@ignaloidas @sun too lazy to look it up.

TL;DR Linus hates ZFS for some unfathomable reason. ZFS uses a bunch of internal Linux APIs that are only exported with EXPORT_GPL() macros, thus supposedly only available to GPL kernel modules. ZFS itself is licenced under CDDL (:rms: approved free software loicence), so to circumvent the restriction they threw in a wrapper module that re-exports those GPL-only functions for ZFS to use. Loooinooos isn't too happy about this and mentioned a few times that this might constitute a copyright protection violation under DMCA and that ZFS devs need to worry.