File Cloning with Block Reference Table by Pawel Dawidek

From the 2020 OpenZFS Developer Summit slides: https://drive.google.com/file/d/1csE8OuPotfhaFi9KvTGKMGy86KxrBu2W/view?usp=sharing Details: https://openzfs.org/wiki/OpenZFS_Developer_Summit_2020