Initially I thought to support the .L dialect, but now I'm not that sure. Tread on a directory is not that hard, and I personally like that more than the .L alternative of the Treaddir, it's ugly. Some .L stuff may be interesting to support, at least for symlinks, but at least for a first version I want to keep it simple and implement plain 9P2000.

Implement Topen plus some basic testing. ORCLOSE (remove file when the fid is clunked) is mapped to O_CLOEXEC and tried to be honoured on fid_free. "vanilla" 9P2000 uses reads on directories to list the entries while 9P2000.L (and .U too possibly) introduces an explicit Treaddir. I'm planning to support 9P2000-style read-on-dir but not yet.