diff --git a/sys/geom/geom.h b/sys/geom/geom.h
index 82ce8fe2690d..015baea4deb4 100644
--- a/sys/geom/geom.h
+++ b/sys/geom/geom.h
@@ -87,12 +87,22 @@ typedef void g_dumpconf_t (struct sbuf *, const char *indent, struct g_geom *,
  */
 struct g_class {
 	const char		*name;
+	u_int			version;
 	g_taste_t		*taste;
 	g_config_t		*config;
 	g_ctl_req_t		*ctlreq;
 	g_init_t		*init;
 	g_fini_t		*fini;
 	g_ctl_destroy_geom_t	*destroy_geom;
+	/*
+	 * Defaults values for geom methods
+	 */
+	g_start_t		*start;
+	g_spoiled_t		*spoiled;
+	g_dumpconf_t		*dumpconf;
+	g_access_t		*access;
+	g_orphan_t		*orphan;
+	g_ioctl_t		*ioctl;
 	/*
 	 * The remaining elements are private
 	 */
@@ -100,6 +110,9 @@ struct g_class {
 	LIST_HEAD(,g_geom)	geom;
 };
 
+#define G_VERSION_00	0x19950323
+#define G_VERSION	G_VERSION_00
+
 /*
  * The g_geom is an instance of a g_class.
  */
diff --git a/sys/geom/geom_subr.c b/sys/geom/geom_subr.c
index 2e957699f344..c7058ea857fa 100644
--- a/sys/geom/geom_subr.c
+++ b/sys/geom/geom_subr.c
@@ -177,7 +177,14 @@ g_modevent(module_t mod, int type, void *data)
 	struct g_hh00 *hh;
 	int error;
 	static int g_ignition;
+	struct g_class *mp;
 
+	mp = data;
+	if (mp->version != G_VERSION) {
+		printf("GEOM class %s has Wrong version %x\n",
+		    mp->name, mp->version);
+		return (EINVAL);
+	}
 	if (!g_ignition) {
 		g_ignition++;
 		g_init();
@@ -234,6 +241,13 @@ g_new_geomf(struct g_class *mp, const char *fmt, ...)
 	TAILQ_INSERT_HEAD(&geoms, gp, geoms);
 	strcpy(gp->name, sbuf_data(sb));
 	sbuf_delete(sb);
+	/* Fill in defaults from class */
+	gp->start = mp->start;
+	gp->spoiled = mp->spoiled;
+	gp->dumpconf = mp->dumpconf;
+	gp->access = mp->access;
+	gp->orphan = mp->orphan;
+	gp->ioctl = mp->ioctl;
 	return (gp);
 }