[PATCH] Use refcount_t for peropen reference counting in libnetfs.

[Flavio Cruz]

* libnetfs/netfs.h: Use refcount_t.
* libnetfs/make-peropen.c: Initialize to 1 with refcount_init just like in 
libdiskfs.
* libnetfs/make-protid.c: Don't increment the count here. Do it like libdiskfs.
* libnetfs/io-duplicate.c: Add refcount_ref since netfs_make_protid no longer 
increments the refcount.
* libnetfs/io-reauthenticate.c: Likewise.
* libnetfs/io-restrict-auth.c: Likewise.
* libnetfs/release-peropen.c: Dereference without locking.
---
 libnetfs/io-duplicate.c      |  1 +
 libnetfs/io-reauthenticate.c |  2 ++
 libnetfs/io-restrict-auth.c  |  2 ++
 libnetfs/make-peropen.c      |  2 +-
 libnetfs/make-protid.c       |  1 -
 libnetfs/netfs.h             |  2 +-
 libnetfs/release-peropen.c   | 38 ++++++++++++++++++--------------------
 7 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/libnetfs/io-duplicate.c b/libnetfs/io-duplicate.c
index b2c3a3a..263f9e8 100644
--- a/libnetfs/io-duplicate.c
+++ b/libnetfs/io-duplicate.c
@@ -34,6 +34,7 @@ netfs_S_io_duplicate (struct protid *user,
   if (err)
     return err;
   
+  refcount_ref (&user->po->refcnt);
   pthread_mutex_lock (&user->po->np->lock);
   newpi = netfs_make_protid (user->po, clone);
   *newport = ports_get_right (newpi);
diff --git a/libnetfs/io-reauthenticate.c b/libnetfs/io-reauthenticate.c
index 8ff4182..b2d4a44 100644
--- a/libnetfs/io-reauthenticate.c
+++ b/libnetfs/io-reauthenticate.c
@@ -34,12 +34,14 @@ netfs_S_io_reauthenticate (struct protid *user, mach_port_t 
rend_port)
   /* This routine must carefully ignore EINTR because we
      are a simpleroutine, so callers won't know to restart. */
 
+  refcount_ref (&user->po->refcnt);
   pthread_mutex_lock (&user->po->np->lock);
   do
     newpi = netfs_make_protid (user->po, 0);
   while (! newpi && errno == EINTR);
   if (! newpi)
     {
+      refcount_deref (&user->po->refcnt);
       pthread_mutex_unlock (&user->po->np->lock);
       return errno;
     }
diff --git a/libnetfs/io-restrict-auth.c b/libnetfs/io-restrict-auth.c
index 0c3403d..79b7d09 100644
--- a/libnetfs/io-restrict-auth.c
+++ b/libnetfs/io-restrict-auth.c
@@ -43,6 +43,7 @@ netfs_S_io_restrict_auth (struct protid *user,
     return err;
 
   pthread_mutex_lock (&user->po->np->lock);
+  refcount_ref (&user->po->refcnt);
   newpi = netfs_make_protid (user->po, new_user);
   if (newpi)
     {
@@ -52,6 +53,7 @@ netfs_S_io_restrict_auth (struct protid *user,
     }
   else
     {
+      refcount_deref (&user->po->refcnt);
       pthread_mutex_unlock (&user->po->np->lock);
       iohelp_free_iouser (new_user);
       err = ENOMEM;
diff --git a/libnetfs/make-peropen.c b/libnetfs/make-peropen.c
index f7be58b..413e914 100644
--- a/libnetfs/make-peropen.c
+++ b/libnetfs/make-peropen.c
@@ -31,7 +31,7 @@ netfs_make_peropen (struct node *np, int flags, struct 
peropen *context)
 
   po->filepointer = 0;
   po->lock_status = LOCK_UN;
-  po->refcnt = 0;
+  refcount_init (&po->refcnt, 1);
   po->openstat = flags;
   po->np = np;
   po->path = NULL;
diff --git a/libnetfs/make-protid.c b/libnetfs/make-protid.c
index bf18283..995ac1e 100644
--- a/libnetfs/make-protid.c
+++ b/libnetfs/make-protid.c
@@ -36,7 +36,6 @@ netfs_make_protid (struct peropen *po, struct iouser *cred)
   if (errno)
     return 0;
 
-  po->refcnt++;
   pi->po = po;
   pi->user = cred;
   pi->shared_object = MACH_PORT_NULL;
diff --git a/libnetfs/netfs.h b/libnetfs/netfs.h
index fbe2c60..3f94ccd 100644
--- a/libnetfs/netfs.h
+++ b/libnetfs/netfs.h
@@ -51,7 +51,7 @@ struct peropen
 {
   loff_t filepointer;
   int lock_status;
-  int refcnt;
+  refcount_t refcnt;
   int openstat;
 
   struct node *np;
diff --git a/libnetfs/release-peropen.c b/libnetfs/release-peropen.c
index c206b43..01af97d 100644
--- a/libnetfs/release-peropen.c
+++ b/libnetfs/release-peropen.c
@@ -24,29 +24,27 @@
 void
 netfs_release_peropen (struct peropen *po)
 {
+  if (refcount_deref (&po->refcnt) > 0)
+    return;
+
   pthread_mutex_lock (&po->np->lock);
-  if (--po->refcnt)
-    pthread_mutex_unlock (&po->np->lock);
-  else
-    {
-      if (po->root_parent)
-       mach_port_deallocate (mach_task_self (), po->root_parent);
+  if (po->root_parent)
+    mach_port_deallocate (mach_task_self (), po->root_parent);
 
-      if (po->shadow_root && po->shadow_root != po->np)
-       {
-         pthread_mutex_lock (&po->shadow_root->lock);
-         netfs_nput (po->shadow_root);
-       }
-      if (po->shadow_root_parent)
-       mach_port_deallocate (mach_task_self (), po->shadow_root_parent);
+  if (po->shadow_root && po->shadow_root != po->np)
+    {
+      pthread_mutex_lock (&po->shadow_root->lock);
+      netfs_nput (po->shadow_root);
+    }
+  if (po->shadow_root_parent)
+    mach_port_deallocate (mach_task_self (), po->shadow_root_parent);
 
-      if (po->lock_status != LOCK_UN)
-       fshelp_acquire_lock (&po->np->userlock, &po->lock_status,
-                            &po->np->lock, LOCK_UN);
+  if (po->lock_status != LOCK_UN)
+    fshelp_acquire_lock (&po->np->userlock, &po->lock_status,
+                        &po->np->lock, LOCK_UN);
 
-      netfs_nput (po->np);
+  netfs_nput (po->np);
 
-      free (po->path);
-      free (po);
-    }
+  free (po->path);
+  free (po);
 }
-- 
2.6.4