Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750944AbXBRMuV (ORCPT ); Sun, 18 Feb 2007 07:50:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750953AbXBRMuV (ORCPT ); Sun, 18 Feb 2007 07:50:21 -0500 Received: from lazybastard.de ([212.112.238.170]:59373 "EHLO longford.lazybastard.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750941AbXBRMuU (ORCPT ); Sun, 18 Feb 2007 07:50:20 -0500 Date: Sun, 18 Feb 2007 12:46:18 +0000 From: =?utf-8?B?SsO2cm4=?= Engel To: Sorin Faibish Cc: Bill Davidsen , Juan Piernas Canovas , Jan Engelhardt , kernel list Subject: Re: [ANNOUNCE] DualFS: File System with Meta-data and Data Separation Message-ID: <20070218124617.GA3523@lazybastard.org> References: <20070215200922.GB24643@lazybastard.org> <20070216091321.GA28092@lazybastard.org> <45D642A4.5010009@tmr.com> <20070217151108.GA301@lazybastard.org> <45D7450F.6090309@tmr.com> <20070217183646.GE301@lazybastard.org> <20070218055936.GF301@lazybastard.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20070218055936.GF301@lazybastard.org> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1247 Lines: 28 Maybe this is a decent approach to deal with the problem. First some definitions. T is the target segment to be cleaned, S is the spare segment that valid data is written to, O are other segments that contain indirect blocks I for valid data D in T. Have two different GC mechanisms to choose between: 1. Regular GC that copies D and I into S. On average D+I should require less space than S can offer. 2. Slow GC only copies D into S. Indirect blocks get modified in-place in O. This variant requires more seeks due to writing in various O, but it guarantees that D always requires less space than S can offer. Whenever you are running out of spare segments and are in danger of the deadlock, switch to mechanism 2. Now your correctness problem is reduced to a performance problem. Jörn -- To recognize individual spam features you have to try to get into the mind of the spammer, and frankly I want to spend as little time inside the minds of spammers as possible. -- Paul Graham - 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/