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

[Daniel P. Berrange]

On Thu, Mar 21, 2013 at 11:50:40PM -0500, Doug Goldstein wrote:
> So still trying to figure out what I'm doing wrong with LXC because I
> just can't get any joy. So I'll go one issue at a time.
> 
> The following VM definition:
> <domain type='lxc'>
>   <name>testdeb</name>
>   <uuid>df03b2ce-725a-42e2-39e4-d646be8facb3</uuid>
>   <memory unit='KiB'>332768</memory>
>   <currentMemory unit='KiB'>332768</currentMemory>
>   <vcpu placement='static'>1</vcpu>
>   <os>
>     <type arch='x86_64'>exe</type>
>     <init>/sbin/init</init>
>   </os>
>   <clock offset='utc'/>
>   <on_poweroff>destroy</on_poweroff>
>   <on_reboot>restart</on_reboot>
>   <on_crash>destroy</on_crash>
>   <devices>
>     <emulator>/usr/libexec/libvirt_lxc</emulator>
>     <filesystem type='block' accessmode='passthrough'>
>       <source dev='/dev/mapper/vms-testdeb'/>
>       <target dir='/'/>
>     </filesystem>

So, it seems I only tested 'type=block with non-/ filesystem
mounts. I can confirm it is broken for <target dir="/"/>.

The fix is not exactly trivial, so might take me a while


> Now if I do the following:
> # mkdir /mnt/testdeb
> # mount /dev/mapper/vms-testdeb /mnt/testdeb
> 
> And change the definition to:
> 
>     <filesystem type='mount' accessmode='passthrough'>
>       <source dir='/mnt/testdeb'/>
>       <target dir='/'/>
>     </filesystem>
> 
> It at least appears to work. The LXC domain boots but believes it only
> has R/O access to its /.

What does /proc/mounts say inside the container for '/' ? When I
do this I get a full R+W filesystem in the container


Daniel
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