Can't update Hassio or several add-ons: why?

so wanted to revive an older HA Pi to dedicate it to a Z-wave usb stick… Older as in 100.1.

Some of the add-ons worked out, but 2 important ones, SSH and Samba error out. Just as trying to update Hassio itself:

19-11-30 22:30:35 INFO (MainThread) [hassio.homeassistant] Update Home Assistant to version 0.102.3
19-11-30 22:30:35 INFO (SyncWorker_2) [hassio.docker.interface] Update image homeassistant/raspberrypi3-homeassistant:0.100.1 to homeassistant/raspberrypi3-homeassistant:0.102.3
19-11-30 22:30:35 INFO (SyncWorker_2) [hassio.docker.interface] Pull image homeassistant/raspberrypi3-homeassistant tag 0.102.3.
19-11-30 22:30:37 ERROR (SyncWorker_2) [hassio.docker.interface] Can't install homeassistant/raspberrypi3-homeassistant:0.102.3 -> 500 Server Error: Internal Server Error ("readlink /mnt/data/docker/overlay2/l: invalid argument").
19-11-30 22:30:37 WARNING (MainThread) [hassio.homeassistant] Update Home Assistant image fails

and the same error for the ssh add-on:

19-11-30 22:34:16 INFO (SyncWorker_6) [hassio.docker.interface] Update image homeassistant/armv7-addon-ssh:6.4 to homeassistant/armv7-addon-ssh:7.0
19-11-30 22:34:16 INFO (SyncWorker_6) [hassio.docker.interface] Pull image homeassistant/armv7-addon-ssh tag 7.0.
19-11-30 22:34:18 ERROR (SyncWorker_6) [hassio.docker.interface] Can't install homeassistant/armv7-addon-ssh:7.0 -> 500 Server Error: Internal Server Error ("readlink /mnt/data/docker/overlay2/l: invalid argument").

what could be the cause of this, and, more importantly, how do I solve this?
Please have a look? thanks!

sorry, should have searched better, @cogneato solve it for me here: Update | Problem

hassio su repair

don’t understand the why, but it was the how…
thanks!