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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 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 EA529C43603 for ; Thu, 12 Dec 2019 22:46:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AD54D22527 for ; Thu, 12 Dec 2019 22:46:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="mQC0Xvzm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731007AbfLLWq0 (ORCPT ); Thu, 12 Dec 2019 17:46:26 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:51462 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730707AbfLLWq0 (ORCPT ); Thu, 12 Dec 2019 17:46:26 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xBCMiDQp080238; Thu, 12 Dec 2019 22:46:22 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2019-08-05; bh=UpOYe5/eemoqvnNgJueQwccjL5Kfdfpw+LyjP29qFxc=; b=mQC0XvzmA7/DzwZ5r6rGx9g4oJcPMeqgoMN3lJQT2/xp4bVBDGDius9wZ/ZPuAOOYR5n XrtJ6JSx/DURw69VRIYEv33vC3X9gFTRA9CC4DyFP48Eh9ogQ0gQEG8S/iRjQHuAoe/W VcKJ9wl8S8UEzn7cJGvvWxWY/oMtRDRayO7DEU7waeaGTc+vXgwaYywFSbLVAh8oHV4w ao7Y6lsqraonu2BPSNUH3sP1nfN+OME46gg2E4BWYp5QgzwsUQChddiMMvCbuU65uzZE 8WLPilCaJSja7yKAmiogJ2tK1aXNwowEd9sKUHlCvx0E3KhLOB7M6u6l62Sco1x5lmzz Xw== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2130.oracle.com with ESMTP id 2wrw4njtxt-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 12 Dec 2019 22:46:22 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xBCMiKq3019999; Thu, 12 Dec 2019 22:46:21 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3020.oracle.com with ESMTP id 2wumw1yv7u-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 12 Dec 2019 22:46:21 +0000 Received: from abhmp0006.oracle.com (abhmp0006.oracle.com [141.146.116.12]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id xBCMkJIX007684; Thu, 12 Dec 2019 22:46:19 GMT Received: from localhost (/10.145.178.64) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 12 Dec 2019 14:46:19 -0800 Date: Thu, 12 Dec 2019 14:46:18 -0800 From: "Darrick J. Wong" To: Brian Foster Cc: sandeen@sandeen.net, linux-xfs@vger.kernel.org, alex@zadara.com Subject: Re: [PATCH 6/6] xfs_repair: check plausibility of root dir pointer before trashing it\ Message-ID: <20191212224618.GE99875@magnolia> References: <157547906289.974712.8933333382010386076.stgit@magnolia> <157547910268.974712.78208912903649937.stgit@magnolia> <20191205143858.GF48368@bfoster> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191205143858.GF48368@bfoster> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9469 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1912120174 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9469 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1912120174 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Thu, Dec 05, 2019 at 09:38:58AM -0500, Brian Foster wrote: > On Wed, Dec 04, 2019 at 09:05:02AM -0800, Darrick J. Wong wrote: > > From: Darrick J. Wong > > > > If sb_rootino doesn't point to where we think mkfs should have allocated > > the root directory, check to see if the alleged root directory actually > > looks like a root directory. If so, we'll let it live because someone > > could have changed sunit since formatting time, and that changes the > > root directory inode estimate. > > > > Signed-off-by: Darrick J. Wong > > --- > > repair/xfs_repair.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 45 insertions(+) > > > > > > diff --git a/repair/xfs_repair.c b/repair/xfs_repair.c > > index abd568c9..b0407f4b 100644 > > --- a/repair/xfs_repair.c > > +++ b/repair/xfs_repair.c > > @@ -426,6 +426,37 @@ _("would reset superblock %s inode pointer to %"PRIu64"\n"), > > *ino = expected_ino; > > } > > > > +/* Does the root directory inode look like a plausible root directory? */ > > +static bool > > +has_plausible_rootdir( > > + struct xfs_mount *mp) > > +{ > > + struct xfs_inode *ip; > > + xfs_ino_t ino; > > + int error; > > + bool ret = false; > > + > > + error = -libxfs_iget(mp, NULL, mp->m_sb.sb_rootino, 0, &ip, > > + &xfs_default_ifork_ops); > > + if (error) > > + goto out; > > + if (!S_ISDIR(VFS_I(ip)->i_mode)) > > + goto out_rele; > > + > > + error = -libxfs_dir_lookup(NULL, ip, &xfs_name_dotdot, &ino, NULL); > > + if (error) > > + goto out_rele; > > + > > + /* The root directory '..' entry points to the directory. */ > > + if (ino == mp->m_sb.sb_rootino) > > + ret = true; > > + > > +out_rele: > > + libxfs_irele(ip); > > +out: > > + return ret; > > +} > > + > > /* > > * Make sure that the first 3 inodes in the filesystem are the root directory, > > * the realtime bitmap, and the realtime summary, in that order. > > @@ -436,6 +467,20 @@ calc_mkfs( > > { > > xfs_ino_t rootino = libxfs_ialloc_calc_rootino(mp, -1); > > > > + /* > > + * If the root inode isn't where we think it is, check its plausibility > > + * as a root directory. It's possible that somebody changed sunit > > + * since the filesystem was created, which can change the value of the > > + * above computation. Don't blow up the root directory if this is the > > + * case. > > + */ > > + if (mp->m_sb.sb_rootino != rootino && has_plausible_rootdir(mp)) { > > + do_warn( > > +_("sb root inode value %" PRIu64 " inconsistent with alignment (expected %"PRIu64")\n"), > > + mp->m_sb.sb_rootino, rootino); > > + rootino = mp->m_sb.sb_rootino; > > + } > > + > > A slightly unfortunate side effect of this is that there's seemingly no > straightforward way for a user to "clear" this state/warning. We've > solved the major problem by allowing repair to handle this condition, > but AFAICT this warning will persist unless the stripe unit is changed > back to its original value. Heh, I apparently never replied to this. :( > IOW, what if this problem exists simply because a user made a mistake > and wants to undo it? It's probably easy enough for us to say "use > whatever you did at mkfs time," but what if that's unknown or was set > automatically? I feel like that is the type of thing that in practice > could result in unnecessary bugs or error reports unless the tool can > make a better suggestion to the end user. For example, could we check > the geometry on secondary supers (if they exist) against the current > rootino and use that as a secondary form of verification and/or suggest > the user reset to that geometry (if desired)? That sounds reasonable. > OTOH, I guess we'd have to consider what happens if the filesystem was > grown in that scenario too.. :/ I think it would be fine, so long as we're careful with the if-then chain. Specifically: a. If we dislike the rootino that we compute with the ondisk sunit value, and... b. The thing sb_rootino points to actually does look like the root directory, and... c. One of the secondary supers has an sunit value that gives us a rootino calculation that matches the sb_rootino that we just checked out... ...then we'll propose correcting the primary sb_unit to the value we found in (c). > > (Actually on a quick test, it looks like growfs updates every super, > even preexisting..). I'll throw that onto the V3 series. --D > > Brian > > > ensure_fixed_ino(&mp->m_sb.sb_rootino, rootino, > > _("root")); > > ensure_fixed_ino(&mp->m_sb.sb_rbmino, rootino + 1, > > >