Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751669Ab3COEoT (ORCPT ); Fri, 15 Mar 2013 00:44:19 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:51474 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751031Ab3COEoR (ORCPT ); Fri, 15 Mar 2013 00:44:17 -0400 Date: Fri, 15 Mar 2013 04:44:11 +0000 From: Al Viro To: "J. R. Okajima" Cc: Miklos Szeredi , Andrew Morton , torvalds@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, hch@infradead.org, apw@canonical.com, nbd@openwrt.org, neilb@suse.de, jordipujolp@gmail.com, ezk@fsl.cs.sunysb.edu, dhowells@redhat.com, sedat.dilek@googlemail.com, mszeredi@suse.cz Subject: Re: [PATCH 0/9] overlay filesystem: request for inclusion (v17) Message-ID: <20130315044411.GW21522@ZenIV.linux.org.uk> References: <1363184193-1796-1-git-send-email-miklos@szeredi.hu> <20130313160854.54ac0491044371b4db214698@linux-foundation.org> <20130315012541.GU21522@ZenIV.linux.org.uk> <19058.1363320936@jrobl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <19058.1363320936@jrobl> 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: 1359 Lines: 31 On Fri, Mar 15, 2013 at 01:15:36PM +0900, J. R. Okajima wrote: > +- whiteout is hardlinked in order to reduce the consumption of inodes > + on branch *blink* Whiteouts have no inodes at all. Filesystem has an additional kind of directory entries, recognizable as whiteouts. How they are done is up to filesystem in question. > +- kernel thread for removing the dir who has a plenty of whiteouts Again, implementation detail for individual filesystem. > +The whiteout in aufs is very similar to Unionfs's. That is represented > +by its filename. UnionMount takes an approach of a file mode, but I am > +afraid several utilities (find(1) or something) will have to support it. Why the devil should find(1) even see them? I really don't believe that it's a good idea to try making them fs-agnostic; it's an implementation detail of filesystem, with things like "is this directory empty?" very much belonging to the fs in question... I don't know; maybe it's my experience of dealing with umsdos that has badly soured me on that kind of approach, but IME this kind of schemes tend to be brittle as hell ;-/ -- 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/