Merge recent vendor changes:

3100 zvol rename fails with EBUSY when dirty
3104 eliminate empty bpobjs
3120 zinject hangs in zfsdev_ioctl() due to uninitialized zc

References:
  https://www.illumos.org/issues/3100
  https://www.illumos.org/issues/3104
  https://www.illumos.org/issues/3120

Obtained from:	illumos (vendor/illumos, vendor/illumos-sys)
MFC after:	2 weeks

22 files changed, 200 insertions, 51 deletions

diff --git a/UPDATING b/UPDATING
index fc00ae0..73a107c 100644
--- a/UPDATING
+++ b/UPDATING
@@ -24,6 +24,13 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 10.x IS SLOW:
 	disable the most expensive debugging functionality run
 	"ln -s 'abort:false,junk:false' /etc/malloc.conf".)
 
+20120828:
+	A new ZFS feature flag "com.delphix:empty_bpobj" has been merged
+	to -HEAD. Pools that have empty_bpobj in active state can not be
+	imported read-write with ZFS implementations that do not support
+	this feature. For more information read the zpool-features(5)
+	manual page.
+
 20120727:
 	The sparc64 ZFS loader has been changed to no longer try to auto-
 	detect ZFS providers based on diskN aliases but now requires these
diff --git a/cddl/contrib/opensolaris/cmd/zinject/zinject.c b/cddl/contrib/opensolaris/cmd/zinject/zinject.c
index 51d2fc9..d17ed53 100644
--- a/cddl/contrib/opensolaris/cmd/zinject/zinject.c
+++ b/cddl/contrib/opensolaris/cmd/zinject/zinject.c
@@ -297,11 +297,9 @@ static int
 iter_handlers(int (*func)(int, const char *, zinject_record_t *, void *),
     void *data)
 {
-	zfs_cmd_t zc;
+	zfs_cmd_t zc = { 0 };
 	int ret;
 
-	zc.zc_guid = 0;
-
 	while (ioctl(zfs_fd, ZFS_IOC_INJECT_LIST_NEXT, &zc) == 0)
 		if ((ret = func((int)zc.zc_guid, zc.zc_name,
 		    &zc.zc_inject_record, data)) != 0)
@@ -424,7 +422,7 @@ static int
 cancel_one_handler(int id, const char *pool, zinject_record_t *record,
     void *data)
 {
-	zfs_cmd_t zc;
+	zfs_cmd_t zc = { 0 };
 
 	zc.zc_guid = (uint64_t)id;
 
@@ -457,7 +455,7 @@ cancel_all_handlers(void)
 static int
 cancel_handler(int id)
 {
-	zfs_cmd_t zc;
+	zfs_cmd_t zc = { 0 };
 
 	zc.zc_guid = (uint64_t)id;
 
@@ -479,7 +477,7 @@ static int
 register_handler(const char *pool, int flags, zinject_record_t *record,
     int quiet)
 {
-	zfs_cmd_t zc;
+	zfs_cmd_t zc = { 0 };
 
 	(void) strcpy(zc.zc_name, pool);
 	zc.zc_inject_record = *record;
@@ -536,7 +534,7 @@ register_handler(const char *pool, int flags, zinject_record_t *record,
 int
 perform_action(const char *pool, zinject_record_t *record, int cmd)
 {
-	zfs_cmd_t zc;
+	zfs_cmd_t zc = { 0 };
 
 	ASSERT(cmd == VDEV_STATE_DEGRADED || cmd == VDEV_STATE_FAULTED);
 	(void) strlcpy(zc.zc_name, pool, sizeof (zc.zc_name));
diff --git a/cddl/contrib/opensolaris/cmd/zpool/zpool-features.5 b/cddl/contrib/opensolaris/cmd/zpool/zpool-features.5
index a0ba9b5..f4ca97f 100644
--- a/cddl/contrib/opensolaris/cmd/zpool/zpool-features.5
+++ b/cddl/contrib/opensolaris/cmd/zpool/zpool-features.5
@@ -21,7 +21,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd Aug 27, 2012
+.Dd Aug 28, 2012
 .Dt ZPOOL-FEATURES 8
 .Os
 .Sh NAME
@@ -162,6 +162,29 @@ This feature is only
 while
 .Sy freeing
 is non\-zero.
+.It Sy empty_bpobj
+.Bl -column "READ\-ONLY COMPATIBLE" "com.delphix:empty_bpobj"
+.It GUID Ta com.delphix:empty_bpobj
+.It READ\-ONLY COMPATIBLE Ta yes
+.It DEPENDENCIES Ta none
+.El
+.Pp
+This feature increases the performance of creating and using a large number
+of snapshots of a single filesystem or volume, and also reduces the disk
+space required.
+.Pp
+When there are many snapshots, each snapshot uses many Block Pointer Objects
+.Pq bpobj's
+to track blocks associated with that snapshot.
+However, in common use cases, most of these bpobj's are empty.
+This feature allows us to create each bpobj on-demand, thus eliminating the
+empty bpobjs.
+.Pp
+This feature is
+.Sy active
+while there are any filesystems, volumes, or snapshots which were created
+after enabling this feature.
+.El
 .Sh SEE ALSO
 .Xr zpool 8
 .Sh AUTHORS
diff --git a/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_dataset.c b/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_dataset.c
index 63c2a05..8ce5030 100644
--- a/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_dataset.c
+++ b/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_dataset.c
@@ -3546,7 +3546,7 @@ zfs_rollback(zfs_handle_t *zhp, zfs_handle_t *snap, boolean_t force)
 	    zhp->zfs_type == ZFS_TYPE_VOLUME);
 
 	/*
-	 * Destroy all recent snapshots and its dependends.
+	 * Destroy all recent snapshots and their dependents.
 	 */
 	cb.cb_force = force;
 	cb.cb_target = snap->zfs_name;
diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zfeature_common.c b/sys/cddl/contrib/opensolaris/common/zfs/zfeature_common.c
index 6dadd99..1a5948e 100644
--- a/sys/cddl/contrib/opensolaris/common/zfs/zfeature_common.c
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zfeature_common.c
@@ -152,4 +152,7 @@ zpool_feature_init(void)
 	zfeature_register(SPA_FEATURE_ASYNC_DESTROY,
 	    "com.delphix:async_destroy", "async_destroy",
 	    "Destroy filesystems asynchronously.", B_TRUE, B_FALSE, NULL);
+	zfeature_register(SPA_FEATURE_EMPTY_BPOBJ,
+	    "com.delphix:empty_bpobj", "empty_bpobj",
+	    "Snapshots use less space.", B_TRUE, B_FALSE, NULL);
 }
diff --git a/sys/cddl/contrib/opensolaris/common/zfs/zfeature_common.h b/sys/cddl/contrib/opensolaris/common/zfs/zfeature_common.h
index b57eb43..cb786b2 100644
--- a/sys/cddl/contrib/opensolaris/common/zfs/zfeature_common.h
+++ b/sys/cddl/contrib/opensolaris/common/zfs/zfeature_common.h
@@ -50,6 +50,7 @@ typedef int (zfeature_func_t)(zfeature_info_t *fi, void *arg);
 
 static enum spa_feature {
 	SPA_FEATURE_ASYNC_DESTROY,
+	SPA_FEATURE_EMPTY_BPOBJ,
 	SPA_FEATURES
 } spa_feature_t;
 
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c
index 022921c..d5f8d40 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c
@@ -20,13 +20,61 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright (c) 2012 by Delphix. All rights reserved.
  */
 
 #include <sys/bpobj.h>
 #include <sys/zfs_context.h>
 #include <sys/refcount.h>
 #include <sys/dsl_pool.h>
+#include <sys/zfeature.h>
+#include <sys/zap.h>
+
+/*
+ * Return an empty bpobj, preferably the empty dummy one (dp_empty_bpobj).
+ */
+uint64_t
+bpobj_alloc_empty(objset_t *os, int blocksize, dmu_tx_t *tx)
+{
+	zfeature_info_t *empty_bpobj_feat =
+	    &spa_feature_table[SPA_FEATURE_EMPTY_BPOBJ];
+	spa_t *spa = dmu_objset_spa(os);
+	dsl_pool_t *dp = dmu_objset_pool(os);
+
+	if (spa_feature_is_enabled(spa, empty_bpobj_feat)) {
+		if (!spa_feature_is_active(spa, empty_bpobj_feat)) {
+			ASSERT3U(dp->dp_empty_bpobj, ==, 0);
+			dp->dp_empty_bpobj =
+			    bpobj_alloc(os, SPA_MAXBLOCKSIZE, tx);
+			VERIFY(zap_add(os,
+			    DMU_POOL_DIRECTORY_OBJECT,
+			    DMU_POOL_EMPTY_BPOBJ, sizeof (uint64_t), 1,
+			    &dp->dp_empty_bpobj, tx) == 0);
+		}
+		spa_feature_incr(spa, empty_bpobj_feat, tx);
+		ASSERT(dp->dp_empty_bpobj != 0);
+		return (dp->dp_empty_bpobj);
+	} else {
+		return (bpobj_alloc(os, blocksize, tx));
+	}
+}
+
+void
+bpobj_decr_empty(objset_t *os, dmu_tx_t *tx)
+{
+	zfeature_info_t *empty_bpobj_feat =
+	    &spa_feature_table[SPA_FEATURE_EMPTY_BPOBJ];
+	dsl_pool_t *dp = dmu_objset_pool(os);
+
+	spa_feature_decr(dmu_objset_spa(os), empty_bpobj_feat, tx);
+	if (!spa_feature_is_active(dmu_objset_spa(os), empty_bpobj_feat)) {
+		VERIFY3U(0, ==, zap_remove(dp->dp_meta_objset,
+		    DMU_POOL_DIRECTORY_OBJECT,
+		    DMU_POOL_EMPTY_BPOBJ, tx));
+		VERIFY3U(0, ==, dmu_object_free(os, dp->dp_empty_bpobj, tx));
+		dp->dp_empty_bpobj = 0;
+	}
+}
 
 uint64_t
 bpobj_alloc(objset_t *os, int blocksize, dmu_tx_t *tx)
@@ -53,6 +101,7 @@ bpobj_free(objset_t *os, uint64_t obj, dmu_tx_t *tx)
 	int epb;
 	dmu_buf_t *dbuf = NULL;
 
+	ASSERT(obj != dmu_objset_pool(os)->dp_empty_bpobj);
 	VERIFY3U(0, ==, bpobj_open(&bpo, os, obj));
 
 	mutex_enter(&bpo.bpo_lock);
@@ -320,6 +369,12 @@ bpobj_enqueue_subobj(bpobj_t *bpo, uint64_t subobj, dmu_tx_t *tx)
 
 	ASSERT(bpo->bpo_havesubobj);
 	ASSERT(bpo->bpo_havecomp);
+	ASSERT(bpo->bpo_object != dmu_objset_pool(bpo->bpo_os)->dp_empty_bpobj);
+
+	if (subobj == dmu_objset_pool(bpo->bpo_os)->dp_empty_bpobj) {
+		bpobj_decr_empty(bpo->bpo_os, tx);
+		return;
+	}
 
 	VERIFY3U(0, ==, bpobj_open(&subbpo, bpo->bpo_os, subobj));
 	VERIFY3U(0, ==, bpobj_space(&subbpo, &used, &comp, &uncomp));
@@ -388,6 +443,7 @@ bpobj_enqueue(bpobj_t *bpo, const blkptr_t *bp, dmu_tx_t *tx)
 	blkptr_t *bparray;
 
 	ASSERT(!BP_IS_HOLE(bp));
+	ASSERT(bpo->bpo_object != dmu_objset_pool(bpo->bpo_os)->dp_empty_bpobj);
 
 	/* We never need the fill count. */
 	stored_bp.blk_fill = 0;
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_objset.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_objset.c
index 09d13db..f4f4e1a 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_objset.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_objset.c
@@ -1187,15 +1187,6 @@ dmu_objset_is_dirty(objset_t *os, uint64_t txg)
 	    !list_is_empty(&os->os_free_dnodes[txg & TXG_MASK]));
 }
 
-boolean_t
-dmu_objset_is_dirty_anywhere(objset_t *os)
-{
-	for (int t = 0; t < TXG_SIZE; t++)
-		if (dmu_objset_is_dirty(os, t))
-			return (B_TRUE);
-	return (B_FALSE);
-}
-
 static objset_used_cb_t *used_cbs[DMU_OST_NUMTYPES];
 
 void
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
index 49bf9fa..f54853f 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
@@ -1258,6 +1258,17 @@ dsl_dataset_dirty(dsl_dataset_t *ds, dmu_tx_t *tx)
 	}
 }
 
+boolean_t
+dsl_dataset_is_dirty(dsl_dataset_t *ds)
+{
+	for (int t = 0; t < TXG_SIZE; t++) {
+		if (txg_list_member(&ds->ds_dir->dd_pool->dp_dirty_datasets,
+		    ds, t))
+			return (B_TRUE);
+	}
+	return (B_FALSE);
+}
+
 /*
  * The unique space in the head dataset can be calculated by subtracting
  * the space used in the most recent snapshot, that is still being used
@@ -3495,10 +3506,6 @@ dsl_dataset_set_quota_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 	if (ds->ds_quota != effective_value) {
 		dmu_buf_will_dirty(ds->ds_dbuf, tx);
 		ds->ds_quota = effective_value;
-
-		spa_history_log_internal(LOG_DS_REFQUOTA,
-		    ds->ds_dir->dd_pool->dp_spa, tx, "%lld dataset = %llu ",
-		    (longlong_t)ds->ds_quota, ds->ds_object);
 	}
 }
 
@@ -3602,10 +3609,6 @@ dsl_dataset_set_reservation_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 
 	dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV, delta, 0, 0, tx);
 	mutex_exit(&ds->ds_dir->dd_lock);
-
-	spa_history_log_internal(LOG_DS_REFRESERV,
-	    ds->ds_dir->dd_pool->dp_spa, tx, "%lld dataset = %llu",
-	    (longlong_t)effective_value, ds->ds_object);
 }
 
 int
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deadlist.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deadlist.c
index dd6db21..4f39c39 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deadlist.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deadlist.c
@@ -20,7 +20,7 @@
  */
 /*
  * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2011 by Delphix. All rights reserved.
+ * Copyright (c) 2012 by Delphix. All rights reserved.
  */
 
 #include <sys/dsl_dataset.h>
@@ -163,12 +163,49 @@ dsl_deadlist_free(objset_t *os, uint64_t dlobj, dmu_tx_t *tx)
 
 	for (zap_cursor_init(&zc, os, dlobj);
 	    zap_cursor_retrieve(&zc, &za) == 0;
-	    zap_cursor_advance(&zc))
-		bpobj_free(os, za.za_first_integer, tx);
+	    zap_cursor_advance(&zc)) {
+		uint64_t obj = za.za_first_integer;
+		if (obj == dmu_objset_pool(os)->dp_empty_bpobj)
+			bpobj_decr_empty(os, tx);
+		else
+			bpobj_free(os, obj, tx);
+	}
 	zap_cursor_fini(&zc);
 	VERIFY3U(0, ==, dmu_object_free(os, dlobj, tx));
 }
 
+static void
+dle_enqueue(dsl_deadlist_t *dl, dsl_deadlist_entry_t *dle,
+    const blkptr_t *bp, dmu_tx_t *tx)
+{
+	if (dle->dle_bpobj.bpo_object ==
+	    dmu_objset_pool(dl->dl_os)->dp_empty_bpobj) {
+		uint64_t obj = bpobj_alloc(dl->dl_os, SPA_MAXBLOCKSIZE, tx);
+		bpobj_close(&dle->dle_bpobj);
+		bpobj_decr_empty(dl->dl_os, tx);
+		VERIFY3U(0, ==, bpobj_open(&dle->dle_bpobj, dl->dl_os, obj));
+		VERIFY3U(0, ==, zap_update_int_key(dl->dl_os, dl->dl_object,
+		    dle->dle_mintxg, obj, tx));
+	}
+	bpobj_enqueue(&dle->dle_bpobj, bp, tx);
+}
+
+static void
+dle_enqueue_subobj(dsl_deadlist_t *dl, dsl_deadlist_entry_t *dle,
+    uint64_t obj, dmu_tx_t *tx)
+{
+	if (dle->dle_bpobj.bpo_object !=
+	    dmu_objset_pool(dl->dl_os)->dp_empty_bpobj) {
+		bpobj_enqueue_subobj(&dle->dle_bpobj, obj, tx);
+	} else {
+		bpobj_close(&dle->dle_bpobj);
+		bpobj_decr_empty(dl->dl_os, tx);
+		VERIFY3U(0, ==, bpobj_open(&dle->dle_bpobj, dl->dl_os, obj));
+		VERIFY3U(0, ==, zap_update_int_key(dl->dl_os, dl->dl_object,
+		    dle->dle_mintxg, obj, tx));
+	}
+}
+
 void
 dsl_deadlist_insert(dsl_deadlist_t *dl, const blkptr_t *bp, dmu_tx_t *tx)
 {
@@ -197,7 +234,7 @@ dsl_deadlist_insert(dsl_deadlist_t *dl, const blkptr_t *bp, dmu_tx_t *tx)
 		dle = avl_nearest(&dl->dl_tree, where, AVL_BEFORE);
 	else
 		dle = AVL_PREV(&dl->dl_tree, dle);
-	bpobj_enqueue(&dle->dle_bpobj, bp, tx);
+	dle_enqueue(dl, dle, bp, tx);
 }
 
 /*
@@ -217,7 +254,7 @@ dsl_deadlist_add_key(dsl_deadlist_t *dl, uint64_t mintxg, dmu_tx_t *tx)
 
 	dle = kmem_alloc(sizeof (*dle), KM_SLEEP);
 	dle->dle_mintxg = mintxg;
-	obj = bpobj_alloc(dl->dl_os, SPA_MAXBLOCKSIZE, tx);
+	obj = bpobj_alloc_empty(dl->dl_os, SPA_MAXBLOCKSIZE, tx);
 	VERIFY3U(0, ==, bpobj_open(&dle->dle_bpobj, dl->dl_os, obj));
 	avl_add(&dl->dl_tree, dle);
 
@@ -243,8 +280,7 @@ dsl_deadlist_remove_key(dsl_deadlist_t *dl, uint64_t mintxg, dmu_tx_t *tx)
 	dle = avl_find(&dl->dl_tree, &dle_tofind, NULL);
 	dle_prev = AVL_PREV(&dl->dl_tree, dle);
 
-	bpobj_enqueue_subobj(&dle_prev->dle_bpobj,
-	    dle->dle_bpobj.bpo_object, tx);
+	dle_enqueue_subobj(dl, dle_prev, dle->dle_bpobj.bpo_object, tx);
 
 	avl_remove(&dl->dl_tree, dle);
 	bpobj_close(&dle->dle_bpobj);
@@ -302,7 +338,7 @@ dsl_deadlist_clone(dsl_deadlist_t *dl, uint64_t maxtxg,
 		if (dle->dle_mintxg >= maxtxg)
 			break;
 
-		obj = bpobj_alloc(dl->dl_os, SPA_MAXBLOCKSIZE, tx);
+		obj = bpobj_alloc_empty(dl->dl_os, SPA_MAXBLOCKSIZE, tx);
 		VERIFY3U(0, ==, zap_add_int_key(dl->dl_os, newobj,
 		    dle->dle_mintxg, obj, tx));
 	}
@@ -400,7 +436,7 @@ dsl_deadlist_insert_bpobj(dsl_deadlist_t *dl, uint64_t obj, uint64_t birth,
 	dle = avl_find(&dl->dl_tree, &dle_tofind, &where);
 	if (dle == NULL)
 		dle = avl_nearest(&dl->dl_tree, where, AVL_BEFORE);
-	bpobj_enqueue_subobj(&dle->dle_bpobj, obj, tx);
+	dle_enqueue_subobj(dl, dle, obj, tx);
 }
 
 static int
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dir.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dir.c
index 8472f46..43650f3 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dir.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dir.c
@@ -1061,10 +1061,6 @@ dsl_dir_set_quota_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 	mutex_enter(&dd->dd_lock);
 	dd->dd_phys->dd_quota = effective_value;
 	mutex_exit(&dd->dd_lock);
-
-	spa_history_log_internal(LOG_DS_QUOTA, dd->dd_pool->dp_spa,
-	    tx, "%lld dataset = %llu ",
-	    (longlong_t)effective_value, dd->dd_phys->dd_head_dataset_obj);
 }
 
 int
@@ -1177,10 +1173,6 @@ dsl_dir_set_reservation_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 		    delta, 0, 0, tx);
 	}
 	mutex_exit(&dd->dd_lock);
-
-	spa_history_log_internal(LOG_DS_RESERVATION, dd->dd_pool->dp_spa,
-	    tx, "%lld dataset = %llu",
-	    (longlong_t)effective_value, dd->dd_phys->dd_head_dataset_obj);
 }
 
 int
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_pool.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_pool.c
index 9706509..9aba627 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_pool.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_pool.c
@@ -151,8 +151,6 @@ dsl_pool_open(dsl_pool_t *dp)
 	dsl_dataset_t *ds;
 	uint64_t obj;
 
-	ASSERT(!dmu_objset_is_dirty_anywhere(dp->dp_meta_objset));
-
 	rw_enter(&dp->dp_config_rwlock, RW_WRITER);
 	err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
 	    DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1,
@@ -209,6 +207,15 @@ dsl_pool_open(dsl_pool_t *dp)
 			goto out;
 	}
 
+	if (spa_feature_is_active(dp->dp_spa,
+	    &spa_feature_table[SPA_FEATURE_EMPTY_BPOBJ])) {
+		err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
+		    DMU_POOL_EMPTY_BPOBJ, sizeof (uint64_t), 1,
+		    &dp->dp_empty_bpobj);
+		if (err != 0)
+			goto out;
+	}
+
 	err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
 	    DMU_POOL_TMP_USERREFS, sizeof (uint64_t), 1,
 	    &dp->dp_tmp_userrefs_obj);
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/bpobj.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/bpobj.h
index 3771a95..af975c7 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/bpobj.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/bpobj.h
@@ -20,6 +20,7 @@
  */
 /*
  * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012 by Delphix. All rights reserved.
  */
 
 #ifndef	_SYS_BPOBJ_H
@@ -67,7 +68,9 @@ typedef struct bpobj {
 typedef int bpobj_itor_t(void *arg, const blkptr_t *bp, dmu_tx_t *tx);
 
 uint64_t bpobj_alloc(objset_t *mos, int blocksize, dmu_tx_t *tx);
+uint64_t bpobj_alloc_empty(objset_t *os, int blocksize, dmu_tx_t *tx);
 void bpobj_free(objset_t *os, uint64_t obj, dmu_tx_t *tx);
+void bpobj_decr_empty(objset_t *os, dmu_tx_t *tx);
 
 int bpobj_open(bpobj_t *bpo, objset_t *mos, uint64_t object);
 void bpobj_close(bpobj_t *bpo);
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu.h
index c6943e1..ef9d0cc 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu.h
@@ -314,6 +314,7 @@ typedef void dmu_buf_evict_func_t(struct dmu_buf *db, void *user_ptr);
 #define	DMU_POOL_SCAN			"scan"
 #define	DMU_POOL_FREE_BPOBJ		"free_bpobj"
 #define	DMU_POOL_BPTREE_OBJ		"bptree_obj"
+#define	DMU_POOL_EMPTY_BPOBJ		"empty_bpobj"
 
 /*
  * Allocate an object from this objset.  The range of object numbers
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu_objset.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu_objset.h
index d687642..fac0f9f 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu_objset.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu_objset.h
@@ -161,7 +161,6 @@ timestruc_t dmu_objset_snap_cmtime(objset_t *os);
 /* called from dsl */
 void dmu_objset_sync(objset_t *os, zio_t *zio, dmu_tx_t *tx);
 boolean_t dmu_objset_is_dirty(objset_t *os, uint64_t txg);
-boolean_t dmu_objset_is_dirty_anywhere(objset_t *os);
 objset_t *dmu_objset_create_impl(spa_t *spa, struct dsl_dataset *ds,
     blkptr_t *bp, dmu_objset_type_t type, dmu_tx_t *tx);
 int dmu_objset_open_impl(spa_t *spa, struct dsl_dataset *ds, blkptr_t *bp,
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_dataset.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_dataset.h
index e3affeb..d030cd7 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_dataset.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_dataset.h
@@ -271,6 +271,7 @@ int dsl_dataset_space_written(dsl_dataset_t *oldsnap, dsl_dataset_t *new,
     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp);
 int dsl_dataset_space_wouldfree(dsl_dataset_t *firstsnap, dsl_dataset_t *last,
     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp);
+boolean_t dsl_dataset_is_dirty(dsl_dataset_t *ds);
 
 int dsl_dsobj_to_dsname(char *pname, uint64_t obj, char *buf);
 
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_pool.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_pool.h
index 2da251c..6f60614 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_pool.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dsl_pool.h
@@ -88,6 +88,7 @@ typedef struct dsl_pool {
 	uint64_t dp_tmp_userrefs_obj;
 	bpobj_t dp_free_bpobj;
 	uint64_t dp_bptree_obj;
+	uint64_t dp_empty_bpobj;
 
 	struct dsl_scan *dp_scan;
 
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zap.h b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zap.h
index 4d7b315..092669c 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zap.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zap.h
@@ -300,6 +300,8 @@ int zap_increment_int(objset_t *os, uint64_t obj, uint64_t key, int64_t delta,
 /* Here the key is an int and the value is a different int. */
 int zap_add_int_key(objset_t *os, uint64_t obj,
     uint64_t key, uint64_t value, dmu_tx_t *tx);
+int zap_update_int_key(objset_t *os, uint64_t obj,
+    uint64_t key, uint64_t value, dmu_tx_t *tx);
 int zap_lookup_int_key(objset_t *os, uint64_t obj,
     uint64_t key, uint64_t *valuep);
 
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zap.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zap.c
index fa1d99f..c22f2ce 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zap.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zap.c
@@ -1094,6 +1094,16 @@ zap_add_int_key(objset_t *os, uint64_t obj,
 }
 
 int
+zap_update_int_key(objset_t *os, uint64_t obj,
+    uint64_t key, uint64_t value, dmu_tx_t *tx)
+{
+	char name[20];
+
+	(void) snprintf(name, sizeof (name), "%llx", (longlong_t)key);
+	return (zap_update(os, obj, name, 8, 1, &value, tx));
+}
+
+int
 zap_lookup_int_key(objset_t *os, uint64_t obj, uint64_t key, uint64_t *valuep)
 {
 	char name[20];
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfeature.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfeature.c
index b9250df..d532ccc 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfeature.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfeature.c
@@ -221,7 +221,12 @@ feature_get_refcount(objset_t *os, uint64_t read_obj, uint64_t write_obj,
 	uint64_t refcount;
 	uint64_t zapobj = feature->fi_can_readonly ? write_obj : read_obj;
 
-	ASSERT(0 != zapobj);
+	/*
+	 * If the pool is currently being created, the feature objects may not
+	 * have been allocated yet.  Act as though all features are disabled.
+	 */
+	if (zapobj == 0)
+		return (ENOTSUP);
 
 	err = zap_lookup(os, zapobj, feature->fi_guid, sizeof (uint64_t), 1,
 	    &refcount);
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
index 01eddbd..2ad7490 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
@@ -1839,9 +1839,9 @@ zfsvfs_teardown(zfsvfs_t *zfsvfs, boolean_t unmounting)
 	/*
 	 * Evict cached data
 	 */
-	if (dmu_objset_is_dirty_anywhere(zfsvfs->z_os))
-		if (!(zfsvfs->z_vfs->vfs_flag & VFS_RDONLY))
-			txg_wait_synced(dmu_objset_pool(zfsvfs->z_os), 0);
+	if (dsl_dataset_is_dirty(dmu_objset_ds(zfsvfs->z_os)) &&
+	    !(zfsvfs->z_vfs->vfs_flag & VFS_RDONLY))
+		txg_wait_synced(dmu_objset_pool(zfsvfs->z_os), 0);
 	(void) dmu_objset_evict_dbufs(zfsvfs->z_os);
 
 	return (0);
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zvol.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zvol.c
index 3a93d6f..1b2a4da 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zvol.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zvol.c
@@ -671,8 +671,18 @@ zvol_last_close(zvol_state_t *zv)
 {
 	zil_close(zv->zv_zilog);
 	zv->zv_zilog = NULL;
+
 	dmu_buf_rele(zv->zv_dbuf, zvol_tag);
 	zv->zv_dbuf = NULL;
+
+	/*
+	 * Evict cached data
+	 */
+	if (dsl_dataset_is_dirty(dmu_objset_ds(zv->zv_objset)) &&
+	    !(zv->zv_flags & ZVOL_RDONLY))
+		txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
+	(void) dmu_objset_evict_dbufs(zv->zv_objset);
+
 	dmu_objset_disown(zv->zv_objset, zvol_tag);
 	zv->zv_objset = NULL;
 }