[Nova] Instances can't be started after compute nodes unexpectedly shut down because of power outage

Hi folks, Because of power outage, Most of our compute nodes unexpectedly shut down and now I can not start our instances. Error message is "Failed to get "write" lock another process using the image?". Instances Power status is No State. Full error log is http://paste.openstack.org/show/754107/. My environment is OpenStack Pike on Ubuntu 16.04 LTS servers and Instances are on a nfs shared storage. Nova version is 16.1.6.dev2. qemu version is 2.10.1. libvirt version is 3.6.0. I saw a commit [1], but it doesn't solve this problem. There are important instances on my environment. How can I rescue my instances? What would you suggest ? Thanks, Gökhan [1] https://review.opendev.org/#/c/509774/