ref: 57b20be7670925f2b3c0a4e56ca5e5c5348e7f6f
dir: /sys/src/cmd/ext4srv/NOTES/
Based on https://github.com/gkostka/lwext4 None of the sources are GPL-licensed: * xattr handling removed altogether * extents logic replaced with a BSD-3 licensed one found in https://github.com/ngkaho1234/lwext