From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f45.google.com (mail-pb0-f45.google.com [209.85.160.45]) by kanga.kvack.org (Postfix) with ESMTP id 7CE256B0031 for ; Thu, 9 Jan 2014 02:32:08 -0500 (EST) Received: by mail-pb0-f45.google.com with SMTP id rp16so2681372pbb.32 for ; Wed, 08 Jan 2014 23:32:08 -0800 (PST) Received: from mail02-md.ns.itscom.net (mail02-md.ns.itscom.net. [175.177.155.112]) by mx.google.com with ESMTP id n8si3060749pax.15.2014.01.08.23.32.06 for ; Wed, 08 Jan 2014 23:32:07 -0800 (PST) From: "J. R. Okajima" Subject: Re: [LSF/MM ATTEND] Stackable Union Filesystem Implementation In-Reply-To: References: <20140107122301.GC16640@quack.suse.cz> <6469.1389157809@jrobl> Date: Thu, 09 Jan 2014 16:32:05 +0900 Message-ID: <523.1389252725@jrobl> Sender: owner-linux-mm@kvack.org List-ID: To: Saket Sinha Cc: Jan Kara , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, lsf-pc@lists.linux-foundation.org Saket Sinha: > > For such purpose, a "block device level union" (instead of filesystem > > level union) may be an option for you, such as "dm snapshot". > > > I imagine that this would make things more complicated as ideally this > should be done in a filesystem driver. Again a "block device level > union" would all the more have lesser chances of getting this > filesystem driver included in the mainline kernel as kernel > maintainers prefer the drivers to be as simple as possible. ?? I am afraid that I cannot fully understand what you wrote. If you think "dm snapshot" does not exist currently, and you or someone else are going to develop a new feature, that is wrong. You already have "dm snapshot" feature and you can "stack" the block devices by using it. (cf. http://aufs.sourceforge.net/aufs2/report/sq/sq.pdf which is a bit old) J. R. Okajima -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org