00000004 D _unix_io_manager     libext2fs       unix_io
00000004 D _test_io_manager     libext2fs       test_io
00000004 D _test_io_backing_manager libext2fs   test_io
00000004 D _test_io_cb_read_blk libext2fs       test_io
00000004 D _test_io_cb_write_blk libext2fs      test_io
00000004 D _test_io_cb_set_blksize libext2fs    test_io