[libvirt] Problems with <filesystem type='block'>

[Daniel P. Berrange]

On Sun, Mar 03, 2013 at 05:24:39PM -0600, Doug Goldstein wrote:
> On Fri, Dec 21, 2012 at 10:15 PM, Lars Kellogg-Stedman <lars at oddbit.com> wrote:
> > Using libvirt 1.0.1, I'm trying to start an LXC container using the
> > '<filesytem type="block">' syntax, like this:
> >
> >     <filesystem type="block" accessmode="passthrough">
> >       <source dev="/dev/vg_files/vm-foobar-root" />
> >       <target dir="/" />
> >     </filesystem>
> >
> > The specified block device exists:
> >
> >     # ls -lL /dev/vg_files/vm-foobar-root
> >     brw-rw---- 1 root disk 253, 19 Dec 21 22:23 /dev/vg_files/vm-foobar-root
> >
> > If I start the domain, it appears to start without any errors...
> >
> >     # virsh start foobar
> >     Domain foobar started


> I just gave it a whirl. And I'm able to reproduce the same issue you
> are seeing. The issue appears to be that
> lxcContainerMountFsBlockAuto() is never being called. It was added in
> http://www.redhat.com/archives/libvir-list/2011-August/msg00201.html
> Hopefully I'll have more info soon.

I tried this with latest GIT and did not experience any problems.

# dd if=/dev/zero of=disk.img count=100 bs=1M
# losetup -f /root/disk.img 
# losetup -a
/dev/loop1: [64768]:3774561 (/root/disk.img)
# virsh -c lxc:/// dumpxml busy | xpath /domain/devices/filesystem[2]
Found 1 nodes:
-- NODE --
<filesystem type="block" accessmode="passthrough">
      <source dev="/dev/loop1" />
      <target dir="/mnt" />
    </filesystem>
# virsh -c lxc:/// start busy
Domain busy started

# virsh -c lxc:/// console busy
Connected to domain busy
Escape character is ^]

# ls /mnt/
lost+found
# grep /mnt /proc/mounts  
/.oldroot/dev/loop1 /mnt ext2 rw,seclabel,relatime 0 0

Regards,
Daniel
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