patch first-pass

@@ -56,11 +56,12 @@
 static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
 static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx);
 
 #ifndef __lint
 extern inline void dmu_buf_init_user(dmu_buf_user_t *dbu,
-    dmu_buf_evict_func_t *evict_func, dmu_buf_t **clear_on_evict_dbufp);
+    dmu_buf_evict_func_t *evict_func_prep, dmu_buf_evict_func_t *evict_func,
+    dmu_buf_t **clear_on_evict_dbufp);
 #endif /* ! __lint */
 
 /*
  * Global data structures and functions for the dbuf cache.
  */

@@ -297,10 +298,13 @@
 #ifdef ZFS_DEBUG
         if (dbu->dbu_clear_on_evict_dbufp != NULL)
                 *dbu->dbu_clear_on_evict_dbufp = NULL;
 #endif
 
+        if (dbu->dbu_evict_func_prep != NULL)
+                dbu->dbu_evict_func_prep(dbu);
+
         /*
          * Invoke the callback from a taskq to avoid lock order reversals
          * and limit stack depth.
          */
         taskq_dispatch_ent(dbu_evict_taskq, dbu->dbu_evict_func, dbu, 0,