On 4/10/19 3:33 PM, Jim Fehlig wrote:
On 4/10/19 12:25 PM, Daniel Henrique Barboza wrote:
On 4/10/19 3:08 PM, Jim Fehlig wrote:
I noticed libvirt-tck test domain/207-disk-media-change.t started failing after updating to libvirt 5.2.0. A bisection fingered commit f1d65853
commit f1d6585300001c7b23b8796a0faa4411c3531996 Author: Daniel Henrique Barboza <danielhb413@gmail.com> Date: Fri Mar 15 18:06:45 2019 -0300
domain_conf: check device address before attach
This commit prevents a media change on CDROM devices.
Thanks for letting us know. I'll run libvirt-tck (any pointers are appreciated - first time I've heard about this test suite) and see if I can get a fix going.
It's easy to reproduce outside of libvirt-tck. Simply start a VM with a cdrom device and then try to update the <source> element with 'virsh attach-device ...'. E.g. with the VM running try to "eject" the cdrom
# cat update-empty-cdrom.xml <disk type='file' device='cdrom'> <target dev='hdc'/> </disk>
# virsh attach-device test update-empty-cdrom.xml error: Failed to attach device from update-empty-cdrom.xml error: Requested operation is not valid: Domain already contains a device with the same address
To give a background on this patch, this was intended to avoid a situation where a hotplug of a device with the same ID would fall back to a cleanup code that ended up unplugging the previous existing device in the guest. This was happening when using the QEMU driver. What I didn't expect is for a CD-ROM media to be changed using a attach-device command. I think that the CD-ROM type has specific rules of not hot-unplugging itself (i.e. the driver) in the situation I described above. What I was expecting for CDROM change media was a VIR_DOMAIN_DEVICE_ACTION_UPDATE action instead, so this usage completely went under the radar for that patch. In fact, there are "update-device" and "change-media" commands that, according to the man page, are meant for the purpose of media change. However, the same man page doesn't prohibit the use of attach-device for media change either. I am not sure why have a change-media command if attach-device is supposed to handle media change as well, but for now let's fix the usage of attach-device with CDROM. Thanks, DHB
Regards, Jim