For the recent 12.2.3 Luminous release we've found that it is not
possible to mount a device when using filestore 
We are trying to find out how this was able to get pass our functional
testing, in the meantime the workaround for this problem is to add the
mount options in ceph.conf (as explained in the tracker ticket).
Hopefully we can get another release soon enough to get this properly
fixed for everyone.
Apologies for anyone affected.
ceph-users mailing list