Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754124Ab1CVTiM (ORCPT ); Tue, 22 Mar 2011 15:38:12 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:41205 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752822Ab1CVTiK (ORCPT ); Tue, 22 Mar 2011 15:38:10 -0400 Date: Tue, 22 Mar 2011 19:38:07 +0000 From: Al Viro To: Miklos Szeredi Cc: Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, apw@canonical.com, nbd@openwrt.org, neilb@suse.de Subject: Re: [PATCH 0/6 v7] overlay filesystem - request for inclusion Message-ID: <20110322193807.GX22723@ZenIV.linux.org.uk> References: <20110322152602.053930811@szeredi.hu> <20110322183919.GV22723@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1136 Lines: 23 On Tue, Mar 22, 2011 at 07:58:17PM +0100, Miklos Szeredi wrote: > > > and its protection against renames is > > > nowhere near enough. ??I might be missing something subtle, but... > > Protection is exactly as for userspace callers. AFAICT. BTW, what filesystems can act as upper layers and how are you going to prevent modifications of upper layer in normal way? It is mounted, after all, or you would be unable to find it when mounting overlayfs. And it might be mounted in any number of places, not all even visible to you... I realize that you have it listed as a problem, but do you have any ideas on how to deal with that? If you allow NFS as upper layer, you really have a problem; with this approach you probably want to prevent that very forcibly. Not that your open() handling would work correctly with NFS, even with no modifications from other clients or from server... -- 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/