From owner-freebsd-hackers  Wed Mar 13  9:38: 2 2002
Delivered-To: freebsd-hackers@freebsd.org
Received: from vbook.express.ru (asplinux.ru [195.133.213.194])
	by hub.freebsd.org (Postfix) with ESMTP id 3DD6D37B402
	for <hackers@freebsd.org>; Wed, 13 Mar 2002 09:37:59 -0800 (PST)
Received: from localhost ([127.0.0.1])
	by vbook.express.ru with esmtp (Exim 3.33 #1)
	id 16lCgJ-0000u4-00; Wed, 13 Mar 2002 20:36:55 +0300
Subject: Re: unionfs and getcwd problem.
From: "Vladimir B. " Grebenschikov <vova@express.ru>
To: BOUWSMA Beery <freebsd-user@dcf77-zeit.netscum.dyndns.dk>
Cc: Takanori Watanabe <takawata@shidahara1.planet.sci.kobe-u.ac.jp>,
	hackers@freebsd.org
In-Reply-To: <200203102147.g2ALlDw00249@beerswilling.netscum.dyndns.dk>
References: <200202251435.XAA91094@shidahara1.planet.sci.kobe-u.ac.jp>
	<1015415443.3157.2.camel@vbook.express.ru> 
	<200203102147.g2ALlDw00249@beerswilling.netscum.dyndns.dk>
Content-Type: text/plain
Content-Transfer-Encoding: 7bit
X-Mailer: Evolution/1.0.2 
Date: 13 Mar 2002 20:36:55 +0300
Message-Id: <1016041015.748.56.camel@vbook.express.ru>
Mime-Version: 1.0
Sender: owner-freebsd-hackers@FreeBSD.ORG
Precedence: bulk
List-ID: <freebsd-hackers.FreeBSD.ORG>
List-Archive: <http://docs.freebsd.org/mail/> (Web Archive)
List-Help: <mailto:majordomo@FreeBSD.ORG?subject=help> (List Instructions)
List-Subscribe: <mailto:majordomo@FreeBSD.ORG?subject=subscribe%20freebsd-hackers>
List-Unsubscribe: <mailto:majordomo@FreeBSD.ORG?subject=unsubscribe%20freebsd-hackers>
X-Loop: FreeBSD.ORG

On Mon, 2002-03-11 at 00:47, BOUWSMA Beery wrote:

> Thanks!  I'm pleased to report that I applied your patch to my
> -stable source, and now I'm able to `make buildworld' with my
> rw unionfs mount of my local hacks, atop a ro nullfs mount with
> unaltered source, which I'm doing right now.
> 
> The only obvious `problem' is when a non-r00t user attempts to
> access the union-mounted fs when the shadow directories have not
> yet been created, and `permission denied' is returned for all
> directories that exist below, but not in the unionfs fs.  E.g.:

Yes, it is because of feature of unionfs to create shadow directories
with credentionals of proceses doing "rise" operation.

And if process have no permissions to write into parent directory
operation fail.

One of possible workarounds do as root find /union/mount/point
to create all shadow directories.

Another solution is to change behaviour of unionfs to use root-cred
while make shadows, and then put attributes/ownership from lower layer
to shadows. 
(but this will take a bit of kernel hacking)

> thanks,
> barry bouwsma

-- 
TSB "Russian Express", Moscow
Vladimir B. Grebenschikov, vova@express.ru


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message