You assume that child-roots is on the default place: rm -rf /opt/lool mkdir -p /opt/lool/child-roots If something else is configured in /etc/loolwsd/loolwsd.xml this will not work. You should remove the content of the /real/ child-roots not the folder itself, since it is a absolute stupid idea to place this temporary often written user generated content on the same filesystem.
It is not an absolutely stupid idea to put child-roots to the same filesystem, because hard linking is much faster than copying. Nevertheless, the bug report is valid.