diff --git a/tools/python/xen/xend/XendAPI.py b/tools/python/xen/xend/XendAPI.py
index 077ceefddf..1573be3b58 100644
--- a/tools/python/xen/xend/XendAPI.py
+++ b/tools/python/xen/xend/XendAPI.py
@@ -1327,12 +1327,15 @@ class XendAPI:
         return xen_api_success(sr.list_images())
 
     def sr_get_virtual_allocation(self, session, sr_ref):
+        sr = XendNode.instance().get_sr()        
         return sr.used_space_bytes()
 
     def sr_get_physical_utilisation(self, session, sr_ref):
+        sr = XendNode.instance().get_sr()        
         return sr.used_space_bytes()
 
     def sr_get_physical_size(self, session, sr_ref):
+        sr = XendNode.instance().get_sr()        
         return sr.total_space_bytes()
     
     def sr_get_type(self, session, sr_ref):