cstyle fixes
dsl_dataset_set_fsid_guid should use ZFS_SPACE_CHECK_RESERVED
dsl_dataset_set_fsid_guid _check and _sync func declared static,
removed from dsl_dataset.h
rewrite unique_valid
6333 ZFS should let the user specify or modify the fsid_guid of a dataset

*** 337,346 ****
--- 337,348 ----
      zprop_source_t source, uint64_t value, dmu_tx_t *tx);
  void dsl_dataset_zapify(dsl_dataset_t *ds, dmu_tx_t *tx);
  boolean_t dsl_dataset_is_zapified(dsl_dataset_t *ds);
  boolean_t dsl_dataset_has_resume_receive_state(dsl_dataset_t *ds);
  int dsl_dataset_rollback(const char *fsname, void *owner, nvlist_t *result);
+ int dsl_dataset_set_fsid_guid(const char *ddname, zprop_source_t source,
+     uint64_t fsid_guid);
  
  void dsl_dataset_deactivate_feature(uint64_t dsobj,
      spa_feature_t f, dmu_tx_t *tx);
  
  #ifdef ZFS_DEBUG