nsmux can shutdown all dynamic translators on exit

Now nsmux can shutdown all of its dynamic translators on exit, thus
doing sufficient cleanup. One can tell nsmux to shutdown dynamic
translators using the ``--recursive'' option to settrans. Note that
because fsys_goaway returns immediately as the RPC is processed, while
the receiver may still remain in memory, doing something like

  settrans -g --recursive foo

where nsmux is sitting on foo will almost always result in a ``Server
busy'' error message. The reason is that libnetfs counts how many open
ports to its nodes there are at shutdown and in most cases it does the
check *before* the dynamic translators manage to drop their
references. Therefore, the aforementioned command gracefully kills all
dynamic translators. Invoked the second time, this command will
shutdown nsmux, too. Immediate shutdown with killing dynamic
translators can be achieved via

  settrans -gf --recursive foo

1 files changed, 5 insertions, 3 deletions

diff --git a/node.h b/node.h
index 72adcbebb..d930a3b69 100644
--- a/node.h
+++ b/node.h
@@ -32,6 +32,7 @@
 #include <hurd/netfs.h>
 /*---------------------------------------------------------------------------*/
 #include "lnode.h"
+#include "trans.h"
 /*---------------------------------------------------------------------------*/
 
 /*---------------------------------------------------------------------------*/
@@ -74,9 +75,10 @@ struct netnode
   /*a port to the underlying filesystem */
   file_t port;
 
-  /*the control port of the translator sitting on this node, in case
-    this node is a shadow node */
-  fsys_t trans_cntl;
+  /*a reference to the element in the list of dynamic translators
+    corresponding to the translator sitting on this node, in case this
+    node is a shadow node */
+  struct trans_el * dyntrans;
 
   /*the reference to the shadow node that is below the current shadow
     node in the dynamic translator stack */