From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264858AbUGMITK (ORCPT ); Tue, 13 Jul 2004 04:19:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264668AbUGMITK (ORCPT ); Tue, 13 Jul 2004 04:19:10 -0400 Received: from pimout3-ext.prodigy.net ([207.115.63.102]:1791 "EHLO pimout3-ext.prodigy.net") by vger.kernel.org with ESMTP id S264902AbUGMIKo (ORCPT ); Tue, 13 Jul 2004 04:10:44 -0400 Date: Tue, 13 Jul 2004 01:09:50 -0700 From: Chris Wedgwood To: Anton Ertl Cc: linux-kernel@vger.kernel.org, Jan Knutar , L A Walsh Subject: Re: XFS: how to NOT null files on fsck? Message-ID: <20040713080950.GA1810@taniwha.stupidest.org> References: <200407050247.53743.norberto+linux-kernel@bensa.ath.cx> <200407102143.49838.jk-lkml@sci.fi> <20040710184601.GB5014@taniwha.stupidest.org> <200407101555.27278.norberto+linux-kernel@bensa.ath.cx> <20040710191914.GA5471@taniwha.stupidest.org> <2hgxc-5x9-9@gated-at.bofh.it> <2004Jul13.092529@mips.complang.tuwien.ac.at> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2004Jul13.092529@mips.complang.tuwien.ac.at> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 13, 2004 at 07:25:29AM +0000, Anton Ertl wrote: > A secure FS must ensure that other people's deleted data does not > end up in the file. AFAIK FSs don't record owners for free blocks, > so they can only ensure this by zeroing the blocks. How can free blocks have an owner? They wouldn't be free then. > So I doubt that you will see any different behaviour from an FS that > keeps only meta-data consistent and writes meta-data before data. You do, some fs' will return stale data. > It's too hard to fix the applications, since there is no easy way to > test that they are really fixed. No, it's not hard to fix the applications and it's easy to tell if they are fixed. > Also, the number of applications is much higher than the number of > file systems. You don't fix all applications, only ones where data is critical and their handling of it is poor. MTAs like postfix don't have a problem for example, they are generally written well. > The file system should provide something that I call in-order > semantics, i.e., that the disk state always represents an existing > (possibly old) logical state of the FS, not some state that never > existed, or some existing state with missing data. ext3 and reiserfs have what amounts to this as an option right now. It has some performance implications but I'm told works great. I don't think the current XFS behaviour is undesirable or broken. --cw