when trying to use files added via a datapack fs any operation on those files will give a io error.

steps to reproduce:

1. make a datapack containing an fs. (mine contained binary of the ion shell cross-compiled to run on in the vm(size 5.5M))
2. load up the world containing the datapack, (no error will be thrown by mc)
3. try run something like ls on /mnt/builtin/{datapack}/
4. it will throw an I/O error