Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754676AbYBNPaa (ORCPT ); Thu, 14 Feb 2008 10:30:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752718AbYBNPaQ (ORCPT ); Thu, 14 Feb 2008 10:30:16 -0500 Received: from www.tglx.de ([62.245.132.106]:40049 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752391AbYBNPaP convert rfc822-to-8bit (ORCPT ); Thu, 14 Feb 2008 10:30:15 -0500 Date: Thu, 14 Feb 2008 16:30:01 +0100 From: =?UTF-8?B?SGFucy1Kw7xyZ2Vu?= Koch To: Jan Engelhardt Cc: Andi Kleen , Jasper Bryant-Greene , rzryyvzy , linux-kernel@vger.kernel.org Subject: Re: Is there a "blackhole" /dev/null directory? Message-ID: <20080214163001.31918e32@dilbert.local> In-Reply-To: References: <20080214093051.7240852AB0E31@trashmail.net> <1202981957.10928.17.camel@phobos.jasper.bg> <20080214161942.55ce5089@dilbert.local> Organization: Linutronix X-Mailer: Claws Mail 3.2.0 (GTK+ 2.12.2; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1415 Lines: 41 Am Thu, 14 Feb 2008 16:23:37 +0100 (CET) schrieb Jan Engelhardt : > > On Feb 14 2008 16:19, Hans-Jürgen Koch wrote: > >> > >> Q: What if a program attempts to mkdir /dev/nullmnt/foo to just > >> create a file /dev/nullmnt/foo/barfile? > >> A: /dev/nullmnt/foo must continue to exist or be accepted for a > >> while, or perhaps for eternity. > > > >Well, the problem seems to be that a "directory" is not just data but > >also contains metadata. While it's easy to write data to /dev/null, > >you cannot simply discard metadata associated with a directory. So, > >such a "/dev/null-directory" would have to remember metadata (at > >least all created filenames including subdirectories) in the same > >way as other filesystems do. Only file _content_ can be discarded. > > Not even that. Suppose a userspace program (whose output you'd like > to discard) does: [...] Well, if an application wants to read back written data, you can never use such a thing, not even in simple cases where the existing /dev/null would be enough. > } > > >To be honest, I still cannot see many sensible usecases for that... > > I agree. Good :-) 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/