Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263633AbTF3N2I (ORCPT ); Mon, 30 Jun 2003 09:28:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263743AbTF3N2I (ORCPT ); Mon, 30 Jun 2003 09:28:08 -0400 Received: from thebsh.namesys.com ([212.16.7.65]:55750 "HELO thebsh.namesys.com") by vger.kernel.org with SMTP id S263633AbTF3N2E (ORCPT ); Mon, 30 Jun 2003 09:28:04 -0400 Message-ID: <3F003E40.1040902@namesys.com> Date: Mon, 30 Jun 2003 17:42:24 +0400 From: Hans Reiser User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030617 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Jesse Pollard CC: rmoser , viro@parcelfarce.linux.theplanet.co.uk, linux-kernel@vger.kernel.org Subject: Re: File System conversion -- ideas References: <200306291011.h5TABQXB000391@81-2-122-30.bradfords.org.uk> <20030629194215.GG27348@parcelfarce.linux.theplanet.co.uk> <200306291545410600.02136814@smtp.comcast.net> <03063008265401.14007@tabby> In-Reply-To: <03063008265401.14007@tabby> X-Enigmail-Version: 0.76.1.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2590 Lines: 75 Jesse Pollard wrote: >On Sunday 29 June 2003 14:45, rmoser wrote: > > >>*********** REPLY SEPARATOR *********** >> >>On 6/29/2003 at 8:42 PM viro@parcelfarce.linux.theplanet.co.uk wrote: >> >> >>>On Sun, Jun 29, 2003 at 08:28:47PM +0100, Jamie Lokier wrote: >>> >>> >>>>Consider that many people choose ext3 rather than reiser simply >>>>because it is easy to convert ext2 to ext3, and hard to convert ext2 >>>>to reiser (and hard to convert back if they don't like it). I have >>>>seen this written by many people who choose to use ext3. Thus proving >>>>that there is value in in-place filesystem conversion :) >>>> >>>> >>>Uh-huh. You want to get in-kernel conversion between ext* and reiserfs? >>>With recoverable state if aborted? Get real. >>> >>> >>no, in-kernel conversion between everything. You don't think it can be >>done? It's not that difficult a problem to manage data like that :D >> >> > >You are ASSUMING that the new filesystem requires lessthan or equal amount >of metadata. This is NOT always true. A conversion of a full EXT2 to Riserfs >would fail simply because there is no free space to expand the needed >additional overhead. > Uh, you mean converting reiserfs to ext2 would fail.... we are more space efficient.... > >Going in the other direction usually is possible (again, depending on the >filesystem) but there are exceptions... Try converting an EXT2 to DosFS. >In place. And maintain a recoverable state when aborted. > >Not gonna happen. > >Too much depends on what the target filesystem is, and what it may require. > >Consider another - switching to an extent filesystem... If the datablocks >don't move, then you need MORE extents than the current indirect pointers. >And each extent is LARGER than the indirect pointers. > >Then you have to compress/condense the extents (requiring shuffling data >blocks around to reduce the number of extents). Each requires free space >to do it's work, and the amount of free blocks is not the same. > >Faster to do a copy. more reliable too. and recoverable. >- >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/ > > > > -- Hans - 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/