From: Dave Chinner <david@fromorbit.com>
To: Brian Foster <bfoster@redhat.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 5/9] repair: detect CRC errors in AG headers
Date: Wed, 16 Apr 2014 07:52:14 +1000 [thread overview]
Message-ID: <20140415215214.GO15995@dastard> (raw)
In-Reply-To: <20140415194029.GC3470@laptop.bfoster>
On Tue, Apr 15, 2014 at 03:40:29PM -0400, Brian Foster wrote:
> On Tue, Apr 15, 2014 at 06:24:57PM +1000, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> >
> > repair doesn't currently detect verifier errors in AG header
> > blocks - apart from the primary superblock they are not detected.
> > They are, fortunately, corrected in the important cases (AGF, AGI
> > and AGFL) because these structures are rebuilt in phase 5, but if
> > you run xfs_repair in checking mode it won't report them as bad.
> >
> > Signed-off-by: Dave Chinner <dchinner@redhat.com>
....
> > @@ -1285,7 +1287,7 @@ scan_ag(
> > do_warn(_("would reset bad agf for ag %d\n"), agno);
> > }
> > }
> > - if (status & XR_AG_AGI) {
> > + if (agi_dirty || status & XR_AG_AGI) {
> > if (!no_modify) {
> > do_warn(_("reset bad agi for ag %d\n"), agno);
> > agi_dirty = 1;
>
> There are a few asserts a bit further down this function that assume
> *_dirty is set only when in !no_modify mode. E.g.:
>
> ASSERT(agi_dirty == 0 || (agi_dirty && !no_modify));
>
> You'll probably want to remove those. Or...
I thought I caught all of those...
>
> > @@ -1295,15 +1297,9 @@ scan_ag(
> > }
> >
> > if (status && no_modify) {
> > - libxfs_putbuf(agibuf);
> > - libxfs_putbuf(agfbuf);
> > - libxfs_putbuf(sbbuf);
> > - free(sb);
> > -
> > do_warn(_("bad uncorrected agheader %d, skipping ag...\n"),
> > agno);
> > -
> > - return;
> > + goto out_free;
> > }
>
> Would we want to skip the ag, as such, on a CRC error in no_modify mode?
> If so, perhaps we could set the status variable on crc errors and
> bitwise or the value returned from verify_set_agheader().
I figured that for CRC errors we really should try to validate
everything if we can. If nothing else fails the validation, then it
might be a bit flip in an unused portion of the sector and in that
case we can actually continue onwards. IOWs, a CRC error is not
necessarily fatal....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2014-04-15 21:52 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-15 8:24 [PATCH 0/9] xfs_db, xfs_repair: improve CRC error detection Dave Chinner
2014-04-15 8:24 ` [PATCH 1/9] db: don't claim unchecked CRCs are correct Dave Chinner
2014-04-21 7:00 ` Christoph Hellwig
2014-04-21 23:13 ` Dave Chinner
2014-04-15 8:24 ` [PATCH 2/9] db: verify buffer on type change Dave Chinner
2014-04-21 7:02 ` Christoph Hellwig
2014-04-21 23:14 ` Dave Chinner
2014-04-15 8:24 ` [PATCH 3/9] repair: ensure prefetched buffers have CRCs validated Dave Chinner
2014-04-15 19:40 ` Brian Foster
2014-04-15 21:46 ` Dave Chinner
2014-04-15 22:06 ` Brian Foster
2014-04-16 0:41 ` Dave Chinner
2014-04-15 8:24 ` [PATCH 4/9] repair: detect and correct CRC errors in directory blocks Dave Chinner
2014-04-21 7:08 ` Christoph Hellwig
2014-04-15 8:24 ` [PATCH 5/9] repair: detect CRC errors in AG headers Dave Chinner
2014-04-15 19:40 ` Brian Foster
2014-04-15 21:52 ` Dave Chinner [this message]
2014-04-21 7:11 ` Christoph Hellwig
2014-04-21 23:35 ` Dave Chinner
2014-04-22 6:47 ` Christoph Hellwig
2014-04-22 9:10 ` Dave Chinner
2014-04-22 9:41 ` Christoph Hellwig
2014-04-15 8:24 ` [PATCH 6/9] repair: report AG btree verifier errors Dave Chinner
2014-04-15 19:40 ` Brian Foster
2014-04-15 21:53 ` Dave Chinner
2014-04-15 8:24 ` [PATCH 7/9] repair: remove more dirv1 leftovers Dave Chinner
2014-04-16 13:23 ` Brian Foster
2014-04-21 7:14 ` Christoph Hellwig
2014-04-21 7:13 ` Christoph Hellwig
2014-04-15 8:25 ` [PATCH 8/9] repair: handle remote sylmlink CRC errors Dave Chinner
2014-04-16 13:23 ` Brian Foster
2014-04-15 8:25 ` [PATCH 9/9] repair: detect and handle attribute tree " Dave Chinner
2014-04-16 13:25 ` Brian Foster
2014-04-21 23:27 ` Dave Chinner
-- strict thread matches above, loose matches on Subject: below --
2014-04-24 5:01 [PATCH 0/9 V2] xfs_db, xfs_repair: improve CRC error detection Dave Chinner
2014-04-24 5:01 ` [PATCH 5/9] repair: detect CRC errors in AG headers Dave Chinner
2014-04-25 5:55 ` Christoph Hellwig
2014-04-28 21:04 [PATCH 0/9 v3] xfs_db, xfs_repair: improve CRC error detection Dave Chinner
2014-04-28 21:04 ` [PATCH 5/9] repair: detect CRC errors in AG headers Dave Chinner
2014-04-29 14:06 ` Brian Foster
2014-05-01 23:27 ` Dave Chinner
2014-04-29 18:16 ` Christoph Hellwig
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