From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753055AbcBAP4w (ORCPT ); Mon, 1 Feb 2016 10:56:52 -0500 Received: from mga04.intel.com ([192.55.52.120]:22300 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751630AbcBAP4u (ORCPT ); Mon, 1 Feb 2016 10:56:50 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,380,1449561600"; d="scan'208";a="905938777" From: Rui Wang To: koct9i@gmail.com Cc: rui.y.wang@intel.com, miklos@szeredi.hu, viro@zeniv.linux.org.uk, linux-unionfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, vgoyal@redhat.com Subject: Re: [PATCH] ovl: fix getcwd() failure after unsuccessful rmdir Date: Mon, 1 Feb 2016 23:36:52 +0800 Message-Id: <1454341012-15062-1-git-send-email-rui.y.wang@intel.com> X-Mailer: git-send-email 1.7.5.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 30, 2016 5:44 PM Konstantin Khlebnikov wrote: > On Fri, Jan 8, 2016 at 6:09 PM, Rui Wang wrote: > ovl_remove_upper() should do d_drop() only after it successfully > removes the dir, otherwise a subsequent getcwd() system call will > fail, breaking userspace programs. > > This is to fix: https://bugzilla.kernel.org/show_bug.cgi?id=110491 > > Signed-off-by: Rui Wang > > Reviewed-by: Konstantin Khlebnikov > > The same problem also in ovl_remove_and_whiteout() - when we remove > non-pure dentry. It checks that directory isn't empty before, but > I'm sure that vfs_rename which exchanges dentry and whiteout could > fail for some reason and we'll end with unhashed dentry when nothing > actually has been changed. Yes I had the same feeling. There's a "goto out_d_drop" which causes d_drop() to be called if ovl_do_rename() fails. but I wasn't able to find a way to reproduce this problem, so I only fixed the problem described in bug110491. It's what I could reliably test. Thanks Rui