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

*** 1128,1138 ****
                  sa_buf_rele(db, NULL);
                  ZFS_OBJ_HOLD_EXIT(zfsvfs, obj_num);
                  return (SET_ERROR(EINVAL));
          }
  
!         hdl = dmu_buf_get_user(db);
          if (hdl != NULL) {
                  zp  = sa_get_userdata(hdl);
  
  
                  /*
--- 1128,1138 ----
                  sa_buf_rele(db, NULL);
                  ZFS_OBJ_HOLD_EXIT(zfsvfs, obj_num);
                  return (SET_ERROR(EINVAL));
          }
  
!         hdl = (sa_handle_t *)dmu_buf_get_user(db);
          if (hdl != NULL) {
                  zp  = sa_get_userdata(hdl);
  
  
                  /*