2 files changed, 370 insertions, 56 deletions

diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c
index e0ea07280..8ccbd5e8b 100644
--- a/cmd/zdb/zdb.c
+++ b/cmd/zdb/zdb.c
@@ -813,6 +813,12 @@ get_checkpoint_refcount(vdev_t *vd)
 }
 
 static int
+get_log_spacemap_refcount(spa_t *spa)
+{
+	return (avl_numnodes(&spa->spa_sm_logs_by_txg));
+}
+
+static int
 verify_spacemap_refcounts(spa_t *spa)
 {
 	uint64_t expected_refcount = 0;
@@ -826,6 +832,7 @@ verify_spacemap_refcounts(spa_t *spa)
 	actual_refcount += get_obsolete_refcount(spa->spa_root_vdev);
 	actual_refcount += get_prev_obsolete_spacemap_refcount(spa);
 	actual_refcount += get_checkpoint_refcount(spa->spa_root_vdev);
+	actual_refcount += get_log_spacemap_refcount(spa);
 
 	if (expected_refcount != actual_refcount) {
 		(void) printf("space map refcount mismatch: expected %lld != "
@@ -924,7 +931,7 @@ dump_spacemap(objset_t *os, space_map_t *sm)
 			alloc -= entry_run;
 		entry_id++;
 	}
-	if ((uint64_t)alloc != space_map_allocated(sm)) {
+	if (alloc != space_map_allocated(sm)) {
 		(void) printf("space_map_object alloc (%lld) INCONSISTENT "
 		    "with space map summary (%lld)\n",
 		    (longlong_t)space_map_allocated(sm), (longlong_t)alloc);
@@ -990,23 +997,45 @@ dump_metaslab(metaslab_t *msp)
 
 	ASSERT(msp->ms_size == (1ULL << vd->vdev_ms_shift));
 	dump_spacemap(spa->spa_meta_objset, msp->ms_sm);
+
+	if (spa_feature_is_active(spa, SPA_FEATURE_LOG_SPACEMAP)) {
+		(void) printf("\tFlush data:\n\tunflushed txg=%llu\n\n",
+		    (u_longlong_t)metaslab_unflushed_txg(msp));
+	}
 }
 
 static void
 print_vdev_metaslab_header(vdev_t *vd)
 {
 	vdev_alloc_bias_t alloc_bias = vd->vdev_alloc_bias;
-	const char *bias_str;
+	const char *bias_str = "";
+	if (alloc_bias == VDEV_BIAS_LOG || vd->vdev_islog) {
+		bias_str = VDEV_ALLOC_BIAS_LOG;
+	} else if (alloc_bias == VDEV_BIAS_SPECIAL) {
+		bias_str = VDEV_ALLOC_BIAS_SPECIAL;
+	} else if (alloc_bias == VDEV_BIAS_DEDUP) {
+		bias_str = VDEV_ALLOC_BIAS_DEDUP;
+	}
+
+	uint64_t ms_flush_data_obj = 0;
+	if (vd->vdev_top_zap != 0) {
+		int error = zap_lookup(spa_meta_objset(vd->vdev_spa),
+		    vd->vdev_top_zap, VDEV_TOP_ZAP_MS_UNFLUSHED_PHYS_TXGS,
+		    sizeof (uint64_t), 1, &ms_flush_data_obj);
+		if (error != ENOENT) {
+			ASSERT0(error);
+		}
+	}
+
+	(void) printf("\tvdev %10llu   %s",
+	    (u_longlong_t)vd->vdev_id, bias_str);
 
-	bias_str = (alloc_bias == VDEV_BIAS_LOG || vd->vdev_islog) ?
-	    VDEV_ALLOC_BIAS_LOG :
-	    (alloc_bias == VDEV_BIAS_SPECIAL) ? VDEV_ALLOC_BIAS_SPECIAL :
-	    (alloc_bias == VDEV_BIAS_DEDUP) ? VDEV_ALLOC_BIAS_DEDUP :
-	    vd->vdev_islog ? "log" : "";
+	if (ms_flush_data_obj != 0) {
+		(void) printf("   ms_unflushed_phys object %llu",
+		    (u_longlong_t)ms_flush_data_obj);
+	}
 
-	(void) printf("\tvdev %10llu   %s\n"
-	    "\t%-10s%5llu   %-19s   %-15s   %-12s\n",
-	    (u_longlong_t)vd->vdev_id, bias_str,
+	(void) printf("\n\t%-10s%5llu   %-19s   %-15s   %-12s\n",
 	    "metaslabs", (u_longlong_t)vd->vdev_ms_count,
 	    "offset", "spacemap", "free");
 	(void) printf("\t%15s   %19s   %15s   %12s\n",
@@ -1173,6 +1202,24 @@ dump_metaslabs(spa_t *spa)
 }
 
 static void
+dump_log_spacemaps(spa_t *spa)
+{
+	(void) printf("\nLog Space Maps in Pool:\n");
+	for (spa_log_sm_t *sls = avl_first(&spa->spa_sm_logs_by_txg);
+	    sls; sls = AVL_NEXT(&spa->spa_sm_logs_by_txg, sls)) {
+		space_map_t *sm = NULL;
+		VERIFY0(space_map_open(&sm, spa_meta_objset(spa),
+		    sls->sls_sm_obj, 0, UINT64_MAX, SPA_MINBLOCKSHIFT));
+
+		(void) printf("Log Spacemap object %llu txg %llu\n",
+		    (u_longlong_t)sls->sls_sm_obj, (u_longlong_t)sls->sls_txg);
+		dump_spacemap(spa->spa_meta_objset, sm);
+		space_map_close(sm);
+	}
+	(void) printf("\n");
+}
+
+static void
 dump_dde(const ddt_t *ddt, const ddt_entry_t *dde, uint64_t index)
 {
 	const ddt_phys_t *ddp = dde->dde_phys;
@@ -3782,6 +3829,84 @@ static metaslab_ops_t zdb_metaslab_ops = {
 	NULL	/* alloc */
 };
 
+typedef int (*zdb_log_sm_cb_t)(spa_t *spa, space_map_entry_t *sme,
+    uint64_t txg, void *arg);
+
+typedef struct unflushed_iter_cb_arg {
+	spa_t *uic_spa;
+	uint64_t uic_txg;
+	void *uic_arg;
+	zdb_log_sm_cb_t uic_cb;
+} unflushed_iter_cb_arg_t;
+
+static int
+iterate_through_spacemap_logs_cb(space_map_entry_t *sme, void *arg)
+{
+	unflushed_iter_cb_arg_t *uic = arg;
+	return (uic->uic_cb(uic->uic_spa, sme, uic->uic_txg, uic->uic_arg));
+}
+
+static void
+iterate_through_spacemap_logs(spa_t *spa, zdb_log_sm_cb_t cb, void *arg)
+{
+	if (!spa_feature_is_active(spa, SPA_FEATURE_LOG_SPACEMAP))
+		return;
+
+	spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
+	for (spa_log_sm_t *sls = avl_first(&spa->spa_sm_logs_by_txg);
+	    sls; sls = AVL_NEXT(&spa->spa_sm_logs_by_txg, sls)) {
+		space_map_t *sm = NULL;
+		VERIFY0(space_map_open(&sm, spa_meta_objset(spa),
+		    sls->sls_sm_obj, 0, UINT64_MAX, SPA_MINBLOCKSHIFT));
+
+		unflushed_iter_cb_arg_t uic = {
+			.uic_spa = spa,
+			.uic_txg = sls->sls_txg,
+			.uic_arg = arg,
+			.uic_cb = cb
+		};
+
+		VERIFY0(space_map_iterate(sm, space_map_length(sm),
+		    iterate_through_spacemap_logs_cb, &uic));
+		space_map_close(sm);
+	}
+	spa_config_exit(spa, SCL_CONFIG, FTAG);
+}
+
+/* ARGSUSED */
+static int
+load_unflushed_svr_segs_cb(spa_t *spa, space_map_entry_t *sme,
+    uint64_t txg, void *arg)
+{
+	spa_vdev_removal_t *svr = arg;
+
+	uint64_t offset = sme->sme_offset;
+	uint64_t size = sme->sme_run;
+
+	/* skip vdevs we don't care about */
+	if (sme->sme_vdev != svr->svr_vdev_id)
+		return (0);
+
+	vdev_t *vd = vdev_lookup_top(spa, sme->sme_vdev);
+	metaslab_t *ms = vd->vdev_ms[offset >> vd->vdev_ms_shift];
+	ASSERT(sme->sme_type == SM_ALLOC || sme->sme_type == SM_FREE);
+
+	if (txg < metaslab_unflushed_txg(ms))
+		return (0);
+
+	vdev_indirect_mapping_t *vim = vd->vdev_indirect_mapping;
+	ASSERT(vim != NULL);
+	if (offset >= vdev_indirect_mapping_max_offset(vim))
+		return (0);
+
+	if (sme->sme_type == SM_ALLOC)
+		range_tree_add(svr->svr_allocd_segs, offset, size);
+	else
+		range_tree_remove(svr->svr_allocd_segs, offset, size);
+
+	return (0);
+}
+
 /* ARGSUSED */
 static void
 claim_segment_impl_cb(uint64_t inner_offset, vdev_t *vd, uint64_t offset,
@@ -3830,36 +3955,35 @@ zdb_claim_removing(spa_t *spa, zdb_cb_t *zcb)
 	vdev_t *vd = vdev_lookup_top(spa, svr->svr_vdev_id);
 	vdev_indirect_mapping_t *vim = vd->vdev_indirect_mapping;
 
+	ASSERT0(range_tree_space(svr->svr_allocd_segs));
+
+	range_tree_t *allocs = range_tree_create(NULL, NULL);
 	for (uint64_t msi = 0; msi < vd->vdev_ms_count; msi++) {
 		metaslab_t *msp = vd->vdev_ms[msi];
 
 		if (msp->ms_start >= vdev_indirect_mapping_max_offset(vim))
 			break;
 
-		ASSERT0(range_tree_space(svr->svr_allocd_segs));
+		ASSERT0(range_tree_space(allocs));
+		if (msp->ms_sm != NULL)
+			VERIFY0(space_map_load(msp->ms_sm, allocs, SM_ALLOC));
+		range_tree_vacate(allocs, range_tree_add, svr->svr_allocd_segs);
+	}
+	range_tree_destroy(allocs);
 
-		if (msp->ms_sm != NULL) {
-			VERIFY0(space_map_load(msp->ms_sm,
-			    svr->svr_allocd_segs, SM_ALLOC));
+	iterate_through_spacemap_logs(spa, load_unflushed_svr_segs_cb, svr);
 
-			/*
-			 * Clear everything past what has been synced unless
-			 * it's past the spacemap, because we have not allocated
-			 * mappings for it yet.
-			 */
-			uint64_t vim_max_offset =
-			    vdev_indirect_mapping_max_offset(vim);
-			uint64_t sm_end = msp->ms_sm->sm_start +
-			    msp->ms_sm->sm_size;
-			if (sm_end > vim_max_offset)
-				range_tree_clear(svr->svr_allocd_segs,
-				    vim_max_offset, sm_end - vim_max_offset);
-		}
+	/*
+	 * Clear everything past what has been synced,
+	 * because we have not allocated mappings for
+	 * it yet.
+	 */
+	range_tree_clear(svr->svr_allocd_segs,
+	    vdev_indirect_mapping_max_offset(vim),
+	    vd->vdev_asize - vdev_indirect_mapping_max_offset(vim));
 
-		zcb->zcb_removing_size +=
-		    range_tree_space(svr->svr_allocd_segs);
-		range_tree_vacate(svr->svr_allocd_segs, claim_segment_cb, vd);
-	}
+	zcb->zcb_removing_size += range_tree_space(svr->svr_allocd_segs);
+	range_tree_vacate(svr->svr_allocd_segs, claim_segment_cb, vd);
 
 	spa_config_exit(spa, SCL_CONFIG, FTAG);
 }
@@ -4070,6 +4194,82 @@ zdb_leak_init_exclude_checkpoint(spa_t *spa, zdb_cb_t *zcb)
 	}
 }
 
+static int
+count_unflushed_space_cb(spa_t *spa, space_map_entry_t *sme,
+    uint64_t txg, void *arg)
+{
+	int64_t *ualloc_space = arg;
+
+	uint64_t offset = sme->sme_offset;
+	uint64_t vdev_id = sme->sme_vdev;
+
+	vdev_t *vd = vdev_lookup_top(spa, vdev_id);
+	if (!vdev_is_concrete(vd))
+		return (0);
+
+	metaslab_t *ms = vd->vdev_ms[offset >> vd->vdev_ms_shift];
+	ASSERT(sme->sme_type == SM_ALLOC || sme->sme_type == SM_FREE);
+
+	if (txg < metaslab_unflushed_txg(ms))
+		return (0);
+
+	if (sme->sme_type == SM_ALLOC)
+		*ualloc_space += sme->sme_run;
+	else
+		*ualloc_space -= sme->sme_run;
+
+	return (0);
+}
+
+static int64_t
+get_unflushed_alloc_space(spa_t *spa)
+{
+	if (dump_opt['L'])
+		return (0);
+
+	int64_t ualloc_space = 0;
+	iterate_through_spacemap_logs(spa, count_unflushed_space_cb,
+	    &ualloc_space);
+	return (ualloc_space);
+}
+
+static int
+load_unflushed_cb(spa_t *spa, space_map_entry_t *sme, uint64_t txg, void *arg)
+{
+	maptype_t *uic_maptype = arg;
+
+	uint64_t offset = sme->sme_offset;
+	uint64_t size = sme->sme_run;
+	uint64_t vdev_id = sme->sme_vdev;
+
+	vdev_t *vd = vdev_lookup_top(spa, vdev_id);
+
+	/* skip indirect vdevs */
+	if (!vdev_is_concrete(vd))
+		return (0);
+
+	metaslab_t *ms = vd->vdev_ms[offset >> vd->vdev_ms_shift];
+
+	ASSERT(sme->sme_type == SM_ALLOC || sme->sme_type == SM_FREE);
+	ASSERT(*uic_maptype == SM_ALLOC || *uic_maptype == SM_FREE);
+
+	if (txg < metaslab_unflushed_txg(ms))
+		return (0);
+
+	if (*uic_maptype == sme->sme_type)
+		range_tree_add(ms->ms_allocatable, offset, size);
+	else
+		range_tree_remove(ms->ms_allocatable, offset, size);
+
+	return (0);
+}
+
+static void
+load_unflushed_to_ms_allocatables(spa_t *spa, maptype_t maptype)
+{
+	iterate_through_spacemap_logs(spa, load_unflushed_cb, &maptype);
+}
+
 static void
 load_concrete_ms_allocatable_trees(spa_t *spa, maptype_t maptype)
 {
@@ -4093,7 +4293,7 @@ load_concrete_ms_allocatable_trees(spa_t *spa, maptype_t maptype)
 			    (longlong_t)vd->vdev_ms_count);
 
 			mutex_enter(&msp->ms_lock);
-			metaslab_unload(msp);
+			range_tree_vacate(msp->ms_allocatable, NULL, NULL);
 
 			/*
 			 * We don't want to spend the CPU manipulating the
@@ -4110,6 +4310,8 @@ load_concrete_ms_allocatable_trees(spa_t *spa, maptype_t maptype)
 			mutex_exit(&msp->ms_lock);
 		}
 	}
+
+	load_unflushed_to_ms_allocatables(spa, maptype);
 }
 
 /*
@@ -4124,7 +4326,7 @@ load_indirect_ms_allocatable_tree(vdev_t *vd, metaslab_t *msp,
 	vdev_indirect_mapping_t *vim = vd->vdev_indirect_mapping;
 
 	mutex_enter(&msp->ms_lock);
-	metaslab_unload(msp);
+	range_tree_vacate(msp->ms_allocatable, NULL, NULL);
 
 	/*
 	 * We don't want to spend the CPU manipulating the
@@ -4383,7 +4585,6 @@ zdb_leak_fini(spa_t *spa, zdb_cb_t *zcb)
 				range_tree_vacate(msp->ms_allocatable,
 				    zdb_leak, vd);
 			}
-
 			if (msp->ms_loaded) {
 				msp->ms_loaded = B_FALSE;
 			}
@@ -4520,7 +4721,8 @@ dump_block_stats(spa_t *spa)
 	total_alloc = norm_alloc +
 	    metaslab_class_get_alloc(spa_log_class(spa)) +
 	    metaslab_class_get_alloc(spa_special_class(spa)) +
-	    metaslab_class_get_alloc(spa_dedup_class(spa));
+	    metaslab_class_get_alloc(spa_dedup_class(spa)) +
+	    get_unflushed_alloc_space(spa);
 	total_found = tzb->zb_asize - zcb.zcb_dedup_asize +
 	    zcb.zcb_removing_size + zcb.zcb_checkpoint_size;
 
@@ -5393,11 +5595,24 @@ mos_obj_refd_multiple(uint64_t obj)
 }
 
 static void
+mos_leak_vdev_top_zap(vdev_t *vd)
+{
+	uint64_t ms_flush_data_obj;
+	int error = zap_lookup(spa_meta_objset(vd->vdev_spa),
+	    vd->vdev_top_zap, VDEV_TOP_ZAP_MS_UNFLUSHED_PHYS_TXGS,
+	    sizeof (ms_flush_data_obj), 1, &ms_flush_data_obj);
+	if (error == ENOENT)
+		return;
+	ASSERT0(error);
+
+	mos_obj_refd(ms_flush_data_obj);
+}
+
+static void
 mos_leak_vdev(vdev_t *vd)
 {
 	mos_obj_refd(vd->vdev_dtl_object);
 	mos_obj_refd(vd->vdev_ms_array);
-	mos_obj_refd(vd->vdev_top_zap);
 	mos_obj_refd(vd->vdev_indirect_config.vic_births_object);
 	mos_obj_refd(vd->vdev_indirect_config.vic_mapping_object);
 	mos_obj_refd(vd->vdev_leaf_zap);
@@ -5415,11 +5630,33 @@ mos_leak_vdev(vdev_t *vd)
 		mos_obj_refd(space_map_object(ms->ms_sm));
 	}
 
+	if (vd->vdev_top_zap != 0) {
+		mos_obj_refd(vd->vdev_top_zap);
+		mos_leak_vdev_top_zap(vd);
+	}
+
 	for (uint64_t c = 0; c < vd->vdev_children; c++) {
 		mos_leak_vdev(vd->vdev_child[c]);
 	}
 }
 
+static void
+mos_leak_log_spacemaps(spa_t *spa)
+{
+	uint64_t spacemap_zap;
+	int error = zap_lookup(spa_meta_objset(spa),
+	    DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_LOG_SPACEMAP_ZAP,
+	    sizeof (spacemap_zap), 1, &spacemap_zap);
+	if (error == ENOENT)
+		return;
+	ASSERT0(error);
+
+	mos_obj_refd(spacemap_zap);
+	for (spa_log_sm_t *sls = avl_first(&spa->spa_sm_logs_by_txg);
+	    sls; sls = AVL_NEXT(&spa->spa_sm_logs_by_txg, sls))
+		mos_obj_refd(sls->sls_sm_obj);
+}
+
 static int
 dump_mos_leaks(spa_t *spa)
 {
@@ -5451,6 +5688,10 @@ dump_mos_leaks(spa_t *spa)
 	mos_obj_refd(spa->spa_l2cache.sav_object);
 	mos_obj_refd(spa->spa_spares.sav_object);
 
+	if (spa->spa_syncing_log_sm != NULL)
+		mos_obj_refd(spa->spa_syncing_log_sm->sm_object);
+	mos_leak_log_spacemaps(spa);
+
 	mos_obj_refd(spa->spa_condensing_indirect_phys.
 	    scip_next_mapping_object);
 	mos_obj_refd(spa->spa_condensing_indirect_phys.
@@ -5528,6 +5769,79 @@ dump_mos_leaks(spa_t *spa)
 	return (rv);
 }
 
+typedef struct log_sm_obsolete_stats_arg {
+	uint64_t lsos_current_txg;
+
+	uint64_t lsos_total_entries;
+	uint64_t lsos_valid_entries;
+
+	uint64_t lsos_sm_entries;
+	uint64_t lsos_valid_sm_entries;
+} log_sm_obsolete_stats_arg_t;
+
+static int
+log_spacemap_obsolete_stats_cb(spa_t *spa, space_map_entry_t *sme,
+    uint64_t txg, void *arg)
+{
+	log_sm_obsolete_stats_arg_t *lsos = arg;
+
+	uint64_t offset = sme->sme_offset;
+	uint64_t vdev_id = sme->sme_vdev;
+
+	if (lsos->lsos_current_txg == 0) {
+		/* this is the first log */
+		lsos->lsos_current_txg = txg;
+	} else if (lsos->lsos_current_txg < txg) {
+		/* we just changed log - print stats and reset */
+		(void) printf("%-8llu valid entries out of %-8llu - txg %llu\n",
+		    (u_longlong_t)lsos->lsos_valid_sm_entries,
+		    (u_longlong_t)lsos->lsos_sm_entries,
+		    (u_longlong_t)lsos->lsos_current_txg);
+		lsos->lsos_valid_sm_entries = 0;
+		lsos->lsos_sm_entries = 0;
+		lsos->lsos_current_txg = txg;
+	}
+	ASSERT3U(lsos->lsos_current_txg, ==, txg);
+
+	lsos->lsos_sm_entries++;
+	lsos->lsos_total_entries++;
+
+	vdev_t *vd = vdev_lookup_top(spa, vdev_id);
+	if (!vdev_is_concrete(vd))
+		return (0);
+
+	metaslab_t *ms = vd->vdev_ms[offset >> vd->vdev_ms_shift];
+	ASSERT(sme->sme_type == SM_ALLOC || sme->sme_type == SM_FREE);
+
+	if (txg < metaslab_unflushed_txg(ms))
+		return (0);
+	lsos->lsos_valid_sm_entries++;
+	lsos->lsos_valid_entries++;
+	return (0);
+}
+
+static void
+dump_log_spacemap_obsolete_stats(spa_t *spa)
+{
+	log_sm_obsolete_stats_arg_t lsos;
+	bzero(&lsos, sizeof (lsos));
+
+	(void) printf("Log Space Map Obsolete Entry Statistics:\n");
+
+	iterate_through_spacemap_logs(spa,
+	    log_spacemap_obsolete_stats_cb, &lsos);
+
+	/* print stats for latest log */
+	(void) printf("%-8llu valid entries out of %-8llu - txg %llu\n",
+	    (u_longlong_t)lsos.lsos_valid_sm_entries,
+	    (u_longlong_t)lsos.lsos_sm_entries,
+	    (u_longlong_t)lsos.lsos_current_txg);
+
+	(void) printf("%-8llu valid entries out of %-8llu - total\n\n",
+	    (u_longlong_t)lsos.lsos_valid_entries,
+	    (u_longlong_t)lsos.lsos_total_entries);
+}
+
 static void
 dump_zpool(spa_t *spa)
 {
@@ -5557,6 +5871,10 @@ dump_zpool(spa_t *spa)
 		dump_metaslabs(spa);
 	if (dump_opt['M'])
 		dump_metaslab_groups(spa);
+	if (dump_opt['d'] > 2 || dump_opt['m']) {
+		dump_log_spacemaps(spa);
+		dump_log_spacemap_obsolete_stats(spa);
+	}
 
 	if (dump_opt['d'] || dump_opt['i']) {
 		spa_feature_t f;
@@ -5635,9 +5953,8 @@ dump_zpool(spa_t *spa)
 			}
 		}
 
-		if (rc == 0) {
+		if (rc == 0)
 			rc = verify_device_removal_feature_counts(spa);
-		}
 	}
 
 	if (rc == 0 && (dump_opt['b'] || dump_opt['c']))
diff --git a/cmd/ztest/ztest.c b/cmd/ztest/ztest.c
index f67d94fa8..3b1be5d40 100644
--- a/cmd/ztest/ztest.c
+++ b/cmd/ztest/ztest.c
@@ -2924,24 +2924,12 @@ vdev_lookup_by_path(vdev_t *vd, const char *path)
 	return (NULL);
 }
 
-/*
- * Find the first available hole which can be used as a top-level.
- */
-int
-find_vdev_hole(spa_t *spa)
+static int
+spa_num_top_vdevs(spa_t *spa)
 {
 	vdev_t *rvd = spa->spa_root_vdev;
-	int c;
-
-	ASSERT(spa_config_held(spa, SCL_VDEV, RW_READER) == SCL_VDEV);
-
-	for (c = 0; c < rvd->vdev_children; c++) {
-		vdev_t *cvd = rvd->vdev_child[c];
-
-		if (cvd->vdev_ishole)
-			break;
-	}
-	return (c);
+	ASSERT3U(spa_config_held(spa, SCL_VDEV, RW_READER), ==, SCL_VDEV);
+	return (rvd->vdev_children);
 }
 
 /*
@@ -2966,7 +2954,7 @@ ztest_vdev_add_remove(ztest_ds_t *zd, uint64_t id)
 
 	spa_config_enter(spa, SCL_VDEV, FTAG, RW_READER);
 
-	ztest_shared->zs_vdev_next_leaf = find_vdev_hole(spa) * leaves;
+	ztest_shared->zs_vdev_next_leaf = spa_num_top_vdevs(spa) * leaves;
 
 	/*
 	 * If we have slogs then remove them 1/4 of the time.
@@ -3073,7 +3061,7 @@ ztest_vdev_class_add(ztest_ds_t *zd, uint64_t id)
 	leaves = MAX(zs->zs_mirrors + zs->zs_splits, 1) * ztest_opts.zo_raidz;
 
 	spa_config_enter(spa, SCL_VDEV, FTAG, RW_READER);
-	ztest_shared->zs_vdev_next_leaf = find_vdev_hole(spa) * leaves;
+	ztest_shared->zs_vdev_next_leaf = spa_num_top_vdevs(spa) * leaves;
 	spa_config_exit(spa, SCL_VDEV, FTAG);
 
 	nvroot = make_vdev_root(NULL, NULL, NULL, ztest_opts.zo_vdev_size, 0,
@@ -7329,6 +7317,15 @@ ztest_init(ztest_shared_t *zs)
 
 	for (i = 0; i < SPA_FEATURES; i++) {
 		char *buf;
+
+		/*
+		 * 75% chance of using the log space map feature. We want ztest
+		 * to exercise both the code paths that use the log space map
+		 * feature and the ones that don't.
+		 */
+		if (i == SPA_FEATURE_LOG_SPACEMAP && ztest_random(4) == 0)
+			continue;
+
 		VERIFY3S(-1, !=, asprintf(&buf, "feature@%s",
 		    spa_feature_table[i].fi_uname));
 		VERIFY3U(0, ==, nvlist_add_uint64(props, buf, 0));