From: tytso@mit.edu Subject: Re: [PATCH 2.6.27.y 2/3] ext4: Fix file fragmentation during large file write. Date: Fri, 28 May 2010 21:06:57 -0400 Message-ID: <20100529010657.GM26177@thunk.org> References: <4C001888.8020006@jaysonking.com> <4C001901.1070207@jaysonking.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Stable team , LKML , Greg Kroah-Hartman , "Aneesh Kumar K.V" , Dave Chinner , Ext4 Developers List , Kay Diederichs To: "Jayson R. King" Return-path: Received: from thunk.org ([69.25.196.29]:36616 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754783Ab0E2BHJ (ORCPT ); Fri, 28 May 2010 21:07:09 -0400 Content-Disposition: inline In-Reply-To: <4C001901.1070207@jaysonking.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, May 28, 2010 at 02:26:57PM -0500, Jayson R. King wrote: > From: Aneesh Kumar K.V > Date: Thu Oct 16 10:10:36 2008 -0400 > Subject: ext4: Fix file fragmentation during large file write. > > commit 22208dedbd7626e5fc4339c417f8d24cc21f79d7 upstream. > > The range_cyclic writeback mode uses the address_space writeback_index > as the start index for writeback. With delayed allocation we were > updating writeback_index wrongly resulting in highly fragmented file. > This patch reduces the number of extents reduced from 4000 to 27 for a > 3GB file. This isn't a critical bug fix either. I don't really care a whole lot, since I don't plan to support ext4 with all of these patches but if you haven't been doing a full set of testing with these patches, I'd be very concerned about whether ext4 would be stable after applying this patch series. What sort of testing _have_ you done? - Ted