zpool import speedup

*** 261,270 ****
--- 261,271 ----
  #define DMU_SPILL_BLKID         (-2ULL)
  /*
   * Public routines to create, destroy, open, and close objsets.
   */
  int dmu_objset_hold(const char *name, void *tag, objset_t **osp);
+ int dmu_objset_hold_nolock(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);
  void dmu_objset_rele(objset_t *os, void *tag);
  void dmu_objset_disown(objset_t *os, void *tag);
  int dmu_objset_open_ds(struct dsl_dataset *ds, objset_t **osp);
*** 277,286 ****
--- 278,289 ----
      struct nvlist *errlist);
  int dmu_objset_snapshot_one(const char *fsname, const char *snapname);
  int dmu_objset_snapshot_tmp(const char *, const char *, int);
  int dmu_objset_find(char *name, int func(const char *, void *), void *arg,
      int flags);
+ int dmu_objset_find_parallel(char *name, int func(const char *, void *),
+     void *arg, int flags);
  void dmu_objset_byteswap(void *buf, size_t size);
  int dsl_dataset_rename_snapshot(const char *fsname,
      const char *oldsnapname, const char *newsnapname, boolean_t recursive);
  
  typedef struct dmu_buf {