From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [RFC] O_NOACC: open without any access Date: Tue, 23 Jun 2009 10:34:08 -0400 Message-ID: <20090623143408.GA2147@infradead.org> References: <20090623134640.GA13831@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: hch@infradead.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, viro@ZenIV.linux.org.uk, adilger@sun.com, dhowells@redhat.com, alan@lxorguk.ukuu.org.uk, akpm@linux-foundation.org To: Miklos Szeredi Return-path: Received: from bombadil.infradead.org ([18.85.46.34]:58194 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752857AbZFWOeF (ORCPT ); Tue, 23 Jun 2009 10:34:05 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, Jun 23, 2009 at 04:12:22PM +0200, Miklos Szeredi wrote: > > an issue ioctls + stat / etc on it ut not actually read/write it. > > Two differences between open("foo", 3) and open("foo", O_NOACC): > > 1) open with "3" requires _read_and_write_ permissions on foo, but > does not allow either read or write. Not sure what the logic in > that, but that's the way it has always been. Which is a quite sensible requirement if we want to do ioctls. > > 2) open with "3" calls driver's ->open() with any side effect that > may have. Open with O_NOACC doesn't do that, and hence if we > want to allow ioctls they need a new interface which gets a > "struct path" instead of a "struct file". Well, we'll need ->open to support ioctls, and I think it's good to go down that road.