.

bigfile/_bigfile.c

@@ -991,7 +991,7 @@ pyfileh_open(PyObject *pyfile0, PyObject *args)
         return NULL;
 
     Py_INCREF(pyfile);
-    err = fileh_open(pyfileh, pyfile, ram);
+    err = fileh_open(pyfileh, pyfile, ram, DONT_MMAP_OVERLAY);  // XXX -> MMAP_OVERLAY if requested
     if (err) {
         XPyErr_SetFromErrno();
         Py_DECREF(pyfile);

bigfile/file_zodb.py

@@ -666,7 +666,7 @@ class _ZBigFileH(object):
             self.zfileh = wcfileh
         else:
             # XXX
-            self.zfileh = zfile._v_file.fileh_open(mmap_overlay=_use_wcfs)
+            self.zfileh = zfile._v_file.fileh_open()
 
         # FIXME zfile._p_jar could be None (ex. ZBigFile is newly created
         #       before first commit)