Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754209Ab1DSDFp (ORCPT ); Mon, 18 Apr 2011 23:05:45 -0400 Received: from mtoichi12.ns.itscom.net ([219.110.2.182]:38246 "EHLO mtoichi12.ns.itscom.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754110Ab1DSDFn (ORCPT ); Mon, 18 Apr 2011 23:05:43 -0400 From: "J. R. Okajima" Subject: Re: [PATCH 6/6] overlay: overlay filesystem documentation To: Miklos Szeredi Cc: viro@ZenIV.linux.org.uk, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, apw@canonical.com, nbd@openwrt.org, neilb@suse.de, hramrach@centrum.cz, Miklos Szeredi In-Reply-To: <1303142440-26328-7-git-send-email-miklos@szeredi.hu> References: <1303142440-26328-1-git-send-email-miklos@szeredi.hu> <1303142440-26328-7-git-send-email-miklos@szeredi.hu> Date: Tue, 19 Apr 2011 12:05:17 +0900 Message-ID: <7795.1303182317@jrobl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1074 Lines: 31 Hello Miklos, Miklos Szeredi: > +The lower filesystem can be any filesystem supported by Linux and does > +not need to be writable. The lower filesystem can even be another > +overlayfs. ... When user mounts overlayfs over and over like this, # mount -t overlayfs -o upper=/rw1,lower=/ro1 none /ovl1 # mount -t overlayfs -o upper=/rw2,lower=/ovl1 none /ovl2 ::: # mount -t overlayfs -o upper=/rwN,lower=/ovl{N-1} none /ovlN And if he modify a file in the bottom RO layer, then overlayfs copies-up the file into each RW layer? - 'fileA' exists in only /ro1. - nested mounts. - run "echo append >> /ovlN/fileA" - is fileA copied-up to /rw1, and then to /rw2, and then ... to /rwN? If user specify a single dir as every upper laery, then the copyup will be done only once, or such RW layers are not allowed? J. R. Okajima -- 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/