void unmapBuffersForOwner(PagedFileStorage fileStorage) {
    Map<Long, DirectBufferWrapper> buffers = getBuffersForOwner(fileStorage);

    pagesAllocationLock.lock();
    try {
      if (!buffers.isEmpty()) {
        pagesAccessLock.lock();
        try {
          for (Long key : buffers.keySet()) {
            pagesByPageId.remove(key);
          }
        }
        finally {
          pagesAccessLock.unlock();
        }
      }

      disposeRemovedSegments(fileStorage);
    }
    finally {
      pagesAllocationLock.unlock();
    }
  }
void unmapBuffersForOwner(PagedFileStorage fileStorage)