VOLUME_CACHE_QUEUED_FLAG
if ((cache->index[physical_page] & VOLUME_CACHE_QUEUED_FLAG) == 0) {
read_queue_index | VOLUME_CACHE_QUEUED_FLAG);
read_queue_index = cache->index[physical_page] & ~VOLUME_CACHE_QUEUED_FLAG;
queued = (index_value & VOLUME_CACHE_QUEUED_FLAG) != 0;
queued = (index_value & VOLUME_CACHE_QUEUED_FLAG) != 0;
index = index_value & ~VOLUME_CACHE_QUEUED_FLAG;