Introduce path_get()

This introduces the symmetric function to path_put() for getting a reference
to the dentry and vfsmount of a struct path in the right order.

Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/namei.c

@@ -362,6 +362,19 @@ int deny_write_access(struct file * file)
 	return 0;
 }
 
+/**
+ * path_get - get a reference to a path
+ * @path: path to get the reference to
+ *
+ * Given a path increment the reference count to the dentry and the vfsmount.
+ */
+void path_get(struct path *path)
+{
+	mntget(path->mnt);
+	dget(path->dentry);
+}
+EXPORT_SYMBOL(path_get);
+
 /**
  * path_put - put a reference to a path
  * @path: path to put the reference to
@@ -1160,8 +1173,8 @@ static int do_path_lookup(int dfd, const char *name,
 		if (retval)
 			goto fput_fail;
 
-		nd->path.mnt = mntget(file->f_path.mnt);
-		nd->path.dentry = dget(dentry);
+		nd->path = file->f_path;
+		path_get(&file->f_path);
 
 		fput_light(file, fput_needed);
 	}

include/linux/path.h

@@ -9,6 +9,7 @@ struct path {
 	struct dentry *dentry;
 };
 
+extern void path_get(struct path *);
 extern void path_put(struct path *);
 
 #endif  /* _LINUX_PATH_H */