Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756071Ab1BWVmg (ORCPT ); Wed, 23 Feb 2011 16:42:36 -0500 Received: from zeniv.linux.org.uk ([195.92.253.2]:57361 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753663Ab1BWVme (ORCPT ); Wed, 23 Feb 2011 16:42:34 -0500 Date: Wed, 23 Feb 2011 13:42:27 -0800 From: Joel Becker To: Chris Mason Cc: "Martin K. Petersen" , djwong , Jens Axboe , linux-kernel , linux-fsdevel , Mingming Cao , linux-scsi Subject: Re: [RFC] block integrity: Fix write after checksum calculation problem Message-ID: <20110223214227.GL4020@noexit> Mail-Followup-To: Chris Mason , "Martin K. Petersen" , djwong , Jens Axboe , linux-kernel , linux-fsdevel , Mingming Cao , linux-scsi References: <20110222020022.GH32261@tux1.beaverton.ibm.com> <20110223202446.GG4020@noexit> <1298493173-sup-8301@think> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1298493173-sup-8301@think> X-Burt-Line: Trees are cool. X-Red-Smith: Ninety feet between bases is perhaps as close as man has ever come to perfection. User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1144 Lines: 31 On Wed, Feb 23, 2011 at 03:35:11PM -0500, Chris Mason wrote: > > ocfs2 handles stable metadata for its checksums when feeding > > things to the journal. If we're doing pagecache-based I/O, is the > > pagecache going to help here for data? > > Data is much easier than metadata. All you really need is to wait on > writeback in file_write, wait on writeback in page_mkwrite, and make > sure you don't free blocks back to the allocator that are actively under > IO. > > I expect the hard part to be jbd and metadata in ext34. Yeah, catching use-without-access is not trivial. I keep thinking we've found them all, and then another bug crops up ;-) At least our checksums catch it. Joel -- "The doctrine of human equality reposes on this: that there is no man really clever who has not found that he is stupid." - Gilbert K. Chesterson http://www.jlbec.org/ jlbec@evilplan.org -- 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/