From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Reiser Subject: Re: viewprinting processes and process oriented permissions got funded by DARPA Date: Tue, 13 Apr 2004 20:42:12 -0700 Message-ID: <407CB314.8020700@namesys.com> References: <407C304F.4080804@namesys.com> <407C930D.5010407@namesys.com> <20040414022248.GA92870@colin2.muc.de> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com In-Reply-To: <20040414022248.GA92870@colin2.muc.de> List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Andi Kleen Cc: reiserfs-list@namesys.com Andi Kleen wrote: >On Tue, Apr 13, 2004 at 06:25:33PM -0700, Hans Reiser wrote: > > >>Andi Kleen wrote: >> >> >> >>>Amazing. You managed to write all this without ever mentioning >>>that linux 2.6 already has per process name spaces (=views) in >>>form of CLONE_NS. >>> >>>-Andi >>> >>> >>Can you specify exclude *.c in them? I think that your =views is a >>simplistic statement. >> >> > >You can add any files/directories you want (mount --bind). Excluding >is not directly supported. > >Doing it by directories is more natural though as it works with mount >points. Basically it mirrors the plan9 implementation and in >plan9 it is extensively used. I don't know of any uses in Linux >so far, but the infrastructure is there in the kernel. > >I don't doubt that your proposal is more powerful (and more complicated >and vapour right now), but I think you should mention prior work >in linux and plan9 before discussing clearcase at least. > >-Andi > > > > > Clearcase is the most powerful instantiation of those ideas in filesystems, and predates plan 9 (it originated with Apollo). I think that it is the appropriate reference academically. Just because it is a piece of shit in its implementation details does not prevent it from standing head and shoulders above the rest of the field in its functionality. I am still thinking through how we will implement views in Reiser4. It needs to be efficient and scalable to large numbers of bindings. I need to go reading through the per process name space code: I don't know if it will, for instance, scale to a thousand specifications. Clearcase probably also would not. I am thinking about whether we should exclude names before searching the FS for matches, or after. I think before, but it needs a lot of thought. -- Hans