Method prepare_command

src/mon/MDSMonitor.cc:1479–1562

}

bool MDSMonitor::prepare_command(MonOpRequestRef op)
{
  op->mark_mdsmon_event(__func__);
  auto m = op->get_req<MMonCommand>();
  int r = -EINVAL;
  stringstream ss;
  bufferlist rdata;

  cmdmap_t cmdmap;
  if (!cmdmap_from_json(m->cmd, &cmdmap, ss)) {
    string rs = ss.str();
    mon.reply_command(op, -EINVAL, rs, rdata, get_last_committed());
    return false;
  }

  string prefix;
  cmd_getval(cmdmap, "prefix", prefix);

  /* Refuse access if message not associated with a valid session */
  MonSession *session = op->get_session();
  if (!session) {
    mon.reply_command(op, -EACCES, "access denied", rdata, get_last_committed());
    return false;
  }

  auto &pending = get_pending_fsmap_writeable();

  for (const auto &h : handlers) {
    r = h->can_handle(prefix, op, pending, cmdmap, ss);
    if (r == 1) {
      ; // pass, since we got the right handler.
    } else if (r == 0) {
      continue;
    } else {
      goto out;
    }

    r = h->handle(&mon, pending, op, cmdmap, ss);

    if (r == -EAGAIN) {
      // message has been enqueued for retry; return.
      dout(4) << __func__ << " enqueue for retry by prepare_command" << dendl;
      return false;
    } else {
      if (r == 0) {
	// On successful updates, print the updated map
	print_map(pending);
      }
      // Successful or not, we're done: respond.
      goto out;
    }
  }

  r = filesystem_command(pending, op, prefix, cmdmap, ss);
  if (r >= 0) {
    goto out;
  } else if (r == -EAGAIN) {
    // Do not reply, the message has been enqueued for retry