--- a/usr/src/uts/common/fs/zfs/dmu_tx.c	Mon Mar 27 08:39:17 2006 -0800
+++ b/usr/src/uts/common/fs/zfs/dmu_tx.c	Mon Mar 27 14:12:51 2006 -0800
@@ -347,7 +347,7 @@
 	    list_link_active(&dn->dn_dirty_link[2]) |
 	    list_link_active(&dn->dn_dirty_link[3]);
 	mutex_exit(&dn->dn_objset->os_lock);
-	if (dn->dn_assigned_tx || dirty)
+	if (dirty || dn->dn_assigned_tx || dn->dn_phys->dn_nlevels == 0)
 		return;
 
 	/*