_fstrans_start
static inline int _fstrans_start(struct mount *, enum fstrans_lock_type, int);
error = _fstrans_start(mp, FSTRANS_SHARED, 1);
return _fstrans_start(mp, FSTRANS_SHARED, 0);
error = _fstrans_start(mp, FSTRANS_LAZY, 1);