From owner-freebsd-current Sun Oct 20 01:05:18 1996 Return-Path: owner-current Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id BAA15127 for current-outgoing; Sun, 20 Oct 1996 01:05:18 -0700 (PDT) Received: from spiff.cc.iastate.edu (spiff.cc.iastate.edu [129.186.142.89]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id BAA15121 for ; Sun, 20 Oct 1996 01:05:13 -0700 (PDT) Received: by spiff.cc.iastate.edu with sendmail-5.65 id ; Sun, 20 Oct 1996 03:05:11 -0500 Message-Id: <9610200805.AA20179@spiff.cc.iastate.edu> To: current@freebsd.org Reply-To: graphix@iastate.edu Subject: union mounts Date: Sun, 20 Oct 1996 03:05:10 CDT From: Kent Vander Velden Sender: owner-current@freebsd.org X-Loop: FreeBSD.org Precedence: bulk After searching the mail list archives I have a bad feeling that that union mounts do not work but hoped that perhaps they where fixed in current. To make certain that I do not misunderstand the way in which a union mount is supposed to work I do: mount -t union -o -b /usr/src /original/usr/src I would like to be able to modify code that exists in /usr/src and as I modify it (at least the first time) have it copied to /original/usr/src. All new additions in /original/usr/src exist only in /original/usr/src. All of the files that are in /usr/src appear in /original/usr/src. /usr/src should never be altered unless the files are referenced via /usr/src. What happens is that a directory listing of /original/usr/src displays only the files that where created in /original/usr/src and not those in /usr/src. If I access a file that should exist in /original/usr/src/ because of the mount, the file does exist. If I access a directory that should exist there, a new directory is created. The code that is in /usr/src/sys/miscfs/unionfs/ suggest that I should replace certain files in /usr/src/lib/libc/gen/ but the suggested replacements do not compile (perhaps fixable... did not look that closely at the errors). If I compile a current kernel with the null and union filesystems staticly linked the system will die on startup with a page fault. At the moment I am using a union mount with the lkm module. Do union mounts work or do I misunderstand the use of them? Thanks. --- Kent Vander Velden graphix@iastate.edu