diff -r a4a41525180c -r 4d1382fd96ff mercurial/context.py
--- a/mercurial/context.py	Wed Jul 08 17:01:09 2015 +0900
+++ b/mercurial/context.py	Wed Jul 08 17:01:09 2015 +0900
@@ -1316,6 +1316,11 @@
         self._repo.dirstate.setparents(node)
         self._repo.dirstate.endparentchange()
 
+        # write changes out explicitly, because nesting wlock at
+        # runtime may prevent 'wlock.release()' in 'repo.commit()'
+        # from immediately doing so for subsequent changing files
+        self._repo.dirstate.write()
+
 class workingctx(committablectx):
     """A workingctx object makes access to data related to
     the current working directory convenient.