This log message is for a boot volume (created from image) which is actually attached and than reset to available:


2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager [req-3c679b45-ab7d-4fe2-bded-ba7db533bc0d 91c84696756645daa02de7e70def58fb e2a9a87d227647d481255205c42c5c80 - default default] Volume d31c87da-82e8-4f96-887e-74dac56b7dc3 revert to snapshot c7db0d01-b9b4-4f71-ba21-7c0784c2549a failed with [errno 30] error rolling back image b'volume-d31c87da-82e8-4f96-887e-74dac56b7dc3' to snapshot b'snapshot-c7db0d01-b9b4-4f71-ba21-7c0784c2549a'.: rbd.ReadOnlyImage: [errno 30] error rolling back image b'volume-d31c87da-82e8-4f96-887e-74dac56b7dc3' to snapshot b'snapshot-c7db0d01-b9b4-4f71-ba21-7c0784c2549a'
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager Traceback (most recent call last):
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager   File "/var/lib/kolla/venv/lib/python3.6/site-packages/cinder/volume/manager.py", line 1063, in revert_to_snapshot
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager     self._revert_to_snapshot(context, volume, snapshot)
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager   File "/var/lib/kolla/venv/lib/python3.6/site-packages/cinder/volume/manager.py", line 1011, in _revert_to_snapshot
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager     self.driver.revert_to_snapshot(context, volume, snapshot)
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager   File "/var/lib/kolla/venv/lib/python3.6/site-packages/cinder/volume/drivers/rbd.py", line 1294, in revert_to_snapshot
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager     image.rollback_to_snap(snapshot.name)
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager   File "/var/lib/kolla/venv/lib/python3.6/site-packages/eventlet/tpool.py", line 190, in doit
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager     result = proxy_call(self._autowrap, f, *args, **kwargs)
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager   File "/var/lib/kolla/venv/lib/python3.6/site-packages/eventlet/tpool.py", line 148, in proxy_call
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager     rv = execute(f, *args, **kwargs)
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager   File "/var/lib/kolla/venv/lib/python3.6/site-packages/eventlet/tpool.py", line 129, in execute
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager     six.reraise(c, e, tb)
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager   File "/usr/lib/python3.6/site-packages/six.py", line 703, in reraise
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager     raise value
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager   File "/var/lib/kolla/venv/lib/python3.6/site-packages/eventlet/tpool.py", line 83, in tworker
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager     rv = meth(*args, **kwargs)
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager   File "rbd.pyx", line 2882, in rbd.requires_not_closed.wrapper
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager   File "rbd.pyx", line 3621, in rbd.Image.rollback_to_snap
2022-02-09 21:20:58.720 31 ERROR cinder.volume.manager rbd.ReadOnlyImage: [errno 30] error rolling back image b'volume-d31c87da-82e8-4f96-887e-74dac56b7dc3' to snapshot b'snapshot-c7db0d01-b9b4-4f71-ba21-7c0784c2549a'