ddt_phys_free
ddt_phys_free(ddt, ddk, ddp, txg);
ddt_phys_free(ddt, ddk, ddp, txg);
extern void ddt_phys_free(ddt_t *ddt, ddt_key_t *ddk, ddt_phys_t *ddp,
ddt_phys_free(ddt, ddk, ddp, zio->io_txg);