From owner-freebsd-hackers@FreeBSD.ORG Thu Mar 10 18:45:37 2005 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 793AD16A4CE; Thu, 10 Mar 2005 18:45:37 +0000 (GMT) Received: from filer.fsl.cs.sunysb.edu (filer.fsl.cs.sunysb.edu [130.245.126.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id DFA8E43D1F; Thu, 10 Mar 2005 18:45:36 +0000 (GMT) (envelope-from ezk@fsl.cs.sunysb.edu) Received: from agora.fsl.cs.sunysb.edu (agora.fsl.cs.sunysb.edu [130.245.126.12])j2AIj1mX018840; Thu, 10 Mar 2005 13:45:01 -0500 Received: from agora.fsl.cs.sunysb.edu (localhost.localdomain [127.0.0.1]) j2AIj0aL008588; Thu, 10 Mar 2005 13:45:00 -0500 Received: (from ezk@localhost) by agora.fsl.cs.sunysb.edu (8.12.11/8.12.8/Submit) id j2AIj0LB008584; Thu, 10 Mar 2005 13:45:00 -0500 Date: Thu, 10 Mar 2005 13:45:00 -0500 Message-Id: <200503101845.j2AIj0LB008584@agora.fsl.cs.sunysb.edu> From: Erez Zadok To: Lou Kamenov In-reply-to: Your message of "Thu, 10 Mar 2005 12:24:17 EST." <76f962c6050310092461fc850@mail.gmail.com> X-MailKey: Erez_Zadok X-Mailman-Approved-At: Fri, 11 Mar 2005 13:28:16 +0000 cc: cwright@cs.sunysb.edu cc: Mikhail Teterin cc: freebsd-fs@freebsd.org cc: hackers@freebsd.org cc: David Schultz cc: Jeremie Le Hen Subject: Re: the current status of nullfs, unionfs X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Mar 2005 18:45:37 -0000 In message <76f962c6050310092461fc850@mail.gmail.com>, Lou Kamenov writes: > On Thu, 10 Mar 2005 09:19:10 -0500, Michael W. Lucas > wrote: > > On Thu, Mar 10, 2005 at 12:38:43PM +0100, Jeremie Le Hen wrote: > > But the mere existence of even a basic regression test would be a > > start and would encourage people to not hose things further. > [..] > > Folks, don't let the fact that you're not a guru stop you from taking > > a kiddie step and submitting a basic test! > [..] > > I do use unionfs on daily basis. Mostly to union $home/bin directories and > such. For the last 1.5y I had it crash only 2 times. Of course trying > to unmount /bin > will turn into hell. I've used it successfully with pdumpfs from ports > to restore > old filespace view. I surely think that a stable unionfs will be a > good thing (tm). > > Erez's unionfs has the same problem, the case there is that you wont be > able to unmount it at all. (At least last time I tried with 1.0.3) You should NEVER be allowed to unmount an underlying file system of a stackable file system, if it's busy or in use, no more than you can remove a /dev/sda drive while ffs is mounted on it. Our approach in the Linux unionfs is to prevent users from shooting themselves too much in the foot. :-) However, our unionfs does provide mechanisms such that read-only or non-busy file system branches in the union, *can* indeed be removed safely. Generally we can support arbitrary insertions and removals of branches anywhere in the (fan-out) union; however, we found out that most of our unionfs users rarely want or need that. BTW, the latest version of our linux unionfs is 1.0.9. There has been a lot of work done on our unionfs recently, and it was deemed stable enough that several LiveCD distros, including the just-released Knoppix 3.8, are using it. > Problem or not it could be easily solved with simple heuristics. > Building a filespace > with unioning shouldnt really be that hard. > > best, > l > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" > Erez.