--- geom_subr.c.orig	Sat Jan 17 01:19:58 2004
+++ geom_subr.c	Sat Jan 17 19:28:55 2004
@@ -288,6 +288,9 @@ g_new_consumer(struct g_geom *gp)
 	struct g_consumer *cp;
 
 	g_topology_assert();
+	KASSERT(!(gp->flags & G_GEOM_WITHER),
+	    ("g_new_consumer called on geom(%s) with WITHER flag set (class %s)",
+	    gp->name, gp->class->name));
 	KASSERT(gp->orphan != NULL,
 	    ("g_new_consumer on geom(%s) (class %s) without orphan",
 	    gp->name, gp->class->name));
@@ -365,6 +368,9 @@ g_new_providerf(struct g_geom *gp, const
 	va_list ap;
 
 	g_topology_assert();
+	KASSERT(!(gp->flags & G_GEOM_WITHER),
+	    ("g_new_providerf called on geom(%s) with WITHER flag set (class %s)",
+	    gp->name, gp->class->name));
 	sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND);
 	va_start(ap, fmt);
 	sbuf_vprintf(sb, fmt, ap);
@@ -388,6 +394,9 @@ void
 g_error_provider(struct g_provider *pp, int error)
 {
 
+	KASSERT(!(pp->geom->flags & G_GEOM_WITHER),
+	    ("error change for provider(%s) on geom(%s) with WITHER flag set (class %s)",
+	    pp->geom->name, pp->geom->class->name));
 	pp->error = error;
 }
 
@@ -504,6 +513,8 @@ g_attach(struct g_consumer *cp, struct g
 
 	g_topology_assert();
 	KASSERT(cp->provider == NULL, ("attach but attached"));
+	if (pp->geom->flags & G_GEOM_WITHER)
+		return (EPERM);	/* XXX: ENXIO? pp->error? */
 	cp->provider = pp;
 	LIST_INSERT_HEAD(&pp->consumers, cp, consumers);
 	error = redo_rank(cp->geom);