Method scanOpenWrite

src/iocore/cache/CacheVC.cc:907–994

}

int
CacheVC::scanOpenWrite(int /* event ATS_UNUSED */, Event * /* e ATS_UNUSED */)
{
  Dbg(dbg_ctl_cache_scan_truss, "inside %p:scanOpenWrite", this);
  cancel_trigger();
  // get volume lock
  if (writer_lock_retry > SCAN_WRITER_LOCK_MAX_RETRY) {
    int r = _action.continuation->handleEvent(CACHE_EVENT_SCAN_OPERATION_BLOCKED, nullptr);
    Dbg(dbg_ctl_cache_scan, "still haven't got the writer lock, asking user..");
    switch (r) {
    case CACHE_SCAN_RESULT_RETRY:
      writer_lock_retry = 0;
      break;
    case CACHE_SCAN_RESULT_CONTINUE:
      SET_HANDLER(&CacheVC::scanObject);
      return scanObject(EVENT_IMMEDIATE, nullptr);
    }
  }
  int ret = 0;
  {
    CACHE_TRY_LOCK(lock, stripe->mutex, mutex->thread_holding);
    if (!lock.is_locked()) {
      Dbg(dbg_ctl_cache_scan, "stripe->mutex %p:scanOpenWrite", this);
      VC_SCHED_LOCK_RETRY();
    }

    Dbg(dbg_ctl_cache_scan, "trying for writer lock");
    if (stripe->open_write(this, false, 1)) {
      writer_lock_retry++;
      SET_HANDLER(&CacheVC::scanOpenWrite);
      mutex->thread_holding->schedule_in_local(this, scan_msec_delay);
      return EVENT_CONT;
    }

    ink_assert(this->od);
    // put all the alternates in the open directory vector
    int alt_count = vector.count();
    for (int i = 0; i < alt_count; i++) {
      write_vector->insert(vector.get(i));
    }
    od->writing_vec = true;
    vector.clear(false);
    // check that the directory entry was not overwritten
    // if so return failure
    Dbg(dbg_ctl_cache_scan, "got writer lock");
    Dir *l = nullptr;
    Dir  d;
    Doc *doc = reinterpret_cast<Doc *>(buf->data() + offset);
    offset   = reinterpret_cast<char *>(doc) - buf->data() + stripe->round_to_approx_size(doc->len);
    // if the doc contains some data, then we need to create
    // a new directory entry for this fragment. Remember the
    // offset and the key in earliest_key
    dir_assign(&od->first_dir, &dir);
    if (doc->total_len) {
      dir_assign(&od->single_doc_dir, &dir);
      dir_set_tag(&od->single_doc_dir, doc->key.slice32(2));
      od->single_doc_key    = doc->key;
      od->move_resident_alt = true;