struct bio *inmate, struct dm_bio_prison_cell **ref);
void dm_cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios);
-void dm_cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio); // FIXME: bio arg not needed
void dm_cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list *inmates);
void dm_cell_error(struct dm_bio_prison_cell *cell);