From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:48540 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727615AbeGSWIV (ORCPT ); Thu, 19 Jul 2018 18:08:21 -0400 From: Jeff Mahoney Subject: [PATCH] mkfs: avoid divide-by-zero when hardware reports optimal i/o size as 0 Message-ID: <6f62dbc6-f516-e8b5-1f08-6be227a61219@suse.com> Date: Thu, 19 Jul 2018 17:23:22 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: "linux-xfs@vger.kernel.org" , Eric Sandeen , Dave Chinner Commit 051b4e37f5e (mkfs: factor AG alignment) factored out the AG alignment code into a separate function. It got rid of redundant checks for dswidth != 0 since calc_stripe_factors was supposed to guarantee that if dsunit is non-zero dswidth will be as well. Unfortunately, there's hardware out there that reports its optimal i/o size as larger than the maximum i/o size, which the kernel treats as broken and zeros out the optimal i/o size. We'll accept the multi-sector dsunit but have a zero dswidth and hit a divide-by-zero in align_ag_geometry. To resolve this we can check the topology before consuming it, default to using the stripe unit as the stripe width, and warn the user about it. Fixes: 051b4e37f5e (mkfs: factor AG alignment) Signed-off-by: Jeff Mahoney --- mkfs/xfs_mkfs.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c index a135e06e..35542e57 100644 --- a/mkfs/xfs_mkfs.c +++ b/mkfs/xfs_mkfs.c @@ -2295,6 +2295,12 @@ _("data stripe width (%d) must be a multiple of the data stripe unit (%d)\n"), if (!dsunit) { dsunit = ft->dsunit; dswidth = ft->dswidth; + if (dsunit && dswidth == 0) { + fprintf(stderr, +_("%s: Volume reports stripe unit of %d bytes but stripe width of 0. Using stripe width of %d bytes, which may not be optimal.\n"), + progname, dsunit << 9, dsunit << 9); + dswidth = dsunit; + } use_dev = true; } else { /* check and warn is alignment is sub-optimal */ -- 2.16.4