Prepared struct node for stacks of shadow nodes

So far dynamic translator stacks were created in the following
fashion: nsmux created a shadow node on which the whole
dynamic translator stack was built. This commit starts the
transition to a different strategy: the new approach consists
in setting *each* dynamic translator on its personal shadow
node. To achieve such functionality the set of fiels of struct
node was modified and the bits of code that manipulated these
fields were stripped out. The code is not functional now. The
coming commits will bring it back to life.

4 files changed, 26 insertions, 134 deletions

diff --git a/lib.c b/lib.c
index e8cb3a0d9..17de80318 100644
--- a/lib.c
+++ b/lib.c
@@ -1,5 +1,5 @@
 /*---------------------------------------------------------------------------*/
-/*lib.h*/
+/*lib.c*/
 /*---------------------------------------------------------------------------*/
 /*Basic routines for filesystem manipulations*/
 /*---------------------------------------------------------------------------*/
diff --git a/node.c b/node.c
index f98966a45..7df0afc17 100644
--- a/node.c
+++ b/node.c
@@ -94,9 +94,10 @@ error_t node_create (lnode_t * lnode, node_t ** node)
       node_new->nn->flags = 0;
       node_new->nn->ncache_next = node_new->nn->ncache_prev = NULL;
 
-      /*initialize the list of translators */
-      node_new->nn->trans = NULL;
-      node_new->nn->ntrans = node_new->nn->translen = 0;
+      /*initialize the data fields dealing with positioning this node
+	in the dynamic translator stack */
+      node_new->nn->trans_cntl = MACH_PORT_NULL;
+      node_new->nn->below = NULL;
 
       /*store the result of creation in the second parameter */
       *node = node_new;
@@ -148,9 +149,10 @@ error_t node_create_proxy (lnode_t * lnode, node_t ** node)
       node_new->nn->flags = 0;
       node_new->nn->ncache_next = node_new->nn->ncache_prev = NULL;
 
-      /*initialize the list of translators */
-      node_new->nn->trans = NULL;
-      node_new->nn->ntrans = node_new->nn->translen = 0;
+      /*initialize the data fields dealing with positioning this node
+	in the dynamic translator stack */
+      node_new->nn->trans_cntl = MACH_PORT_NULL;
+      node_new->nn->below = NULL;
 
       /*store the result of creation in the second parameter */
       *node = node_new;
@@ -172,12 +174,8 @@ void node_destroy (node_t * np)
   if (np->nn->port != MACH_PORT_NULL)
     PORT_DEALLOC (np->nn->port);
 
-  /*If there are translators to kill */
-  if (np->nn->lnode->dir && np->nn->trans)
-    {
-      /*kill all translators on the underlying nodes */
-      node_kill_translators (np);
-    }
+  /*TODO: If this node is a shadow node, kill the translator sitting
+    on this node. */
 
   /*Lock the lnode corresponding to the current node */
   mutex_lock (&np->nn->lnode->lock);
@@ -665,6 +663,7 @@ error_t node_set_translators (struct protid * diruser, node_t * np,
 			      size_t ntrans, int flags, char * filename,
 			      mach_port_t * port)
 {
+#if 0
   error_t err;
   mach_port_t p;
 
@@ -760,11 +759,6 @@ error_t node_set_translators (struct protid * diruser, node_t * np,
 	if(!np->nn->port)
 	  return ENOENT;
 
-	np->nn->port_notrans = file_name_lookup_under
-	  (diruser->po->np->nn->port, filename, flags | O_NOTRANS, 0);
-	if(!np->nn->port)
-	  return ENOENT;
-
 	/*duplicate the supplied user */
 	err = iohelp_dup_iouser (&user, diruser->user);
 	if (err)
@@ -897,40 +891,10 @@ error_t node_set_translators (struct protid * diruser, node_t * np,
   /*Return the port */
   *port = p;
 
+#endif
+
   /*Everything is OK here */
   return 0;
 }				/*node_set_translators */
 
 /*---------------------------------------------------------------------------*/
-/*Kills all translators on the nodes belonging to the given directory*/
-void node_kill_translators (node_t * node)
-{
-  /*If the node has no translators */
-  if (node->nn->trans == NULL)
-    /*nothing to do */
-    return;
-
-  error_t err = 0;
-
-  /*The current element in the port list */
-  port_el_t *p_el;
-
-  /*While the list of control ports is not empty */
-  for (p_el = node->nn->cntl_ports; p_el; p_el = node->nn->cntl_ports)
-    {
-      /*kill the current translator */
-      err = fsys_goaway (p_el->p, 0);
-
-      /*If the translator says it is busy, force it to go away */
-      if (err == EBUSY)
-	err = fsys_goaway (p_el->p, FSYS_GOAWAY_FORCE);
-
-      /*move the beginning of the list of control ports forward */
-      node->nn->cntl_ports = p_el->next;
-
-      /*destroy the current cell in the list of ports */
-      free (p_el);
-    }
-}				/*node_kill_translators */
-
-/*---------------------------------------------------------------------------*/
diff --git a/node.h b/node.h
index 0f7201083..062c4e827 100644
--- a/node.h
+++ b/node.h
@@ -78,22 +78,13 @@ struct netnode
   /*a port to the underlying filesystem */
   file_t port;
 
-  /*the port to the untranslated version of the node */
-  file_t port_notrans;
+  /*the control port of the translator sitting on this node, in case
+    this node is a shadow node */
+  fsys_t trans_cntl;
 
-  /*the malloced set of translators which have to be stacked upon this node
-     and upon its children; the corresponding translators will have to decide
-     on their own whether to accept directories or not */
-  char *trans;
-
-  /*the number of translators listed in `translators` */
-  size_t ntrans;
-
-  /*the length of the list of translators (in bytes) */
-  size_t translen;
-
-  /*the list of control ports to the translators being set on this node */
-  port_el_t *cntl_ports;
+  /*the reference to the shadow node that is below the current shadow
+    node in the dynamic translator stack */
+  node_t * below;
 
   /*the neighbouring entries in the cache */
   node_t *ncache_prev, *ncache_next;
@@ -161,14 +152,4 @@ error_t node_set_translators (struct protid *diruser, node_t * np,
 			      size_t ntrans, int flags, char * filename,
 			      mach_port_t * port);
 /*---------------------------------------------------------------------------*/
-/*Kill the topmost translator for this node*/
-/*This function will normally be called from netfs_attempt_lookup,
-  therefore it's better that the caller should provide the parent node
-  for `node`.*/
-error_t node_kill_translator (node_t * dir, node_t * node);
-/*---------------------------------------------------------------------------*/
-/*Kills all translators on the current node or on all underlying nodes
-  it the current node is a directory*/
-void node_kill_translators (node_t * node);
-/*---------------------------------------------------------------------------*/
 #endif /*__NODE_H__*/
diff --git a/nsmux.c b/nsmux.c
index 459e03a1e..8017781d9 100644
--- a/nsmux.c
+++ b/nsmux.c
@@ -551,9 +551,6 @@ error_t
   /*The port to the requested file */
   mach_port_t p;
 
-  /*The port to the untranslated version of the requested file */
-  mach_port_t p_notrans;
-
   /*The lnode corresponding to the entry we are supposed to fetch */
   lnode_t *lnode;
 
@@ -591,8 +588,6 @@ error_t
 	/*If there is some port, free it */
 	if (p != MACH_PORT_NULL)
 	  PORT_DEALLOC (p);
-	if (p_notrans != MACH_PORT_NULL)
-	  PORT_DEALLOC (p_notrans);
       }
     /*If there is a node to return */
     if (*node)
@@ -645,19 +640,13 @@ error_t
 	    if (p == MACH_PORT_NULL)
 	      return EBADF;
 
-	    /*obtain the untranslated version of the file, too (for filters) */
-	    p_notrans = file_name_lookup_under
-	      (dir->nn->port, name, O_NOTRANS, 0);
-	    if (p_notrans == MACH_PORT_NULL)
-	      return EBADF;
-
 	    /*If a proxy node is not required */
 	    if (!proxy)
 	      /*stop here, we want only the port to the file */
 	      return 0;
 	  }
 	else
-	    p = p_notrans = MACH_PORT_NULL;
+	    p = MACH_PORT_NULL;
       }
     else
       {
@@ -667,18 +656,12 @@ error_t
 	      (dir->nn->port, name, flags | O_READ | O_DIRECTORY, 0);
 	    if (p == MACH_PORT_NULL)
 	      return EBADF;		/*not enough rights? */
-
-	    /*obtain the untranslated version of the file, too (for filters) */
-	    p_notrans = file_name_lookup_under
-	      (dir->nn->port, name, O_NOTRANS, 0);
-	    if (p_notrans == MACH_PORT_NULL)
-	      return EBADF;
 	  }
 	else
 	  /*If we are at the last component of the path and need to
 	    open a directory, do not do the lookup; the translator
 	    starting procedure will do that.*/
-	  p = p_notrans = MACH_PORT_NULL;
+	  p =MACH_PORT_NULL;
 
 	/*we have a directory here */
 	isdir = 1;
@@ -726,9 +709,8 @@ error_t
 	return err;
       }
 
-    /*Store the ports in the node */
+    /*Store the port in the node */
     (*node)->nn->port = p;
-    (*node)->nn->port_notrans = p_notrans;
 
     /*Fill in the flag about the node being a directory */
     if (isdir)
@@ -866,12 +848,6 @@ error_t
       ++ntrans;
       ++translen;
 
-      /*copy the list of translators we have just built in the new
-	proxy node */
-      (*node)->nn->trans = trans;
-      (*node)->nn->ntrans = ntrans;
-      (*node)->nn->translen = translen;
-
       /*we don't own the list of translators any more */
       trans = NULL;
       ntrans = 0;
@@ -1047,21 +1023,8 @@ error_t
 		/*just return the port */
 		goto justport;
 
-	      /*If a proxy for setting up translators has just been created */
-	      if (np->nn->trans)
-		{
-		  /*set the list of translators on this node */
-		  node_set_translators
-		    (diruser, np, np->nn->trans, np->nn->ntrans, flags,
-		     filename, &file);
-
-		  /*lock the the node and add a new reference */
-		  mutex_lock (&np->lock);
-		  netfs_nref (np);
-
-		  /*return `file` as the resulting port */
-		  goto justport;
-		}
+	      /*If a shadow node has just been created, set the
+		required translator on it */
 	    }
 	}
 
@@ -1629,23 +1592,7 @@ kern_return_t
   /*If the node is not the root node of nsmux */
   if (np != netfs_root_node)
     {
-      /*the control port to the translator sitting on the real node */
-      mach_port_t p;
-
-      /*obtain the control port for the translator sitting on the real node;
-         provide the bottommost translator, so that the filter (and this is
-         most probably a request of such a translator) should be able to trace
-         the real translator stack */
-      err = file_get_translator_cntl (np->nn->port_notrans, &p);
-      if (err)
-	return err;
-
-      /*set the parameters accordingly */
-      *cntltype = MACH_MSG_TYPE_MOVE_SEND;
-      *cntl = p;
-
-      /*return the result of operations */
-      return err;
+      /*TODO: The functionality here will be provided later */
     }
 
   /*Lock the node */