re #13613 rb4516 Tunables needs volatile keyword

*** 2158,2171 ****
                  nfs_rw_exit(&svp->sv_lock);
          }
          return (svp);
  }
  
! static ushort_t nfs4_max_threads = 8;   /* max number of active async threads */
! uint_t nfs4_bsize = 32 * 1024;  /* client `block' size */
! static uint_t nfs4_async_clusters = 1;  /* # of reqs from each async queue */
! static uint_t nfs4_cots_timeo = NFS_COTS_TIMEO;
  
  /*
   * Remap the root filehandle for the given filesystem.
   *
   * results returned via the nfs4_error_t parameter.
--- 2158,2171 ----
                  nfs_rw_exit(&svp->sv_lock);
          }
          return (svp);
  }
  
! volatile ushort_t nfs4_max_threads = 8; /* max number of active async threads */
! volatile uint_t nfs4_bsize = 32 * 1024; /* client `block' size */
! volatile uint_t nfs4_async_clusters = 1; /* # of reqs from each async queue */
! volatile uint_t nfs4_cots_timeo = NFS_COTS_TIMEO;
  
  /*
   * Remap the root filehandle for the given filesystem.
   *
   * results returned via the nfs4_error_t parameter.