Index: head/sys/geom/gate/g_gate.c
===================================================================
--- head/sys/geom/gate/g_gate.c
+++ head/sys/geom/gate/g_gate.c
@@ -616,8 +616,8 @@
 			G_GATE_DEBUG(1, "Invalid media size.");
 			return (EINVAL);
 		}
-		/* TODO */
-		return (EOPNOTSUPP);
+		g_resize_provider(pp, ggio->gctl_mediasize);
+		return (0);
 	}
 
 	if ((ggio->gctl_modify & GG_MODIFY_INFO) != 0)