Method mds_command

src/client/Client.cc:6748–6845

* * @mds_spec one of ID, rank, GID, "*" * */

 *
 */
int Client::mds_command(
    const std::string &mds_spec,
    const vector<string>& cmd,
    const bufferlist& inbl,
    bufferlist *outbl,
    string *outs,
    Context *onfinish,
    bool one_shot)
{
  RWRef_t iref_reader(initialize_state, CLIENT_INITIALIZED);
  if (!iref_reader.is_state_satisfied())
    return -ENOTCONN;

  std::unique_lock cl(client_lock);

  int r;
  r = authenticate();
  if (r < 0) {
    return r;
  }

  r = fetch_fsmap(false);
  if (r < 0) {
    return r;
  }

  // Look up MDS target(s) of the command
  std::vector<mds_gid_t> targets;
  r = resolve_mds(mds_spec, &targets);
  if (r < 0) {
    return r;
  }

  // If daemons are laggy, we won't send them commands.  If all
  // are laggy then we fail.
  std::vector<mds_gid_t> non_laggy;
  for (const auto& gid : targets) {
    const auto info = fsmap->get_info_gid(gid);
    if (!info.laggy()) {
      non_laggy.push_back(gid);
    }
  }
  if (non_laggy.size() == 0) {
    *outs = "All targeted MDS daemons are laggy";
    return -ENOENT;
  }

  if (metadata.empty()) {
    // We are called on an unmounted client, so metadata
    // won't be initialized yet.
    populate_metadata("");
  }

  ceph_tid_t multi_target_id = 0;
  if (non_laggy.size() > 1) {
      std::scoped_lock cmd_lock(command_lock);
      multi_target_id = command_table.get_new_multi_target_id();
  }