4047 panic from dbuf_free_range() from dmu_free_object() while doing zfs receive
Reviewed by: Adam Leventhal <ahl@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>

*** 113,122 ****
--- 113,123 ----
          dn->dn_newuid = 0;
          dn->dn_newgid = 0;
          dn->dn_id_flags = 0;
  
          dn->dn_dbufs_count = 0;
+         dn->dn_unlisted_l0_blkid = 0;
          list_create(&dn->dn_dbufs, sizeof (dmu_buf_impl_t),
              offsetof(dmu_buf_impl_t, db_link));
  
          dn->dn_moved = 0;
          return (0);
*** 165,174 ****
--- 166,176 ----
          ASSERT0(dn->dn_newuid);
          ASSERT0(dn->dn_newgid);
          ASSERT0(dn->dn_id_flags);
  
          ASSERT0(dn->dn_dbufs_count);
+         ASSERT0(dn->dn_unlisted_l0_blkid);
          list_destroy(&dn->dn_dbufs);
  }
  
  void
  dnode_init(void)
*** 470,479 ****
--- 472,482 ----
          dn->dn_olduid = 0;
          dn->dn_oldgid = 0;
          dn->dn_newuid = 0;
          dn->dn_newgid = 0;
          dn->dn_id_flags = 0;
+         dn->dn_unlisted_l0_blkid = 0;
  
          dmu_zfetch_rele(&dn->dn_zfetch);
          kmem_cache_free(dnode_cache, dn);
          arc_space_return(sizeof (dnode_t), ARC_SPACE_OTHER);
  }
*** 700,709 ****
--- 703,713 ----
          ASSERT(refcount_count(&odn->dn_tx_holds) == 0);
          refcount_transfer(&ndn->dn_holds, &odn->dn_holds);
          ASSERT(list_is_empty(&ndn->dn_dbufs));
          list_move_tail(&ndn->dn_dbufs, &odn->dn_dbufs);
          ndn->dn_dbufs_count = odn->dn_dbufs_count;
+         ndn->dn_unlisted_l0_blkid = odn->dn_unlisted_l0_blkid;
          ndn->dn_bonus = odn->dn_bonus;
          ndn->dn_have_spill = odn->dn_have_spill;
          ndn->dn_zio = odn->dn_zio;
          ndn->dn_oldused = odn->dn_oldused;
          ndn->dn_oldflags = odn->dn_oldflags;
*** 734,743 ****
--- 738,748 ----
          odn->dn_dbuf = NULL;
          odn->dn_handle = NULL;
          list_create(&odn->dn_dbufs, sizeof (dmu_buf_impl_t),
              offsetof(dmu_buf_impl_t, db_link));
          odn->dn_dbufs_count = 0;
+         odn->dn_unlisted_l0_blkid = 0;
          odn->dn_bonus = NULL;
          odn->dn_zfetch.zf_dnode = NULL;
  
          /*
           * Set the low bit of the objset pointer to ensure that dnode_move()
*** 1521,1531 ****
          rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
          blksz = dn->dn_datablksz;
          blkshift = dn->dn_datablkshift;
          epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
  
!         if (len == -1ULL) {
                  len = UINT64_MAX - off;
                  trunc = TRUE;
          }
  
          /*
--- 1526,1536 ----
          rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
          blksz = dn->dn_datablksz;
          blkshift = dn->dn_datablkshift;
          epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
  
!         if (len == DMU_OBJECT_END) {
                  len = UINT64_MAX - off;
                  trunc = TRUE;
          }
  
          /*