And for added context from previous thread - the change to make `O_NONBLOCK` behave differently on 9pfs in the kernel was a deliberate change.
As a result, I personally am not inclined to go upstream to ask them to fix it. If the decision for wine is that this is a WONTFIX (which I'd understand) then I'm offering to fix docs/wiki to indicate 9pfs isn't currently supported (if pointed at roughly the pieces that need changing).