Userspace eBPF for Userspace File System

[tdaudi]

GSoC related idea https://eunomia.dev/others/ideas/#userspace-ebpf-for-userspace-file-system

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Hello !

I've been exploring GSoC ideas and found this particular one extremely interesting.

However, I could not find any references in the code to how Bpftime utilizes the VFS, thus I couldn't identify any scenarios where libfuse or ExtFuse would be useful for Bpftime.

So I have some questions about this :

• How VFS is currently used by bpftime ?
• ExtFuse store data in maps with 2 << 16 size. It can be changed, but the memory usage could dramatically increase depending on the scenario. Could it be worth it ? I believe it will require sudo permissions for any cases because it's hooking VFS which is I believe not something desirable (i guess).
• The expectation for this idea in the GSoC is a PoC of an implementation of fuse/ExtFuse. Do you have recommendations for use cases that could make the difference using this tool instead of VFS ?

Thanks 🤓