Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757545AbYFXVfo (ORCPT ); Tue, 24 Jun 2008 17:35:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754277AbYFXVfg (ORCPT ); Tue, 24 Jun 2008 17:35:36 -0400 Received: from rgminet01.oracle.com ([148.87.113.118]:13230 "EHLO rgminet01.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753646AbYFXVff (ORCPT ); Tue, 24 Jun 2008 17:35:35 -0400 Date: Tue, 24 Jun 2008 14:34:39 -0700 From: Joel Becker To: Louis Rilling Cc: linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com Subject: Re: configfs: Q: item leak in a failing configfs_attach_group()? Message-ID: <20080624213439.GB2785@mail.oracle.com> Mail-Followup-To: Louis Rilling , linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com References: <20080624141649.GH7621@hawkmoon.kerlabs.com> <20080624171051.GD4184@ca-server1.us.oracle.com> <20080624180456.GA32036@hawkmoon.kerlabs.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080624180456.GA32036@hawkmoon.kerlabs.com> X-Burt-Line: Trees are cool. X-Red-Smith: Ninety feet between bases is perhaps as close as man has ever come to perfection. User-Agent: Mutt/1.5.18 (2008-05-17) X-Brightmail-Tracker: AAAAAQAAAAI= X-Brightmail-Tracker: AAAAAQAAAAI= X-Whitelist: TRUE X-Whitelist: TRUE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1976 Lines: 56 On Tue, Jun 24, 2008 at 08:04:56PM +0200, Louis Rilling wrote: > On Tue, Jun 24, 2008 at 10:10:51AM -0700, Joel Becker wrote: > > On Tue, Jun 24, 2008 at 04:16:49PM +0200, Louis Rilling wrote: > > > Hi, > > > > > > I'd like an opinion on the following scenario: > > > > > > process 1: process 2: > > > configfs_mkdir("A") > > > attach_group("A") > > > attach_item("A") > > > d_instantiate("A") > > > populate_groups("A") > > > mutex_lock("A") > > > attach_group("A/B") > > > attach_item("A") > > > d_instantiate("A/B") > > > mkdir("A/B/C") > > > do_path_lookup("A/B/C", LOOKUP_PARENT) > > > > This has to sleep until > > configfs_mkdir("A") finishes. > > It's waiting on A->d_parent's > > i_mutex, which is held by > > sys_mkdirat(). > > Can you be more precise? I don't see where do_path_lookup() locks an inode It doesn't. It's in lookup_create(), which takes the mutex on the parent of 'A'. Note that the end of sys_mkdirat() explicitly drops that mutex - it couldn't do so if it hadn't been taken :-) Joel -- "You cannot bring about prosperity by discouraging thrift. You cannot strengthen the weak by weakening the strong. You cannot help the wage earner by pulling down the wage payer. You cannot further the brotherhood of man by encouraging class hatred. You cannot help the poor by destroying the rich. You cannot build character and courage by taking away a man's initiative and independence. You cannot help men permanently by doing for them what they could and should do for themselves." - Abraham Lincoln Joel Becker Principal Software Developer Oracle E-mail: joel.becker@oracle.com Phone: (650) 506-8127 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/