btrfs-progs-4.0.1 released May 2015.
Pushed as: >*btrfs-progs-4.0.1 (13 Jun 2015) > > 13 Jun 2015; Sergei Trofimovich <slyfox@gentoo.org> +btrfs-progs-4.0.1.ebuild: > Version bump, bug #551842 by akiraba_honata@yahoo.co.jp. Thanks!