From owner-freebsd-fs@FreeBSD.ORG Thu Jan 17 17:58:12 2008 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DD90516A419; Thu, 17 Jan 2008 17:58:12 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.freebsd.org (Postfix) with ESMTP id 943C113C46B; Thu, 17 Jan 2008 17:58:12 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from phobos.samsco.home (phobos.samsco.home [192.168.254.11]) (authenticated bits=0) by pooker.samsco.org (8.13.8/8.13.8) with ESMTP id m0HHw8jB001680; Thu, 17 Jan 2008 10:58:09 -0700 (MST) (envelope-from scottl@samsco.org) Message-ID: <478F9730.7040204@samsco.org> Date: Thu, 17 Jan 2008 10:58:08 -0700 From: Scott Long User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.11) Gecko/20071128 SeaMonkey/1.1.7 MIME-Version: 1.0 To: Rick Macklem References: <18CC5A4A2AC36D7FF57615EE@ganymede.hub.org> <478AF6BC.8050604@highperformance.net> <20080114142124.Y55696@fledge.watson.org> <876FB8E38251C27B14CCCA29@atlantis.pc.cs.cmu.edu> <20080116203521.K15541@fledge.watson.org> <478F8BF2.4070700@samsco.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH authentication, not delayed by milter-greylist-2.0.2 (pooker.samsco.org [168.103.85.57]); Thu, 17 Jan 2008 10:58:09 -0700 (MST) X-Spam-Status: No, score=-1.4 required=5.4 tests=ALL_TRUSTED autolearn=failed version=3.1.8 X-Spam-Checker-Version: SpamAssassin 3.1.8 (2007-02-13) on pooker.samsco.org Cc: freebsd-fs@freebsd.org, freebsd-afs@freebsd.org, openafs-devel@openafs.org, port-freebsd@openafs.org Subject: Re: VFS KPI was Re: [OpenAFS-devel] Re: AFS ... or equivalent ... X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 17 Jan 2008 17:58:13 -0000 Rick Macklem wrote: > > > On Thu, 17 Jan 2008, Scott Long wrote: > >> >> Both Solaris and OSX seem to have found the path out of the VFS locking >> woods, and it would indeed be really nice if FreeBSD could follow suit. > Yes, I didn't mention Solaris (because I've never looked at it), but > being able to easily port file system code from OpenSolaris sounds like > it might be a big win. ZFS is an obvious example, but there is also > stuff like pNFS in the pipe that would be nice. (I'm going to try and > get my nfsv4 code into FreeBSD, but it will only be nfsv4.0 and I have > no urge to do 4.1/pNFS.) And others mentioned that there is quite a bit > of momentum w.r.t. OpenAFS in Solaris. > > rick > It's not just about portability, though. I know that some will argue with me on this, but the current VFS API is prohibitively difficult to use properly if you're trying to write, port, or debug a filesystem. You have to worry about interactions between vnode locks, vnode interlocks, and mount locks even before you start locking your own filesystem-private structures. Vectors like VOP_RECLAIM are a delicate and unforgiving minefield. Gaining better portability would of course be a big win, but an even bigger win would be gaining the ability of mere mortal programmers to understand and get involved in filesystems in FreeBSD. Scott