Fix ResourceWarnings in FileStorage.pack()

src/ZODB/FileStorage/FileStorage.py

@@ -1034,10 +1034,13 @@ class FileStorage(
         # want to invest much in the old packer, at least for now.
         assert referencesf is not None
         p = FileStoragePacker(storage, referencesf, stop, gc)
+        try:
             opos = p.pack()
             if opos is None:
                 return None
             return opos, p.index
+        finally:
+            p.close()
 
     def pack(self, t, referencesf, gc=None):
         """Copy data from the current database file to a packed file

src/ZODB/FileStorage/fspack.py

@@ -382,6 +382,15 @@ class FileStoragePacker(FileStorageFormatter):
         self.toid2tid = {}
         self.toid2tid_delete = {}
 
+        self._tfile = None
+
+    def close(self):
+        self._file.close()
+        if self._tfile is not None:
+            self._tfile.close()
+        if self.blob_removed is not None:
+            self.blob_removed.close()
+
     def pack(self):
         # Pack copies all data reachable at the pack time or later.
         #