From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750747AbWGQLYK (ORCPT ); Mon, 17 Jul 2006 07:24:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750744AbWGQLYJ (ORCPT ); Mon, 17 Jul 2006 07:24:09 -0400 Received: from [212.70.42.180] ([212.70.42.180]:3082 "EHLO raad.intranet") by vger.kernel.org with ESMTP id S1750742AbWGQLYH (ORCPT ); Mon, 17 Jul 2006 07:24:07 -0400 From: Al Boldi To: linux-fsdevel@vger.kernel.org Subject: Re: "Why Reuser 4 still is not in" doc Date: Mon, 17 Jul 2006 14:25:19 +0300 User-Agent: KMail/1.5 Cc: linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Message-Id: <200607171425.19816.a1426z@gawab.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jan Engelhardt wrote: > >> > (aside from the VFS integration debate) > >> > >> Anybody know what's in Reiser4 that VFS doesn't like (link please)? > > > > Reiser4 plug-ins have (had?) the ability to alter the semantics of > > things, like making files into directories inside > > Yes, it changes the semantics. Suddenly you can "cd linux-2.6.17.tar.bz2". > But what will stat() return? S_IFDIR? S_IFREG? S_IFANY? A .tar parser in > kernelspace is almost never the right thing. And then a cpio parser, > because that's what initramfs'es are made of. Not to forget .zip, because > that's omnipresent. Oh of course we'd also need bzip2 and gzip decoder. > BASE64 and UU anyone? Using this as an argument against plug-ins is a bit strange. I suppose somebody could go overboard and use plug-ins to implement a subKernel. Would this then imply that plug-ins are wrong? > > which you could see meta-files like > > file/uid and file/size which contained meta-data and such accessible as > > normal files to all the unix tools (which is a very good idea IMO). You > > could get things like chmod by just 'echo root > > > >> file/owner' or something, very nice. > > I wish you a lot of fun with users in LDAP or other exotic storage > methods. By making Everything possible through echo, you are violating the > unix philosophy that one tool should do one thing (though echo does just > that). The unix philosophy would hold with plug-ins, as this would aid flexibility. Using plug-ins is a form of modularization, much like the 'one tool should do one thing' approach. > And in this case, echo would be chown, chmod, tar, bzip2 all at > once. This sounds familiar, I think I have seen this with explorer.exe > (and its uncountable DLLs), which lets you change everything within the > same window. Nothing wrong with that, unless you have an allergy against explorer. > What I think is promising are the compression/encryption plugins. ext2 > and 3 had an attribute (`lsattr`) for compression but it does not seem > like ever implemented. Now that's a great example for using a plug-in in the wright place. > > This was frowned upon by kernel developers who felt that it belonged in > > the kernel VFS (if at all), rather than in reiser4 directly. This is really the crux of the issue. Introducing plug-ins into the FS is really the wrong place, when we already have an abstracted VFS that allows this to be fanned out to its children. Thanks! -- Al