-int dsl_read(zio_t *pio, spa_t *spa, const blkptr_t *bpp, arc_buf_t *pbuf,
- arc_done_func_t *done, void *private, int priority, int zio_flags,
- uint32_t *arc_flags, const zbookmark_t *zb);
-int dsl_read_nolock(zio_t *pio, spa_t *spa, const blkptr_t *bpp,
- arc_done_func_t *done, void *private, int priority, int zio_flags,
- uint32_t *arc_flags, const zbookmark_t *zb);