ZoL PR 9145

*** 44,53 ****
--- 44,54 ----
  /*
   * dnode_hold() flags.
   */
  #define DNODE_MUST_BE_ALLOCATED 1
  #define DNODE_MUST_BE_FREE      2
+ #define DNODE_DRY_RUN           4
  
  /*
   * dnode_next_offset() flags.
   */
  #define DNODE_FIND_HOLE         1
*** 391,400 ****
--- 392,402 ----
  int dnode_hold_impl(struct objset *dd, uint64_t object, int flag, int dn_slots,
      void *ref, dnode_t **dnp);
  boolean_t dnode_add_ref(dnode_t *dn, void *ref);
  void dnode_rele(dnode_t *dn, void *ref);
  void dnode_rele_and_unlock(dnode_t *dn, void *tag, boolean_t evicting);
+ int dnode_try_claim(objset_t *os, uint64_t object, int slots);
  void dnode_setdirty(dnode_t *dn, dmu_tx_t *tx);
  void dnode_sync(dnode_t *dn, dmu_tx_t *tx);
  void dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs,
      dmu_object_type_t bonustype, int bonuslen, int dn_slots, dmu_tx_t *tx);
  void dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize,
*** 509,523 ****
           * Number of times dnode_hold(..., DNODE_MUST_BE_FREE) requested
           * a range of dnode slots which would overflow the dnode_phys_t.
           */
          kstat_named_t dnode_hold_free_overflow;
          /*
-          * Number of times a dnode_hold(...) was attempted on a dnode
-          * which had already been unlinked in an earlier txg.
-          */
-         kstat_named_t dnode_hold_free_txg;
-         /*
           * Number of times dnode_free_interior_slots() needed to retry
           * acquiring a slot zrl lock due to contention.
           */
          kstat_named_t dnode_free_interior_lock_retry;
          /*
--- 511,520 ----