6536 zfs send: want a way to disable setting of DRR_FLAG_FREERECORDS
Reviewed by: Anil Vijarnia <avijarnia@racktopsystems.com>
Reviewed by: Kim Shrier <kshrier@racktopsystems.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>

*** 22,31 ****
--- 22,32 ----
   * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
   * Copyright (c) 2011, 2015 by Delphix. All rights reserved.
   * Copyright (c) 2014, Joyent, Inc. All rights reserved.
   * Copyright 2014 HybridCluster. All rights reserved.
+  * Copyright 2016 RackTop Systems.
   */
  
  #include <sys/dmu.h>
  #include <sys/dmu_impl.h>
  #include <sys/dmu_tx.h>
*** 56,65 ****
--- 57,68 ----
  
  /* Set this tunable to TRUE to replace corrupt data with 0x2f5baddb10c */
  int zfs_send_corrupt_data = B_FALSE;
  int zfs_send_queue_length = 16 * 1024 * 1024;
  int zfs_recv_queue_length = 16 * 1024 * 1024;
+ /* Set this tunable to FALSE to disable setting of DRR_FLAG_FREERECORDS */
+ int zfs_send_set_freerecords_bit = B_TRUE;
  
  static char *dmu_recv_tag = "dmu_recv_tag";
  const char *recv_clone_name = "%recv";
  
  #define BP_SPAN(datablkszsec, indblkshift, level) \
*** 743,752 ****
--- 746,756 ----
          if (is_clone)
                  drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_CLONE;
          drr->drr_u.drr_begin.drr_toguid = dsl_dataset_phys(to_ds)->ds_guid;
          if (dsl_dataset_phys(to_ds)->ds_flags & DS_FLAG_CI_DATASET)
                  drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_CI_DATA;
+         if (zfs_send_set_freerecords_bit)
                  drr->drr_u.drr_begin.drr_flags |= DRR_FLAG_FREERECORDS;
  
          if (ancestor_zb != NULL) {
                  drr->drr_u.drr_begin.drr_fromguid =
                      ancestor_zb->zbm_guid;