Method _readdir_r_cb

src/client/Client.cc:10026–10245

NB: this is used for both readdir and readdir_snapdiff results processing hence it should be request type agnostic

// hence it should be request type agnostic
//
int Client::_readdir_r_cb(int op,
  dir_result_t *d,
  add_dirent_cb_t cb,
  fill_readdir_args_cb_t fill_cb,
  void *p,
  unsigned want,
  unsigned flags,
  bool getref,
  bool bypass_cache)
{
  int caps = statx_to_mask(flags, want);
  int rstat_on_dir = cct->_conf->client_dirsize_rbytes ? CEPH_STAT_RSTAT : 0;

  RWRef_t mref_reader(mount_state, CLIENT_MOUNTING);
  if (!mref_reader.is_state_satisfied())
    return -ENOTCONN;

  std::unique_lock cl(client_lock);

  dir_result_t *dirp = static_cast<dir_result_t*>(d);

  ldout(cct, 10) << __func__ << " " << *dirp->inode << " offset " << hex << dirp->offset
		 << dec << " at_end=" << dirp->at_end()
		 << " hash_order=" << dirp->hash_order() << dendl;

  struct dirent de;
  struct ceph_statx stx;
  memset(&de, 0, sizeof(de));
  memset(&stx, 0, sizeof(stx));

  InodeRef& diri = dirp->inode;

  if (dirp->at_end())
    return 0;

  if (dirp->offset == 0) {
    ldout(cct, 15) << " including ." << dendl;
    ceph_assert(diri->dentries.size() < 2); // can't have multiple hard-links to a dir
    uint64_t next_off = 1;

    int r;
    r = _getattr(diri, caps | rstat_on_dir, dirp->perms);
    if (r < 0)
      return r;

    fill_statx(diri, caps, &stx);
    fill_dirent(&de, ".", S_IFDIR, stx.stx_ino, next_off);

    Inode *inode = NULL;
    if (getref) {
      inode = diri.get();
      _ll_get(inode);
    }

    cl.unlock();
    r = cb(p, &de, &stx, next_off, inode);
    cl.lock();
    if (r < 0)