overlay_dev_flag_t
overlay_io_start(overlay_dev_t *odd, overlay_dev_flag_t flag)
overlay_io_done(overlay_dev_t *odd, overlay_dev_flag_t flag)
overlay_io_wait(overlay_dev_t *odd, overlay_dev_flag_t flag)
overlay_dev_flag_t odd_flags; /* protected by odd_lock */
extern void overlay_io_start(overlay_dev_t *, overlay_dev_flag_t);
extern void overlay_io_done(overlay_dev_t *, overlay_dev_flag_t);