Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 22 Apr 2002 07:01:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 22 Apr 2002 07:01:05 -0400 Received: from firewall.conet.cz ([213.175.54.250]:54802 "EHLO localhost.localdomain") by vger.kernel.org with ESMTP id ; Mon, 22 Apr 2002 07:01:05 -0400 Message-ID: <3CC3ECD2.9000205@conet.cz> Date: Mon, 22 Apr 2002 12:58:26 +0200 From: =?ISO-8859-2?Q?Libor_Van=ECk?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:0.9.9) Gecko/20020311 X-Accept-Language: en-us, en MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: Adding snapshot capability to Linux Content-Type: text/plain; charset=ISO-8859-2; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, I'm going to start my dissertation work which is "Adding snapshop capability to Linux kernel with copy-on-write support". My idea is add it as another VFS - I know that there is some snapshot support in LVM but it's working on "device-level" and I'd like/have to do it on fs level. My idea is to use it this way: - I have running system with some "/foo" dir - I want to make snapshot of "/foo/bar" to "/foo/snap1" - I run "mount -t snapshot /foo/bar /foo/snap1" - This creates virtual image of "/foo/bar" to the "/foo/snap1" with hidden file (something like journal) in "/foo/snap1" - all files are linked to "/foo/bar" - Whenever is some file/dir changed in "/foo/bar" there is created physical copy of it to the snapshot(s) before writing changes (for making records about this will be used the hidden file) - Of course that one directory can be snapshoted more times - Probably the hidden file with records about all snapshots and details should be stored in "/foo/bar" - Question is how to handle ACLs and EA for XFS/JFS/... and if it won't collide with journal I'd like to do it not only because I have to but I want people to use it (I want to make it GPL) and maybe it will be one nice day part of Linux kernel ;-) So I'd like if you can send me any suggestions/tips/warnings/links etc. before I start coding so I know what should I avoid/use. Thanks, Libor - 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/