To: hch@infradead.org
CC: miklos@szeredi.hu, hch@infradead.org, akpm@linux-foundation.org,
       linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
In-reply-to: <20070921131409.GA9988@infradead.org> (message from Christoph
	Hellwig on Fri, 21 Sep 2007 14:14:09 +0100)
Subject: Re: [patch 5/5] VFS: allow filesystem to override mknod capability checks
References: <20070921122343.307289079@szeredi.hu> <20070921123336.095183254@szeredi.hu> <20070921124504.GC8088@infradead.org> <E1IYiH4-0001eQ-00@dorka.pomaz.szeredi.hu> <20070921131409.GA9988@infradead.org>
Message-Id: <E1IYiOv-0001f6-00@dorka.pomaz.szeredi.hu>
From: Miklos Szeredi <miklos@szeredi.hu>
Date: Fri, 21 Sep 2007 15:18:33 +0200
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1133
Lines: 23

> > Take this example: I've loopback mounted an UML disk image using fuse
> > (no privileges required), and want to create some device nodes.  I
> > can't yet boot the UML because the device node is missing from the
> > image.  So what should I do.  Currently I have to manipulate the
> > mounted image as root.  But that's really shouldn't be needed.
> 
> That's something that shouldn't be solved in the filesystem, but rather
> through exact semantics of unprivilegued mounts.  Given that an
> unprivilegued implies ignoring the device files we can easily allow
> users to create them, because they're nothing special anymore.

Exacly.  And we already have an API for that: mknod(2).  It would be
quite stupid to introduce _another_ API to do the same.  It would mean
that all the tools, like mknod(8) would not work with the new API.

Or am I misunderstanding your suggestion?

Miklos
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