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/diskfs.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'libdiskfs/diskfs.h')

diff --git a/libdiskfs/diskfs.h b/libdiskfs/diskfs.h
index e3285271..e59ba996 100644
--- a/libdiskfs/diskfs.h
+++ b/libdiskfs/diskfs.h
@@ -820,12 +820,12 @@ diskfs_create_node (struct node *dir, const char *name, mode_t mode,
 		    struct dirstat *ds);
 
 /* Create and return a protid for an existing peropen PO in CRED,
-   referring to user USER.  */
+   referring to user USER.  On success, consume a reference to PO.  */
 error_t diskfs_create_protid (struct peropen *po, struct iouser *user,
 			      struct protid **cred);
 
 /* Build and return in CRED a protid which has no user identification, for
-   peropen PO.  */
+   peropen PO.  On success, consume a reference to PO.  */
 error_t diskfs_start_protid (struct peropen *po, struct protid **cred);
 
 /* Finish building protid CRED started with diskfs_start_protid;
-- 
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