Also keep in mind that NFSv4 is mostly adds necessary complexity. Not accidental complexity.
For example, NFSv4 supports accessing files that have been unlinked, but still have one or more open file descriptors. NFSv3 does not. It needs to resort to a technique named ‘silly renames’.
For example, NFSv4 supports accessing files that have been unlinked, but still have one or more open file descriptors. NFSv3 does not. It needs to resort to a technique named ‘silly renames’.
http://linux-nfs.org/wiki/index.php/Server-side_silly_rename