* Find or create an extent which includes @index, core function to manage
  * extent tree.
  */
-struct osc_extent *osc_extent_find(const struct lu_env *env,
-                                  struct osc_object *obj, pgoff_t index,
-                                  int *grants)
+static struct osc_extent *osc_extent_find(const struct lu_env *env,
+                                         struct osc_object *obj, pgoff_t index,
+                                         int *grants)
 
 {
        struct client_obd *cli = osc_cli(obj);
        }
 }
 
-void osc_unreserve_grant(struct client_obd *cli,
-                        unsigned int reserved, unsigned int unused)
+static void osc_unreserve_grant(struct client_obd *cli,
+                               unsigned int reserved, unsigned int unused)
 {
        client_obd_list_lock(&cli->cl_loi_list_lock);
        __osc_unreserve_grant(cli, reserved, unused);