+int mdd_file_lock(const struct lu_env *env, struct md_object *obj,
+ struct lov_mds_md *lmm, struct ldlm_extent *extent,
+ struct lustre_handle *lockh);
+int mdd_file_unlock(const struct lu_env *env, struct md_object *obj,
+ struct lov_mds_md *lmm, struct lustre_handle *lockh);