Method _read

src/client/Client.cc:11557–11770

}

int64_t Client::_read(Fh *f, int64_t offset, uint64_t size, bufferlist *bl,
                      Context *onfinish, bool read_for_write)
{
  ceph_assert(ceph_mutex_is_locked_by_me(client_lock));

  ldout(cct, 10) << __func__ << " " << f->inode.get() << " " << offset << "~"
                 << size << dendl;

  if ((f->mode & CEPH_FILE_MODE_RD) == 0 && !read_for_write)
    return -EBADF;

  // zero bytes read is not supported by osd
  if (size == 0) {
    if (onfinish) {
      onfinish->complete(0);
    }
    return 0;
  }

  int want, have = 0;
  bool movepos = false;
  std::unique_ptr<Context> iofinish = nullptr;
  std::unique_ptr<C_Read_Finisher> crf = nullptr;
  int64_t rc = 0;
  const auto& conf = cct->_conf;
  Inode *in = f->inode.get();
  utime_t lat;
  utime_t start = mono_clock_now();
  CRF_iofinish *crf_iofinish = nullptr;

  //bool lazy = f->mode == CEPH_FILE_MODE_LAZY;

  if (offset < 0) {
    lock_fh_pos(f);
    offset = f->pos;
    movepos = true;
  }
  loff_t start_pos = offset;

  if (in->inline_version == 0) {
    auto r = _getattr(in, CEPH_STAT_CAP_INLINE_DATA, f->actor_perms, true);
    if (r < 0) {
      rc = r;
      goto done;
    }
    ceph_assert(in->inline_version > 0);
  }

retry:
  if (f->mode & CEPH_FILE_MODE_LAZY)
    want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
  else
    want = CEPH_CAP_FILE_CACHE;
  {
    auto r = get_caps(f, CEPH_CAP_FILE_RD, want, &have, -1);
    if (r < 0) {
      rc = r;
      goto done;