StorPool: encrypted volumes cannot be attached

[Peter Penchev]

The StorPool Cinder driver still overrides the internal _attach_volume() and _detach_volume() methods, even after the base driver was modified to use os-brick for attaching volumes locally e.g. for transferring Glance image data. This, coupled with the fact that _attach_volume() (through _connect_device()) is now supposed to also return connection information, leads to an attempt to access missing connection information after attaching an encrypted volume.

The fix is trivial: remove the _attach_volume() and _detach_volume() methods from the StorPool driver, as done in https://review.opendev.org/c/openstack/cinder/+/787296

The patch from the above review has been in use in the StorPool driver's CI system since April; actually, the Cinder/Nova encrypted volume tests did not pass without it. We believe that the "cannot attach encrypted volumes" bug (due to the missing "conn" member of the returned structure) has been present at least since the Newton release, so the fix should probably be backported at least to Wallaby, if not earlier.

Thanks in advance for your time, and keep up the great work!

[Sofia Enriquez (lsofia-enriquez)]

Fix proposed to master https://review.opendev.org/c/openstack/cinder/+/787296

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/cinder/+/787296
Committed: https://opendev.org/openstack/cinder/commit/8a75d036f65a8da335170910f1820308dbfabedb
Submitter: "Zuul (22348)"
Branch: master

commit 8a75d036f65a8da335170910f1820308dbfabedb
Author: Peter Penchev <email address hidden>
Date: Tue Apr 20 17:46:41 2021 +0300

    StorPool: drop _attach_volume() and _detach_volume()

    Our os-brick connector already handles the "keep track of which volume
    is attached for what reason" calls to storpool.spopenstack. However,
    we need to explicitly specify the access mode in initialize_connection()
    now, since our os-brick connector does not know how to divine it yet.
    (this will come later with the "attach snapshot" functionality)

    Incidentally, this fixes the "create an encrypted volume" flow, since
    our _attach_volume() implementation never actually returned a connector
    in the attachment info...

    Change-Id: I5da7ae04b87b4fd52a682a6545060e852174f6c8
    Closes-Bug: #1939241