static bool not_same_qid(const V9fsQID *qid1, const V9fsQID *qid2)
{
    return
        qid1->type != qid2->type ||
        qid1->version != qid2->version ||
        qid1->path != qid2->path;
}

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.