- Marking a non-static function as inline doesn't actually work and is
   now causing problems - drop that

 - Introduce BCACHEFS_LOG_PREFIX for when we want to prefix log messages
   with bcachefs (filesystem name)

 - Userspace doesn't have real percpu variables (maybe we can get this
   fixed someday), put an #ifdef around bch2_disk_reservation_add()
   fastpath
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>