vfs: do_last(): make exit RCU safe

Allow returning from do_last() with LOOKUP_RCU still set on the "out:" and
"exit:" labels.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

fs/namei.c

@@ -2383,7 +2383,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 out:
 	if (want_write)
 		mnt_drop_write(nd->path.mnt);
-	path_put(&nd->path);
+	terminate_walk(nd);
 	return filp;
 
 exit_mutex_unlock: