Merge commit 'refs/top-bases/linux-libspl' into linux-libspl

1 files changed, 1330 insertions, 0 deletions

diff --git a/module/zfs/dsl_dir.c b/module/zfs/dsl_dir.c
new file mode 100644
index 000000000..9a76d989a
--- /dev/null
+++ b/module/zfs/dsl_dir.c
@@ -0,0 +1,1330 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#include <sys/dmu.h>
+#include <sys/dmu_objset.h>
+#include <sys/dmu_tx.h>
+#include <sys/dsl_dataset.h>
+#include <sys/dsl_dir.h>
+#include <sys/dsl_prop.h>
+#include <sys/dsl_synctask.h>
+#include <sys/dsl_deleg.h>
+#include <sys/spa.h>
+#include <sys/zap.h>
+#include <sys/zio.h>
+#include <sys/arc.h>
+#include <sys/sunddi.h>
+#include "zfs_namecheck.h"
+
+static uint64_t dsl_dir_space_towrite(dsl_dir_t *dd);
+static void dsl_dir_set_reservation_sync(void *arg1, void *arg2,
+    cred_t *cr, dmu_tx_t *tx);
+
+
+/* ARGSUSED */
+static void
+dsl_dir_evict(dmu_buf_t *db, void *arg)
+{
+	dsl_dir_t *dd = arg;
+	int t;
+
+	for (t = 0; t < TXG_SIZE; t++) {
+		ASSERT(!txg_list_member(&dd->dd_pool->dp_dirty_dirs, dd, t));
+		ASSERT(dd->dd_tempreserved[t] == 0);
+		ASSERT(dd->dd_space_towrite[t] == 0);
+	}
+
+	if (dd->dd_parent)
+		dsl_dir_close(dd->dd_parent, dd);
+
+	spa_close(dd->dd_pool->dp_spa, dd);
+
+	/*
+	 * The props callback list should be empty since they hold the
+	 * dir open.
+	 */
+	list_destroy(&dd->dd_prop_cbs);
+	mutex_destroy(&dd->dd_lock);
+	kmem_free(dd, sizeof (dsl_dir_t));
+}
+
+int
+dsl_dir_open_obj(dsl_pool_t *dp, uint64_t ddobj,
+    const char *tail, void *tag, dsl_dir_t **ddp)
+{
+	dmu_buf_t *dbuf;
+	dsl_dir_t *dd;
+	int err;
+
+	ASSERT(RW_LOCK_HELD(&dp->dp_config_rwlock) ||
+	    dsl_pool_sync_context(dp));
+
+	err = dmu_bonus_hold(dp->dp_meta_objset, ddobj, tag, &dbuf);
+	if (err)
+		return (err);
+	dd = dmu_buf_get_user(dbuf);
+#ifdef ZFS_DEBUG
+	{
+		dmu_object_info_t doi;
+		dmu_object_info_from_db(dbuf, &doi);
+		ASSERT3U(doi.doi_type, ==, DMU_OT_DSL_DIR);
+		ASSERT3U(doi.doi_bonus_size, >=, sizeof (dsl_dir_phys_t));
+	}
+#endif
+	if (dd == NULL) {
+		dsl_dir_t *winner;
+		int err;
+
+		dd = kmem_zalloc(sizeof (dsl_dir_t), KM_SLEEP);
+		dd->dd_object = ddobj;
+		dd->dd_dbuf = dbuf;
+		dd->dd_pool = dp;
+		dd->dd_phys = dbuf->db_data;
+		mutex_init(&dd->dd_lock, NULL, MUTEX_DEFAULT, NULL);
+
+		list_create(&dd->dd_prop_cbs, sizeof (dsl_prop_cb_record_t),
+		    offsetof(dsl_prop_cb_record_t, cbr_node));
+
+		if (dd->dd_phys->dd_parent_obj) {
+			err = dsl_dir_open_obj(dp, dd->dd_phys->dd_parent_obj,
+			    NULL, dd, &dd->dd_parent);
+			if (err)
+				goto errout;
+			if (tail) {
+#ifdef ZFS_DEBUG
+				uint64_t foundobj;
+
+				err = zap_lookup(dp->dp_meta_objset,
+				    dd->dd_parent->dd_phys->dd_child_dir_zapobj,
+				    tail, sizeof (foundobj), 1, &foundobj);
+				ASSERT(err || foundobj == ddobj);
+#endif
+				(void) strcpy(dd->dd_myname, tail);
+			} else {
+				err = zap_value_search(dp->dp_meta_objset,
+				    dd->dd_parent->dd_phys->dd_child_dir_zapobj,
+				    ddobj, 0, dd->dd_myname);
+			}
+			if (err)
+				goto errout;
+		} else {
+			(void) strcpy(dd->dd_myname, spa_name(dp->dp_spa));
+		}
+
+		winner = dmu_buf_set_user_ie(dbuf, dd, &dd->dd_phys,
+		    dsl_dir_evict);
+		if (winner) {
+			if (dd->dd_parent)
+				dsl_dir_close(dd->dd_parent, dd);
+			mutex_destroy(&dd->dd_lock);
+			kmem_free(dd, sizeof (dsl_dir_t));
+			dd = winner;
+		} else {
+			spa_open_ref(dp->dp_spa, dd);
+		}
+	}
+
+	/*
+	 * The dsl_dir_t has both open-to-close and instantiate-to-evict
+	 * holds on the spa.  We need the open-to-close holds because
+	 * otherwise the spa_refcnt wouldn't change when we open a
+	 * dir which the spa also has open, so we could incorrectly
+	 * think it was OK to unload/export/destroy the pool.  We need
+	 * the instantiate-to-evict hold because the dsl_dir_t has a
+	 * pointer to the dd_pool, which has a pointer to the spa_t.
+	 */
+	spa_open_ref(dp->dp_spa, tag);
+	ASSERT3P(dd->dd_pool, ==, dp);
+	ASSERT3U(dd->dd_object, ==, ddobj);
+	ASSERT3P(dd->dd_dbuf, ==, dbuf);
+	*ddp = dd;
+	return (0);
+
+errout:
+	if (dd->dd_parent)
+		dsl_dir_close(dd->dd_parent, dd);
+	mutex_destroy(&dd->dd_lock);
+	kmem_free(dd, sizeof (dsl_dir_t));
+	dmu_buf_rele(dbuf, tag);
+	return (err);
+
+}
+
+void
+dsl_dir_close(dsl_dir_t *dd, void *tag)
+{
+	dprintf_dd(dd, "%s\n", "");
+	spa_close(dd->dd_pool->dp_spa, tag);
+	dmu_buf_rele(dd->dd_dbuf, tag);
+}
+
+/* buf must be long enough (MAXNAMELEN + strlen(MOS_DIR_NAME) + 1 should do) */
+void
+dsl_dir_name(dsl_dir_t *dd, char *buf)
+{
+	if (dd->dd_parent) {
+		dsl_dir_name(dd->dd_parent, buf);
+		(void) strcat(buf, "/");
+	} else {
+		buf[0] = '\0';
+	}
+	if (!MUTEX_HELD(&dd->dd_lock)) {
+		/*
+		 * recursive mutex so that we can use
+		 * dprintf_dd() with dd_lock held
+		 */
+		mutex_enter(&dd->dd_lock);
+		(void) strcat(buf, dd->dd_myname);
+		mutex_exit(&dd->dd_lock);
+	} else {
+		(void) strcat(buf, dd->dd_myname);
+	}
+}
+
+/* Calculate name legnth, avoiding all the strcat calls of dsl_dir_name */
+int
+dsl_dir_namelen(dsl_dir_t *dd)
+{
+	int result = 0;
+
+	if (dd->dd_parent) {
+		/* parent's name + 1 for the "/" */
+		result = dsl_dir_namelen(dd->dd_parent) + 1;
+	}
+
+	if (!MUTEX_HELD(&dd->dd_lock)) {
+		/* see dsl_dir_name */
+		mutex_enter(&dd->dd_lock);
+		result += strlen(dd->dd_myname);
+		mutex_exit(&dd->dd_lock);
+	} else {
+		result += strlen(dd->dd_myname);
+	}
+
+	return (result);
+}
+
+int
+dsl_dir_is_private(dsl_dir_t *dd)
+{
+	int rv = FALSE;
+
+	if (dd->dd_parent && dsl_dir_is_private(dd->dd_parent))
+		rv = TRUE;
+	if (dataset_name_hidden(dd->dd_myname))
+		rv = TRUE;
+	return (rv);
+}
+
+
+static int
+getcomponent(const char *path, char *component, const char **nextp)
+{
+	char *p;
+	if (path == NULL)
+		return (ENOENT);
+	/* This would be a good place to reserve some namespace... */
+	p = strpbrk(path, "/@");
+	if (p && (p[1] == '/' || p[1] == '@')) {
+		/* two separators in a row */
+		return (EINVAL);
+	}
+	if (p == NULL || p == path) {
+		/*
+		 * if the first thing is an @ or /, it had better be an
+		 * @ and it had better not have any more ats or slashes,
+		 * and it had better have something after the @.
+		 */
+		if (p != NULL &&
+		    (p[0] != '@' || strpbrk(path+1, "/@") || p[1] == '\0'))
+			return (EINVAL);
+		if (strlen(path) >= MAXNAMELEN)
+			return (ENAMETOOLONG);
+		(void) strcpy(component, path);
+		p = NULL;
+	} else if (p[0] == '/') {
+		if (p-path >= MAXNAMELEN)
+			return (ENAMETOOLONG);
+		(void) strncpy(component, path, p - path);
+		component[p-path] = '\0';
+		p++;
+	} else if (p[0] == '@') {
+		/*
+		 * if the next separator is an @, there better not be
+		 * any more slashes.
+		 */
+		if (strchr(path, '/'))
+			return (EINVAL);
+		if (p-path >= MAXNAMELEN)
+			return (ENAMETOOLONG);
+		(void) strncpy(component, path, p - path);
+		component[p-path] = '\0';
+	} else {
+		ASSERT(!"invalid p");
+	}
+	*nextp = p;
+	return (0);
+}
+
+/*
+ * same as dsl_open_dir, ignore the first component of name and use the
+ * spa instead
+ */
+int
+dsl_dir_open_spa(spa_t *spa, const char *name, void *tag,
+    dsl_dir_t **ddp, const char **tailp)
+{
+	char buf[MAXNAMELEN];
+	const char *next, *nextnext = NULL;
+	int err;
+	dsl_dir_t *dd;
+	dsl_pool_t *dp;
+	uint64_t ddobj;
+	int openedspa = FALSE;
+
+	dprintf("%s\n", name);
+
+	err = getcomponent(name, buf, &next);
+	if (err)
+		return (err);
+	if (spa == NULL) {
+		err = spa_open(buf, &spa, FTAG);
+		if (err) {
+			dprintf("spa_open(%s) failed\n", buf);
+			return (err);
+		}
+		openedspa = TRUE;
+
+		/* XXX this assertion belongs in spa_open */
+		ASSERT(!dsl_pool_sync_context(spa_get_dsl(spa)));
+	}
+
+	dp = spa_get_dsl(spa);
+
+	rw_enter(&dp->dp_config_rwlock, RW_READER);
+	err = dsl_dir_open_obj(dp, dp->dp_root_dir_obj, NULL, tag, &dd);
+	if (err) {
+		rw_exit(&dp->dp_config_rwlock);
+		if (openedspa)
+			spa_close(spa, FTAG);
+		return (err);
+	}
+
+	while (next != NULL) {
+		dsl_dir_t *child_ds;
+		err = getcomponent(next, buf, &nextnext);
+		if (err)
+			break;
+		ASSERT(next[0] != '\0');
+		if (next[0] == '@')
+			break;
+		dprintf("looking up %s in obj%lld\n",
+		    buf, dd->dd_phys->dd_child_dir_zapobj);
+
+		err = zap_lookup(dp->dp_meta_objset,
+		    dd->dd_phys->dd_child_dir_zapobj,
+		    buf, sizeof (ddobj), 1, &ddobj);
+		if (err) {
+			if (err == ENOENT)
+				err = 0;
+			break;
+		}
+
+		err = dsl_dir_open_obj(dp, ddobj, buf, tag, &child_ds);
+		if (err)
+			break;
+		dsl_dir_close(dd, tag);
+		dd = child_ds;
+		next = nextnext;
+	}
+	rw_exit(&dp->dp_config_rwlock);
+
+	if (err) {
+		dsl_dir_close(dd, tag);
+		if (openedspa)
+			spa_close(spa, FTAG);
+		return (err);
+	}
+
+	/*
+	 * It's an error if there's more than one component left, or
+	 * tailp==NULL and there's any component left.
+	 */
+	if (next != NULL &&
+	    (tailp == NULL || (nextnext && nextnext[0] != '\0'))) {
+		/* bad path name */
+		dsl_dir_close(dd, tag);
+		dprintf("next=%p (%s) tail=%p\n", next, next?next:"", tailp);
+		err = ENOENT;
+	}
+	if (tailp)
+		*tailp = next;
+	if (openedspa)
+		spa_close(spa, FTAG);
+	*ddp = dd;
+	return (err);
+}
+
+/*
+ * Return the dsl_dir_t, and possibly the last component which couldn't
+ * be found in *tail.  Return NULL if the path is bogus, or if
+ * tail==NULL and we couldn't parse the whole name.  (*tail)[0] == '@'
+ * means that the last component is a snapshot.
+ */
+int
+dsl_dir_open(const char *name, void *tag, dsl_dir_t **ddp, const char **tailp)
+{
+	return (dsl_dir_open_spa(NULL, name, tag, ddp, tailp));
+}
+
+uint64_t
+dsl_dir_create_sync(dsl_pool_t *dp, dsl_dir_t *pds, const char *name,
+    dmu_tx_t *tx)
+{
+	objset_t *mos = dp->dp_meta_objset;
+	uint64_t ddobj;
+	dsl_dir_phys_t *dsphys;
+	dmu_buf_t *dbuf;
+
+	ddobj = dmu_object_alloc(mos, DMU_OT_DSL_DIR, 0,
+	    DMU_OT_DSL_DIR, sizeof (dsl_dir_phys_t), tx);
+	if (pds) {
+		VERIFY(0 == zap_add(mos, pds->dd_phys->dd_child_dir_zapobj,
+		    name, sizeof (uint64_t), 1, &ddobj, tx));
+	} else {
+		/* it's the root dir */
+		VERIFY(0 == zap_add(mos, DMU_POOL_DIRECTORY_OBJECT,
+		    DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1, &ddobj, tx));
+	}
+	VERIFY(0 == dmu_bonus_hold(mos, ddobj, FTAG, &dbuf));
+	dmu_buf_will_dirty(dbuf, tx);
+	dsphys = dbuf->db_data;
+
+	dsphys->dd_creation_time = gethrestime_sec();
+	if (pds)
+		dsphys->dd_parent_obj = pds->dd_object;
+	dsphys->dd_props_zapobj = zap_create(mos,
+	    DMU_OT_DSL_PROPS, DMU_OT_NONE, 0, tx);
+	dsphys->dd_child_dir_zapobj = zap_create(mos,
+	    DMU_OT_DSL_DIR_CHILD_MAP, DMU_OT_NONE, 0, tx);
+	if (spa_version(dp->dp_spa) >= SPA_VERSION_USED_BREAKDOWN)
+		dsphys->dd_flags |= DD_FLAG_USED_BREAKDOWN;
+	dmu_buf_rele(dbuf, FTAG);
+
+	return (ddobj);
+}
+
+/* ARGSUSED */
+int
+dsl_dir_destroy_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	dsl_dir_t *dd = arg1;
+	dsl_pool_t *dp = dd->dd_pool;
+	objset_t *mos = dp->dp_meta_objset;
+	int err;
+	uint64_t count;
+
+	/*
+	 * There should be exactly two holds, both from
+	 * dsl_dataset_destroy: one on the dd directory, and one on its
+	 * head ds.  Otherwise, someone is trying to lookup something
+	 * inside this dir while we want to destroy it.  The
+	 * config_rwlock ensures that nobody else opens it after we
+	 * check.
+	 */
+	if (dmu_buf_refcount(dd->dd_dbuf) > 2)
+		return (EBUSY);
+
+	err = zap_count(mos, dd->dd_phys->dd_child_dir_zapobj, &count);
+	if (err)
+		return (err);
+	if (count != 0)
+		return (EEXIST);
+
+	return (0);
+}
+
+void
+dsl_dir_destroy_sync(void *arg1, void *tag, cred_t *cr, dmu_tx_t *tx)
+{
+	dsl_dir_t *dd = arg1;
+	objset_t *mos = dd->dd_pool->dp_meta_objset;
+	uint64_t val, obj;
+	dd_used_t t;
+
+	ASSERT(RW_WRITE_HELD(&dd->dd_pool->dp_config_rwlock));
+	ASSERT(dd->dd_phys->dd_head_dataset_obj == 0);
+
+	/* Remove our reservation. */
+	val = 0;
+	dsl_dir_set_reservation_sync(dd, &val, cr, tx);
+	ASSERT3U(dd->dd_phys->dd_used_bytes, ==, 0);
+	ASSERT3U(dd->dd_phys->dd_reserved, ==, 0);
+	for (t = 0; t < DD_USED_NUM; t++)
+		ASSERT3U(dd->dd_phys->dd_used_breakdown[t], ==, 0);
+
+	VERIFY(0 == zap_destroy(mos, dd->dd_phys->dd_child_dir_zapobj, tx));
+	VERIFY(0 == zap_destroy(mos, dd->dd_phys->dd_props_zapobj, tx));
+	VERIFY(0 == dsl_deleg_destroy(mos, dd->dd_phys->dd_deleg_zapobj, tx));
+	VERIFY(0 == zap_remove(mos,
+	    dd->dd_parent->dd_phys->dd_child_dir_zapobj, dd->dd_myname, tx));
+
+	obj = dd->dd_object;
+	dsl_dir_close(dd, tag);
+	VERIFY(0 == dmu_object_free(mos, obj, tx));
+}
+
+boolean_t
+dsl_dir_is_clone(dsl_dir_t *dd)
+{
+	return (dd->dd_phys->dd_origin_obj &&
+	    (dd->dd_pool->dp_origin_snap == NULL ||
+	    dd->dd_phys->dd_origin_obj !=
+	    dd->dd_pool->dp_origin_snap->ds_object));
+}
+
+void
+dsl_dir_stats(dsl_dir_t *dd, nvlist_t *nv)
+{
+	mutex_enter(&dd->dd_lock);
+	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
+	    dd->dd_phys->dd_used_bytes);
+	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_QUOTA, dd->dd_phys->dd_quota);
+	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_RESERVATION,
+	    dd->dd_phys->dd_reserved);
+	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO,
+	    dd->dd_phys->dd_compressed_bytes == 0 ? 100 :
+	    (dd->dd_phys->dd_uncompressed_bytes * 100 /
+	    dd->dd_phys->dd_compressed_bytes));
+	if (dd->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) {
+		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDSNAP,
+		    dd->dd_phys->dd_used_breakdown[DD_USED_SNAP]);
+		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDDS,
+		    dd->dd_phys->dd_used_breakdown[DD_USED_HEAD]);
+		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDREFRESERV,
+		    dd->dd_phys->dd_used_breakdown[DD_USED_REFRSRV]);
+		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDCHILD,
+		    dd->dd_phys->dd_used_breakdown[DD_USED_CHILD] +
+		    dd->dd_phys->dd_used_breakdown[DD_USED_CHILD_RSRV]);
+	}
+	mutex_exit(&dd->dd_lock);
+
+	rw_enter(&dd->dd_pool->dp_config_rwlock, RW_READER);
+	if (dsl_dir_is_clone(dd)) {
+		dsl_dataset_t *ds;
+		char buf[MAXNAMELEN];
+
+		VERIFY(0 == dsl_dataset_hold_obj(dd->dd_pool,
+		    dd->dd_phys->dd_origin_obj, FTAG, &ds));
+		dsl_dataset_name(ds, buf);
+		dsl_dataset_rele(ds, FTAG);
+		dsl_prop_nvlist_add_string(nv, ZFS_PROP_ORIGIN, buf);
+	}
+	rw_exit(&dd->dd_pool->dp_config_rwlock);
+}
+
+void
+dsl_dir_dirty(dsl_dir_t *dd, dmu_tx_t *tx)
+{
+	dsl_pool_t *dp = dd->dd_pool;
+
+	ASSERT(dd->dd_phys);
+
+	if (txg_list_add(&dp->dp_dirty_dirs, dd, tx->tx_txg) == 0) {
+		/* up the hold count until we can be written out */
+		dmu_buf_add_ref(dd->dd_dbuf, dd);
+	}
+}
+
+static int64_t
+parent_delta(dsl_dir_t *dd, uint64_t used, int64_t delta)
+{
+	uint64_t old_accounted = MAX(used, dd->dd_phys->dd_reserved);
+	uint64_t new_accounted = MAX(used + delta, dd->dd_phys->dd_reserved);
+	return (new_accounted - old_accounted);
+}
+
+void
+dsl_dir_sync(dsl_dir_t *dd, dmu_tx_t *tx)
+{
+	ASSERT(dmu_tx_is_syncing(tx));
+
+	dmu_buf_will_dirty(dd->dd_dbuf, tx);
+
+	mutex_enter(&dd->dd_lock);
+	ASSERT3U(dd->dd_tempreserved[tx->tx_txg&TXG_MASK], ==, 0);
+	dprintf_dd(dd, "txg=%llu towrite=%lluK\n", tx->tx_txg,
+	    dd->dd_space_towrite[tx->tx_txg&TXG_MASK] / 1024);
+	dd->dd_space_towrite[tx->tx_txg&TXG_MASK] = 0;
+	mutex_exit(&dd->dd_lock);
+
+	/* release the hold from dsl_dir_dirty */
+	dmu_buf_rele(dd->dd_dbuf, dd);
+}
+
+static uint64_t
+dsl_dir_space_towrite(dsl_dir_t *dd)
+{
+	uint64_t space = 0;
+	int i;
+
+	ASSERT(MUTEX_HELD(&dd->dd_lock));
+
+	for (i = 0; i < TXG_SIZE; i++) {
+		space += dd->dd_space_towrite[i&TXG_MASK];
+		ASSERT3U(dd->dd_space_towrite[i&TXG_MASK], >=, 0);
+	}
+	return (space);
+}
+
+/*
+ * How much space would dd have available if ancestor had delta applied
+ * to it?  If ondiskonly is set, we're only interested in what's
+ * on-disk, not estimated pending changes.
+ */
+uint64_t
+dsl_dir_space_available(dsl_dir_t *dd,
+    dsl_dir_t *ancestor, int64_t delta, int ondiskonly)
+{
+	uint64_t parentspace, myspace, quota, used;
+
+	/*
+	 * If there are no restrictions otherwise, assume we have
+	 * unlimited space available.
+	 */
+	quota = UINT64_MAX;
+	parentspace = UINT64_MAX;
+
+	if (dd->dd_parent != NULL) {
+		parentspace = dsl_dir_space_available(dd->dd_parent,
+		    ancestor, delta, ondiskonly);
+	}
+
+	mutex_enter(&dd->dd_lock);
+	if (dd->dd_phys->dd_quota != 0)
+		quota = dd->dd_phys->dd_quota;
+	used = dd->dd_phys->dd_used_bytes;
+	if (!ondiskonly)
+		used += dsl_dir_space_towrite(dd);
+
+	if (dd->dd_parent == NULL) {
+		uint64_t poolsize = dsl_pool_adjustedsize(dd->dd_pool, FALSE);
+		quota = MIN(quota, poolsize);
+	}
+
+	if (dd->dd_phys->dd_reserved > used && parentspace != UINT64_MAX) {
+		/*
+		 * We have some space reserved, in addition to what our
+		 * parent gave us.
+		 */
+		parentspace += dd->dd_phys->dd_reserved - used;
+	}
+
+	if (dd == ancestor) {
+		ASSERT(delta <= 0);
+		ASSERT(used >= -delta);
+		used += delta;
+		if (parentspace != UINT64_MAX)
+			parentspace -= delta;
+	}
+
+	if (used > quota) {
+		/* over quota */
+		myspace = 0;
+
+		/*
+		 * While it's OK to be a little over quota, if
+		 * we think we are using more space than there
+		 * is in the pool (which is already 1.6% more than
+		 * dsl_pool_adjustedsize()), something is very
+		 * wrong.
+		 */
+		ASSERT3U(used, <=, spa_get_space(dd->dd_pool->dp_spa));
+	} else {
+		/*
+		 * the lesser of the space provided by our parent and
+		 * the space left in our quota
+		 */
+		myspace = MIN(parentspace, quota - used);
+	}
+
+	mutex_exit(&dd->dd_lock);
+
+	return (myspace);
+}
+
+struct tempreserve {
+	list_node_t tr_node;
+	dsl_pool_t *tr_dp;
+	dsl_dir_t *tr_ds;
+	uint64_t tr_size;
+};
+
+static int
+dsl_dir_tempreserve_impl(dsl_dir_t *dd, uint64_t asize, boolean_t netfree,
+    boolean_t ignorequota, boolean_t checkrefquota, list_t *tr_list,
+    dmu_tx_t *tx, boolean_t first)
+{
+	uint64_t txg = tx->tx_txg;
+	uint64_t est_inflight, used_on_disk, quota, parent_rsrv;
+	struct tempreserve *tr;
+	int enospc = EDQUOT;
+	int txgidx = txg & TXG_MASK;
+	int i;
+	uint64_t ref_rsrv = 0;
+
+	ASSERT3U(txg, !=, 0);
+	ASSERT3S(asize, >, 0);
+
+	mutex_enter(&dd->dd_lock);
+
+	/*
+	 * Check against the dsl_dir's quota.  We don't add in the delta
+	 * when checking for over-quota because they get one free hit.
+	 */
+	est_inflight = dsl_dir_space_towrite(dd);
+	for (i = 0; i < TXG_SIZE; i++)
+		est_inflight += dd->dd_tempreserved[i];
+	used_on_disk = dd->dd_phys->dd_used_bytes;
+
+	/*
+	 * On the first iteration, fetch the dataset's used-on-disk and
+	 * refreservation values. Also, if checkrefquota is set, test if
+	 * allocating this space would exceed the dataset's refquota.
+	 */
+	if (first && tx->tx_objset) {
+		int error;
+		dsl_dataset_t *ds = tx->tx_objset->os->os_dsl_dataset;
+
+		error = dsl_dataset_check_quota(ds, checkrefquota,
+		    asize, est_inflight, &used_on_disk, &ref_rsrv);
+		if (error) {
+			mutex_exit(&dd->dd_lock);
+			return (error);
+		}
+	}
+
+	/*
+	 * If this transaction will result in a net free of space,
+	 * we want to let it through.
+	 */
+	if (ignorequota || netfree || dd->dd_phys->dd_quota == 0)
+		quota = UINT64_MAX;
+	else
+		quota = dd->dd_phys->dd_quota;
+
+	/*
+	 * Adjust the quota against the actual pool size at the root.
+	 * To ensure that it's possible to remove files from a full
+	 * pool without inducing transient overcommits, we throttle
+	 * netfree transactions against a quota that is slightly larger,
+	 * but still within the pool's allocation slop.  In cases where
+	 * we're very close to full, this will allow a steady trickle of
+	 * removes to get through.
+	 */
+	if (dd->dd_parent == NULL) {
+		uint64_t poolsize = dsl_pool_adjustedsize(dd->dd_pool, netfree);
+		if (poolsize < quota) {
+			quota = poolsize;
+			enospc = ENOSPC;
+		}
+	}
+
+	/*
+	 * If they are requesting more space, and our current estimate
+	 * is over quota, they get to try again unless the actual
+	 * on-disk is over quota and there are no pending changes (which
+	 * may free up space for us).
+	 */
+	if (used_on_disk + est_inflight > quota) {
+		if (est_inflight > 0 || used_on_disk < quota)
+			enospc = ERESTART;
+		dprintf_dd(dd, "failing: used=%lluK inflight = %lluK "
+		    "quota=%lluK tr=%lluK err=%d\n",
+		    used_on_disk>>10, est_inflight>>10,
+		    quota>>10, asize>>10, enospc);
+		mutex_exit(&dd->dd_lock);
+		return (enospc);
+	}
+
+	/* We need to up our estimated delta before dropping dd_lock */
+	dd->dd_tempreserved[txgidx] += asize;
+
+	parent_rsrv = parent_delta(dd, used_on_disk + est_inflight,
+	    asize - ref_rsrv);
+	mutex_exit(&dd->dd_lock);
+
+	tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
+	tr->tr_ds = dd;
+	tr->tr_size = asize;
+	list_insert_tail(tr_list, tr);
+
+	/* see if it's OK with our parent */
+	if (dd->dd_parent && parent_rsrv) {
+		boolean_t ismos = (dd->dd_phys->dd_head_dataset_obj == 0);
+
+		return (dsl_dir_tempreserve_impl(dd->dd_parent,
+		    parent_rsrv, netfree, ismos, TRUE, tr_list, tx, FALSE));
+	} else {
+		return (0);
+	}
+}
+
+/*
+ * Reserve space in this dsl_dir, to be used in this tx's txg.
+ * After the space has been dirtied (and dsl_dir_willuse_space()
+ * has been called), the reservation should be canceled, using
+ * dsl_dir_tempreserve_clear().
+ */
+int
+dsl_dir_tempreserve_space(dsl_dir_t *dd, uint64_t lsize, uint64_t asize,
+    uint64_t fsize, uint64_t usize, void **tr_cookiep, dmu_tx_t *tx)
+{
+	int err;
+	list_t *tr_list;
+
+	if (asize == 0) {
+		*tr_cookiep = NULL;
+		return (0);
+	}
+
+	tr_list = kmem_alloc(sizeof (list_t), KM_SLEEP);
+	list_create(tr_list, sizeof (struct tempreserve),
+	    offsetof(struct tempreserve, tr_node));
+	ASSERT3S(asize, >, 0);
+	ASSERT3S(fsize, >=, 0);
+
+	err = arc_tempreserve_space(lsize, tx->tx_txg);
+	if (err == 0) {
+		struct tempreserve *tr;
+
+		tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
+		tr->tr_size = lsize;
+		list_insert_tail(tr_list, tr);
+
+		err = dsl_pool_tempreserve_space(dd->dd_pool, asize, tx);
+	} else {
+		if (err == EAGAIN) {
+			txg_delay(dd->dd_pool, tx->tx_txg, 1);
+			err = ERESTART;
+		}
+		dsl_pool_memory_pressure(dd->dd_pool);
+	}
+
+	if (err == 0) {
+		struct tempreserve *tr;
+
+		tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
+		tr->tr_dp = dd->dd_pool;
+		tr->tr_size = asize;
+		list_insert_tail(tr_list, tr);
+
+		err = dsl_dir_tempreserve_impl(dd, asize, fsize >= asize,
+		    FALSE, asize > usize, tr_list, tx, TRUE);
+	}
+
+	if (err)
+		dsl_dir_tempreserve_clear(tr_list, tx);
+	else
+		*tr_cookiep = tr_list;
+
+	return (err);
+}
+
+/*
+ * Clear a temporary reservation that we previously made with
+ * dsl_dir_tempreserve_space().
+ */
+void
+dsl_dir_tempreserve_clear(void *tr_cookie, dmu_tx_t *tx)
+{
+	int txgidx = tx->tx_txg & TXG_MASK;
+	list_t *tr_list = tr_cookie;
+	struct tempreserve *tr;
+
+	ASSERT3U(tx->tx_txg, !=, 0);
+
+	if (tr_cookie == NULL)
+		return;
+
+	while ((tr = list_head(tr_list))) {
+		if (tr->tr_dp) {
+			dsl_pool_tempreserve_clear(tr->tr_dp, tr->tr_size, tx);
+		} else if (tr->tr_ds) {
+			mutex_enter(&tr->tr_ds->dd_lock);
+			ASSERT3U(tr->tr_ds->dd_tempreserved[txgidx], >=,
+			    tr->tr_size);
+			tr->tr_ds->dd_tempreserved[txgidx] -= tr->tr_size;
+			mutex_exit(&tr->tr_ds->dd_lock);
+		} else {
+			arc_tempreserve_clear(tr->tr_size);
+		}
+		list_remove(tr_list, tr);
+		kmem_free(tr, sizeof (struct tempreserve));
+	}
+
+	kmem_free(tr_list, sizeof (list_t));
+}
+
+static void
+dsl_dir_willuse_space_impl(dsl_dir_t *dd, int64_t space, dmu_tx_t *tx)
+{
+	int64_t parent_space;
+	uint64_t est_used;
+
+	mutex_enter(&dd->dd_lock);
+	if (space > 0)
+		dd->dd_space_towrite[tx->tx_txg & TXG_MASK] += space;
+
+	est_used = dsl_dir_space_towrite(dd) + dd->dd_phys->dd_used_bytes;
+	parent_space = parent_delta(dd, est_used, space);
+	mutex_exit(&dd->dd_lock);
+
+	/* Make sure that we clean up dd_space_to* */
+	dsl_dir_dirty(dd, tx);
+
+	/* XXX this is potentially expensive and unnecessary... */
+	if (parent_space && dd->dd_parent)
+		dsl_dir_willuse_space_impl(dd->dd_parent, parent_space, tx);
+}
+
+/*
+ * Call in open context when we think we're going to write/free space,
+ * eg. when dirtying data.  Be conservative (ie. OK to write less than
+ * this or free more than this, but don't write more or free less).
+ */
+void
+dsl_dir_willuse_space(dsl_dir_t *dd, int64_t space, dmu_tx_t *tx)
+{
+	dsl_pool_willuse_space(dd->dd_pool, space, tx);
+	dsl_dir_willuse_space_impl(dd, space, tx);
+}
+
+/* call from syncing context when we actually write/free space for this dd */
+void
+dsl_dir_diduse_space(dsl_dir_t *dd, dd_used_t type,
+    int64_t used, int64_t compressed, int64_t uncompressed, dmu_tx_t *tx)
+{
+	int64_t accounted_delta;
+	boolean_t needlock = !MUTEX_HELD(&dd->dd_lock);
+
+	ASSERT(dmu_tx_is_syncing(tx));
+	ASSERT(type < DD_USED_NUM);
+
+	dsl_dir_dirty(dd, tx);
+
+	if (needlock)
+		mutex_enter(&dd->dd_lock);
+	accounted_delta = parent_delta(dd, dd->dd_phys->dd_used_bytes, used);
+	ASSERT(used >= 0 || dd->dd_phys->dd_used_bytes >= -used);
+	ASSERT(compressed >= 0 ||
+	    dd->dd_phys->dd_compressed_bytes >= -compressed);
+	ASSERT(uncompressed >= 0 ||
+	    dd->dd_phys->dd_uncompressed_bytes >= -uncompressed);
+	dd->dd_phys->dd_used_bytes += used;
+	dd->dd_phys->dd_uncompressed_bytes += uncompressed;
+	dd->dd_phys->dd_compressed_bytes += compressed;
+
+	if (dd->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) {
+		ASSERT(used > 0 ||
+		    dd->dd_phys->dd_used_breakdown[type] >= -used);
+		dd->dd_phys->dd_used_breakdown[type] += used;
+#ifdef DEBUG
+		dd_used_t t;
+		uint64_t u = 0;
+		for (t = 0; t < DD_USED_NUM; t++)
+			u += dd->dd_phys->dd_used_breakdown[t];
+		ASSERT3U(u, ==, dd->dd_phys->dd_used_bytes);
+#endif
+	}
+	if (needlock)
+		mutex_exit(&dd->dd_lock);
+
+	if (dd->dd_parent != NULL) {
+		dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD,
+		    accounted_delta, compressed, uncompressed, tx);
+		dsl_dir_transfer_space(dd->dd_parent,
+		    used - accounted_delta,
+		    DD_USED_CHILD_RSRV, DD_USED_CHILD, tx);
+	}
+}
+
+void
+dsl_dir_transfer_space(dsl_dir_t *dd, int64_t delta,
+    dd_used_t oldtype, dd_used_t newtype, dmu_tx_t *tx)
+{
+	boolean_t needlock = !MUTEX_HELD(&dd->dd_lock);
+
+	ASSERT(dmu_tx_is_syncing(tx));
+	ASSERT(oldtype < DD_USED_NUM);
+	ASSERT(newtype < DD_USED_NUM);
+
+	if (delta == 0 || !(dd->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN))
+		return;
+
+	dsl_dir_dirty(dd, tx);
+	if (needlock)
+		mutex_enter(&dd->dd_lock);
+	ASSERT(delta > 0 ?
+	    dd->dd_phys->dd_used_breakdown[oldtype] >= delta :
+	    dd->dd_phys->dd_used_breakdown[newtype] >= -delta);
+	ASSERT(dd->dd_phys->dd_used_bytes >= ABS(delta));
+	dd->dd_phys->dd_used_breakdown[oldtype] -= delta;
+	dd->dd_phys->dd_used_breakdown[newtype] += delta;
+	if (needlock)
+		mutex_exit(&dd->dd_lock);
+}
+
+static int
+dsl_dir_set_quota_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	dsl_dir_t *dd = arg1;
+	uint64_t *quotap = arg2;
+	uint64_t new_quota = *quotap;
+	int err = 0;
+	uint64_t towrite;
+
+	if (new_quota == 0)
+		return (0);
+
+	mutex_enter(&dd->dd_lock);
+	/*
+	 * If we are doing the preliminary check in open context, and
+	 * there are pending changes, then don't fail it, since the
+	 * pending changes could under-estimate the amount of space to be
+	 * freed up.
+	 */
+	towrite = dsl_dir_space_towrite(dd);
+	if ((dmu_tx_is_syncing(tx) || towrite == 0) &&
+	    (new_quota < dd->dd_phys->dd_reserved ||
+	    new_quota < dd->dd_phys->dd_used_bytes + towrite)) {
+		err = ENOSPC;
+	}
+	mutex_exit(&dd->dd_lock);
+	return (err);
+}
+
+/* ARGSUSED */
+static void
+dsl_dir_set_quota_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
+{
+	dsl_dir_t *dd = arg1;
+	uint64_t *quotap = arg2;
+	uint64_t new_quota = *quotap;
+
+	dmu_buf_will_dirty(dd->dd_dbuf, tx);
+
+	mutex_enter(&dd->dd_lock);
+	dd->dd_phys->dd_quota = new_quota;
+	mutex_exit(&dd->dd_lock);
+
+	spa_history_internal_log(LOG_DS_QUOTA, dd->dd_pool->dp_spa,
+	    tx, cr, "%lld dataset = %llu ",
+	    (longlong_t)new_quota, dd->dd_phys->dd_head_dataset_obj);
+}
+
+int
+dsl_dir_set_quota(const char *ddname, uint64_t quota)
+{
+	dsl_dir_t *dd;
+	int err;
+
+	err = dsl_dir_open(ddname, FTAG, &dd, NULL);
+	if (err)
+		return (err);
+
+	if (quota != dd->dd_phys->dd_quota) {
+		/*
+		 * If someone removes a file, then tries to set the quota, we
+		 * want to make sure the file freeing takes effect.
+		 */
+		txg_wait_open(dd->dd_pool, 0);
+
+		err = dsl_sync_task_do(dd->dd_pool, dsl_dir_set_quota_check,
+		    dsl_dir_set_quota_sync, dd, &quota, 0);
+	}
+	dsl_dir_close(dd, FTAG);
+	return (err);
+}
+
+int
+dsl_dir_set_reservation_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	dsl_dir_t *dd = arg1;
+	uint64_t *reservationp = arg2;
+	uint64_t new_reservation = *reservationp;
+	uint64_t used, avail;
+	int64_t delta;
+
+	if (new_reservation > INT64_MAX)
+		return (EOVERFLOW);
+
+	/*
+	 * If we are doing the preliminary check in open context, the
+	 * space estimates may be inaccurate.
+	 */
+	if (!dmu_tx_is_syncing(tx))
+		return (0);
+
+	mutex_enter(&dd->dd_lock);
+	used = dd->dd_phys->dd_used_bytes;
+	delta = MAX(used, new_reservation) -
+	    MAX(used, dd->dd_phys->dd_reserved);
+	mutex_exit(&dd->dd_lock);
+
+	if (dd->dd_parent) {
+		avail = dsl_dir_space_available(dd->dd_parent,
+		    NULL, 0, FALSE);
+	} else {
+		avail = dsl_pool_adjustedsize(dd->dd_pool, B_FALSE) - used;
+	}
+
+	if (delta > 0 && delta > avail)
+		return (ENOSPC);
+	if (delta > 0 && dd->dd_phys->dd_quota > 0 &&
+	    new_reservation > dd->dd_phys->dd_quota)
+		return (ENOSPC);
+	return (0);
+}
+
+/* ARGSUSED */
+static void
+dsl_dir_set_reservation_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
+{
+	dsl_dir_t *dd = arg1;
+	uint64_t *reservationp = arg2;
+	uint64_t new_reservation = *reservationp;
+	uint64_t used;
+	int64_t delta;
+
+	dmu_buf_will_dirty(dd->dd_dbuf, tx);
+
+	mutex_enter(&dd->dd_lock);
+	used = dd->dd_phys->dd_used_bytes;
+	delta = MAX(used, new_reservation) -
+	    MAX(used, dd->dd_phys->dd_reserved);
+	dd->dd_phys->dd_reserved = new_reservation;
+
+	if (dd->dd_parent != NULL) {
+		/* Roll up this additional usage into our ancestors */
+		dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD_RSRV,
+		    delta, 0, 0, tx);
+	}
+	mutex_exit(&dd->dd_lock);
+
+	spa_history_internal_log(LOG_DS_RESERVATION, dd->dd_pool->dp_spa,
+	    tx, cr, "%lld dataset = %llu",
+	    (longlong_t)new_reservation, dd->dd_phys->dd_head_dataset_obj);
+}
+
+int
+dsl_dir_set_reservation(const char *ddname, uint64_t reservation)
+{
+	dsl_dir_t *dd;
+	int err;
+
+	err = dsl_dir_open(ddname, FTAG, &dd, NULL);
+	if (err)
+		return (err);
+	err = dsl_sync_task_do(dd->dd_pool, dsl_dir_set_reservation_check,
+	    dsl_dir_set_reservation_sync, dd, &reservation, 0);
+	dsl_dir_close(dd, FTAG);
+	return (err);
+}
+
+static dsl_dir_t *
+closest_common_ancestor(dsl_dir_t *ds1, dsl_dir_t *ds2)
+{
+	for (; ds1; ds1 = ds1->dd_parent) {
+		dsl_dir_t *dd;
+		for (dd = ds2; dd; dd = dd->dd_parent) {
+			if (ds1 == dd)
+				return (dd);
+		}
+	}
+	return (NULL);
+}
+
+/*
+ * If delta is applied to dd, how much of that delta would be applied to
+ * ancestor?  Syncing context only.
+ */
+static int64_t
+would_change(dsl_dir_t *dd, int64_t delta, dsl_dir_t *ancestor)
+{
+	if (dd == ancestor)
+		return (delta);
+
+	mutex_enter(&dd->dd_lock);
+	delta = parent_delta(dd, dd->dd_phys->dd_used_bytes, delta);
+	mutex_exit(&dd->dd_lock);
+	return (would_change(dd->dd_parent, delta, ancestor));
+}
+
+struct renamearg {
+	dsl_dir_t *newparent;
+	const char *mynewname;
+};
+
+/*ARGSUSED*/
+static int
+dsl_dir_rename_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	dsl_dir_t *dd = arg1;
+	struct renamearg *ra = arg2;
+	dsl_pool_t *dp = dd->dd_pool;
+	objset_t *mos = dp->dp_meta_objset;
+	int err;
+	uint64_t val;
+
+	/* There should be 2 references: the open and the dirty */
+	if (dmu_buf_refcount(dd->dd_dbuf) > 2)
+		return (EBUSY);
+
+	/* check for existing name */
+	err = zap_lookup(mos, ra->newparent->dd_phys->dd_child_dir_zapobj,
+	    ra->mynewname, 8, 1, &val);
+	if (err == 0)
+		return (EEXIST);
+	if (err != ENOENT)
+		return (err);
+
+	if (ra->newparent != dd->dd_parent) {
+		/* is there enough space? */
+		uint64_t myspace =
+		    MAX(dd->dd_phys->dd_used_bytes, dd->dd_phys->dd_reserved);
+
+		/* no rename into our descendant */
+		if (closest_common_ancestor(dd, ra->newparent) == dd)
+			return (EINVAL);
+
+		if ((err = dsl_dir_transfer_possible(dd->dd_parent,
+		    ra->newparent, myspace)))
+			return (err);
+	}
+
+	return (0);
+}
+
+static void
+dsl_dir_rename_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
+{
+	dsl_dir_t *dd = arg1;
+	struct renamearg *ra = arg2;
+	dsl_pool_t *dp = dd->dd_pool;
+	objset_t *mos = dp->dp_meta_objset;
+	int err;
+
+	ASSERT(dmu_buf_refcount(dd->dd_dbuf) <= 2);
+
+	if (ra->newparent != dd->dd_parent) {
+		dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD,
+		    -dd->dd_phys->dd_used_bytes,
+		    -dd->dd_phys->dd_compressed_bytes,
+		    -dd->dd_phys->dd_uncompressed_bytes, tx);
+		dsl_dir_diduse_space(ra->newparent, DD_USED_CHILD,
+		    dd->dd_phys->dd_used_bytes,
+		    dd->dd_phys->dd_compressed_bytes,
+		    dd->dd_phys->dd_uncompressed_bytes, tx);
+
+		if (dd->dd_phys->dd_reserved > dd->dd_phys->dd_used_bytes) {
+			uint64_t unused_rsrv = dd->dd_phys->dd_reserved -
+			    dd->dd_phys->dd_used_bytes;
+
+			dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD_RSRV,
+			    -unused_rsrv, 0, 0, tx);
+			dsl_dir_diduse_space(ra->newparent, DD_USED_CHILD_RSRV,
+			    unused_rsrv, 0, 0, tx);
+		}
+	}
+
+	dmu_buf_will_dirty(dd->dd_dbuf, tx);
+
+	/* remove from old parent zapobj */
+	err = zap_remove(mos, dd->dd_parent->dd_phys->dd_child_dir_zapobj,
+	    dd->dd_myname, tx);
+	ASSERT3U(err, ==, 0);
+
+	(void) strcpy(dd->dd_myname, ra->mynewname);
+	dsl_dir_close(dd->dd_parent, dd);
+	dd->dd_phys->dd_parent_obj = ra->newparent->dd_object;
+	VERIFY(0 == dsl_dir_open_obj(dd->dd_pool,
+	    ra->newparent->dd_object, NULL, dd, &dd->dd_parent));
+
+	/* add to new parent zapobj */
+	err = zap_add(mos, ra->newparent->dd_phys->dd_child_dir_zapobj,
+	    dd->dd_myname, 8, 1, &dd->dd_object, tx);
+	ASSERT3U(err, ==, 0);
+
+	spa_history_internal_log(LOG_DS_RENAME, dd->dd_pool->dp_spa,
+	    tx, cr, "dataset = %llu", dd->dd_phys->dd_head_dataset_obj);
+}
+
+int
+dsl_dir_rename(dsl_dir_t *dd, const char *newname)
+{
+	struct renamearg ra;
+	int err;
+
+	/* new parent should exist */
+	err = dsl_dir_open(newname, FTAG, &ra.newparent, &ra.mynewname);
+	if (err)
+		return (err);
+
+	/* can't rename to different pool */
+	if (dd->dd_pool != ra.newparent->dd_pool) {
+		err = ENXIO;
+		goto out;
+	}
+
+	/* new name should not already exist */
+	if (ra.mynewname == NULL) {
+		err = EEXIST;
+		goto out;
+	}
+
+	err = dsl_sync_task_do(dd->dd_pool,
+	    dsl_dir_rename_check, dsl_dir_rename_sync, dd, &ra, 3);
+
+out:
+	dsl_dir_close(ra.newparent, FTAG);
+	return (err);
+}
+
+int
+dsl_dir_transfer_possible(dsl_dir_t *sdd, dsl_dir_t *tdd, uint64_t space)
+{
+	dsl_dir_t *ancestor;
+	int64_t adelta;
+	uint64_t avail;
+
+	ancestor = closest_common_ancestor(sdd, tdd);
+	adelta = would_change(sdd, -space, ancestor);
+	avail = dsl_dir_space_available(tdd, ancestor, adelta, FALSE);
+	if (avail < space)
+		return (ENOSPC);
+
+	return (0);
+}