Re: [Qemu-devel] Regression opening read-only cdroms

[Avi Kivity]

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.

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