Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750712AbVKIMmi (ORCPT ); Wed, 9 Nov 2005 07:42:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750714AbVKIMmi (ORCPT ); Wed, 9 Nov 2005 07:42:38 -0500 Received: from [195.23.16.24] ([195.23.16.24]:43975 "EHLO linuxbipbip.grupopie.com") by vger.kernel.org with ESMTP id S1750712AbVKIMmi (ORCPT ); Wed, 9 Nov 2005 07:42:38 -0500 Message-ID: <4371EEBA.2080706@grupopie.com> Date: Wed, 09 Nov 2005 12:42:34 +0000 From: Paulo Marques Organization: Grupo PIE User-Agent: Mozilla Thunderbird 1.0.6 (X11/20050716) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Jeff Garzik CC: Jens Axboe , Neil Brown , Linux Kernel , Miklos Szeredi Subject: Re: userspace block driver? References: <4371A4ED.9020800@pobox.com> <17265.42782.188870.907784@cse.unsw.edu.au> <4371A944.6070302@pobox.com> <20051109075455.GN3699@suse.de> <4371ACE6.7010503@pobox.com> In-Reply-To: <4371ACE6.7010503@pobox.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1587 Lines: 47 Jeff Garzik wrote: > Jens Axboe wrote: >> On Wed, Nov 09 2005, Jeff Garzik wrote: >>> Neil Brown wrote: >>>> On Wednesday November 9, jgarzik@pobox.com wrote: >>>> >>>>> Has anybody put any thought towards how a userspace block driver >>>>> would work? >>>> >>>> Isn't this was enbd does? http://www.it.uc3m.es/~ptb/nbd/ >>> >>> Is there something there relevant for modern kernels? I would sure >>> hope I could come up with something more lightweight than that. >> >> I was going to say drbd, but then you did say more lightweight :-) >[...] > > loop is a closer model to a generic userspace block device than nbd, I > think. That got me thinking... theoretically we should be able to do a FUSE server that served a single file that could be used by a loopback device, couldn't we? IIRC, Miklos Szeredi tried hard to avoid the deadlock scenarios that nbd suffers from in FUSE, but I don't know if it would stand being called by the loopback device. If it works, it should be extremely simple to do the server. Just check the FUSE hello world server example: http://fuse.sourceforge.net/helloworld.html I've CC'ed Miklos Szeredi to see if he can shed some light on the loopback <-> FUSE combination... -- Paulo Marques - www.grupopie.com The rule is perfect: in all matters of opinion our adversaries are insane. Mark Twain - 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/