Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760642Ab0FQSj3 (ORCPT ); Thu, 17 Jun 2010 14:39:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:21396 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757184Ab0FQSj2 (ORCPT ); Thu, 17 Jun 2010 14:39:28 -0400 Date: Thu, 17 Jun 2010 14:39:13 -0400 From: Valerie Aurora To: Alex Riesen Cc: Alexander Viro , Miklos Szeredi , Jan Blunck , Christoph Hellwig , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 17/38] union-mount: Union mounts documentation Message-ID: <20100617183912.GA14389@shell> References: <1276627208-17242-1-git-send-email-vaurora@redhat.com> <1276627208-17242-18-git-send-email-vaurora@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1251 Lines: 27 On Thu, Jun 17, 2010 at 10:01:30AM +0200, Alex Riesen wrote: > On Tue, Jun 15, 2010 at 20:39, Valerie Aurora wrote: > > +git://git.kernel.org/pub/scm/fs/ext2/val/e2fsprogs.git > > + > > +Currently, whiteout directory entries are not returned to userland. > > +While the directory type for whiteouts, DT_WHT, has been defined for > > +many years, very little userland code handles them. ??Userland will > > +never see fallthru directory entries. > > This may be a dumb question (I must admit I did only very little research), > but how does one cleanup the topmost layer of whiteouts and fallthroughs, > so that the entries of lower layer(s) can be made visible again? I'm not sure how best to do this. We don't want to add more system calls. One thought of mine has been to do this offline, when the file system is unmounted. For example, e2fsck could add a feature to delete whiteouts and fallthrus. Another option is to add a flag to an existing system call. Any ideas? -VAL -- 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/