From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id nAU6iBux202801 for ; Mon, 30 Nov 2009 00:44:11 -0600 Received: from mail.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 860191D9F09F for ; Sun, 29 Nov 2009 22:44:39 -0800 (PST) Received: from mail.internode.on.net (bld-mail19.adl2.internode.on.net [150.101.137.104]) by cuda.sgi.com with ESMTP id 9WGFj2DT6YzjbtpH for ; Sun, 29 Nov 2009 22:44:39 -0800 (PST) Date: Mon, 30 Nov 2009 17:43:56 +1100 From: Dave Chinner Subject: Re: Writing journal only in Big Endian format Message-ID: <20091130064356.GD30608@discord.disaster> References: <409bd82b0911292117n5aa11961u86e787d20acbd2b3@mail.gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <409bd82b0911292117n5aa11961u86e787d20acbd2b3@mail.gmail.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Nitin Arora Cc: "sandeen-xfs@sandeen.net" , "p.mironchik@velesys.com" , "hch@xfs.org" , xfs@oss.sgi.com On Mon, Nov 30, 2009 at 10:47:41AM +0530, Nitin Arora wrote: > The problem is that big endian machine cannot recognize the > journal which was written in little endian format by the little > endian machine and once the journal is zerod out it can be > mouted. > > Now the solution to above problem seems writing journal always in > big endian format. Or you could just replay the log on the little endian machine and do a clean unmount, then you should be able to move it to the big endian machine without losing anything. > Please suggest me, Is there any design limitation in XFS for this. No design limitation, just a *lot* of work to change. If you don't have a few months handy to work on this, I'd just use the above method.... > Is it okay and feasible to implement it if yes then please give > some pointers so that it can be implemented, All log headers, tails and sector fills need to be converted, every log item format routine needs a big-endian version, log recovery needs to be able to read both host-format and big-endian logs, all the userspace tools need to learn about different log formats, QA tests need to be written, etc. > under some suitable > compile time switch. It could be done with a superblock feature bit, so the same kernel could support both big-endian logs and host format. Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs