From owner-freebsd-arch@FreeBSD.ORG Thu Sep 18 11:18:59 2003 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4B4A816A4B3 for ; Thu, 18 Sep 2003 11:18:59 -0700 (PDT) Received: from fledge.watson.org (fledge.watson.org [204.156.12.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id 573A343FBD for ; Thu, 18 Sep 2003 11:18:58 -0700 (PDT) (envelope-from robert@fledge.watson.org) Received: from fledge.watson.org (localhost [127.0.0.1]) by fledge.watson.org (8.12.9/8.12.9) with ESMTP id h8IIIsgL002174; Thu, 18 Sep 2003 14:18:54 -0400 (EDT) (envelope-from robert@fledge.watson.org) Received: from localhost (robert@localhost)h8IIIsoC002171; Thu, 18 Sep 2003 14:18:54 -0400 (EDT) Date: Thu, 18 Sep 2003 14:18:54 -0400 (EDT) From: Robert Watson X-Sender: robert@fledge.watson.org To: "M. Warner Losh" In-Reply-To: <20030918.121507.32721201.imp@bsdimp.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII cc: bms@spc.org cc: phk@phk.freebsd.dk cc: freebsd-arch@freebsd.org Subject: Re: devd limitations / automounting removable storage X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 18 Sep 2003 18:18:59 -0000 On Thu, 18 Sep 2003, M. Warner Losh wrote: > In message: > Robert Watson writes: > : For ifnet events, we can use routing sockets. I don't know that we have > : GEOM events as yet. One reason to separately handle GEOM from devfs would > : be that GEOM "objects" tend to be storage devices or related notions, > : whereas devfs entries could be any number of things. > > While this is true, one can ask a /dev entry what kind of object it is. > Since one can do that, one can construct filters that will only do > things for storage objects. Opening a device to ask it what it might be is generally a bad idea -- you can block other consumers from using the device (and related devices), cause a variety side-effects, etc. Also, I'm not clear that you can get a useful result using open/fstat/stat/ioctl to figure out what something is without apriori knowledge of device numbers, and even then the utility is limited. If you have a network layer announcement "Hey, this interface arrived", then there's no question that it's a network interface. > I worry about putting these new event streams at the wrong level and/or > having too many of them making it hard to know what the appropriate > level/event to do something at is. Agreed. Robert N M Watson FreeBSD Core Team, TrustedBSD Projects robert@fledge.watson.org Network Associates Laboratories