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>

include/sys/bqueue.h

@@ -0,0 +1,54 @@
+/*
+ * CDDL HEADER START
+ *
+ * This file and its contents are supplied under the terms of the
+ * Common Development and Distribution License ("CDDL"), version 1.0.
+ * You may only use this file in accordance with the terms of version
+ * 1.0 of the CDDL.
+ *
+ * A full copy of the text of the CDDL should have accompanied this
+ * source.  A copy of the CDDL is also available via the Internet at
+ * http://www.illumos.org/license/CDDL.
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2014 by Delphix. All rights reserved.
+ */
+
+#ifndef	_BQUEUE_H
+#define	_BQUEUE_H
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+#include	<sys/zfs_context.h>
+
+typedef struct bqueue {
+	list_t bq_list;
+	kmutex_t bq_lock;
+	kcondvar_t bq_add_cv;
+	kcondvar_t bq_pop_cv;
+	uint64_t bq_size;
+	uint64_t bq_maxsize;
+	size_t bq_node_offset;
+} bqueue_t;
+
+typedef struct bqueue_node {
+	list_node_t bqn_node;
+	uint64_t bqn_size;
+} bqueue_node_t;
+
+
+int bqueue_init(bqueue_t *, uint64_t, size_t);
+void bqueue_destroy(bqueue_t *);
+void bqueue_enqueue(bqueue_t *, void *, uint64_t);
+void *bqueue_dequeue(bqueue_t *);
+boolean_t bqueue_empty(bqueue_t *);
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif	/* _BQUEUE_H */