Yes, the incompatibility of any version of openafs with the linux kernel 4.4 and newer is known upstream. In addition to the build-breaking changes in linux, there are some changes in when ERESTART can be returned, that openafs is also unadapted for; running with just the patches to fix the build could lead to data corruption.
Unfortunately, it does not seem that anyone from upstream has been able to investigate the scope of such issues or propose a patch, so I do not expect there to be a version of openafs usable with the recent kernel for some time. -Ben
