Image volume cache limits misbehave when only one is set

[Alan Bishop]

The image volume cache has two configurable limits:
- image_volume_cache_max_size_gb
- image_volume_cache_max_count

The code functions correctly when both values are zero (i.e. unlimited), and
when both values are assigned a non-zero value (both limits enforced).
However, the system misbehaves when only one limit is configured and the
other is disabled.

If only one limit is enforced, the system always removes existing entries
before adding a new entry. In other words, it behaves as if the
image_volume_cache_max_count is set to 1, regardless of how the limit is
actually configured.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/603145

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/603145
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=74249de6398dbec8592591667b83a5612bf4a969
Submitter: Zuul
Branch: master

commit 74249de6398dbec8592591667b83a5612bf4a969
Author: Alan Bishop <email address hidden>
Date: Mon Sep 17 10:09:06 2018 -0400

    Fix image volume cache max size and max count limits

    Fix the code that enforces the image volume cache max size and max count
    limits so that each limit functions independently from the other.

    This fixes a bug where the code would function correctly when both were
    set to zero (unlimited) or when both limits were set (non-zero), but would
    misbehave when only one limit was set and the other unlimited.

    Closes-Bug: #1792944
    Change-Id: I8b4843c2e9392139b42d6e2ebd2c5e1cd09d4c7a

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/rocky
Review: https://review.openstack.org/605757

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/605757
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=4c2b41d5b531c1e3cd87172d30f280f89e2505a3
Submitter: Zuul
Branch: stable/rocky

commit 4c2b41d5b531c1e3cd87172d30f280f89e2505a3
Author: Alan Bishop <email address hidden>
Date: Mon Sep 17 10:09:06 2018 -0400

    Fix image volume cache max size and max count limits

    Fix the code that enforces the image volume cache max size and max count
    limits so that each limit functions independently from the other.

    This fixes a bug where the code would function correctly when both were
    set to zero (unlimited) or when both limits were set (non-zero), but would
    misbehave when only one limit was set and the other unlimited.

    Closes-Bug: #1792944
    Change-Id: I8b4843c2e9392139b42d6e2ebd2c5e1cd09d4c7a
    (cherry picked from commit 74249de6398dbec8592591667b83a5612bf4a969)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/queens
Review: https://review.openstack.org/606187

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/606187
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=fe0c082529c301e28fd7dd517f564eaaed944475
Submitter: Zuul
Branch: stable/queens

commit fe0c082529c301e28fd7dd517f564eaaed944475
Author: Alan Bishop <email address hidden>
Date: Mon Sep 17 10:09:06 2018 -0400

    Fix image volume cache max size and max count limits

    Fix the code that enforces the image volume cache max size and max count
    limits so that each limit functions independently from the other.

    This fixes a bug where the code would function correctly when both were
    set to zero (unlimited) or when both limits were set (non-zero), but would
    misbehave when only one limit was set and the other unlimited.

    Closes-Bug: #1792944
    Change-Id: I8b4843c2e9392139b42d6e2ebd2c5e1cd09d4c7a
    (cherry picked from commit 74249de6398dbec8592591667b83a5612bf4a969)
    (cherry picked from commit 4c2b41d5b531c1e3cd87172d30f280f89e2505a3)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/cinder 12.0.4 release.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/pike
Review: https://review.openstack.org/612470

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/612470
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=ec1a8e36ee3d71da97c758f6bd92ff0d88c2edd7
Submitter: Zuul
Branch: stable/pike

commit ec1a8e36ee3d71da97c758f6bd92ff0d88c2edd7
Author: Alan Bishop <email address hidden>
Date: Mon Sep 17 10:09:06 2018 -0400

    Fix image volume cache max size and max count limits

    Fix the code that enforces the image volume cache max size and max count
    limits so that each limit functions independently from the other.

    This fixes a bug where the code would function correctly when both were
    set to zero (unlimited) or when both limits were set (non-zero), but would
    misbehave when only one limit was set and the other unlimited.

    Closes-Bug: #1792944
    Change-Id: I8b4843c2e9392139b42d6e2ebd2c5e1cd09d4c7a
    (cherry picked from commit 74249de6398dbec8592591667b83a5612bf4a969)
    (cherry picked from commit 4c2b41d5b531c1e3cd87172d30f280f89e2505a3)
    (cherry picked from commit fe0c082529c301e28fd7dd517f564eaaed944475)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/cinder 13.0.1 release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/cinder 11.2.0 release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/cinder 14.0.0.0rc1 release candidate.