Commented on the master review but thought I'd weigh in here, also..
Hit the same bug today and found your proposal under review. Testing it against grizzly, cinder successfully wipes the -cow devices but later fails to lvremove, http://paste.ubuntu.com/6085414/.
I've stepped through the process manually, included is debug output of lvremove on a snapshot that had its corresponding -cow device dd'd: http://paste.ubuntu.com/6085596/
Joseph-
Commented on the master review but thought I'd weigh in here, also..
Hit the same bug today and found your proposal under review. Testing it against grizzly, cinder successfully wipes the -cow devices but later fails to lvremove, http:// paste.ubuntu. com/6085414/.
I've stepped through the process manually, included is debug output of lvremove on a snapshot that had its corresponding -cow device dd'd: http:// paste.ubuntu. com/6085596/