From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268703AbUHYVPW (ORCPT ); Wed, 25 Aug 2004 17:15:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268812AbUHYVKv (ORCPT ); Wed, 25 Aug 2004 17:10:51 -0400 Received: from fw.osdl.org ([65.172.181.6]:22459 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S268602AbUHYVAb (ORCPT ); Wed, 25 Aug 2004 17:00:31 -0400 Date: Wed, 25 Aug 2004 14:00:01 -0700 (PDT) From: Linus Torvalds To: viro@parcelfarce.linux.theplanet.co.uk cc: Christoph Hellwig , Hans Reiser , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Alexander Lyamin aka FLX , ReiserFS List Subject: Re: silent semantic changes with reiser4 In-Reply-To: <20040825204240.GI21964@parcelfarce.linux.theplanet.co.uk> Message-ID: References: <20040824202521.GA26705@lst.de> <412CEE38.1080707@namesys.com> <20040825200859.GA16345@lst.de> <20040825204240.GI21964@parcelfarce.linux.theplanet.co.uk> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 25 Aug 2004 viro@parcelfarce.linux.theplanet.co.uk wrote: > > On Wed, Aug 25, 2004 at 01:22:55PM -0700, Linus Torvalds wrote: > > > > It's the UNIX way. > > Not if you allow link(2) on them. Heh. I don't think that's a very strong argument against being "unixy", considering how traditional unix _used_ to handle directories. mkdir/rmdir/rename only came later. Now, obviously they did come later for a good reason, but still.. The interesting part is that thanks to the dcache, we should be perfectly able to actually _see_ circular links etc, so some of the problems with linking directories should actually be quite solvable - something that is _not_ true for a traditional UNIX VFS layer. Of course, the dcache introduces some new problems of its own wrt directory aliasing, but I don't actually think that should be fundamental either. Treating them more as a "static mountpoint" from an FS angle and less as a traditional Unix hardlink should be doable, I'd have thought. (Also, it's entirely possible that the filesystem may not support some of the more esoteric linking/renaming operations. For example, in a traditional xattrs setup where the xattr is linked on-disk with the file it is associated with, you simply _can't_ link it somewhere else, or rename it to any other directory. That's not a VFS layer issue, obviously, but I thought I'd bring up the point that file-as-dir cases may have limitations that normal files don't have). > And not if you design and market your stuff as a general-purpose > backdoor into kernel. Now that's a separate argument, and not one I'm personally interested in arguing at least right now. I haven't actually looked at the reiser4 code, so I'm really _only_ arguing against special-case attributes. Linus