As most of you know there was a problem with legacy addons mounting on linux after update 158. Update 159 was released shortly after to fix this problem. Legacy addons now mount, however workshop files (specified in workshop.vdf) are not loading at all. I am aware that it could be a problem due to the first file in the list being invalid, thus not mounting the ones below this; however I have checked for this by removing each one and converting them with GMAD into a folder and testing them that way.
Look at the change log for update 158. Garry removed workshop.vdf. You now have to create a workshop collection and point the server to that.