Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758555Ab3EQW0B (ORCPT ); Fri, 17 May 2013 18:26:01 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:54028 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756818Ab3EQVhJ (ORCPT ); Fri, 17 May 2013 17:37:09 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mike Snitzer , Alasdair G Kergon Subject: [ 014/102] dm stripe: fix regression in stripe_width calculation Date: Fri, 17 May 2013 14:35:29 -0700 Message-Id: <20130517213245.821266131@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.rc0.20.gb99dd2e In-Reply-To: <20130517213244.277411019@linuxfoundation.org> References: <20130517213244.277411019@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2765 Lines: 80 3.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mike Snitzer commit d793e684277124d55c5d2444007e224635821346 upstream. Fix a regression in the calculation of the stripe_width in the dm stripe target which led to incorrect processing of device limits. The stripe_width is the stripe device length divided by the number of stripes. The group of commits in the range f14fa69 ("dm stripe: fix size test") to eb850de ("dm stripe: support for non power of 2 chunksize") interfered with each other (a merging error) and led to the stripe_width being set incorrectly to the stripe device length divided by chunk_size * stripe_count. For example, a stripe device's table with: 0 33553920 striped 3 512 ... should result in a stripe_width of 11184640 (33553920 / 3), but due to the bug it was getting set to 21845 (33553920 / (512 * 3)). The impact of this bug is that device topologies that previously worked fine with the stripe target are no longer considered valid. In particular, there is a higher risk of seeing this issue if one of the stripe devices has a 4K logical block size. Resulting in an error message like this: "device-mapper: table: 253:4: len=21845 not aligned to h/w logical block size 4096 of dm-1" The fix is to swap the order of the divisions and to use a temporary variable for the second one, so that width retains the intended value. Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-stripe.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) --- a/drivers/md/dm-stripe.c +++ b/drivers/md/dm-stripe.c @@ -94,7 +94,7 @@ static int get_stripe(struct dm_target * static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv) { struct stripe_c *sc; - sector_t width; + sector_t width, tmp_len; uint32_t stripes; uint32_t chunk_size; int r; @@ -116,15 +116,16 @@ static int stripe_ctr(struct dm_target * } width = ti->len; - if (sector_div(width, chunk_size)) { + if (sector_div(width, stripes)) { ti->error = "Target length not divisible by " - "chunk size"; + "number of stripes"; return -EINVAL; } - if (sector_div(width, stripes)) { + tmp_len = width; + if (sector_div(tmp_len, chunk_size)) { ti->error = "Target length not divisible by " - "number of stripes"; + "chunk size"; return -EINVAL; } -- 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/