Index: md.c
===================================================================
RCS file: /home/ncvs/src/sys/dev/md/md.c,v
retrieving revision 1.74
diff -u -r1.74 md.c
--- md.c	2002/10/21 20:08:28	1.74
+++ md.c	2002/11/24 23:43:40
@@ -79,6 +79,7 @@
 #include <sys/stdint.h>
 #include <sys/sysctl.h>
 #include <sys/vnode.h>
+#include <sys/stat.h>
 
 #include <vm/vm.h>
 #include <vm/vm_object.h>
@@ -807,6 +808,7 @@
 	struct md_s *sc;
 	struct vattr vattr;
 	struct nameidata nd;
+	struct stat sb;
 	int error, flags;
 
 	flags = FREAD|FWRITE;
@@ -828,6 +830,13 @@
 		(void) vn_close(nd.ni_vp, flags, td->td_ucred, td);
 		return (error ? error : EINVAL);
 	}
+
+	error = vn_stat(nd.ni_vp, &sb, td->td_ucred, NOCRED, td);
+	if (error)
+		return (error);
+	if (sb.st_size == 0)
+		return (EINVAL);
+	
 	VOP_UNLOCK(nd.ni_vp, 0, td);
 
 	if (mdio->md_options & MD_AUTOUNIT) {