From: Badari Pulavarty Subject: Re: Delayed allocation and page_lock vs transaction start ordering Date: Tue, 15 Apr 2008 10:58:25 -0700 Message-ID: <1208282305.18386.67.camel@badari-desktop> References: <20080415161430.GC28699@duck.suse.cz> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org, sandeen@redhat.com To: Jan Kara Return-path: Received: from e5.ny.us.ibm.com ([32.97.182.145]:43143 "EHLO e5.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751803AbYDOR6Y (ORCPT ); Tue, 15 Apr 2008 13:58:24 -0400 Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e5.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id m3FHwNLZ020087 for ; Tue, 15 Apr 2008 13:58:23 -0400 Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id m3FHwNgi222818 for ; Tue, 15 Apr 2008 13:58:23 -0400 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m3FHwM4J001761 for ; Tue, 15 Apr 2008 13:58:23 -0400 In-Reply-To: <20080415161430.GC28699@duck.suse.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, 2008-04-15 at 18:14 +0200, Jan Kara wrote: > Hi, > > I've ported my patch inversing locking ordering of page_lock and > transaction start to ext4 (on top of ext4 patch queue). Everything except > delayed allocation is converted (the patch is below for interested > readers). I am curious on the following code: ext4_ordered_writepage() + * Note that we don't need to start a transaction unless we're journaling + * data because we should have holes filled from ext4_page_mkwrite(). If + * we are journaling data, we cannot start transaction directly because + * transaction start ranks above page lock so we have to do some magic... Currently you are starting a transaction when the page is locked. What do you plan to do here ? Thanks, Badari