From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:49054 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752303AbdDKATi (ORCPT ); Mon, 10 Apr 2017 20:19:38 -0400 Date: Mon, 10 Apr 2017 17:19:32 -0700 From: "Darrick J. Wong" Subject: Re: [PATCH 2/4] xfs_db: use iocursor type to guess btree geometry if bad magic Message-ID: <20170411001932.GA5094@birch.djwong.org> References: <149186446125.32572.5134583964816531229.stgit@birch.djwong.org> <149186447366.32572.11858750403661352513.stgit@birch.djwong.org> <20170411000332.GB12369@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170411000332.GB12369@dastard> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Dave Chinner Cc: sandeen@redhat.com, linux-xfs@vger.kernel.org On Tue, Apr 11, 2017 at 10:03:32AM +1000, Dave Chinner wrote: > On Mon, Apr 10, 2017 at 03:47:53PM -0700, Darrick J. Wong wrote: > > From: Darrick J. Wong > > > > The function block_to_bt plays an integral role in determining the btree > > geometry of a block that we want to manipulate with the debugger. > > Normally we use the block magic to find the geometry profile, but if the > > magic is bad we'll never find it and return NULL. The callers of this > > function do not check for NULL and crash. > > > > Therefore, if we can't find a geometry profile matching the magic > > number, use the iocursor type to guess the profile and scowl about that > > to stdout. This makes it so that even with a corrupt magic we can try > > to print the fields instead of crashing the debugger. > > > > Signed-off-by: Darrick J. Wong > > --- > > v2: be less macro-happy and only evaluate hascrc once > > --- > > db/btblock.c | 52 ++++++++++++++++++++++++++++++++++++++++++++-------- > > 1 file changed, 44 insertions(+), 8 deletions(-) > > > > > > diff --git a/db/btblock.c b/db/btblock.c > > index 835a5f0..e494f3e 100644 > > --- a/db/btblock.c > > +++ b/db/btblock.c > > @@ -25,6 +25,8 @@ > > #include "print.h" > > #include "bit.h" > > #include "init.h" > > +#include "io.h" > > +#include "output.h" > > > > /* > > * Definition of the possible btree block layouts. > > @@ -122,13 +124,50 @@ static struct xfs_db_btree * > > block_to_bt( > > struct xfs_btree_block *bb) > > { > > - struct xfs_db_btree *btp = &btrees[0]; > > + struct xfs_db_btree *btp; > > + uint32_t magic; > > + bool crc; > > + > > + magic = be32_to_cpu((bb)->bb_magic); > > + for (btp = &btrees[0]; btp->magic != 0; btp++) > > + if (magic == btp->magic) > > + return btp; > > {} Sure. --D > > -Dave. > -- > Dave Chinner > david@fromorbit.com > -- > 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