From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Wed, 08 Oct 2008 17:00:27 -0700 (PDT) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.168.29]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id m9900PoE010043 for ; Wed, 8 Oct 2008 17:00:25 -0700 Received: from ipmail05.adl2.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 030104CFE99 for ; Wed, 8 Oct 2008 17:02:04 -0700 (PDT) Received: from ipmail05.adl2.internode.on.net (ipmail05.adl2.internode.on.net [203.16.214.145]) by cuda.sgi.com with ESMTP id 7LYwKLxs7txrg2Zb for ; Wed, 08 Oct 2008 17:02:04 -0700 (PDT) Date: Thu, 9 Oct 2008 11:02:01 +1100 From: Dave Chinner Subject: Re: [PATCH 6/6] XFS: Prevent looping in xfs_sync_inodes_ag Message-ID: <20081009000201.GB9597@disturbed> References: <1223416480-7701-1-git-send-email-david@fromorbit.com> <1223416480-7701-7-git-send-email-david@fromorbit.com> <20081008182138.GB22941@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081008182138.GB22941@infradead.org> Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Christoph Hellwig Cc: xfs@oss.sgi.com On Wed, Oct 08, 2008 at 02:21:38PM -0400, Christoph Hellwig wrote: > On Wed, Oct 08, 2008 at 08:54:40AM +1100, Dave Chinner wrote: > > If the last block of the AG has inodes in it and the AG is an > > exactly power-of-2 size then the last inode in the AG points > > to the last block in the AG. If we try to find the next inode > > in the AG by adding one to the inode number, we increment the > > inode number past the size of the AG. The result is that the > > macro XFS_INO_TO_AGINO() will strip the AG portion of the inode > > number and return an inode number of zero. > > > > That is, instead of terminating the lookup loop because we hit the > > inode number went outside the valid range for the AG, the search > > index returns to zero and we start traversing the radix tree from > > the start again. This results in an endless loop in > > xfs_sync_inodes_ag(). > > > > Fix it be detecting if the new search index decreases as a result of > > incrementing the current inode number. That indicate an overflow and > > hence that we have finished processing the AG so we can terminate > > the loop. > > Shouldn't this get merged into the patch that introduces the radix-tree > based sync? It could be, but I didn't want to have to redo that reviewed patch series. I've only hit this problem once in the past 6 weeks so I thought adding a new patch rather than modifying patches to add the fix was a better way to go.... I can integrate it if you want.... Cheers, Dave. -- Dave Chinner david@fromorbit.com