5056 ZFS deadlock on db_mtx and dn_holds
Reviewed by: Will Andrews <willa@spectralogic.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Dan McDonald <danmcd@omniti.com>

*** 20,29 ****
--- 20,30 ----
   */
  /*
   * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
   * Copyright (c) 2013 Steven Hartland. All rights reserved.
+  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
   */
  
  #include <sys/dsl_pool.h>
  #include <sys/dsl_dataset.h>
  #include <sys/dsl_prop.h>
*** 315,324 ****
--- 316,327 ----
          txg_list_destroy(&dp->dp_dirty_dirs);
  
          arc_flush(dp->dp_spa);
          txg_fini(dp);
          dsl_scan_fini(dp);
+         dmu_buf_user_evict_wait();
+ 
          rrw_destroy(&dp->dp_config_rwlock);
          mutex_destroy(&dp->dp_lock);
          taskq_destroy(dp->dp_vnrele_taskq);
          if (dp->dp_blkstats)
                  kmem_free(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));