FreeBSD merging upstream OpenZFS code

In the recent past the reference implementation for the ZFS advanced filesystem shifted from Illumos to the Linux on ZFS project. More active work was happening in the Linux branch of ZFS and developers have largely agreed to shift focus to using the Linux on ZFS code as the common upstream base. The FreeBSD team is in the process of migrating from their previous implementation to the new OpenZFS code. "Work on merging FreeBSD support in to what was at the time ZFS on Linux began in August 2018. I first publicly proposed transitioning FreeBSD to (new) OpenZFS on December 18th, 2018. FreeBSD support in OpenZFS was finally completed in December 2019. A CFT for downstreaming OpenZFS support in to FreeBSD was first issued on July 8th. All issues that were reported have been addressed or, for a couple of less critical matters there are pull requests in progress with OpenZFS. iXsystems has tested and dogfooded extensively internally. The TrueNAS 12 release is based on OpenZFS with some additional features that have not yet made it upstream." Further information can be found in the change's log message.