Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760153AbXF0GF5 (ORCPT ); Wed, 27 Jun 2007 02:05:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756832AbXF0GFt (ORCPT ); Wed, 27 Jun 2007 02:05:49 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:49520 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756234AbXF0GFs (ORCPT ); Wed, 27 Jun 2007 02:05:48 -0400 Date: Wed, 27 Jun 2007 16:05:31 +1000 From: David Chinner To: Nick Piggin Cc: Chris Mason , David Chinner , Nick Piggin , Linux Kernel Mailing List , Linux Memory Management List , linux-fsdevel@vger.kernel.org Subject: Re: [RFC] fsblock Message-ID: <20070627060531.GV31489@sgi.com> References: <20070624014528.GA17609@wotan.suse.de> <20070626030640.GM989688@sgi.com> <46808E1F.1000509@yahoo.com.au> <20070626092309.GF31489@sgi.com> <20070626123449.GM14224@think.oraclecorp.com> <20070627053245.GA6033@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070627053245.GA6033@wotan.suse.de> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 875 Lines: 24 On Wed, Jun 27, 2007 at 07:32:45AM +0200, Nick Piggin wrote: > I think using fsblock to drive the IO and keep the pagecache flags > uptodate and using a btree in the filesystem to manage extents of block > allocations wouldn't be a bad idea though. Do any filesystems actually > do this? Yes. XFS. But we still need to hold state in buffer heads (BH_delay, BH_unwritten) that is needed to determine what type of allocation/extent conversion is necessary during writeback. i.e. what we originally mapped the page as during the ->prepare_write call. Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group - 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/