[IBM Storwize SVF]:mkvdisk fails with name length issue while creating auxiliary change volume

[Preeti duhan]

Volume backend: SVC

Bug:-

Steps:
1)Create GMCV(global mirror change volume) volume.(chg_aux_volume-test_maha_1-1422a0c1-00000009-boot-0-98bb35fc-be2d)

mkvdisk fails with name length issue while creating auxiliary change volume

Unable to create GMCV volumes since the name of volume is exceeding the limit of characters
Error:
An error occurred while performing a storage operation for the volume chg_aux_volume-test_maha_1-1422a0c1-00000009-boot-0-98bb35fc-be2d. Explanation: Volume driver reported an error: Unable to set up gmcv mode replication for 377bf597-aae3-4e13-8548-4f622c70cb95. Exception: Bad or unexpected response from the storage volume backend API: CLI Exception output: command: ['svctask', 'mkvdisk', '-name', '

Reason :-

We used to consider the default vref['name'] that we get from (<class 'cinder.objects.volume.Volume'> ), But if we use a custom-name template(i.e,being defined at cinder.CONF) rather to default-name.

Only the "target_change_vol_name" is the only variable prone to exceed the supported limit of our storage(i.e 63 characters).

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/cinder/+/790910