From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5A482C43461 for ; Mon, 14 Sep 2020 22:12:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D190208DB for ; Mon, 14 Sep 2020 22:12:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725953AbgINWMF (ORCPT ); Mon, 14 Sep 2020 18:12:05 -0400 Received: from mail105.syd.optusnet.com.au ([211.29.132.249]:42353 "EHLO mail105.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725926AbgINWMF (ORCPT ); Mon, 14 Sep 2020 18:12:05 -0400 Received: from dread.disaster.area (pa49-195-191-192.pa.nsw.optusnet.com.au [49.195.191.192]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id 415593A66F5; Tue, 15 Sep 2020 08:12:02 +1000 (AEST) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1kHwhd-0001so-GI; Tue, 15 Sep 2020 08:12:01 +1000 Date: Tue, 15 Sep 2020 08:12:01 +1000 From: Dave Chinner To: Eric Sandeen Cc: xfs , Zdenek Kabelac Subject: Re: [PATCH] mkfs.xfs: fix ASSERT on too-small device with stripe geometry Message-ID: <20200914221201.GW12131@dread.disaster.area> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=XJ9OtjpE c=1 sm=1 tr=0 cx=a_idp_d a=vvDRHhr1aDYKXl+H6jx2TA==:117 a=vvDRHhr1aDYKXl+H6jx2TA==:17 a=kj9zAlcOel0A:10 a=reM5J-MqmosA:10 a=20KFwNOVAAAA:8 a=7-415B0cAAAA:8 a=jZl85KHjS9e1rR1d_uAA:9 a=CjuIK1q_8ugA:10 a=biEYGPWJfzWAr4FL6Ov7:22 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Mon, Sep 14, 2020 at 01:26:01PM -0500, Eric Sandeen wrote: > When a too-small device is created with stripe geometry, we hit an > assert in align_ag_geometry(): > > # truncate --size=10444800 testfile > # mkfs.xfs -dsu=65536,sw=1 testfile > mkfs.xfs: xfs_mkfs.c:2834: align_ag_geometry: Assertion `cfg->agcount != 0' failed. > > This is because align_ag_geometry() finds that the size of the last > (only) AG is too small, and attempts to trim it off. Obviously 0 > AGs is invalid, and we hit the ASSERT. > > Fix this by skipping the last-ag-trim if there is only one AG, and > add a new test to validate_ag_geometry() which offers a very specific, > clear warning if the device (in dblocks) is smaller than the minimum > allowed AG size. > > Reported-by: Zdenek Kabelac > Signed-off-by: Eric Sandeen > --- > > diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c > index a687f385..da8c5986 100644 > --- a/mkfs/xfs_mkfs.c > +++ b/mkfs/xfs_mkfs.c > @@ -1038,6 +1038,15 @@ validate_ag_geometry( > uint64_t agsize, > uint64_t agcount) > { > + /* Is this device simply too small? */ > + if (dblocks < XFS_AG_MIN_BLOCKS(blocklog)) { > + fprintf(stderr, > + _("device (%lld blocks) too small, need at least %lld blocks\n"), > + (long long)dblocks, > + (long long)XFS_AG_MIN_BLOCKS(blocklog)); > + usage(); > + } Ummm, shouldn't this be caught two checks later down by this: if (agsize > dblocks) { fprintf(stderr, _("agsize (%lld blocks) too big, data area is %lld blocks\n"), (long long)agsize, (long long)dblocks); usage(); } because the agsize has already been validated to be within XFS_AG_MIN_BLOCKS() and XFS_AG_MAX_BLOCKS(), so if dblocks is only 10MB then the agsize must be greater than dblocks as the minimum valid AG size is 16MB.... Also, what's with the repeated agsize < XFS_AG_MIN_BLOCKS(blocklog) and agsize > XFS_AG_MAX_BLOCKS(blocklog) checks in that function? > + > if (agsize < XFS_AG_MIN_BLOCKS(blocklog)) { > fprintf(stderr, > _("agsize (%lld blocks) too small, need at least %lld blocks\n"), > @@ -2827,11 +2836,12 @@ validate: > * and drop the blocks. > */ > if (cfg->dblocks % cfg->agsize != 0 && > + cfg->agcount > 1 && > (cfg->dblocks % cfg->agsize < XFS_AG_MIN_BLOCKS(cfg->blocklog))) { > +printf("%d %d %d\n", cfg->dblocks, cfg->agsize, cfg->dblocks % cfg->agsize); > ASSERT(!cli_opt_set(&dopts, D_AGCOUNT)); > cfg->dblocks = (xfs_rfsblock_t)((cfg->agcount - 1) * cfg->agsize); > cfg->agcount--; > - ASSERT(cfg->agcount != 0); > } We should never get here - this assert and code check is correct and valid - it's pointed us directly to a logic bug in mkfs, so IMO it should not be changed/removed. Cheers, Dave. -- Dave Chinner david@fromorbit.com