(Related to https://bugs.documentfoundation.org/show_bug.cgi?id=136980)

I had errors when I upgraded loowsd on debian 9 with apt.

root # apt update && apt upgrade
[...]
The following packages were automatically installed and are no longer required:
  collaboraofficebasis6.2-calc collaboraofficebasis6.2-draw collaboraofficebasis6.2-en-us collaboraofficebasis6.2-extension-pdf-import collaboraofficebasis6.2-graphicfilter collaboraofficebasis6.2-impress collaboraofficebasis6.2-ooofonts
  collaboraofficebasis6.2-ooolinguistic collaboraofficebasis6.2-writer libstd-rust-1.34
[...]
Setting up loolwsd (6.4.0-2) ...
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/tmp': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/help/idxcontent.xsl': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/help/main_transform.xsl': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/help/idxcaption.xsl': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/EULA_en-US.rtf': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/LICENSE': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/CREDITS.fodt': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/EULA.odt': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/program/libscuilo.so': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/program/gengal': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/program/gengal.bin': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/program/libdlgprovlo.so': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/program/libbootstraplo.so': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/program/libicglo.so': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/program/libxmlfalo.so': Read-only file system
rm: cannot remove '/opt/lool/child-roots/UhakGq3ABKfzVkFa/lo/program/libvbaobjlo.so': Read-only file
[...]
dpkg: error processing package loolwsd (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 loolwsd
E: Sub-process /usr/bin/dpkg returned an error code (1)
root # mount | grep UhakGq3ABKfzVkFa
/dev/sda5 on /opt/lool/child-roots/UhakGq3ABKfzVkFa type ext4 (ro,nosuid,nodev,noatime,seclabel,errors=remount-ro,data=ordered)
/dev/sda5 on /opt/lool/child-roots/UhakGq3ABKfzVkFa/lo type ext4 (ro,nosuid,nodev,noatime,seclabel,errors=remount-ro,data=ordered)
/dev/sda5 on /opt/lool/child-roots/UhakGq3ABKfzVkFa/tmp type ext4 (rw,relatime,seclabel,errors=remount-ro,data=ordered)


I didn't configure these mount points.