Comment 3 for bug 1994521

Reviewed: https://review.opendev.org/c/openstack/cinder/+/862679
Committed: https://opendev.org/openstack/cinder/commit/dfd8f99743a29220ca3face5fdf00a1a6071cf48
Submitter: "Zuul (22348)"
Branch: master

commit dfd8f99743a29220ca3face5fdf00a1a6071cf48
Author: Rajat Dhasmana <email address hidden>
Date: Wed Oct 26 09:55:43 2022 +0000

    3PAR: Error out if vol cannot be converted to base

    Consider volume and snapshots as below:

    v1
    |
    `-- s1
        |
        `-- v2
            |
            `-- s2

    User initiated deletion of snapshot s1.
    It failed with some vague message.

    Initially, it was suspected that ...
    While copying volume v2 (sometimes an intermediate step to break
    volume dependency), we send a request to clone the volume v2 to new
    base volume; and the exception [1] isn't handled properly.

    [1] Conflict (HTTP 409) 32 - volume has a child

    However, on further investigation it was found that ...
    after a new volume v2 (omv-<id>) is created and
    when we try to delete old volume v2 (osv-<id>),
    at this point the exception [1] is thrown as error.

    This is now handled gracefully. Appropriate error is thrown
    if the volume (v2) has snapshot (s2).

    Co-Authored-By: raghavendrat <email address hidden>
    Closes-Bug: #1994521
    Change-Id: I5e7fb425c92cdf8c16d5a86a58ca1a52421543d7