history wasn't protected by a lock.

src/ZODB/FileStorage.py

@@ -184,7 +184,7 @@
 #   may have a back pointer to a version record or to a non-version
 #   record.
 #
-__version__='$Revision: 1.38 $'[11:-2]
+__version__='$Revision: 1.39 $'[11:-2]
 
 import struct, time, os, bpthread, string, base64, sys
 from struct import pack, unpack
@@ -895,6 +895,8 @@ class FileStorage(BaseStorage.BaseStorage):
         return r
 
     def history(self, oid, version=None, length=1, filter=None):
+        self._lock_acquire()
+        try:
             r=[]
             file=self._file
             seek=file.seek
@@ -944,6 +946,7 @@ class FileStorage(BaseStorage.BaseStorage):
 
                 if prev: pos=prev
                 else: return r
+        finally: self._lock_release()
 
 
     def pack(self, t, referencesf):