From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:16682 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753028AbcGGX60 (ORCPT ); Thu, 7 Jul 2016 19:58:26 -0400 Date: Thu, 7 Jul 2016 16:58:13 -0700 From: "Darrick J. Wong" To: Dave Chinner Cc: Brian Foster , linux-fsdevel@vger.kernel.org, vishal.l.verma@intel.com, Dave Chinner , xfs@oss.sgi.com Subject: Re: [PATCH 028/119] xfs: define the on-disk rmap btree format Message-ID: <20160707235813.GA17991@birch.djwong.org> References: <146612627129.12839.3827886950949809165.stgit@birch.djwong.org> <146612645206.12839.17008642336898856662.stgit@birch.djwong.org> <20160707184156.GB33740@bfoster.bfoster> <20160707191813.GB12567@birch.djwong.org> <20160707231455.GJ12670@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160707231455.GJ12670@dastard> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, Jul 08, 2016 at 09:14:55AM +1000, Dave Chinner wrote: > On Thu, Jul 07, 2016 at 12:18:13PM -0700, Darrick J. Wong wrote: > > On Thu, Jul 07, 2016 at 02:41:56PM -0400, Brian Foster wrote: > > > > + if (!xfs_sb_version_hasrmapbt(&mp->m_sb)) > > > > + return false; > > > > + if (!xfs_btree_sblock_v5hdr_verify(bp)) > > > > + return false; > > > > + > > > > + level = be16_to_cpu(block->bb_level); > > > > + if (pag && pag->pagf_init) { > > > > + if (level >= pag->pagf_levels[XFS_BTNUM_RMAPi]) > > > > + return false; > > > > + } else if (level >= mp->m_rmap_maxlevels) > > > > + return false; > > > > > > It looks like the above (level >= mp->m_rmap_maxlevels) check could be > > > independent (rather than an 'else). Otherwise looks good: > > > > Hmmm.... at first I wondered, "Shouldn't we have already checked that > > pag->pagf_levels[XFS_BTNUM_RMAPi] <= mp->m_rmap_maxlevels?" But then I > > realized that no, we don't do that anywhere. Nor does the bnobt/cntbt > > verifier. Am I missing something? (Yes, I am.) > It should have been ranged checked when the AGF is first read in > (i.e. in the verifier), in ASSERTS every time xfs_alloc_read_agf() > is called after initialisation, and then every time the verifier is > run on write of the AGF. You're right. I missed that. :( > > I did see that we at least check the AGF/AGI levels to make sure they don't > > overflow XFS_BTREE_MAXLEVELS, so we're probably fine here. > > Precisely - if the AGF verifier doesn't have a max level check in it > for the rmapbt, then we need to add one there. There's a check there, so we're fine. --D > > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com