From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756754AbYHSTUs (ORCPT ); Tue, 19 Aug 2008 15:20:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753270AbYHSTUj (ORCPT ); Tue, 19 Aug 2008 15:20:39 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:3019 "EHLO spitz.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752623AbYHSTUi (ORCPT ); Tue, 19 Aug 2008 15:20:38 -0400 Date: Tue, 19 Aug 2008 21:20:27 +0200 From: Pavel Machek To: Rik van Riel Cc: Alan Cox , Eric Paris , Arjan van de Ven , Jan Harkes , "Press, Jonathan" , peterz@infradead.org, linux-kernel@vger.kernel.org, malware-list@lists.printk.net, hch@infradead.org, andi@firstfloor.org, viro@ZenIV.linux.org.uk Subject: Re: HSM (was Re: [malware-list] TALPA - a threat model? well sorta.) Message-ID: <20080819192027.GA6484@ucw.cz> References: <20080813205906.559d3f37@lxorguk.ukuu.org.uk> <2629CC4E1D22A64593B02C43E855530304AE4BC2@USILMS12.ca.com> <20080813173529.7069b5f1@cuia.bos.redhat.com> <20080815201622.GD31584@cs.cmu.edu> <20080815150509.20ffb91d@infradead.org> <1219015177.27389.1.camel@localhost.localdomain> <20080818163313.72927af7@lxorguk.ukuu.org.uk> <20080818124339.4b65b6c0@riellaptop.surriel.com> <20080819071416.GA14731@elf.ucw.cz> <20080819121032.02632c09@riellaptop.surriel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080819121032.02632c09@riellaptop.surriel.com> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 2008-08-19 12:10:32, Rik van Riel wrote: > On Tue, 19 Aug 2008 09:14:16 +0200 > Pavel Machek wrote: > > > On Mon 2008-08-18 12:43:39, Rik van Riel wrote: > > > On Mon, 18 Aug 2008 16:33:13 +0100 > > > Alan Cox wrote: > > > > > > > > I could probably buy that, but I don't know how an HSM would > > > > > work. Would we have everything we need at open for them to fire > > > > > off? > > > > > > > > > > /me is HSM clueless and trying to include their needs is > > > > > proving a challenge. > > > > > > > > So don't bother. Its a theoretical use for the most part so we can > > > > mangle the interface later. > > > > > > Think of a consumer HSM application: backup to rsync.net > > > or Amazon S3. > > > > > > Instead of waiting for the whole backup to be restored, > > > you can start using the filesystem immediately. The > > > block-on-open hook can be used by the restore program > > > to fetch files from the remote backup site on an > > > as-needed basis, with a full restore going on in the > > > background. > > > > > > If the block-on-open hook can be used for that (even > > > with additional magic, like creating empty HSM inodes > > > with a special attr to notify "the data lives elsewhere"), > > > HSM should be good. > > > > > > The "data lives elsewhere" bit/xattr/whatever could also > > > be used on directories, so not even the whole directory > > > tree would have to be restored right on restore :) > > > > But is this really needed to be cross-filesystem thing? I'd expect > > this to be implemented with FUSE, maybe FUSE+unionfs... > > If you think FUSE+unionfs is a cleaner solution than one > hook in the VFS, I've got a bridge to sell you. If you can do it with one clean enough hook, I'll buy that bridge. [If you want to do 'list directory before files are there' -- and you seem to want to from description above -- fuse seems like a way to go.] Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html