From mboxrd@z Thu Jan 1 00:00:00 1970 From: Amit Gud Subject: Re: [RFC][PATCH] ChunkFS: fs fission for faster fsck Date: Thu, 26 Apr 2007 10:53:16 -0500 Message-ID: <4630CAEC.2050909@ksu.edu> References: <17965.60841.900376.524639@gargle.gargle.HOWL> <17966.23512.363955.141489@gargle.gargle.HOWL> <17967.15531.450627.972572@gargle.gargle.HOWL> <20070425224710.GB16129@nifty> <20070426141455.GA6155@c2.user-mode-linux.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Valerie Henson , Nikita Danilov , David Lang , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, riel@surriel.com, zab@zabbo.net, arjan@infradead.org, suparna@in.ibm.com, brandon@ifup.org, karunasagark@gmail.com To: Jeff Dike Return-path: Received: from smtp1.cc.ksu.edu ([129.130.7.15]:43335 "EHLO smtp1.cc.ksu.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031292AbXDZPyp (ORCPT ); Thu, 26 Apr 2007 11:54:45 -0400 In-Reply-To: <20070426141455.GA6155@c2.user-mode-linux.org> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Jeff Dike wrote: > How about this case: > > Growing file starts in chunk A. > Overflows into chunk B. > Delete file in chunk A. > Growing file overflows chunk B and spots new free space in > chunk A (and nothing anywhere else) > Overflows into chunk A > Delete file in chunk B. > Overflow into chunk B again. > > Maybe this is not realistic, but in the absence of a mechanism to pull > data back from an overflow chunk, it seems at least a theoretical > possibility that there could be > 1 continuation inodes per file per > chunk. > Preventive measures are taken to limit only one continuation inode per file per chunk. This can be done easily in the chunk allocation algorithm for disk space. Although I'm not quite sure what you mean by "Delete file in chunk A". If you are referring to same file thats growing, then deletion is not possible, because individual parts of any file in any chunk cannot be deleted. AG -- May the source be with you. http://www.cis.ksu.edu/~gud