From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753691AbaJ1Soz (ORCPT ); Tue, 28 Oct 2014 14:44:55 -0400 Received: from rush.cubic.ch ([176.9.78.115]:50430 "EHLO mail2.cubic.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750813AbaJ1Soy (ORCPT ); Tue, 28 Oct 2014 14:44:54 -0400 X-Greylist: delayed 2057 seconds by postgrey-1.27 at vger.kernel.org; Tue, 28 Oct 2014 14:44:54 EDT Message-ID: <544FDC1C.9040908@decentral.ch> Date: Tue, 28 Oct 2014 19:10:36 +0100 From: Tim Tassonis User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: overlayfs: "filesystem of lowerdir is not supported" on cdrom Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Just installed 3.18-rc2 and tried to test the overlayfs stuff: $ mkdir /ovtmp $ mount -t tmpfs tmpfs /ovtmp/ $ mkdir /ovtmp/work $ mkdir /ovtmp/upper $ mkdir /cdrw $ mount /dev/sr0 /mnt $ mount |egrep "ovtmp|sr0" /dev/sr0 on /mnt type iso9660 (ro,relatime) tmpfs on /ovtmp type tmpfs (rw,relatime) $ mount -t overlayfs overlayfs \ -olowerdir=/mnt,upperdir=/ovtmp/upper,workdir=/ovtmp/work /cdrw mount: wrong fs type, bad option, bad superblock on overlayfs, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so. $ dmesg |tail [ 3266.793218] overlayfs: filesystem of lowerdir is not supported However, the doc in Documentation/filesystems/overlayfs.txt states: "The lower filesystem can be any filesystem supported by Linux and does not need to be writable. The lower filesystem can even be another overlayfs. The upper filesystem will normally be writable and if it is it must support the creation of trusted.* extended attributes, and must provide valid d_type in readdir responses, so NFS is not suitable." So: Is the documentation wrong, the error message in dmesg wrong, or have missed something completely? Kind regards Tim