From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Mon, 23 Apr 2007 14:49:36 -0700 (PDT) Received: from pentafluge.infradead.org (pentafluge.infradead.org [213.146.154.40]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with ESMTP id l3NLnXfB014564 for ; Mon, 23 Apr 2007 14:49:34 -0700 Date: Mon, 23 Apr 2007 22:19:52 +0100 From: Christoph Hellwig Subject: Re: possible recursive locking detected Message-ID: <20070423211952.GA13572@infradead.org> References: <20603.194.246.123.250.1177344480.squirrel@derchris.gotdns.org:8080> <462D0D23.7010803@sandeen.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <462D0D23.7010803@sandeen.net> Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Eric Sandeen Cc: Christian Kujau , xfs@oss.sgi.com On Mon, Apr 23, 2007 at 02:46:43PM -0500, Eric Sandeen wrote: > Christian Kujau wrote: > > Hi there, > > > > On Mon, April 2, 2007 19:18, Christian Kujau wrote: > >> when I enabled a few more debug-options in the kernel (vanilla > >> 2.6.21-rc5), I came across: > >> > >> [ INFO: possible recursive locking detected ] > >> 2.6.21-rc5 #2 > > > > The same happened with -rc7, see below. Can anyone comment if this > > is/could lead to a problem? > > > > The consensus seems to be that it is cosmetic. It's not really cosmetic. It means i_lock and i_iolock are beeing acquired without an order that is detectable by lockdep. At the very first it means annotations for lockdep are missing, because acquiring two per-inode locks at the same time is a basic fact in unix filesystems. But deeper than that the rules for taking both locks are not very well defined in XFS. These rules at least need documentation in form of lockdep annotations, and possibly some fixes and cleanups around the more dirty areas like xfs_lock_for_rename() or xfs_lock_dir_and_entry()