5269 zfs: zpool import slow
PORTING: this code relies on the property of taskq_wait to wait
until no more tasks are queued and no more tasks are active. As
we always queue new tasks from within other tasks, task_wait
reliably waits for the full recursion to finish, even though we
enqueue new tasks after taskq_wait has been called.
On platforms other than illumos, taskq_wait may not have this
property.
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Dan McDonald <danmcd@omniti.com>
Reviewed by: George Wilson <george.wilson@delphix.com>

*** 140,149 ****
--- 140,151 ----
  
  /* called from zpl */
  int dmu_objset_hold(const char *name, void *tag, objset_t **osp);
  int dmu_objset_own(const char *name, dmu_objset_type_t type,
      boolean_t readonly, void *tag, objset_t **osp);
+ int dmu_objset_own_obj(struct dsl_pool *dp, uint64_t obj,
+     dmu_objset_type_t type, boolean_t readonly, void *tag, objset_t **osp);
  void dmu_objset_refresh_ownership(objset_t *os, void *tag);
  void dmu_objset_rele(objset_t *os, void *tag);
  void dmu_objset_disown(objset_t *os, void *tag);
  int dmu_objset_from_ds(struct dsl_dataset *ds, objset_t **osp);