Comment 5 for bug 1860165

This issue resurfaced when testing upgrade in an IPv6 lab.

When upgrade needed to be aborted, and a host-downgrade was required for the upgrade to complete, the host-unlock after that failed with ceph error:

Starting ceph services...
=== osd.1 ===
Mounting xfs on controller-1:/var/lib/ceph/osd/ceph-1
Starting Ceph osd.1 on controller-1...
starting osd.1 at - osd_data /var/lib/ceph/osd/ceph-1 /var/lib/ceph/osd/ceph-1/journal
2020-06-10 04:20:26.297 7f59bc2641c0 -1 journal FileJournal::open: ondisk fsid 00000000-0000-0000-0000-000000000000 doesn't match expected f5644198-c1f0-46bc-ae86-e09b0487933a, invalid (someone else's?) journal
2020-06-10 04:20:26.298 7f59bc2641c0 -1 filestore(/var/lib/ceph/osd/ceph-1) mount(1871): failed to open journal /var/lib/ceph/osd/ceph-1/journal: (22) Invalid argument
2020-06-10 04:20:26.298 7f59bc2641c0 -1 osd.1 0 OSD:init: unable to mount object store
2020-06-10 04:20:26.298 7f59bc2641c0 -1 ^[[0;31m ** ERROR: osd init failed: (22) Invalid argument^[[0m
failed: 'ulimit -n 32768; TCMALLOC_MAX_TOTAL_THREAD_CACHE_BYTES=134217728 /usr/bin/ceph-osd -i 1 --pid-file /var/run/ceph/osd.1.pid -c /etc/ceph/ceph.conf --cluster ceph '
Wed Jun 10 04:20:26 UTC 2020
RC was: 1