Re: [libvirt] [PATCH 2/2] util: storage: add JSON backing volume parser 'raw' block driver

On Tue, Feb 14, 2017 at 10:03:54PM +0100, Tomáš Golembiovský wrote: > Hi, > > On Tue, 14 Feb 2017 15:58:45 +0000 > "Richard W.M. Jones" <rjones(a)redhat.com&gt; wrote: > > > The patches compile. > > > > I looked at both commits and they at least superficially seem > > sensible. I'm not intimately familiar enough with the original code > > to review this fully. > > > > However I want to try to test this using libguestfs. I believe the > > following test case should be sufficient: > > > > $ cd /var/tmp > > $ truncate -s 1M backing.img > > $ qemu-img create \ > > -b 'json:{"driver":"raw", "file":{"filename":"/var/tmp/backing.img"}}' \ > > The problem lies in the JSON here. Libvirt lacks the driver probing > mechanism QEMU has (which makes sense). That means one has to be > explicit about the drivers. Try with the following backing definition: > > json:{"driver":"raw", "file":{ "driver":"file", "filename":"/var/tmp/backing.img"}} OK, that works. However it also works with the unpatched version of libvirt, so it's not proof that these patches fix any problem.

Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/