error: unsupported flags (0x4) in function virStorageVolDefParseXML

[Veiko Kukk <veiko.kukk@xxxxxxxxx>]

Hi!

Simple volume definition:
<volume type='file'>
  <name>tstlog01-system</name>
  <capacity unit='GiB'>20</capacity>
  <target>
    <compat>1.1</compat>
    <format type='qcow2'/>
  </target>
</volume>

# virsh vol-create --pool libvirt-ssd0 --file
vm-files/tstlog01/tstlog01-sys
tem-vol.xml --validate
error: Failed to create vol from vm-files/tstlog01/tstlog01-system-vol.xml
error: unsupported flags (0x4) in function virStorageVolDefParseXML

Omitting --validate creates volume
# virsh vol-dumpxml --pool libvirt-ssd0 --vol tstlog01-system
<volume type='file'>
  <name>tstlog01-system</name>
  <key>/var/lib/libvirt/images/tstlog01-system</key>
  <capacity unit='bytes'>21474836480</capacity>
  <allocation unit='bytes'>200704</allocation>
  <physical unit='bytes'>196928</physical>
  <target>
    <path>/var/lib/libvirt/images/tstlog01-system</path>
    <format type='qcow2'/>
    <permissions>
      <mode>0600</mode>
      <owner>0</owner>
      <group>0</group>
      <label>system_u:object_r:virt_image_t:s0</label>
    </permissions>
    <timestamps>
      <atime>1730277533.331347844</atime>
      <mtime>1730277533.329347839</mtime>
      <ctime>1730277533.330347841</ctime>
      <btime>0</btime>
    </timestamps>
  </target>
</volume>

# file /var/lib/libvirt/images/tstlog01-system
/var/lib/libvirt/images/tstlog01-system: QEMU QCOW2 Image (v2),
21474836480 bytes

# virsh vol-create-as libvirt-ssd0 tstlog01-system 20g --format qcow2
Vol tstlog01-system created

# virsh vol-dumpxml --pool libvirt-ssd0 --vol tstlog01-system
<volume type='file'>
  <name>tstlog01-system</name>
  <key>/var/lib/libvirt/images/tstlog01-system</key>
  <capacity unit='bytes'>21474836480</capacity>
  <allocation unit='bytes'>200704</allocation>
  <physical unit='bytes'>196928</physical>
  <target>
    <path>/var/lib/libvirt/images/tstlog01-system</path>
    <format type='qcow2'/>
    <permissions>
      <mode>0600</mode>
      <owner>0</owner>
      <group>0</group>
      <label>system_u:object_r:virt_image_t:s0</label>
    </permissions>
    <timestamps>
      <atime>1730277391.657950326</atime>
      <mtime>1730277391.656950323</mtime>
      <ctime>1730277391.657950326</ctime>
      <btime>0</btime>
    </timestamps>
  </target>
</volume>

It seems both volumes are identical  - the one created without
--validate and the one created with vol-create-as.

Questions:
1) Why does validation fail? How to debug it?
2) Why doesn't libvirt create qcow2 v3 even when specifying compat
1.1? When creating an image using virt-manager on the same libvirt
hypervisor host, v3 images are created.

Alma Linux 9.4, libvirt-10.0.0-6.7.el9_4.alma.1.x86_64,
qemu-kvm-8.2.0-11.el9_4.6.x86_64

With best regards,
Veiko