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>

*** 21,30 ****
--- 21,31 ----
  
  /*
   * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
   * Copyright (c) 2013, 2014, Nexenta Systems, Inc.  All rights reserved.
+  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
   */
  
  /*
   * SPA: Storage Pool Allocator
   *
*** 1086,1095 ****
--- 1087,1098 ----
                  spa_create_zio_taskqs(spa);
          }
  
          list_create(&spa->spa_config_dirty_list, sizeof (vdev_t),
              offsetof(vdev_t, vdev_config_dirty_node));
+         list_create(&spa->spa_evicting_os_list, sizeof (objset_t),
+             offsetof(objset_t, os_evicting_node));
          list_create(&spa->spa_state_dirty_list, sizeof (vdev_t),
              offsetof(vdev_t, vdev_state_dirty_node));
  
          txg_list_create(&spa->spa_vdev_txg_list,
              offsetof(struct vdev, vdev_txg_node));
*** 1112,1124 ****
--- 1115,1130 ----
          ASSERT(spa->spa_dsl_pool == NULL);
          ASSERT(spa->spa_root_vdev == NULL);
          ASSERT(spa->spa_async_zio_root == NULL);
          ASSERT(spa->spa_state != POOL_STATE_UNINITIALIZED);
  
+         spa_evicting_os_wait(spa);
+ 
          txg_list_destroy(&spa->spa_vdev_txg_list);
  
          list_destroy(&spa->spa_config_dirty_list);
+         list_destroy(&spa->spa_evicting_os_list);
          list_destroy(&spa->spa_state_dirty_list);
  
          for (int t = 0; t < ZIO_TYPES; t++) {
                  for (int q = 0; q < ZIO_TASKQ_TYPES; q++) {
                          spa_taskqs_fini(spa, t, q);
*** 2105,2114 ****
--- 2111,2125 ----
                  gethrestime(&spa->spa_loaded_ts);
                  error = spa_load_impl(spa, pool_guid, config, state, type,
                      mosconfig, &ereport);
          }
  
+         /*
+          * Don't count references from objsets that are already closed
+          * and are making their way through the eviction process.
+          */
+         spa_evicting_os_wait(spa);
          spa->spa_minref = refcount_count(&spa->spa_refcount);
          if (error) {
                  if (error != EEXIST) {
                          spa->spa_loaded_ts.tv_sec = 0;
                          spa->spa_loaded_ts.tv_nsec = 0;
*** 3673,3682 ****
--- 3684,3698 ----
  
          spa_config_sync(spa, B_FALSE, B_TRUE);
  
          spa_history_log_version(spa, "create");
  
+         /*
+          * Don't count references from objsets that are already closed
+          * and are making their way through the eviction process.
+          */
+         spa_evicting_os_wait(spa);
          spa->spa_minref = refcount_count(&spa->spa_refcount);
  
          mutex_exit(&spa_namespace_lock);
  
          return (0);
*** 4205,4214 ****
--- 4221,4231 ----
                  /*
                   * Objsets may be open only because they're dirty, so we
                   * have to force it to sync before checking spa_refcnt.
                   */
                  txg_wait_synced(spa->spa_dsl_pool, 0);
+                 spa_evicting_os_wait(spa);
  
                  /*
                   * A pool cannot be exported or destroyed if there are active
                   * references.  If we are resetting a pool, allow references by
                   * fault injection handlers.