OK, then mountall is the offender here, because that's what /etc/init/mountall.conf calls. According to its manpage it runs fsck.
** Also affects: mountall (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/771748 Title: Ubuntu does fsck on every start when using btrfs -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs