From owner-freebsd-hackers@FreeBSD.ORG  Sat Sep 15 12:24:34 2012
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id A01FB106566C
	for <freebsd-hackers@freebsd.org>; Sat, 15 Sep 2012 12:24:34 +0000 (UTC)
	(envelope-from wblock@wonkity.com)
Received: from wonkity.com (wonkity.com [67.158.26.137])
	by mx1.freebsd.org (Postfix) with ESMTP id 5C2F18FC0C
	for <freebsd-hackers@freebsd.org>; Sat, 15 Sep 2012 12:24:34 +0000 (UTC)
Received: from wonkity.com (localhost [127.0.0.1])
	by wonkity.com (8.14.5/8.14.5) with ESMTP id q8FCOXn7040299;
	Sat, 15 Sep 2012 06:24:33 -0600 (MDT)
	(envelope-from wblock@wonkity.com)
Received: from localhost (wblock@localhost)
	by wonkity.com (8.14.5/8.14.5/Submit) with ESMTP id q8FCOWFI040296;
	Sat, 15 Sep 2012 06:24:33 -0600 (MDT)
	(envelope-from wblock@wonkity.com)
Date: Sat, 15 Sep 2012 06:24:32 -0600 (MDT)
From: Warren Block <wblock@wonkity.com>
To: Yuri <yuri@rawbw.com>
In-Reply-To: <50541103.6050608@rawbw.com>
Message-ID: <alpine.BSF.2.00.1209150620130.40275@wonkity.com>
References: <5053C9A1.3030605@rawbw.com>
	<alpine.BSF.2.00.1209142016200.36584@wonkity.com>
	<50541103.6050608@rawbw.com>
User-Agent: Alpine 2.00 (BSF 1167 2008-08-23)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7
	(wonkity.com [127.0.0.1]); Sat, 15 Sep 2012 06:24:33 -0600 (MDT)
Cc: freebsd-hackers@freebsd.org
Subject: Re: Why fdisk can't open root disk with MBR for writing?
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 15 Sep 2012 12:24:34 -0000

On Fri, 14 Sep 2012, Yuri wrote:

> On 09/14/2012 19:23, Warren Block wrote:
>> Did you actually try gpart?  GEOM prevents writes to providers that are in 
>> use, but gpart should handle it correctly if the problem is just that fdisk 
>> doesn't understand GEOM.
>> 
>> # gpart set -a active -i 1 ada0
>> 
>> If that fails, the provider is in use, usually mounted.  The safety can be 
>> disabled, but it's better to figure out what has it in use. 
>
> Yes it is the hard drive with mounted /. But changing the active slice should 
> be safe in any case.
> gpart worked.
> This safety feature is protecting people from themselves. Sounds very 
> familiar.

gpart allowed it, so it's not the safety feature but merely that fdisk 
is aging and can't deal well with GEOM.