Method read_modify_write

src/client/Client.cc:12445–12539

}

int Client::WriteEncMgr::read_modify_write(Context *_iofinish)
{
  get();
  iofinish = new LambdaContext([this, _iofinish](int r) {
    this->put();
    if(_iofinish) {
      _iofinish->complete(r);
    }
  });

#if defined(__linux__)
  if (!denc)
    return do_write();
#else
    return do_write();
#endif

#if defined(__linux__)
  ceph_assert(ceph_mutex_is_locked_by_me(clnt->client_lock));

  int r = 0;

  start_block = fscrypt_block_from_ofs(offset);
  start_block_ofs = fscrypt_block_start(offset);
  ofs_in_start_block = fscrypt_ofs_in_block(offset);
  end_block = fscrypt_block_from_ofs(endoff - 1);
  end_block_ofs = fscrypt_block_start(endoff - 1);
  ofs_in_end_block = fscrypt_ofs_in_block(endoff - 1);

  need_read_start = ofs_in_start_block > 0 || (ofs_in_start_block == 0 && ((endoff - offset) < FSCRYPT_BLOCK_SIZE));
  need_read_end = (endoff <= in->effective_size() && ofs_in_end_block < FSCRYPT_BLOCK_SIZE && start_block != end_block);
  read_start_size = FSCRYPT_BLOCK_SIZE;

  bool need_read = need_read_start | need_read_end;


  if (need_read_start) {
    finish_read_start_ctx.reset(new iofinish_method_ctx<WriteEncMgr>(*this, &WriteEncMgr::finish_read_start_cb, &aioc));

    r = read(start_block_ofs, read_start_size, &startbl, finish_read_start_ctx.get());
    if (r < 0) {
      finish_read_start_ctx.reset();

      ldout(cct, 0) << "failed to read first block: r=" << r << dendl;
      goto done;
    }
  }

  if (need_read_end) {
    finish_read_end_ctx.reset(new iofinish_method_ctx<WriteEncMgr>(*this, &WriteEncMgr::finish_read_end_cb, &aioc));

    r = read(end_block_ofs, FSCRYPT_BLOCK_SIZE, &endbl, finish_read_end_ctx.get());
    if (r < 0) {
      finish_read_end_ctx.reset();

      ldout(cct, 0) << "failed to read end block: r=" << r << dendl;
      goto done;
    }