Bug 886456

This bug was not selected to be addressed in Red Hat Enterprise Linux 6. We will look at it again within the Red Hat Enterprise Linux 7 product.

Steps 1-3 don't fail any more in the current versions but I didn't go through and try to find where we fixed it actually. Marking test-only.

Peter, I test it in steps1-3 with latest libvirt. There is still a error when change-media.
Version:
libvirt-1.2.17-9.el7.x86_64
qemu-kvm-rhev-2.3.0-24.el7.x86_64
Steps:
1. Preparing a running guest, and an iso file.
# virsh list 
 Id    Name                           State
----------------------------------------------------
 10    t62                            running

# virsh dumpxml t62|awk '/<disk/,/<\/disk/'
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/var/lib/libvirt/images/t62.qcow2'/>
      <backingStore/>
      <target dev='vda' bus='virtio'/>
      <alias name='virtio-disk0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </disk>
    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <backingStore/>
      <target dev='sdc' bus='scsi' tray='open'/>
      <readonly/>
      <alias name='scsi0-0-0-2'/>
      <address type='drive' controller='0' bus='0' target='0' unit='2'/>
    </disk>

# ls -Z /var/lib/libvirt/images/boot.iso 
-rw-r--r--. qemu qemu system_u:object_r:virt_content_t:s0 /var/lib/libvirt/images/boot.iso

2. Run virsh change-media, the first time failed, the second time succeed.
# virsh change-media t62 sdc --insert /var/lib/libvirt/images/boot.iso                             
error: Failed to complete action insert on media
error: internal error: unable to execute QEMU command 'eject': Device 'drive-scsi0-0-0-2' is locked

# virsh change-media t62 sdc --insert /var/lib/libvirt/images/boot.iso                             
error: Failed to complete action insert on media
error: internal error: unable to execute QEMU command 'eject': Device 'drive-scsi0-0-0-2' is locked

The log is in change-media-log.

Is it an issue about qemu or libvirt?

Created attachment 1075771 [details]
change-media log file

"Device 'drive-scsi0-0-0-2' is locked" means that the guest locked the CDROM drive. Please umount it from the guest to avoid that problem.

(In reply to Peter Krempa from comment #12)
> "Device 'drive-scsi0-0-0-2' is locked" means that the guest locked the CDROM
> drive. Please umount it from the guest to avoid that problem.

But there is no CDROM mounted in guest when first time change-media and no media in cdrom. I think the issue is not related to guest's mount.

I mistook the second time change-media results in comment10. It should be:
# virsh change-media t62 sdc --insert /var/lib/libvirt/images/boot.iso 
Successfully inserted media.

Peter, pls check the issue in Comment10 and Comment13

Verify it in libvirt-1.2.17-13.el7.x86_64:
1. Enforce selinux and set iso selinux label
# setenforce 1
# chown qemu:qemu /var/lib/libvirt/images/bb.iso
# chcon -u system_u -r object_r -t virt_content_t  /var/lib/libvirt/images/bb.iso
# ls -Z /var/lib/libvirt/images/bb.iso
-rw-r--r--. qemu qemu system_u:object_r:virt_content_t:s0 /var/lib/libvirt/images/bb.iso

2. Setup a domain with empty scsi cdrom
...
<disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <target dev='sdc' bus='scsi'/>
      <readonly/>
      <address type='drive' controller='0' bus='0' target='0' unit='2'/>
    </disk>
   <controller type='scsi' index='0' model='virtio-scsi'>
      <alias name='scsi0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
    </controller>
...

3. Insert cdrom
# virsh start t111
Domain t111 started
# virsh change-media t111 sdc  /var/lib/libvirt/images/bb.iso --insert
Successfully inserted media.
Login guest, mount and read the media successfully.

4. Update cdrom
Destroy and start t111
# virsh destroy t111&&virsh start t111
Domain t111 destroyed
Domain t111 started
update the cdrom
# virsh change-media t111 sdc  /var/lib/libvirt/images/bb.iso --update                          
Successfully updated media.

5.Get selinux info
# ausearch -m VIRT_RESOURCE|grep t111
type=VIRT_RESOURCE msg=audit(1444707931.767:34143): pid=5574 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:virtd_t:s0-s0:c0.c1023 msg='virt=kvm resrc=disk reason=update vm="t111" uuid=11b957c8-2e76-44f5-9959-791d350a4215 old-disk="?" new-disk="/var/lib/libvirt/images/bb.iso" exe="/usr/sbin/libvirtd" hostname=? addr=? terminal=? res=success'

For the issues in Comment10, refer to https://bugzilla.redhat.com/show_bug.cgi?id=1271069

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2015-2202.html