diff --git a/tools/python/xen/xend/xenstore/xstransact.py b/tools/python/xen/xend/xenstore/xstransact.py
index d33b209e8e..ac8269f2ba 100644
--- a/tools/python/xen/xend/xenstore/xstransact.py
+++ b/tools/python/xen/xend/xenstore/xstransact.py
@@ -14,6 +14,9 @@ from xen.xend.xenstore.xsutil import xshandle
 class xstransact:
 
     def __init__(self, path):
+        self.in_transaction = False # Set this temporarily -- if this
+                                    # constructor fails, then we need to
+                                    # protect __del__.
         self.path = path.rstrip("/")
         self.transaction = xshandle().transaction_start()
         self.in_transaction = True