From mboxrd@z Thu Jan 1 00:00:00 1970 From: hooanon05@yahoo.co.jp Subject: Re: [fuse-devel] delta filesystem prototype Date: Sat, 07 Mar 2009 18:12:07 +0900 Message-ID: <8759.1236417127@jrobl> References: <87sklyh3wu.fsf@frosties.localdomain> <200903010138.39329.bs_lists@aakef.fastmail.fm> <87eixhfsyi.fsf@frosties.localdomain> <87y6vlcr6p.fsf@frosties.localdomain> <87mybzd9nn.fsf@frosties.localdomain> <7231.1236312618@jrobl> <874oy6aktq.fsf@frosties.localdomain> <626.1236388569@jrobl> <8763iliu5e.fsf@frosties.localdomain> Cc: bs_lists@aakef.fastmail.fm, fuse-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org To: Goswin von Brederlow Return-path: Received: from vsmtp04.dti.ne.jp ([202.216.231.139]:56872 "EHLO vsmtp04.dti.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752741AbZCGJM1 (ORCPT ); Sat, 7 Mar 2009 04:12:27 -0500 In-Reply-To: <8763iliu5e.fsf@frosties.localdomain> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Goswin von Brederlow: > For unlink and rmdir you need whiteout files. > > For all the rest you just have to keep the file descriptor(s) alive as > long as the file is opened and cache metadat in the internal FD > structure. > > It isn't trivial but it isn't really hard. Generally it is true. Actually deltafs already has something like whiteout. It is a symlink to "(null)". When a user writes something to the file after unlink+rmdir, where can deltafs copyup? At least in the current implementation, there is no place for it. J. R. Okajima