Bug 1305793

Peter,
After failed external system check point snapshot, vm is not resumed. Is it acceptable result?

verified on libvirt-0.10.2-57.el6.x86_64

steps as following
1. Setup libvirt sanlock on a host:
On host A
# setsebool sanlock_use_nfs 1 && setsebool virt_use_nfs 1 && setsebool virt_use_sanlock 1
# cat /etc/libvirt/qemu-sanlock.conf
auto_disk_leases = 1
disk_lease_dir = "/var/lib/libvirt/sanlock"
host_id = 1
user = "sanlock"
group = "sanlock"

# cat /etc/libvirt/qemu.conf
lock_manager = "sanlock"

# cat /etc/sysconfig/sanlock                                              
SANLOCKOPTS="-w 0"

mount nfs server on /mnt
# mount
10.73.194.27:/vol/S3/libvirtauto/yy on /mnt

# service wdmd restart; service sanlock restart; service libvirtd restart

2. start a guest 
<disk type='file' device='disk'>
      <driver name='qemu' type='qcow2' cache='none'/>
      <source file='/mnt/rhel6.qcow2'>
        <seclabel model='selinux' relabel='no'/>
      </source>
      <target dev='vda' bus='virtio'/>
      <alias name='virtio-disk0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </disk>

3. create external disk only snapshot
# virsh snapshot-create-as yy s1 --disk-only --diskspec vda,file=/var/lib/libvirt/images/yy.s1
error: Failed to acquire lock: File exists

# ll /var/lib/libvirt/images/yy.s1
ls: cannot access /var/lib/libvirt/images/yy.s1: No such file or directory

# virsh dumpxml yy | grep disk -a6
 <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2' cache='none'/>
      <source file='/mnt/rhel6.qcow2'>
        <seclabel model='selinux' relabel='no'/>
      </source>
      <target dev='vda' bus='virtio'/>
      <alias name='virtio-disk0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </disk>

4. create external disk only snapshot once more
# virsh snapshot-create-as yy s1 --disk-only --diskspec vda,file=/var/lib/libvirt/images/yy.s1
error: Failed to acquire lock: File exists

###At this point domain job is unlocked###

5. create external system check point snapshot
# virsh snapshot-create-as yy s1 --diskspec vda,file=/mnt/yy.s1 --memspec file=/mnt/yy.mem
error: Failed to acquire lock: File exists

# virsh dumpxml yy | grep disk -a6
<disk type='file' device='disk'>
      <driver name='qemu' type='qcow2' cache='none'/>
      <source file='/mnt/yy.s1'>
        <seclabel model='selinux' relabel='no'/>
      </source>
      <target dev='vda' bus='virtio'/>
      <alias name='virtio-disk0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </disk>

# virsh snapshot-list yy
 Name                 Creation Time             State
------------------------------------------------------------

# virsh list
 Id    Name                           State
----------------------------------------------------
 7     yy                             paused

###At this point vm is not resumed after failed snapshot###

(In reply to yangyang from comment #4)
> Peter,
> After failed external system check point snapshot, vm is not resumed. Is it
> acceptable result?

Yes, that is expected. The failure was triggered by not being able to resume the VM due to a failed locking attempt. At that point the VM can be either restarted in the future, or killed via the 'destroy' api.

Thank Peter's quick response. Move it to verified

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-2016-0738.html