Date: Wed, 6 Aug 2003 00:51:49 +0200
From: Herbert =?iso-8859-1?Q?P=F6tzl?= <herbert@13thfloor.at>
To: viro@parcelfarce.linux.theplanet.co.uk
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: RO --bind mount implementation ...
Message-ID: <20030805225149.GC2594@www.13thfloor.at>
Reply-To: herbert@13thfloor.at
Mail-Followup-To: viro@parcelfarce.linux.theplanet.co.uk,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
References: <20030804221615.GA18521@www.13thfloor.at> <20030805165924.GF12757@parcelfarce.linux.theplanet.co.uk>
Mime-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <20030805165924.GF12757@parcelfarce.linux.theplanet.co.uk>
User-Agent: Mutt/1.3.28i
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1704
Lines: 42

On Tue, Aug 05, 2003 at 05:59:24PM +0100, viro@parcelfarce.linux.theplanet.co.uk wrote:
> On Tue, Aug 05, 2003 at 12:16:15AM +0200, Herbert P?tzl wrote:
>  
> > anyway, I discussed this with some friends, and
> > they pointed out that this would be useful ...
> > so here is the first try ...
> 
> Umm...  You know, the most obvious system call that should care about
> read-only is open(pathname, O_RDWR) ;-)  IOW, taking care of directory
> modifications is not enough - you need to deal with
> 	* opening file for write
> 	* truncation (both from *truncate() and from open() with O_TRUNC)
> 	* metadata changes (timestamps, ownership, permissions)

well, the open case, IMHO is handled by the
lookup_create() modifications, truncate is something
I obviously missed (I missed the intermezzo copies 
too ;) and metadata changes were intentionally ignored
(it's the first try, and I'm glad that you see it as 
a step in the right direction?)

> But yes, it's not that far from where we should eventualy get.

will add the truncate() case soon, maybe it is also
possible to move some parts of the may_create
function to the mnt_may_create (any suggestions for
a better name?), to avoid doing some checks twice ...

any further suggestions?

best,
Herbert
 
> -
> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/