Comment 2 for bug 1458976

Reviewed: https://review.openstack.org/185764
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=75953752e41819b0d2ca770d4d13ed1ccaec685a
Submitter: Jenkins
Branch: master

commit 75953752e41819b0d2ca770d4d13ed1ccaec685a
Author: Xing Yang <email address hidden>
Date: Wed May 27 12:58:04 2015 -0400

    Fix capacity filter to allow oversubscription

    Currently the capacity filter does not allow oversubscrition
    if the free physical capacity is less than the new volume size.
    This was based on the assumption that a new thinly provisioned
    volume will be consumed right away. This assumption does not
    allow us to take full advantage of thin provisioning.

    The fix is to allow oversubscription if thin provisioning is
    supported and max_over_subscription_ratio is greater than or
    equal to 1. The free physical capacity will not be used to
    compare with the new volume size for a backend that supports
    oversubscription in thin provisioning. The oversubscription
    ratio and virtual free capacity will still be used to decide
    whether a backend can be chosen for thin provisioning.

    Closes-Bug: #1458976
    Change-Id: I4c8904445654db839c25ded420915f83c3756f94