3752 want more verifiable dbuf user eviction
Submitted by:   Justin Gibbs <justing@spectralogic.com>
Submitted by:   Will Andrews <willa@spectralogic.com>

*** 125,134 ****
--- 125,139 ----
           */
  
          uint16_t l_hash[1];
  } zap_leaf_phys_t;
  
+ typedef struct zap_leaf_dbuf {
+         uint8_t zldb_pad[offsetof(dmu_buf_t, db_data)];
+         zap_leaf_phys_t *zldb_data;
+ } zap_leaf_dbuf_t;
+ 
  typedef union zap_leaf_chunk {
          struct zap_leaf_entry {
                  uint8_t le_type;                /* always ZAP_CHUNK_ENTRY */
                  uint8_t le_value_intlen;        /* size of value's ints */
                  uint16_t le_next;               /* next entry in hash chain */
*** 150,166 ****
                  uint16_t lf_next;       /* next in free list, or CHAIN_END */
          } l_free;
  } zap_leaf_chunk_t;
  
  typedef struct zap_leaf {
          krwlock_t l_rwlock;
          uint64_t l_blkid;               /* 1<<ZAP_BLOCK_SHIFT byte block off */
          int l_bs;                       /* block size shift */
!         dmu_buf_t *l_dbuf;
!         zap_leaf_phys_t *l_phys;
  } zap_leaf_t;
  
  
  typedef struct zap_entry_handle {
          /* below is set by zap_leaf.c and is public to zap.c */
          uint64_t zeh_num_integers;
          uint64_t zeh_hash;
--- 155,176 ----
                  uint16_t lf_next;       /* next in free list, or CHAIN_END */
          } l_free;
  } zap_leaf_chunk_t;
  
  typedef struct zap_leaf {
+         dmu_buf_user_t db_evict;
          krwlock_t l_rwlock;
          uint64_t l_blkid;               /* 1<<ZAP_BLOCK_SHIFT byte block off */
          int l_bs;                       /* block size shift */
!         union {
!                 dmu_buf_t *l_dmu_db;
!                 zap_leaf_dbuf_t *l_db;
!         } zl_db_u;
  } zap_leaf_t;
  
+ #define l_dbuf zl_db_u.l_dmu_db
+ #define l_phys zl_db_u.l_db->zldb_data
  
  typedef struct zap_entry_handle {
          /* below is set by zap_leaf.c and is public to zap.c */
          uint64_t zeh_num_integers;
          uint64_t zeh_hash;