From owner-freebsd-current@FreeBSD.ORG Mon Jul 10 20:32:07 2006 Return-Path: X-Original-To: freebsd-current@freebsd.org 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 880F416A4DA; Mon, 10 Jul 2006 20:32:07 +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 EFAAF43D4C; Mon, 10 Jul 2006 20:32:06 +0000 (GMT) (envelope-from scottl@samsco.org) Received: from [10.10.3.185] ([69.15.205.254]) (authenticated bits=0) by pooker.samsco.org (8.13.4/8.13.4) with ESMTP id k6AKUSpf048522; Mon, 10 Jul 2006 14:30:34 -0600 (MDT) (envelope-from scottl@samsco.org) Message-ID: <44B2B8DC.8070201@samsco.org> Date: Mon, 10 Jul 2006 14:30:20 -0600 From: Scott Long User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.12) Gecko/20060206 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Christoph Hellwig References: <20060708152801.GA3671@crodrigues.org> <44AFD7DF.8090002@errno.com> <20060708174606.GA29602@infradead.org> <44B2A51A.4040103@samsco.org> <20060710202219.GA29786@infradead.org> In-Reply-To: <20060710202219.GA29786@infradead.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=0.0 required=3.8 tests=none autolearn=failed version=3.1.1 X-Spam-Checker-Version: SpamAssassin 3.1.1 (2006-03-10) on pooker.samsco.org Cc: freebsd-arch@freebsd.org, freebsd-current@freebsd.org, Craig Rodrigues Subject: Re: [RFC] mount can figure out fstype automatically X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 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: Mon, 10 Jul 2006 20:32:07 -0000 Christoph Hellwig wrote: > On Mon, Jul 10, 2006 at 01:06:02PM -0600, Scott Long wrote: > >>So in your opinion and experience, what are the pros and cons of >>maintaining a table of magic numbers? > > > The feature is imensely useful. The implementation won't win any > points for a clean design but works very well in practice. I think > it's definitly better than probing in the kernel because letting a filesystem > driver try to make sense of something that's not it's own format can > lead to all kinds of funnies. Linux does this (iterating all filesystem > types in kernel) for the special case of the root filesystem where mount(8) > is not available, and it showeds various interesting bugs at least in the > fat driver. > How does it resolve situations like with UDF vs iso9660, where both structures can co-exist? Scott