The Linux Kernel, CDDL and Related Issues
<p><pre><code>    anything that has knowledge of and plays with fundamental internal 
    Linux behaviour is clearly a derived work. If you need to muck around
    with core code, you&#x27;re derived, no question about it.
</code></pre>
In 100+ places, the zfsonlinux&#x2F;zfs.git master branch has to change its compile-time behavior depending on the details of the kernel it is being compiled for.  i.e., out of 100+ yes-no questions, you only get a working zfs.ko if you answer each one in the same way the kernel does.  To me, this indicates a strong likelyhood that zfs is way towards the &quot;muck[s] around with core code&quot; end of the spectrum.<p>(The 100+ places I cite are actually a count of 121 uses of the macro ZFS_LINUX_TRY_COMPILE while configuring zfs at zfs-0.6.5-166-gd2f3e29; each one presumably corresponds to one or more #ifdef sites in the actual source code of zfs, each one adapting to a change in the internal details of Linux from 2.6.x to the present day)