Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751260AbWIEEpo (ORCPT ); Tue, 5 Sep 2006 00:45:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751236AbWIEEpn (ORCPT ); Tue, 5 Sep 2006 00:45:43 -0400 Received: from [213.184.169.125] ([213.184.169.125]:15488 "EHLO raad.intranet") by vger.kernel.org with ESMTP id S1750708AbWIEEpn convert rfc822-to-8bit (ORCPT ); Tue, 5 Sep 2006 00:45:43 -0400 From: Al Boldi To: =?utf-8?q?J=C3=B6rn=20Engel?= Subject: Re: [PATCH 00/22][RFC] Unionfs: Stackable Namespace Unification Filesystem Date: Tue, 5 Sep 2006 07:46:44 +0300 User-Agent: KMail/1.5 Cc: Josef Sipek , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, hch@infradead.org, akpm@osdl.org, viro@ftp.linux.org.uk, Pavel Machek References: <20060901013512.GA5788@fsl.cs.sunysb.edu> <20060903110507.GD4884@ucw.cz> <20060904125744.GA1961@wohnheim.fh-wedel.de> In-Reply-To: <20060904125744.GA1961@wohnheim.fh-wedel.de> MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Message-Id: <200609050746.44502.a1426z@gawab.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1313 Lines: 35 Jörn Engel wrote: > On Sun, 3 September 2006 11:05:08 +0000, Pavel Machek wrote: > > > - Modifying a Unionfs branch directly, while the union is mounted, is > > > currently unsupported. Any such change may cause Unionfs to oops > > > and it can even result in data loss! > > > > I'm not sure if that is acceptable. Even root user should be unable to > > oops the kernel using 'normal' actions. > > Direct modification of branches is similar to direct modification of > block devices underneith a mounted filesystem. While I agree that > such a thing _should_ not oops the kernel, I'd bet that you can easily > run a stresstest on a filesystem while randomly flipping bits in the > block device and get just that. Not really a fair comparison. The block level is conceptionally totally different than the fs level, while a stackable fs is within the realms of the fs level. > There are bigger problems in unionfs to worry about. Agreed. Moving basic functionality abstractions into the VFS could easily alleviate theses kinds of problems. Thanks! -- Al - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/