Revert "UBUNTU: SAUCE: (namespace) mqueue: Super blocks must be owned by the...

Revert "UBUNTU: SAUCE: (namespace) mqueue: Super blocks must be owned by the user ns which owns the ipc ns"

BugLink: http://bugs.launchpad.net/bugs/1588056

This reverts commit dec77184.
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

fs/super.c

@@ -951,14 +951,12 @@ static int ns_set_super(struct super_block *sb, void *data)
 	return set_anon_super(sb, NULL);
 }
 
-struct dentry *mount_ns_userns(struct file_system_type *fs_type, int flags,
-	struct user_namespace *user_ns, void *data,
-	int (*fill_super)(struct super_block *, void *, int))
+struct dentry *mount_ns(struct file_system_type *fs_type, int flags,
+	void *data, int (*fill_super)(struct super_block *, void *, int))
 {
 	struct super_block *sb;
 
-	sb = sget_userns(fs_type, ns_test_super, ns_set_super, flags, user_ns,
-			 data);
+	sb = sget(fs_type, ns_test_super, ns_set_super, flags, data);
 	if (IS_ERR(sb))
 		return ERR_CAST(sb);
 
@@ -975,14 +973,6 @@ struct dentry *mount_ns_userns(struct file_system_type *fs_type, int flags,
 
 	return dget(sb->s_root);
 }
-EXPORT_SYMBOL(mount_ns_userns);
-
-struct dentry *mount_ns(struct file_system_type *fs_type, int flags,
-	void *data, int (*fill_super)(struct super_block *, void *, int))
-{
-	return mount_ns_userns(fs_type, flags, current_user_ns(), data,
-			       fill_super);
-}
 
 EXPORT_SYMBOL(mount_ns);
 

include/linux/fs.h

@@ -1976,9 +1976,6 @@ struct file_system_type {
 
 #define MODULE_ALIAS_FS(NAME) MODULE_ALIAS("fs-" NAME)
 
-extern struct dentry *mount_ns_userns(struct file_system_type *fs_type,
-	int flags, struct user_namespace *userns, void *data,
-	int (*fill_super)(struct super_block *, void *, int));
 extern struct dentry *mount_ns(struct file_system_type *fs_type, int flags,
 	void *data, int (*fill_super)(struct super_block *, void *, int));
 extern struct dentry *mount_bdev(struct file_system_type *fs_type,

ipc/mqueue.c

@@ -326,10 +326,8 @@ static struct dentry *mqueue_mount(struct file_system_type *fs_type,
 			 int flags, const char *dev_name,
 			 void *data)
 {
-	struct ipc_namespace *ns = data;
-
 	if (!(flags & MS_KERNMOUNT)) {
-		ns = current->nsproxy->ipc_ns;
+		struct ipc_namespace *ns = current->nsproxy->ipc_ns;
 		/* Don't allow mounting unless the caller has CAP_SYS_ADMIN
 		 * over the ipc namespace.
 		 */
@@ -338,8 +336,7 @@ static struct dentry *mqueue_mount(struct file_system_type *fs_type,
 
 		data = ns;
 	}
-	return mount_ns_userns(fs_type, flags, ns->user_ns, data,
-			       mqueue_fill_super);
+	return mount_ns(fs_type, flags, data, mqueue_fill_super);
 }
 
 static void init_once(void *foo)

ipc/namespace.c

@@ -34,10 +34,8 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
 	ns->ns.ops = &ipcns_operations;
 
 	atomic_set(&ns->count, 1);
-	ns->user_ns = get_user_ns(user_ns);
 	err = mq_init_ns(ns);
 	if (err) {
-		put_user_ns(ns->user_ns);
 		ns_free_inum(&ns->ns);
 		kfree(ns);
 		return ERR_PTR(err);
@@ -48,6 +46,8 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
 	msg_init_ns(ns);
 	shm_init_ns(ns);
 
+	ns->user_ns = get_user_ns(user_ns);
+
 	return ns;
 }