FDB_SYNC
((fdb->fd_state & FDB_ASYNC) || !(fdb->fd_state & FDB_SYNC))) ||
((fdb->fd_state & FDB_SYNC) || !(fdb->fd_state & FDB_ASYNC))));
fdb->fd_state |= b_flags & B_ASYNC ? FDB_ASYNC : FDB_SYNC;
fdb->fd_state & FDB_SYNC);