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 34bef4ee5698..ce22f4efb52f 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
@@ -136,7 +136,7 @@ dsl_dataset_block_born(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx)
 	dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD, delta,
 	    compressed, uncompressed, tx);
 	dsl_dir_transfer_space(ds->ds_dir, used - delta,
-	    DD_USED_REFRSRV, DD_USED_HEAD, tx);
+	    DD_USED_REFRSRV, DD_USED_HEAD, NULL);
 }
 
 int
@@ -179,7 +179,7 @@ dsl_dataset_block_kill(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx,
 		dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
 		    delta, -compressed, -uncompressed, tx);
 		dsl_dir_transfer_space(ds->ds_dir, -used - delta,
-		    DD_USED_REFRSRV, DD_USED_HEAD, tx);
+		    DD_USED_REFRSRV, DD_USED_HEAD, NULL);
 	} else {
 		dprintf_bp(bp, "putting on dead list: %s", "");
 		if (async) {
@@ -2837,7 +2837,7 @@ dsl_dataset_clone_swap_sync_impl(dsl_dataset_t *clone,
 		    origin_head->ds_dir->dd_origin_txg, UINT64_MAX,
 		    &odl_used, &odl_comp, &odl_uncomp);
 		dsl_dir_transfer_space(origin_head->ds_dir, cdl_used - odl_used,
-		    DD_USED_HEAD, DD_USED_SNAP, tx);
+		    DD_USED_HEAD, DD_USED_SNAP, NULL);
 	}
 
 	/* swap ds_*_bytes */
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 5a891d1ba3d6..1862f8cb8d7c 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
@@ -1389,7 +1389,7 @@ dsl_dir_diduse_space(dsl_dir_t *dd, dd_used_t type,
 		    accounted_delta, compressed, uncompressed, tx);
 		dsl_dir_transfer_space(dd->dd_parent,
 		    used - accounted_delta,
-		    DD_USED_CHILD_RSRV, DD_USED_CHILD, tx);
+		    DD_USED_CHILD_RSRV, DD_USED_CHILD, NULL);
 	}
 }
 
@@ -1397,7 +1397,7 @@ void
 dsl_dir_transfer_space(dsl_dir_t *dd, int64_t delta,
     dd_used_t oldtype, dd_used_t newtype, dmu_tx_t *tx)
 {
-	ASSERT(dmu_tx_is_syncing(tx));
+	ASSERT(tx == NULL || dmu_tx_is_syncing(tx));
 	ASSERT(oldtype < DD_USED_NUM);
 	ASSERT(newtype < DD_USED_NUM);
 
@@ -1405,7 +1405,8 @@ dsl_dir_transfer_space(dsl_dir_t *dd, int64_t delta,
 	    !(dsl_dir_phys(dd)->dd_flags & DD_FLAG_USED_BREAKDOWN))
 		return;
 
-	dmu_buf_will_dirty(dd->dd_dbuf, tx);
+	if (tx != NULL)
+		dmu_buf_will_dirty(dd->dd_dbuf, tx);
 	mutex_enter(&dd->dd_lock);
 	ASSERT(delta > 0 ?
 	    dsl_dir_phys(dd)->dd_used_breakdown[oldtype] >= delta :