From owner-freebsd-fs Fri Jan 21 14:20:23 2000 Delivered-To: freebsd-fs@freebsd.org Received: from mail4.aracnet.com (mail4.aracnet.com [216.99.193.36]) by hub.freebsd.org (Postfix) with ESMTP id F32481553B for ; Fri, 21 Jan 2000 14:20:20 -0800 (PST) (envelope-from beattie@aracnet.com) Received: from shell1.aracnet.com (IDENT:root@shell1.aracnet.com [216.99.193.21]) by mail4.aracnet.com (8.9.3/8.9.3) with ESMTP id OAA30191; Fri, 21 Jan 2000 14:20:26 -0800 Received: from localhost by shell1.aracnet.com (8.9.3) id OAA03529; Fri, 21 Jan 2000 14:21:58 -0800 X-Authentication-Warning: shell1.aracnet.com: beattie owned process doing -bs Date: Fri, 21 Jan 2000 14:21:58 -0800 (PST) From: Brian Beattie To: Kelly Yancey Cc: fs@FreeBSD.ORG Subject: Re: UDF, userfs In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Fri, 21 Jan 2000, Kelly Yancey wrote: > On Fri, 21 Jan 2000, Brian Beattie wrote: > > > I have been thinking about the userfs implementation. I will need some > > way for the user process to talk the backend of the userfs kernel code. > > The two ways I have thought of are I/O,, probably ioctl's or a new system > > call. > > ... > Perhaps you have put more thought into it, but > the concern that immediately comes to my mind is how to get VOP function > calls from kernel-space to user-space. Some kind of up-call mechanism > seems in order. You had suggested a pseudo-device, presumably with the > intent to have daemons which implement file systems to read from to > catch VOPs and write to to return data. Basicaly, the user process that implements the filesystem, would issue a calls (i assume an ioctl on a pseudo device, but I am open to suggestions). The userfs module would pass any VOP's back to the process, or return an empty result. One could also implement select support. (exact details still open) This is somewhat counter-intutive, in that one normally thinks of the fs code calling something, and in this case it is called, but the effect is ultimately the same, the operations get passed where they need to go. Brian Beattie | The only problem with beattie@aracnet.com | winning the rat race ... www.aracnet.com/~beattie | in the end you're still a rat To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message