From mboxrd@z Thu Jan 1 00:00:00 1970 From: hooanon05@yahoo.co.jp Subject: Re: [fuse-devel] delta filesystem prototype Date: Mon, 09 Mar 2009 22:35:52 +0900 Message-ID: <7927.1236605752@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> <8759.1236417127@jrobl> <873admyjho.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]:53231 "EHLO vsmtp04.dti.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750853AbZCINlB (ORCPT ); Mon, 9 Mar 2009 09:41:01 -0400 In-Reply-To: <873admyjho.fsf@frosties.localdomain> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Goswin von Brederlow: > hooanon05@yahoo.co.jp writes: :: > > 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. ::: > In the delta branch create a meta/ and files/ directory. In the meta/ > directory you keep whiteout files and stat updates. In files/ you > store only changes in the file data itself. > > So "rm foo/bar/baz" will create meta/foo/bar/baz.whiteout. Then "echo > blafase >>foo/bar/baz" first searches for a file to copy-up, sees the > meta/foo/bar/baz.whiteout and knows the file was deleted. It then > creates a new files/foo/bar/baz. It might have to copy-up foo and > foo/bar for that though. ?? What I am pointing out is systemcall level operation instead of command level. In your example (or implementation approach), can deltafs successfully operate "write(2) to and read(2) from foo/bar/baz" after "rm -r foo/bar"? (from my previous mail) ---------------------------------------------------------------------- - 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