Arvados

From what I've been able to determine (documentation is limited) the way this works is that when a file open request happens, the FUSE daemon can say "this file is actually this other file over here" and return a file descriptor to the other file. Then the kernel essentially substitutes read/write operations on the FUSE file with operations on the real file.

https://github.com/libfuse/libfuse/pull/919

This doesn't really work for us except for situations where one block corresponds to one file.