From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from pb-smtp20.pobox.com ([173.228.157.52]:52595 "EHLO pb-smtp20.pobox.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727600AbeINANQ (ORCPT ); Thu, 13 Sep 2018 20:13:16 -0400 Received: from pb-smtp20.pobox.com (unknown [127.0.0.1]) by pb-smtp20.pobox.com (Postfix) with ESMTP id 96F9029274 for ; Thu, 13 Sep 2018 14:54:57 -0400 (EDT) (envelope-from jdb2@pobox.com) Received: from pb-smtp20.sea.icgroup.com (unknown [127.0.0.1]) by pb-smtp20.pobox.com (Postfix) with ESMTP id 8F8AA29273 for ; Thu, 13 Sep 2018 14:54:57 -0400 (EDT) (envelope-from jdb2@pobox.com) Received: from [192.168.1.20] (unknown [73.55.237.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pb-smtp20.pobox.com (Postfix) with ESMTPSA id 8D0D029272 for ; Thu, 13 Sep 2018 14:54:54 -0400 (EDT) (envelope-from jdb2@pobox.com) Subject: Fwd: Re: How to access "upper" directory of overlayfs programatically References: <5B9AA5EC.8050600@pobox.com> From: Jonathan Busby Message-ID: <5B9AB275.7010408@pobox.com> Date: Thu, 13 Sep 2018 13:54:45 -0500 MIME-Version: 1.0 In-Reply-To: <5B9AA5EC.8050600@pobox.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-unionfs-owner@vger.kernel.org To: linux-unionfs@vger.kernel.org List-ID: Oops... forgot that I was replying to you personally :) -------- Forwarded Message -------- Subject: Re: How to access "upper" directory of overlayfs programatically Date: Thu, 13 Sep 2018 13:01:16 -0500 From: Jonathan Busby To: Amir Goldstein On 09/13/2018 12:33 PM, Jonathan Busby wrote: > > > On 09/12/2018 02:48 PM, Amir Goldstein wrote: >> [changing over to overlayfs list] > > Thanks for this! :D I had been searching for an overlayfs mailing list > but it seems I overlooked unionfs. > >> >> On Wed, Sep 12, 2018 at 8:52 PM Jonathan Busby wrote: >>> >>> Hello. I'm new to this list and I don't know if this is the right forum >>> for my question, but, I've asked this same question on many forums and >>> never received an answer -- please don't flame me. >>> >>> I have a Debian based Linux live system which is running out of RAM and >>> was booted without the "persistent" boot option, so the capser-rw >>> filesystem was never created. >>> >>> I wish to gain access to the "upper" directory of the overlayfs >>> filesystem in the casper init scripts initramfs "/cow/upper" filesystem >>> so that I may programatically save the filesystem, hopefully without >>> having to re-implement cp. >>> >>> I know how to commit the changes of a Debian based live CD session to a >>> storage device, but only if the live session in question was booted with >>> the "persistent" option. >>> >>> I've looked at the overlayfs source code but I still can't figure out >>> how to accomplish what I want. >>> >>> I'm sorry if this is stupid question -- hopefully it's not. >>> >> >> I don't think the programmable API you think of exists, but maybe >> you can get access to upper dir as admin user. >> >> Please share the init scripts responsible for the mounts at live CD boot >> and the content of /proc/self/mountinfo > > The contents of /proc/self/mountinfo are can be found here : > > https://pastebin.com/raw/9uQdJ66w > > The init scripts responsible for the live CD mounts can be found here : > > https://www.dropbox.com/s/j4zqsn8avxrv6zf/initrd-scripts.tar.gz?dl=0 > > Thanks, > > Jonathan > >> >> Thanks, >> Amir. >> I forgot to mention that the init scripts that handle mounting the overlayfs chroot are located in the /scripts/casper directory, and the main script is just called "casper". Regards, Jonathan