diff --git a/sys/sys/errno.h b/sys/sys/errno.h
--- a/sys/sys/errno.h
+++ b/sys/sys/errno.h
@@ -191,6 +191,7 @@
 #define	ENOIOCTL	(-3)		/* ioctl not handled by this layer */
 #define	EDIRIOCTL	(-4)		/* do direct ioctl in GEOM */
 #define	ERELOOKUP	(-5)		/* retry the directory lookup */
+#define	EUNSDEP		(-6)		/* unsatisfied dependency */
 #endif
 
 #ifndef _KERNEL