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From: "Herbert Pötzl" <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 ...
Date: Wed, 6 Aug 2003 00:51:49 +0200	[thread overview]
Message-ID: <20030805225149.GC2594@www.13thfloor.at> (raw)
In-Reply-To: <20030805165924.GF12757@parcelfarce.linux.theplanet.co.uk>

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 Pötzl 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
 
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  reply	other threads:[~2003-08-05 22:51 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-08-04 22:16 RO --bind mount implementation Herbert Pötzl
2003-08-04 23:43 ` Sean Neakums
2003-08-05  0:49   ` Herbert Pötzl
2003-08-05 16:59 ` viro
2003-08-05 22:51   ` Herbert Pötzl [this message]
2003-08-05 23:14     ` Herbert Pötzl

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