diskbackend: Mandate parent_pool when vol_object is passed

We will need parent pool for looking up info about network volumes

virtinst/cli.py

@@ -1579,7 +1579,7 @@ class ParserDisk(VirtCLIParser):
 
         if volname:
             vol_object = poolobj.storageVolLookupByName(volname)
-            inst.set_vol_object(vol_object)
+            inst.set_vol_object(vol_object, poolobj)
             poolobj = None
 
         if ((poolobj or inst.wants_storage_creation()) and

virtinst/devicedisk.py

@@ -536,8 +536,8 @@ class VirtualDisk(VirtualDevice):
         self._set_xmlpath(self.path)
     path = property(_get_path, _set_path)
 
-    def set_vol_object(self, vol_object):
-        self._change_backend(None, vol_object, None)
+    def set_vol_object(self, vol_object, parent_pool):
+        self._change_backend(None, vol_object, parent_pool)
         self._set_xmlpath(self.path)
 
     def set_vol_install(self, vol_install):
@@ -856,9 +856,12 @@ class VirtualDisk(VirtualDevice):
         if not self._storage_backend.will_create_storage():
             return
 
-        volobj = self._storage_backend.create(meter)
-        if volobj:
-            self._change_backend(None, volobj, None)
+        vol_object = self._storage_backend.create(meter)
+        if not vol_object:
+            return
+
+        parent_pool = self.get_vol_install().pool
+        self._change_backend(None, vol_object, parent_pool)
 
     def set_defaults(self, guest):
         if self.is_cdrom():

virtinst/diskbackend.py

@@ -81,7 +81,7 @@ def check_if_path_managed(conn, path):
     """
     vol, ignore = _lookup_vol_by_path(conn, path)
     if vol:
-        return vol, None
+        return vol, vol.storagePoolLookupByVolume()
 
     pool = _lookup_pool_by_dirname(conn, path)
     if not pool:
@@ -107,8 +107,6 @@ def check_if_path_managed(conn, path):
         raise ValueError(_("Cannot use storage %(path)s: %(err)s") %
             {'path' : path, 'err' : verr})
 
-    if vol:
-        pool = None
     return vol, pool
 
 
@@ -434,6 +432,9 @@ class StorageBackend(_StorageBase):
         if self._vol_object is not None:
             self._path = None
 
+        if self._vol_object and not self._parent_pool:
+            raise RuntimeError(
+                "programming error: parent_pool must be specified")
 
         # Cached bits
         self._vol_xml = None