Method fetch_fsmap

src/client/Client.cc:6698–6741

}

int Client::fetch_fsmap(bool user)
{
  ceph_assert(ceph_mutex_is_locked_by_me(client_lock));

  // Retrieve FSMap to enable looking up daemon addresses.  We need FSMap
  // rather than MDSMap because no one MDSMap contains all the daemons, and
  // a `tell` can address any daemon.
  version_t fsmap_latest;
  bs::error_code ec;
  do {
    client_lock.unlock();
    std::tie(fsmap_latest, std::ignore) =
      monclient->get_version("fsmap", ca::use_blocked[ec]);
    client_lock.lock();
  } while (ec == bs::errc::resource_unavailable_try_again);

  if (ec) {
    lderr(cct) << "Failed to learn FSMap version: " << ec << dendl;
    return ceph::from_error_code(ec);
  }

  ldout(cct, 10) << __func__ << " learned FSMap version " << fsmap_latest << dendl;

  if (user) {
    if (!fsmap_user || fsmap_user->get_epoch() < fsmap_latest) {
      monclient->sub_want("fsmap.user", fsmap_latest, CEPH_SUBSCRIBE_ONETIME);
      monclient->renew_subs();
      wait_on_list(waiting_for_fsmap);
    }
    ceph_assert(fsmap_user);
    ceph_assert(fsmap_user->get_epoch() >= fsmap_latest);
  } else {
    if (!fsmap || fsmap->get_epoch() < fsmap_latest) {
      monclient->sub_want("fsmap", fsmap_latest, CEPH_SUBSCRIBE_ONETIME);
      monclient->renew_subs();
      wait_on_list(waiting_for_fsmap);
    }
    ceph_assert(fsmap);
    ceph_assert(fsmap->get_epoch() >= fsmap_latest);
  }
  ldout(cct, 10) << __func__ << " finished waiting for FSMap version "
		 << fsmap_latest << dendl;
  return 0;
}

/**
 *