Yes so I wasn’t specific enough (edited the question), I want to know if there is a way to set the root directory as read-only - only for the user that is working on the notebook - jovyan.
The reason for this is the architecture of our system, so when a user is working I want him to save all his work in a subfolder (that is mounted to the host machine and is not read only) and not be able to save files in the root /home/jovyan directory