This error while downloading datasets: ValueError: I/O operation on closed file

I tried your exact code and it works fine on my computer. The failure could be due to several reasons, like a unstable internet connection or not enough free space in your home folder.

What you can do is to download the file manually using a download manager, put it in ~/.keras/datasets and rename it to cifar-10-batches-py.tar.gz and run the code again, it should pick up the file and continue processing from there.