Right but this fix was on the “qemu 9p server”.

On WSL you would be using the “hyperv 9p server”.

Same Linux 9p client in both cases but that’s not where the fix was.

Reasonable question but the answer is still no.

But when you access files on Windows from WSL2 (e.g., under /mnt/c), the same 9P protocol is being used

Same protocol, but the implementation is at the discretion of whoever writes the server code.

For example I went to check and in crosvm we use a BTreeMap already for Fids for our p9 implementation (thankfully): https://github.com/google/crosvm/blob/main/common/p9/src/ser...

Unless Microsoft is violating the GPL they aren't using the same code as QEMU for 9P.