6267 dn_bonus evicted too early
Reviewed by: Richard Yao <ryao@gentoo.org>
Reviewed by: Xin LI <delphij@freebsd.org>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>

*** 422,431 ****
--- 422,432 ----
                          dbuf_clear(db);
  
                          db_next = AVL_NEXT(&dn->dn_dbufs, &db_marker);
                          avl_remove(&dn->dn_dbufs, &db_marker);
                  } else {
+                         db->db_pending_evict = TRUE;
                          mutex_exit(&db->db_mtx);
                          db_next = AVL_NEXT(&dn->dn_dbufs, db);
                  }
          }
          mutex_exit(&dn->dn_dbufs_mtx);
*** 435,449 ****
  
  void
  dnode_evict_bonus(dnode_t *dn)
  {
          rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
!         if (dn->dn_bonus && refcount_is_zero(&dn->dn_bonus->db_holds)) {
                  mutex_enter(&dn->dn_bonus->db_mtx);
                  dbuf_evict(dn->dn_bonus);
                  dn->dn_bonus = NULL;
          }
          rw_exit(&dn->dn_struct_rwlock);
  }
  
  static void
  dnode_undirty_dbufs(list_t *list)
--- 436,454 ----
  
  void
  dnode_evict_bonus(dnode_t *dn)
  {
          rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
!         if (dn->dn_bonus != NULL) {
!                 if (refcount_is_zero(&dn->dn_bonus->db_holds)) {
                          mutex_enter(&dn->dn_bonus->db_mtx);
                          dbuf_evict(dn->dn_bonus);
                          dn->dn_bonus = NULL;
+                 } else {
+                         dn->dn_bonus->db_pending_evict = TRUE;
                  }
+         }
          rw_exit(&dn->dn_struct_rwlock);
  }
  
  static void
  dnode_undirty_dbufs(list_t *list)
*** 490,500 ****
          ASSERT0(DN_USED_BYTES(dn->dn_phys));
          ASSERT(BP_IS_HOLE(dn->dn_phys->dn_blkptr));
  
          dnode_undirty_dbufs(&dn->dn_dirty_records[txgoff]);
          dnode_evict_dbufs(dn);
-         ASSERT(avl_is_empty(&dn->dn_dbufs));
  
          /*
           * XXX - It would be nice to assert this, but we may still
           * have residual holds from async evictions from the arc...
           *
--- 495,504 ----