lib9p: defer closing down srv until the last request has been responded, Tversion message size

in multithreaded programs, we have to wait until all outstanding
requests have been responded before closing down the srv.

dont make write errors sysfatal(), only print them. in case if
listensrv() is used we dont want to exit the process in respond()
called by some worker thread.

make sure Tversion is only handled when there are no outstanding
requests and make sure message size is sane.

1 files changed, 1 insertions, 0 deletions

diff --git a/sys/include/9p.h b/sys/include/9p.h
index a8fb1fdc1..27bec9b9a 100644
--- a/sys/include/9p.h
+++ b/sys/include/9p.h
@@ -234,6 +234,7 @@ struct Srv {
 
 	QLock	slock;
 	Ref	sref;
+	Ref	rref;
 };
 
 void		srv(Srv*);