From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760760AbYETRJM (ORCPT ); Tue, 20 May 2008 13:09:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754869AbYETRI7 (ORCPT ); Tue, 20 May 2008 13:08:59 -0400 Received: from bohort.kerlabs.com ([62.160.40.57]:57223 "EHLO bohort.kerlabs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754834AbYETRI6 (ORCPT ); Tue, 20 May 2008 13:08:58 -0400 Message-ID: <483305A6.3040906@kerlabs.com> Date: Tue, 20 May 2008 19:08:54 +0200 From: Louis Rilling Organization: Kerlabs User-Agent: IceDove 1.5.0.14pre (X11/20071018) MIME-Version: 1.0 To: Arjan van de Ven CC: Joel.Becker@oracle.com, linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com Subject: Re: [RFC][PATCH 0/3] configfs: Make nested default groups lockdep-friendly References: <20080520163320.025971210@kerlabs.com> <20080520095810.1d50d247@infradead.org> In-Reply-To: <20080520095810.1d50d247@infradead.org> X-Enigmail-Version: 0.94.2.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Arjan van de Ven a écrit : > On Tue, 20 May 2008 18:33:20 +0200 > Louis Rilling wrote: > >> Hi all, >> >> The following patches fix lockdep warnings resulting from (correct) >> recursive locking in configfs. >> >> Current lockdep annotations for inode mutexes in configfs are >> lockdep-friendly provided that: >> 1/ config_groups have at most one level of default groups (see >> configfs_attach_group()), >> 2/ config_groups having default groups are never removed (see >> configfs_detach_prep()). >> >> Since lockdep does not handle such correct recursion, the idea is to >> insert lockdep_off()/lockdep_on() for inode mutexes as soon as the >> level of recursion of the I_MUTEX_PARENT -> I_MUTEX_CHILD dependency >> pattern increases. > > I'm... not entirely happy with such a solution ;( > > there must be a better one. Hmm, to me there are three solutions: 1/ keep lockdep and configfs like they are, and use this patchset 2/ enhance lockdep to handle wariable-depth but correct recursion: seems uncertain... 3/ remove this recursive locking from configfs: unfortunately, it seems that there are a good reasons for doing recursive inode locking, at least when removing a config_group with default groups. So, seems uncertain too... Other ideas? -- Dr Louis Rilling Kerlabs Skype: louis.rilling Batiment Germanium Phone: (+33|0) 6 80 89 08 23 80 avenue des Buttes de Coesmes http://www.kerlabs.com/ 35700 Rennes