This is a feature change rather than a bug. The default smb version has changed from 1.0 to 3.0 with this kernel. Do not be surprised if existing cifs mounts to NAS and samba no longer work with the unhelpful error 22. You can fix broken mounts with the vers=1.0 option. A news item might be appropriate.
Thank you, Harris. Do you have a link with more information on this?
https://lwn.net/Articles/732816/
Sorry we missed this. This was not a bad idea at all. As we're almost a year later, I think we missed the boat on this. I did not see any bugs concerning this, so maybe people were able to work themselves through this.