Re: [PATCH 4/4] Give the mountee the port to the real underlying node in transparent mode.

[Sergiu Ivanov]

>From 48b2e49b18023ffc7b137350dfc61505417b048b Mon Sep 17 00:00:00 2001
From: Sergiu Ivanov <unlimitedscolobb@gmail.com>
Date: Mon, 3 Aug 2009 21:02:05 +0000
Subject: [PATCH 4/4] Give the mountee the port to the real underlying node in 
transparent mode.

* mount.c (start_mountee): Provide the mountee with the port to
the real underlying node if the unionmount is transparent.
(setup_unionmount): Don't use any nodes in starting the mountee
in transparent mode.
---

Hello,

Since we no longer bother to clone the root node after orphaning, this
patch has been modified to reflect the direct usage of the real root
node.

Regards,
scolobb

---
 mount.c |   25 ++++++++++++++++++++-----
 mount.h |    4 ++--
 2 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/mount.c b/mount.c
index e66604e..29cacc8 100644
--- a/mount.c
+++ b/mount.c
@@ -29,6 +29,7 @@
 #include "mount.h"
 #include "lib.h"
 #include "ulfs.h"
+#include "unionfs.h"
 
 /* The command line for starting the mountee.  */
 char * mountee_argz;
@@ -51,8 +52,8 @@ int shutting_down = 0;
 mach_port_t mountee_notify_port;
 
 /* Starts the mountee (given by `argz` and `argz_len`), attaches it to
-   the node `np` and opens a port `port` to the mountee with
-   `flags`.  */
+   the node `np` if the unionmount is non-transparent and opens a port
+   `port` to the mountee with `flags`.  */
 error_t
 start_mountee (node_t * np, char * argz, size_t argz_len, int flags,
               mach_port_t * port)
@@ -97,6 +98,16 @@ start_mountee (node_t * np, char * argz, size_t argz_len, 
int flags,
   {
     err = 0;
 
+    /* If the unionmount is transparent, we only have to supply the
+       real underlying node to the mountee.  */
+    if (transparent_mount)
+      {
+       *underlying = underlying_node;
+       *underlying_type  = MACH_MSG_TYPE_COPY_SEND;
+
+       return 0;
+      }
+
     /* The protid which will contain the port to the node on which the
        mountee will be sitting.  */
     struct protid * newpi;
@@ -177,14 +188,18 @@ setup_unionmount (void)
 {
   error_t err = 0;
 
-  /* Set the mountee on the root node.
+  /* Set up the mountee.
      Note that the O_READ flag does not actually limit access to the
      mountee's filesystem considerably.  Whenever a client looks up a
      node which is not a directory, unionfs will give off a port to
      the node itself, withouth proxying it.  Proxying happens only for
      directory nodes.  */
-  err = start_mountee (netfs_root_node, mountee_argz, mountee_argz_len,
-                      O_READ, &mountee_root);
+  if (!transparent_mount)
+    err = start_mountee (netfs_root_node, mountee_argz, mountee_argz_len,
+                        O_READ, &mountee_root);
+  else
+    err = start_mountee (NULL, mountee_argz, mountee_argz_len,
+                        O_READ, &mountee_root);
   if (err)
     return err;
 
diff --git a/mount.h b/mount.h
index 3e2b8dc..f959c38 100644
--- a/mount.h
+++ b/mount.h
@@ -46,8 +46,8 @@ extern int transparent_mount;
 extern int shutting_down;
 
 /* Starts the mountee (given by `argz` and `argz_len`), attaches it to
-   the node `np` and opens a port `port` to the mountee with
-   `flags`.  */
+   the node `np` if the unionmount is non-transparent and opens a port
+   `port` to the mountee with `flags`.  */
 error_t
 start_mountee (node_t * np, char * argz, size_t argz_len, int flags,
               mach_port_t * port);
-- 
1.6.3.3