From owner-freebsd-current@FreeBSD.ORG Tue Apr 5 22:55:15 2005 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C030E16A4CE for ; Tue, 5 Apr 2005 22:55:15 +0000 (GMT) Received: from cyrus.watson.org (cyrus.watson.org [204.156.12.53]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8536843D3F for ; Tue, 5 Apr 2005 22:55:15 +0000 (GMT) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [204.156.12.50]) by cyrus.watson.org (Postfix) with ESMTP id BA20346B0D; Tue, 5 Apr 2005 18:55:14 -0400 (EDT) Date: Tue, 5 Apr 2005 23:55:27 +0100 (BST) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: Poul-Henning Kamp In-Reply-To: <2871.1112734748@critter.freebsd.dk> Message-ID: <20050405235414.D81173@fledge.watson.org> References: <2871.1112734748@critter.freebsd.dk> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed cc: current@freebsd.org Subject: Re: Panic on mount with write-locked USB media (umass) X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 05 Apr 2005 22:55:15 -0000 On Tue, 5 Apr 2005, Poul-Henning Kamp wrote: > In message <20050405201820.042685D07@ptavv.es.net>, "Kevin Oberman" writes: > >>> It would be useful if mount was smart enough to notice when it is >>> dealing with a read-only device, and try to mount such things >>> read-only, rather than trying to mount things read-write by default and >>> failing. Of course, the system shouldn't panic, either. :-) >> >> I think that is what I said. I am almost sure that this is how it used >> to work. I'm not sure whether the change was caused by something in >> msdosfs or GEOM (or somewhere else), but I sure preferred it when the RO >> device mounted RO. CDs still do this (thankfully). This makes me suspect >> msdosfs is the culprit. > > There are two ways that a filesystem correctly could handle a R/O media: > > 1. Fail with EROFS unless asked t mouned read-only > > 2. Silently downgrade th emount to read-only. > > I personally prefer the first because that way a script does not have to > check if it got the mount it wanted or not. In general, I agree, but this will de-POLA the following command: mount -t cd9660 /dev/acd0 /cdrom I wonder if a useful middle ground is to adopt (1) above except in the case of perenially read-only file systems (cd9660), in which case (2) is adopted? Robert N M Watson