From 520ef2ed66d47bb81a55829a88dda81f62dc95e5 Mon Sep 17 00:00:00 2001
From: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Fri, 20 Jun 2014 13:54:28 +0200
Subject: libdiskfs: fix reference counting of peropen objects

Previously, peropen objects were created with a reference count of
zero.  Therefore, if diskfs_create_protid fails, passing such an
object to diskfs_release_peropen would lead to a reference count
underflow.

* libdiskfs/peropen-make.c (diskfs_peropen_make): Initialize reference
count to one.
* libdiskfs/protid-make.c (diskfs_start_protid): And consume this
reference on success.  Update comment.
(diskfs_create_protid): Update comment.
* libdiskfs/diskfs.h: Update comments.
* libdiskfs/io-duplicate.c (diskfs_S_io_duplicate): Adjust reference
counting accordingly.
* libdiskfs/io-reauthenticate.c (diskfs_S_io_reauthenticate): Likewise.
* libdiskfs/io-restrict-auth.c (diskfs_S_io_restrict_auth): Likewise.
* doc/hurd.texi (Diskfs Internals): Update accordingly.
---
 libdiskfs/io-reauthenticate.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'libdiskfs/io-reauthenticate.c')

diff --git a/libdiskfs/io-reauthenticate.c b/libdiskfs/io-reauthenticate.c
index 69d78bc5..649315f7 100644
--- a/libdiskfs/io-reauthenticate.c
+++ b/libdiskfs/io-reauthenticate.c
@@ -35,11 +35,13 @@ diskfs_S_io_reauthenticate (struct protid *cred,
      are a simpleroutine, so callers won't know to restart. */
 
   pthread_mutex_lock (&cred->po->np->lock);
+  refcount_ref (&cred->po->refcnt);
   do
     err = diskfs_start_protid (cred->po, &newcred);
   while (err == EINTR);
   if (err)
     {
+      refcount_deref (&cred->po->refcnt);
       pthread_mutex_unlock (&cred->po->np->lock);
       return err;
     }
-- 
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