Illumos 5960, 5925

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>

References:
  https://www.illumos.org/issues/5960
  https://www.illumos.org/issues/5925
  https://github.com/illumos/illumos-gate/commit/a2cdcdd

Porting notes:
- [lib/libzfs/libzfs_sendrecv.c]
  - b8864a2 Fix gcc cast warnings
  - 325f023 Add linux kernel device support
  - 5c3f61e Increase Linux pipe buffer size on 'zfs receive'
- [module/zfs/zfs_vnops.c]
  - 3558fd7 Prototype/structure update for Linux
  - c12e3a5 Restructure zfs_readdir() to fix regressions
- [module/zfs/zvol.c]
  - Function @zvol_map_block() isn't needed in ZoL
  - 9965059 Prefetch start and end of volumes
- [module/zfs/dmu.c]
  - Fixed ISO C90 - mixed declarations and code
  - Function dmu_prefetch() 'int i' is initialized before
    the following code block (c90 vs. c99)
- [module/zfs/dbuf.c]
  - fc5bb51 Fix stack dbuf_hold_impl()
  - 9b67f60 Illumos 4757, 4913
  - 34229a2 Reduce stack usage for recursive traverse_visitbp()
- [module/zfs/dmu_send.c]
  - Fixed ISO C90 - mixed declarations and code
  - b58986e Use large stacks when available
  - 241b541 Illumos 5959 - clean up per-dataset feature count code
  - 77aef6f Use vmem_alloc() for nvlists
  - 00b4602 Add linux kernel memory support

Ported-by: kernelOfTruth kerneloftruth@gmail.com
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

cmd/ztest/ztest.c

@@ -3728,7 +3728,8 @@ ztest_dmu_read_write(ztest_ds_t *zd, uint64_t id)
 	 */
 	n = ztest_random(regions) * stride + ztest_random(width);
 	s = 1 + ztest_random(2 * width - 1);
-	dmu_prefetch(os, bigobj, n * chunksize, s * chunksize);
+	dmu_prefetch(os, bigobj, 0, n * chunksize, s * chunksize,
+	    ZIO_PRIORITY_SYNC_READ);
 
 	/*
 	 * Pick a random index and compute the offsets into packobj and bigobj.
@@ -5930,8 +5931,10 @@ ztest_run(ztest_shared_t *zs)
 	 * Right before closing the pool, kick off a bunch of async I/O;
 	 * spa_close() should wait for it to complete.
 	 */
-	for (object = 1; object < 50; object++)
-		dmu_prefetch(spa->spa_meta_objset, object, 0, 1ULL << 20);
+	for (object = 1; object < 50; object++) {
+		dmu_prefetch(spa->spa_meta_objset, object, 0, 0, 1ULL << 20,
+		    ZIO_PRIORITY_SYNC_READ);
+	}
 
 	/* Verify that at least one commit cb was called in a timely fashion */
 	if (zc_cb_counter >= ZTEST_COMMIT_CB_MIN_REG)