From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?utf-8?B?SsO2cm4=?= Engel Subject: Re: [PATCH 01/27] nilfs2: add document Date: Wed, 17 Sep 2008 16:54:38 +0200 Message-ID: <20080917145437.GE8750@logfs.org> References: <1221419304-18572-1-git-send-email-konishi.ryusuke@lab.ntt.co.jp> <1221419304-18572-2-git-send-email-konishi.ryusuke@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Andrew Morton , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: Ryusuke Konishi Return-path: Received: from lazybastard.de ([212.112.238.170]:51406 "EHLO longford.logfs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752416AbYIQOys (ORCPT ); Wed, 17 Sep 2008 10:54:48 -0400 Content-Disposition: inline In-Reply-To: <1221419304-18572-2-git-send-email-konishi.ryusuke@lab.ntt.co.jp> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Mon, 15 September 2008 04:07:58 +0900, Ryusuke Konishi wrote: > + > +The logs include regular files, directory files, symbolic link files > +and several meta data files. The mata data files are the files used > +to maintain file system meta data. The current version of NILFS2 us= es > +the following meta data files: > + > + 1) Inode file (ifile) -- Stores on-disk inodes > + 2) Checkpoint file (cpfile) -- Stores checkpoints > + 3) Segment usage file (sufile) -- Stores allocation state of seg= ments > + 4) Data address translation file -- Maps virtual block numbers to = usual > + (DAT) block numbers. This file serv= es to > + make on-disk blocks relocatabl= e. > + 5) Sketch file (sketch) -- Keeps read-only data which can= be > + associated with checkpoints (o= ptional) How are the sufile and the DAT written? If you naively stick to the log-structured approach, their contents will reflect a filesystem state prior to writing them and be outdated by the time they hit the medium. So either you bend the rules here and update those files in-place or yo= u do something tricky. Can you explain your solution? J=C3=B6rn --=20 Write programs that do one thing and do it well. Write programs to work together. Write programs to handle text streams, because that is a universal interface. -- Doug MacIlroy -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html