Re: [Qemu-devel] block bug: tray status is not updated (and/or guest ignores it)

["Daniel P. Berrange" <berrange@redhat.com>]

On Fri, May 27, 2011 at 10:39:35AM -0300, Luiz Capitulino wrote:
> On Fri, 27 May 2011 18:10:08 +0530
> Amit Shah <amit.shah@redhat.com> wrote:
> 
> > On (Fri) 27 May 2011 [17:04:30], Amit Shah wrote:
> > > On (Fri) 27 May 2011 [17:01:35], Amit Shah wrote:
> > > > On (Thu) 26 May 2011 [15:29:29], Luiz Capitulino wrote:
> > > > > 
> > > > > I'm testing with qemu.git (HEAD aa29141d84d), procedure:
> > > > > 
> > > > > 1. Start a VM with:
> > > > > 
> > > > >  # qemu -hda disks/test.img -enable-kvm -m 1G -cdrom Fedora-14-x86_64-DVD.iso
> > > > > 
> > > > > 2. Then inside the guest run:
> > > > > 
> > > > >  # eject /dev/sr0 && mount /dev/sr0 /mnt
> > > > > 
> > > > > Results:
> > > > > 
> > > > >  Actual: The cdrom is successfully mounted
> > > > >  Expected: The cdrom is not mounted (mount fails, medium not found)
> > > > 
> > > > Really?  That's what you expect? :-)
> 
> That was the VM behavior before 996faf1ad, therefore it's what I was
> expecting.
> 
> > > > Where will the medium go?
> 
> We were leaking it then?
> 
> > > > What happens is mount auto-closes the tray and mounts whatever is
> > > > there, which is the image you provided.  Works as expected, IMO.
> > 
> > Confirmed, that's what happens.
> 
> Ok. I got this by testing my series that adds the BLOCK_MEDIA_EJECT event.
> At first I thought your commit wasn't handling the tray status correctly
> (which would cause problems to the new event), but it seems to work fine,
> specially now that I know what's doing. Sorry for the noise.
> 
> > What's weird though is 'eject' in the monitor makes the cdrom go away
> > -- a subsequent mount in the guest results in a no medium error.  I
> > thought we had solved that, Markus?
> > 
> > By not doing a bdrv_close() in the do_eject()->eject_device() call
> > path this starts working as expected.
> 
> Yes, also note that with the -f option eject is capable of purging
> any block device. I wonder if libvirt (or any client) relies on this.

libvirt will only issue 'eject' on devices which are CDROMs, or Floppy,
never hard disks, etc.

Regards,
Daniel
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