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 10:16:09 +0900 Message-ID: <626.1236388569@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> 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]:49578 "EHLO vsmtp04.dti.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751221AbZCGBQZ (ORCPT ); Fri, 6 Mar 2009 20:16:25 -0500 In-Reply-To: <874oy6aktq.fsf@frosties.localdomain> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Goswin von Brederlow: > I could think of three possible values: > > 1) the sum of the st_blocks of both branches (total space used) > 2) min(size/blocksize, sum of st_blocks) (appox. what the file would use) > 3) st_bocks of read-write branch (read-write space used only) 4) calculate st_blocks by merging based upon bitmap (dmpath) Some applications may not like st_blksize either since it may be different per block. One more difficulty (hard to support issue). - open a file on deltafs - unlink it - rmdir its parent - write or fchmod to it - rewind+read or mmap+read from the opened file - cat it be read correctly? J. R. Okajima