--- geom_dev.c.orig	Fri Mar 18 07:57:58 2005
+++ geom_dev.c	Fri Mar  3 03:03:40 2006
@@ -82,6 +82,10 @@
 	.init = g_dev_init,
 };
 
+/* Device used for dumping memory content. */
+static char dumpdev[128];
+TUNABLE_STR("dumpdev", dumpdev, sizeof(dumpdev));
+
 static struct unrhdr *unithdr;	/* Locked by topology */
 
 static void
@@ -149,6 +153,10 @@
 	    UID_ROOT, GID_OPERATOR, 0640, gp->name);
 	if (pp->flags & G_PF_CANDELETE)
 		dev->si_flags |= SI_CANDELETE;
+	if (dumpdev && strcmp(gp->name, dumpdev) == 0) {
+		printf("Dumping on %s\n", dumpdev);
+		dev->si_flags |= SI_DUMPDEV;
+	}
 	mtx_unlock(&Giant);
 	g_topology_lock();
 	dev->si_iosize_max = MAXPHYS;