GPFS Driver does not limit clone depth for snapshots

[Bill Owen]

GPFS Driver does not limit clone depth for snapshots - there is a potential for snapshot clones to grow without bound regardless of the setting of gpfs_max_clone_depth config flag.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/47264

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/47264
Committed: http://github.com/openstack/cinder/commit/cbb057169094e9d633162cc5645fa19a82325d49
Submitter: Jenkins
Branch: master

commit cbb057169094e9d633162cc5645fa19a82325d49
Author: Bill Owen <email address hidden>
Date: Wed Sep 18 14:30:07 2013 -0700

    GPFS Driver missing clone depth limit for snapshots

    GPFS driver is fixed to handle snapshot clones correctly. Previously,
    these were allowed to grow without respecting limit defined in config
    flag gpfs_max_clone_depth. This change adds the depth check operation
    in create_snapshot.

    To ensure that all clone files are cleaned up, the delete_snapshot
    method now marks snapshots to be deleted with ts file extension
    and attempts to delete the snapshot. If the snapshot cannot be
    deleted because it has clone children, it will be deleted when the
    child is deleted.

    Closes-Bug: #1227366

    Change-Id: I4fb2a720b55dbe033159e6fb341f6e2f1508776e