From: Mingming Cao Subject: Re: [RFC] basic delayed allocation in VFS Date: Mon, 30 Jul 2007 10:49:14 -0700 Message-ID: <1185817755.4023.7.camel@localhost.localdomain> References: <46A8628D.6070103@clusterfs.com> <46A87858.40005@garzik.org> <20070728195114.GA5952@infradead.org> <20070729173035.GU5992@schatzie.adilger.int> <20070729192437.GB14530@infradead.org> Reply-To: cmm@us.ibm.com Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Jeff Garzik , Alex Tomas , ext4 development , linux-fsdevel@vger.kernel.org To: Christoph Hellwig , akpm@linux-foundation.org Return-path: Received: from e3.ny.us.ibm.com ([32.97.182.143]:36888 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932195AbXG3RtR (ORCPT ); Mon, 30 Jul 2007 13:49:17 -0400 In-Reply-To: <20070729192437.GB14530@infradead.org> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Sun, 2007-07-29 at 20:24 +0100, Christoph Hellwig wrote: > On Sun, Jul 29, 2007 at 11:30:36AM -0600, Andreas Dilger wrote: > > Sigh, we HAVE a patch that was only adding delalloc to ext4, but it > > was rejected because "that functionality should go into the VFS". > > Since the performance improvement of delalloc is quite large, we'd > > like to get this into the kernel one way or another. Can we make a > > decision if the ext4-specific delalloc is acceptable? > > I'm a big proponent of having proper common delalloc code, but the > one proposed here is not generic for the existing filesystem using > delalloc. To be fair, what Alex have so far is probably good enough for ext2/3 delayed allocation. > It's still on my todo list to revamp the xfs code to get > rid of some of the existing mess and make it useable genericly. If > the ext4 users are fine with the end result we could move to generic > code. > Are you okay with having a ext4 delayed allocation implementation (i.e. moving the code proposed in this thread to fs/ext4) first? Then later when you come up with a generic delayed allocation for both ext4 and xfs we could make use of that generic implementation. Is that a acceptable approach? Andrew, what do you think? Regards, Mingming