On Wed, Feb 15, 2017 at 12:53:39PM +0100, Tomáš Golembiovský wrote:
On Wed, 15 Feb 2017 10:55:24 +0000 "Richard W.M. Jones" <rjones@redhat.com> wrote:
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@redhat.com> 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.
Ah, sorry. I didn't notice your JSON was bad from the start and I just blindly extended it. The correct JSON should look like this:
json: { "file": { "driver":"raw", "file": { "driver":"file", "filename":"/var/tmp/backing.img" } } }
Ok that does now demonstrate the fix. For reference, here is the full test: $ cd /var/tmp $ rm -f backing.img $ truncate -s 10M backing.img $ qemu-img create -b 'json:{"file":{"driver":"raw", "file":{"driver":"file", "filename":"/var/tmp/backing.img"}}}' -f qcow2 overlay.qcow2 With old libvirt: $ guestfish -a /var/tmp/overlay.qcow2 run libguestfs: error: could not create appliance through libvirt. Try running qemu directly without libvirt using this environment variable: export LIBGUESTFS_BACKEND=direct Original error from libvirt: internal error: missing parser implementation for JSON backing volume driver 'raw' [code=1 int1=-1] With patched libvirt: $ killall libvirtd $ ~/d/libvirt/run guestfish -a /var/tmp/overlay.qcow2 run [no errors printed] Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com Fedora Windows cross-compiler. Compile Windows programs, test, and build Windows installers. Over 100 libraries supported. http://fedoraproject.org/wiki/MinGW