On Fri, Sep 10, 2021 at 15:34:57 +0200, Vojtech Juranek wrote: > On Friday, 10 September 2021 15:12:07 CEST Peter Krempa wrote: > > On Fri, Sep 10, 2021 at 14:53:23 +0200, Vojtech Juranek wrote: > > > Hi, > > > when adding support for CD disk on block based storage into oVirt, > > > I spotted following issue. When starting VM without CD, we add > > > startupPolicy='optional' attribute into <source> element. > > > > > > Whole XML looks like this: > > > <disk type='file' device='cdrom'> > > > > > > <driver name='qemu' error_policy='report'/> > > > <source startupPolicy='optional'/> > > > <target dev='sdc' bus='sata'/> > > > <readonly/> > > > <alias name='ua-d7003457-63c3-4c98-80f0-08ab5042c65e'/> > > > <address type='drive' controller='0' bus='0' target='0' unit='2'/> > > > > > > </disk> > > > > > > To change/insert CD we use libvirt.updateDeviceFlags() with XML which > > > looks like this (for block based disk): > > > > > > <?xml version='1.0' encoding='utf-8'?> > > > <disk device="cdrom" type="block"> > > > > > > <source > > > dev="/rhev/data-center/mnt/blockSD/cdac2a0c-b110-456d-a988-7d588626c8 > > > 71/images/638247d7-b4b1-4d98-87fa-c90235fcf4b1/145e7cd2-f92d-4eec-a8fb > > > -6835b4b652e1" /> <target bus="sata" dev="sdc" /> Please note that according to the updateDevice API docs you should provide a fully-defined XML of the device, and not omit fields you don't want to change. This fact was even discussed today on the mailing list: https://listman.redhat.com/archives/libvir-list/2021-September/msg00246.html > > > > > > </disk> > > > > > > However, updateDeviceFlags() fails with > > > > > > libvirt.libvirtError: XML error: 'startupPolicy' is only valid for > > > 'file' type volume> > > > What is the reason for this error? We don't use `startupPolicy` attribute > > > for block based disks, as shown on example above. > > > > Hmm, the bug is that the disk source change is attempted before the > > update to startup policy, thus the validator is unhappy. > > is this a libvirt bug or intentional behavior and the CD change should be done > in two steps: > * remove startupPolicy from the disk > * do actual change of the disk > ? Fix proposed: https://listman.redhat.com/archives/libvir-list/2021-September/msg00283.html
