Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933152AbXEQFb3 (ORCPT ); Thu, 17 May 2007 01:31:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756322AbXEQFbT (ORCPT ); Thu, 17 May 2007 01:31:19 -0400 Received: from mail.suse.de ([195.135.220.2]:58362 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755358AbXEQFbR (ORCPT ); Thu, 17 May 2007 01:31:17 -0400 From: Neil Brown To: david@lang.hm, Jeff Zheng , Michal Piotrowski , Ingo Molnar , linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Date: Thu, 17 May 2007 15:31:07 +1000 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <17995.59547.368508.202596@notabene.brown> Subject: RE: Software raid0 will crash the file-system, when each disk is 5TB In-Reply-To: message from Neil Brown on Thursday May 17 References: <659F626D666070439A4A5965CD6EBF406836C6@gazelle.ad.endace.com> <6bffcb0e0705151629j78920ca2r9337dccdfc1bb6a9@mail.gmail.com> <17994.19043.771733.453896@notabene.brown> <659F626D666070439A4A5965CD6EBF406B31C5@gazelle.ad.endace.com> <17995.42562.870806.396617@notabene.brown> <659F626D666070439A4A5965CD6EBF406B33ED@gazelle.ad.endace.com> <17995.49602.427417.500049@notabene.brown> <17995.57891.56738.592100@notabene.brown> X-Mailer: VM 7.19 under Emacs 21.4.1 X-face: [Gw_3E*Gng}4rRrKRYotwlE?.2|**#s9D > Uhm, I just noticed something. > 'chunk' is unsigned long, and when it gets shifted up, we might lose > bits. That could still happen with the 4*2.75T arrangement, but is > much more likely in the 2*5.5T arrangement. Actually, it cannot be a problem with the 4*2.75T arrangement. chuck << chunksize_bits will not exceed the size of the underlying device *in*kilobytes*. In that case that is 0xAE9EC800 which will git in a 32bit long. We don't double it to make sectors until after we add zone->dev_offset, which is "sector_t" and so 64bit arithmetic is used. So I'm quite certain this bug will cause exactly the problems experienced!! > > Jeff, can you try this patch? Don't bother about the other tests I mentioned, just try this one. Thanks. NeilBrown > Signed-off-by: Neil Brown > > ### Diffstat output > ./drivers/md/raid0.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff .prev/drivers/md/raid0.c ./drivers/md/raid0.c > --- .prev/drivers/md/raid0.c 2007-05-17 10:33:30.000000000 +1000 > +++ ./drivers/md/raid0.c 2007-05-17 15:02:15.000000000 +1000 > @@ -475,7 +475,7 @@ static int raid0_make_request (request_q > x = block >> chunksize_bits; > tmp_dev = zone->dev[sector_div(x, zone->nb_dev)]; > } > - rsect = (((chunk << chunksize_bits) + zone->dev_offset)<<1) > + rsect = ((((sector_t)chunk << chunksize_bits) + zone->dev_offset)<<1) > + sect_in_chunk; > > bio->bi_bdev = tmp_dev->bdev; - 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/