NEX-9552 zfs_scan_idle throttling harms performance and needs to be removed
Reviewed by: Sanjay Nadkarni <sanjay.nadkarni@nexenta.com>
Reviewed by: Roman Strashkin <roman.strashkin@nexenta.com>
NEX-4582 update wrc test cases for allow to use write back cache per tree of datasets
Reviewed by: Steve Peng <steve.peng@nexenta.com>
Reviewed by: Alex Aizman <alex.aizman@nexenta.com>
5960 zfs recv should prefetch indirect blocks
5925 zfs receive -o origin=
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>

*** 25,36 ****
  typedef enum zio_priority {
          ZIO_PRIORITY_SYNC_READ,
          ZIO_PRIORITY_SYNC_WRITE,        /* ZIL */
          ZIO_PRIORITY_ASYNC_READ,        /* prefetch */
          ZIO_PRIORITY_ASYNC_WRITE,       /* spa_sync() */
!         ZIO_PRIORITY_SCRUB,             /* asynchronous scrub/resilver reads */
!         ZIO_PRIORITY_REMOVAL,           /* reads/writes for vdev removal */
          ZIO_PRIORITY_NUM_QUEUEABLE,
  
          ZIO_PRIORITY_NOW                /* non-queued i/os (e.g. free) */
  } zio_priority_t;
  
--- 25,36 ----
  typedef enum zio_priority {
          ZIO_PRIORITY_SYNC_READ,
          ZIO_PRIORITY_SYNC_WRITE,        /* ZIL */
          ZIO_PRIORITY_ASYNC_READ,        /* prefetch */
          ZIO_PRIORITY_ASYNC_WRITE,       /* spa_sync() */
!         ZIO_PRIORITY_RESILVER,          /* asynchronous resilver reads */
!         ZIO_PRIORITY_SCRUB,             /* asynchronous scrub reads */
          ZIO_PRIORITY_NUM_QUEUEABLE,
  
          ZIO_PRIORITY_NOW                /* non-queued i/os (e.g. free) */
  } zio_priority_t;