From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1MGaOt-0006xQ-7U
	for qemu-devel@nongnu.org; Tue, 16 Jun 2009 11:16:39 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1MGaOn-0006uv-N6
	for qemu-devel@nongnu.org; Tue, 16 Jun 2009 11:16:37 -0400
Received: from [199.232.76.173] (port=58087 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1MGaOn-0006up-GL
	for qemu-devel@nongnu.org; Tue, 16 Jun 2009 11:16:33 -0400
Received: from mx2.redhat.com ([66.187.237.31]:53623)
	by monty-python.gnu.org with esmtp (Exim 4.60)
	(envelope-from <avi@redhat.com>) id 1MGaOn-0004HJ-4L
	for qemu-devel@nongnu.org; Tue, 16 Jun 2009 11:16:33 -0400
Message-ID: <4A37B756.6090008@redhat.com>
Date: Tue, 16 Jun 2009 18:16:38 +0300
From: Avi Kivity <avi@redhat.com>
MIME-Version: 1.0
Subject: Re: [Qemu-devel] Regression opening read-only cdroms
References: <4A37896C.8050208@redhat.com>
	<20090616143259.GA29040@shareable.org>
In-Reply-To: <20090616143259.GA29040@shareable.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Jamie Lokier <jamie@shareable.org>
Cc: Christoph Hellwig <hch@lst.de>, qemu-devel <qemu-devel@nongnu.org>

On 06/16/2009 05:33 PM, Jamie Lokier wrote:
> Avi Kivity wrote:
>    
>> qemu used to be quite happy opening read-only cdrom images, and I was
>> quite happy feeding kvm-autotest a library of read-only iso images.
>>      
>
> 1. While we're here, an _option_ to open an image read-only even when
>     you have write permission would be useful, for those occasions when
>     you want to boot from some valuable image and be certain you aren't
>     modifying it - without having to chmod back and forth in
>     Qemu-wrapper scripts, or copy the image first.
>    

read-only disk images don't make much sense.

Using -snapshot will generally ensure the image is not modified, while 
allowing the guest to write.

> 2. Would it make sense to open CD-ROM images read-only all the time,
>     when they are opened with media=cdrom, or can QEMU's CD-ROM devices
>     write to the images?
>    

We don't emulate cd writers yet, so it makes sense to restict ourselves 
to O_RDONLY for now.

-- 
error compiling committee.c: too many arguments to function