From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp1040.oracle.com ([141.146.126.69]:27670 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752173AbdAZB1k (ORCPT ); Wed, 25 Jan 2017 20:27:40 -0500 Date: Wed, 25 Jan 2017 17:27:32 -0800 From: "Darrick J. Wong" Subject: Re: [PATCH v10 1/5] xfs_db: sanitize agcount on load Message-ID: <20170126012732.GQ9134@birch.djwong.org> References: <148494391629.5256.3328772079712970611.stgit@birch.djwong.org> <148494392247.5256.10692618169002348643.stgit@birch.djwong.org> <20170123213108.GD31202@birch.djwong.org> <6ad3798a-c3f5-fd8f-ab05-62c0f878290c@sandeen.net> <17bbf8d4-39f7-a542-6c9d-3cd96e865ddf@sandeen.net> <886473a5-c0ff-a5b7-38bc-13d4d5d13c3c@sandeen.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Eric Sandeen Cc: sandeen@redhat.com, linux-xfs@vger.kernel.org On Wed, Jan 25, 2017 at 07:17:56PM -0600, Eric Sandeen wrote: > Before we get into libxfs_initialize_perag and try to blindly > allocate a perag struct for every (possibly corrupted number of) > AGs, see if we can read the last one. If not, assume it's corrupt, > and load only the first AG. > > Do this only for an arbitrarily high-ish agcount, so that normal-ish > geometry on a possibly truncated file or device will still do > its best to make all readable AGs available. > > Set xfs_db's exitcode to 1 if this happens. > > Also teach metadump to detect this and exit appropriately if > truncated, as it resets exitcode to 0 for its own purposes internally. > > Signed-off-by: Eric Sandeen Reviewed-by: Darrick J. Wong > --- > > v1->v6: Tale of woe. > v7: blow it all up > v8: use bare libxfs_readbuf so verifiers don't matter, > "ours goes to 1 million!" > v9: Fix printf format, exit metadump with error if things look wonky. > v10: set exitcode to 1 in init(). > > diff --git a/db/init.c b/db/init.c > index ec1e274..59fc3e0 100644 > --- a/db/init.c > +++ b/db/init.c > @@ -58,6 +58,7 @@ init( > { > struct xfs_sb *sbp; > struct xfs_buf *bp; > + unsigned int agcount; > int c; > > setlocale(LC_ALL, ""); > @@ -148,6 +149,7 @@ init( > } > } > > + agcount = sbp->sb_agcount; > mp = libxfs_mount(&xmount, sbp, x.ddev, x.logdev, x.rtdev, > LIBXFS_MOUNT_DEBUGGER); > if (!mp) { > @@ -159,6 +161,10 @@ init( > mp->m_log = &xlog; > blkbb = 1 << mp->m_blkbb_log; > > + /* Did we limit a broken agcount in libxfs_mount? */ > + if (sbp->sb_agcount != agcount) > + exitcode = 1; > + > /* > * xfs_check needs corrected incore superblock values > */ > diff --git a/db/metadump.c b/db/metadump.c > index 1ba6b38..38519f1 100644 > --- a/db/metadump.c > +++ b/db/metadump.c > @@ -2760,6 +2760,16 @@ metadump_f( > return 0; > } > > + /* > + * on load, we sanity-checked agcount and possibly set to 1 > + * if it was corrupted and large. > + */ > + if (mp->m_sb.sb_agcount == 1 && > + XFS_MAX_DBLOCKS(&mp->m_sb) < mp->m_sb.sb_dblocks) { > + print_warning("truncated agcount, giving up"); > + return 0; > + } > + > while ((c = getopt(argc, argv, "aegm:ow")) != EOF) { > switch (c) { > case 'a': > diff --git a/libxfs/init.c b/libxfs/init.c > index a08575a..85e0d15 100644 > --- a/libxfs/init.c > +++ b/libxfs/init.c > @@ -817,6 +817,29 @@ libxfs_mount( > return NULL; > } > > + /* > + * libxfs_initialize_perag will allocate a perag structure for each ag. > + * If agcount is corrupted and insanely high, this will OOM the box. > + * If the agount seems (arbitrarily) high, try to read what would be > + * the last AG, and if that fails for a relatively high agcount, just > + * read the first one and let the user know to check the geometry. > + */ > + if (sbp->sb_agcount > 1000000) { > + bp = libxfs_readbuf(mp->m_dev, > + XFS_AG_DADDR(mp, sbp->sb_agcount - 1, 0), 1, > + !(flags & LIBXFS_MOUNT_DEBUGGER), NULL); > + if (bp->b_error) { > + fprintf(stderr, _("%s: read of AG %u failed\n"), > + progname, sbp->sb_agcount); > + if (!(flags & LIBXFS_MOUNT_DEBUGGER)) > + return NULL; > + fprintf(stderr, _("%s: limiting reads to AG 0\n"), > + progname); > + sbp->sb_agcount = 1; > + } > + libxfs_putbuf(bp); > + } > + > error = libxfs_initialize_perag(mp, sbp->sb_agcount, &mp->m_maxagi); > if (error) { > fprintf(stderr, _("%s: perag init failed\n"), > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html