From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:37796 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730028AbeHAWhW (ORCPT ); Wed, 1 Aug 2018 18:37:22 -0400 From: Eric Sandeen Subject: [PATCH V2] mkfs: avoid divide-by-zero when hardware reports optimal i/o size as 0 Message-ID: Date: Wed, 1 Aug 2018 15:49:45 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: linux-xfs , Jeff Mahoney From: Jeff Mahoney 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. To resolve this we can check the topology before consuming it, and ignore the bad stripe geometry. [sandeen: remove guessing heuristic, just warn and ignore bad data.] Fixes: 051b4e37f5e (mkfs: factor AG alignment) Signed-off-by: Jeff Mahoney Reviewed-by: Eric Sandeen Signed-off-by: Eric Sandeen --- so, I rewrote this a bit. I'm not a fan of guessing what the kernel really must have meant, becaue next time the root cause may be differnt. In other cases we ignore bad geometry, I think we should in this case as well. This will also let me go forward with a factored-out geometry checker, and for user-specified badness we'll warn and exit, for kernel-provided badness we'll warn and ignore. diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c index 1074886..2e53c1e 100644 --- a/mkfs/xfs_mkfs.c +++ b/mkfs/xfs_mkfs.c @@ -2281,11 +2281,20 @@ _("data stripe width (%d) must be a multiple of the data stripe unit (%d)\n"), /* if no stripe config set, use the device default */ if (!dsunit) { - dsunit = ft->dsunit; - dswidth = ft->dswidth; - use_dev = true; + /* Ignore nonsense from device. XXX add more validation */ + if (ft->dsunit && ft->dswidth == 0) { + fprintf(stderr, +_("%s: Volume reports stripe unit of %d bytes and stripe width of 0, ignoring.\n"), + progname, BBTOB(ft->dsunit)); + ft->dsunit = 0; + ft->dswidth = 0; + } else { + dsunit = ft->dsunit; + dswidth = ft->dswidth; + use_dev = true; + } } else { - /* check and warn is alignment is sub-optimal */ + /* check and warn if user-specified alignment is sub-optimal */ if (ft->dsunit && ft->dsunit != dsunit) { fprintf(stderr, _("%s: Specified data stripe unit %d is not the same as the volume stripe unit %d\n"),