def _bdev(dev=None):
 if (dev is None):
  dev = _fssys('cache0')
 else:
  dev = _bcpath(dev)
 if (not dev):
  return False
 else:
  return _devbase(os.path.realpath(os.path.join(dev, '../')))

def _bdev ( dev = None ) : if ( dev is None ) : dev = _fssys ( 'cache0' ) else : dev = _bcpath ( dev ) if ( not dev ) : return False else : return _devbase ( os . path . realpath ( os . path . join ( dev , '../' ) ) )
resolve a bcachex or cache to a real dev :return: basename of bcache dev .