From owner-freebsd-fs Wed Aug 7 17:43:27 2002 Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 35D8737B400 for ; Wed, 7 Aug 2002 17:43:24 -0700 (PDT) Received: from hawk.mail.pas.earthlink.net (hawk.mail.pas.earthlink.net [207.217.120.22]) by mx1.FreeBSD.org (Postfix) with ESMTP id A639743E3B for ; Wed, 7 Aug 2002 17:43:23 -0700 (PDT) (envelope-from tlambert2@mindspring.com) Received: from pool0264.cvx22-bradley.dialup.earthlink.net ([209.179.199.9] helo=mindspring.com) by hawk.mail.pas.earthlink.net with esmtp (Exim 3.33 #1) id 17cbOW-0000tx-00; Wed, 07 Aug 2002 17:43:16 -0700 Message-ID: <3D51BE6F.298F0AF@mindspring.com> Date: Wed, 07 Aug 2002 17:42:23 -0700 From: Terry Lambert X-Mailer: Mozilla 4.79 [en] (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: Kelly Yancey Cc: "David E. Cross" , fs@FreeBSD.ORG, guptar@cs.rpi.edu Subject: Re: vnodes (UFS journaling)? References: <20020807170230.Y6264-100000@gateway.posi.net> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Kelly Yancey wrote: > On Wed, 7 Aug 2002, Terry Lambert wrote: > > "David E. Cross" wrote: > > > Ok, we've noticed an "unfortunate" side-effect of our work. We leak data > > > (part of the journal shows up in other files). I think it is because > > > > What is it that you are trying to do with the vnode? > > > > -- Terry > > > > I believe he is trying to keep a journal, likely as a file on the > filesystem that is being journalled. I don't actually know, but that's > what I would guess. I understand that he's working on a journalling FS. I'm wondering what reaccessing vnodes has to do with journalling? A vnode is an in-core abstract representation of a file in a file system, that has a non-abstract real file association in the FS itself. A vnode doesn't know about the journalling taking place in the underlying FS -- and *shouldn't* know about it. The VFS interface layer is intended as a method of abstracting *exacly* this sort of implementation detail. I'm wondering why journalling would ever be visible via a vnode interaction, as a system artifact, when all the journaling operations are encapsulated in the FS implementation proper, at the non-abstract layer (in FFS terms, journalling would be a per inode operation, not per vnode operation). The *only* place you would really make the underlying structure visible at all, IMO, would be in the addition of VNOPs to add a transactioning interface for user applications. Even then, though, the operations would *still* be abstract. It *seems* like they are trying to implement the journals above the vnode layer, which makes no sense at all... so the question is *why* this is a *vnode* issue at all, ever, under *any* possible interpretation of the problem that's being solved? If they are having data corruption problems, it's lower down. The question, as he asked it, is a total non-sequitur, given his introductory text. It's like asking "Is it shorter to New York, or by bus?". -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message