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, 91 insertions, 0 deletions

diff --git a/nsmux.c b/nsmux.c
index 9e5d28a4e..2eb539e07 100644
--- a/nsmux.c
+++ b/nsmux.c
@@ -34,6 +34,7 @@
 #include <hurd/netfs.h>
 #include <fcntl.h>
 #include <hurd/paths.h>
+#include <hurd/fsys.h>
 /*---------------------------------------------------------------------------*/
 #include "debug.h"
 #include "options.h"
@@ -1640,6 +1641,96 @@ kern_return_t
 }				/*netfs_S_file_get_translator_cntl */
 
 /*---------------------------------------------------------------------------*/
+/* Shutdown the filesystem; flags are as for fsys_goaway. */
+error_t
+netfs_shutdown (int flags)
+{
+  error_t
+  helper (struct node *node)
+    {
+      error_t err;
+      mach_port_t control;
+
+      err = fshelp_fetch_control (&node->transbox, &control);
+      if (!err && (control != MACH_PORT_NULL))
+        {
+          mutex_unlock (&node->lock);
+          err = fsys_goaway (control, flags);
+          mach_port_deallocate (mach_task_self (), control);
+          mutex_lock (&node->lock);
+        }
+      else
+        err = 0;
+
+      if ((err == MIG_SERVER_DIED) || (err == MACH_SEND_INVALID_DEST))
+        err = 0;
+
+      return err;
+    }
+
+  int nports;
+  int err;
+
+  if ((flags & FSYS_GOAWAY_UNLINK)
+      && S_ISDIR (netfs_root_node->nn_stat.st_mode))
+    return EBUSY;
+
+  if (flags & FSYS_GOAWAY_NOWAIT)
+    LOG_MSG("NOWAIT");
+  LOG_MSG("WAIT");
+
+  if (flags & FSYS_GOAWAY_RECURSE)
+    {
+      /*nsmux has been requested shut down recursively. Shut down all
+	dynamic translators. Statically set translators will not be
+	shut down, because libnetfs does not (yet?) do this itself, as
+	different from libdiskfs. */
+      err = trans_shutdown_all (flags);
+
+#ifdef NOTYET
+      err = netfs_node_iterate (helper);
+#endif
+      if (err)
+	return err;
+    }
+
+#ifdef NOTYET
+  rwlock_writer_lock (&netfs_fsys_lock);
+#endif
+
+  /* Permit all current RPC's to finish, and then suspend any new ones.  */
+  err = ports_inhibit_class_rpcs (netfs_protid_class);
+  if (err)
+    {
+#ifdef  NOTYET
+      rwlock_writer_unlock (&netfs_fsys_lock);
+#endif
+      return err;
+    }
+
+  nports = ports_count_class (netfs_protid_class);
+  if (((flags & FSYS_GOAWAY_FORCE) == 0) && nports)
+    /* There are outstanding user ports; resume operations. */
+    {
+      ports_enable_class (netfs_protid_class);
+      ports_resume_class_rpcs (netfs_protid_class);
+#ifdef NOTYET
+      rwlock_writer_unlock (&netfs_fsys_lock);
+#endif
+      return EBUSY;
+    }
+
+  if (!(flags & FSYS_GOAWAY_NOSYNC))
+    {
+      err = netfs_attempt_syncfs (0, flags);
+      if (err)
+        return err;
+    }
+
+  return 0;
+}				/*netfs_shutdown */
+
+/*---------------------------------------------------------------------------*/
 /*Entry point*/
 int main (int argc, char **argv)
 {