From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754031AbYHRKvY (ORCPT ); Mon, 18 Aug 2008 06:51:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752235AbYHRKvO (ORCPT ); Mon, 18 Aug 2008 06:51:14 -0400 Received: from mtagate8.uk.ibm.com ([195.212.29.141]:42757 "EHLO mtagate8.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752040AbYHRKvN (ORCPT ); Mon, 18 Aug 2008 06:51:13 -0400 Message-ID: <48A9541C.9050506@de.ibm.com> Date: Mon, 18 Aug 2008 12:51:08 +0200 From: Carsten Otte Reply-To: carsteno@de.ibm.com Organization: =?ISO-8859-1?Q?BM_Deutschland_Research_=26_Developm?= =?ISO-8859-1?Q?ent_GmbH_/_Vorsitzender_des_Aufsichtsrats=3A_?= =?ISO-8859-1?Q?Martin_Jetter=2CGesch=E4ftsf=FChrung=3A_Herbert_Kir?= =?ISO-8859-1?Q?cher=2CSitz_der_Gesellschaft=3A_B=F6blingen_/_R?= =?ISO-8859-1?Q?egistergericht=3A_Amtsgericht_Stuttgart=2C_HRB_24?= =?ISO-8859-1?Q?3294?= User-Agent: Mozilla-Thunderbird 2.0.0.16 (X11/20080724) MIME-Version: 1.0 To: Nick Piggin CC: Andrew Morton , borntrae@linux.vnet.ibm.com, Jared Hulbert , Linux Kernel Mailing List , Linux Memory Management List , Linus Torvalds , Hugh Dickins Subject: Re: [patch] mm: xip/ext2 fix block allocation race References: <20080818053821.GA3011@wotan.suse.de> <20080818054409.GB3011@wotan.suse.de> <20080818060301.GC3011@wotan.suse.de> In-Reply-To: <20080818060301.GC3011@wotan.suse.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Nick Piggin wrote: > XIP can call into get_xip_mem concurrently with the same file,offset with > create=1. This usually maps down to get_block, which expects the page lock > to prevent such a situation. This causes ext2 to explode for one reason or > another. > > Serialise those calls for the moment. For common usages today, I suspect > get_xip_mem rarely is called to create new blocks. In future as XIP > technologies evolve we might need to look at which operations require > scalability, and rework the locking to suit. > > Signed-off-by: Nick Piggin Acked-by: Carsten Otte