From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Tue, 05 Aug 2008 00:38:44 -0700 (PDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.168.28]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id m757cO22013889 for ; Tue, 5 Aug 2008 00:38:24 -0700 Received: from ipmail04.adl2.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 563B11246DB8 for ; Tue, 5 Aug 2008 00:39:38 -0700 (PDT) Received: from ipmail04.adl2.internode.on.net (ipmail04.adl2.internode.on.net [203.16.214.57]) by cuda.sgi.com with ESMTP id ZbgDJJKgTugaTSgH for ; Tue, 05 Aug 2008 00:39:38 -0700 (PDT) Date: Tue, 5 Aug 2008 17:39:37 +1000 From: Dave Chinner Subject: Re: [PATCH] Use KM_NOFS for debug trace buffers Message-ID: <20080805073937.GC21635@disturbed> References: <4897FCC7.400@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4897FCC7.400@sgi.com> Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Lachlan McIlroy Cc: xfs-oss , xfs-dev On Tue, Aug 05, 2008 at 05:09:59PM +1000, Lachlan McIlroy wrote: > Use KM_NOFS to prevent recursion back into the filesystem which can > cause deadlocks. > > In the case of xfs_iread() we hold the lock on the inode cluster buffer > while allocating memory for the trace buffers. If we recurse back into > XFS to flush data that may require a transaction to allocate extents > which needs log space. This can deadlock with the xfsaild thread which > can't push the tail of the log because it is trying to get the inode > cluster buffer lock. Looks OK. Cheers, Dave. -- Dave Chinner david@fromorbit.com