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 (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id mBUFvQgY026562 for ; Tue, 30 Dec 2008 09:57:28 -0600 Received: from bombadil.infradead.org (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 886A717978B9 for ; Tue, 30 Dec 2008 07:57:26 -0800 (PST) Received: from bombadil.infradead.org (bombadil.infradead.org [18.85.46.34]) by cuda.sgi.com with ESMTP id G95GuHjDHms6b9YO for ; Tue, 30 Dec 2008 07:57:26 -0800 (PST) Date: Tue, 30 Dec 2008 10:57:26 -0500 From: Christoph Hellwig Subject: Re: [PATCH, RFC] directory offset overflows in 2.6.28 Message-ID: <20081230155726.GA30568@infradead.org> References: <20081229220745.GA12966@infradead.org> <20081230001117.GA5220@disturbed> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20081230001117.GA5220@disturbed> 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: Christoph Hellwig , xfs@oss.sgi.com, John Stanley On Tue, Dec 30, 2008 at 11:11:17AM +1100, Dave Chinner wrote: > On Mon, Dec 29, 2008 at 05:07:45PM -0500, Christoph Hellwig wrote: > > The patch below is a dumb version of just putting back the masking, > > to make sure we have the same behavior as in 2.6.27 and earlier. > > I think we should at least hide it in a macro that is well-commented, > > but I suspect we also need to make sure that we never ever get bigger > > offsets in directories in some way. > > I think we need that macro sooner rather than later ;) > In this case, you can do the masking at the time cook is > assigned. I haven't checked, but I suspect the rest will be the > same. That will make the patch less invasive and with a macro > somewhat cleaner... That way we could replace two assignment by one one time each in xfs_dir2_leaf.c and xfs_dir2_block.c. I started working on the macro, but it seems even more hacky. When looking at the big picture we have two problems: - the end of directory marker which always seems to be always too large for 32bit values for 32 bit indices - directories that actually are too large to be represented using 32 bit signed offsets. I guess we just can't support those for apps using the 32bit readdir interface and the EOVERFLOW is valid for those. The current approach as in < 2.6.28 and with this patch breaks that second case in subtile ways. So, I'd just push the first hacky opencoded patch into 2.6.29 and -stable now to revert to the old behaviour with all it's faults, and in the meantime I'll look into a proper way finding a better end of directory indicator. That should also help Russell's BSD concerns. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs