_object, tx);
-               vd->vdev_dtl_smo.smo_object = 0;
-       }
-
        if (vd->vdev_ms != NULL) {
+               metaslab_group_t *mg = vd->vdev_mg;
+
+               metaslab_group_histogram_verify(mg);
+               metaslab_class_histogram_verify(mg->mg_class);
+
                for (m = 0; m < vd->vdev_ms_count; m++) {
                        metaslab_t *msp = vd->vdev_ms[m];
 
-                       if (msp == NULL || msp->ms_smo.smo_object == 0)
+                       if (msp == NULL || msp->ms_sm == NULL)
                                continue;
 
-                       ASSERT0(msp->ms_smo.smo_alloc);
-                       (void) dmu_object_free(mos, msp->ms_smo.smo_object, tx);
-                       msp->ms_smo.smo_object = 0;
+                       mutex_enter(&msp->ms_lock);
+                       /*
+                        * If the metaslab was not loaded when the vdev
+                        * was removed then the histogram accounting may
+                        * not be accurate. Update the histogram information
+                        * here so that we ensure that the metaslab group
+                        * and metaslab class are up-to-date.
+                        */
+                       metaslab_group_histogram_remove(mg, msp);
+
+                       VERIFY0(space_map_allocated(msp->ms_sm));
+                       space_map_free(msp->ms_sm, tx);
+                       space_map_close(msp->ms_sm);
+                       msp->ms_sm = NULL;
+                       mutex_exit(&msp->ms_lock);
                }
+
+               metaslab_group_histogram_verify(mg);
+               metaslab_class_histogram_verify(mg->mg_class);
+               for (i = 0; i < RANGE_TREE_HISTOGRAM_SIZE; i++)
+                       ASSERT0(mg->mg_histogram[i]);
+
        }
 
        if (vd->vdev_ms_array) {
                (void) dmu_object_free(mos, vd->vdev_ms_array, tx);
                vd->vdev_ms_array = 0;
-               vd->vdev_ms_shift = 0;
        }
        dmu_tx_commit(tx);
 }
@@ -2585,9 +2651,12 @@ vdev_accessible(vdev_t *vd, zio_t *zio)
 void
 vdev_get_stats(vdev_t *vd, vdev_stat_t *vs)
 {
-       vdev_t *rvd = vd->vdev_spa->spa_root_vdev;
+       spa_t *spa = vd->vdev_spa;
+       vdev_t *rvd = spa->spa_root_vdev;
        int c, t;
 
+       ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
+
        mutex_enter(&vd->vdev_stat_lock);
        bcopy(&vd->vdev_stat, vs, sizeof (*vs));
        vs->vs_timestamp = gethrtime() - vs->vs_timestamp;
@@ -2596,7 +2665,9 @@ vdev_get_stats(vdev_t *vd, vdev_stat_t *vs)
        if (vd->vdev_ops->vdev_op_leaf)
                vs->vs_rsize += VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE;
        vs->vs_esize = vd->vdev_max_asize - vd->vdev_asize;
-       mutex_exit(&vd->vdev_stat_lock);
+       if (vd->vdev_aux == NULL && vd == vd->vdev_top && !vd->vdev_ishole) {
+               vs->vs_fragmentation = vd->vdev_mg->mg_fragmentation;
+       }
 
        /*
         * If we're getting stats on the root vdev, aggregate the I/O counts
@@ -2607,15 +2678,14 @@ vdev_get_stats(vdev_t *vd, vdev_stat_t *vs)
                        vdev_t *cvd = rvd->vdev_child[c];
                        vdev_stat_t *cvs = &cvd->vdev_stat;
 
-                       mutex_enter(&vd->vdev_stat_lock);
                        for (t = 0; t < ZIO_TYPES; t++) {
                                vs->vs_ops[t] += cvs->vs_ops[t];
                                vs->vs_bytes[t] += cvs->vs_bytes[t];
                        }
                        cvs->vs_scan_removing = cvd->vdev_removing;
-                       mutex_exit(&vd->vdev_stat_lock);
                }
        }
+       mutex_exit(&vd->vdev_stat_lock);
 }
 
 void
@@ -3327,4 +3397,9 @@ EXPORT_SYMBOL(vdev_degrade);
 EXPORT_SYMBOL(vdev_online);
 EXPORT_SYMBOL(vdev_offline);
 EXPORT_SYMBOL(vdev_clear);
+
+module_param(metaslabs_per_vdev, int, 0644);
+MODULE_PARM_DESC(metaslabs_per_vdev,
+       "Divide added vdev into approximately (but no more than) this number "
+       "of metaslabs");
 #endif