From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Dave Chinner <david@fromorbit.com>
Cc: linux-xfs@vger.kernel.org
Subject: Re: [PATCH 11/25] xfs: scrub the AGI
Date: Wed, 4 Oct 2017 16:12:32 -0700 [thread overview]
Message-ID: <20171004231232.GA7122@magnolia> (raw)
In-Reply-To: <20171004221634.GG3666@dastard>
On Thu, Oct 05, 2017 at 09:16:34AM +1100, Dave Chinner wrote:
> On Wed, Oct 04, 2017 at 11:02:04AM -0700, Darrick J. Wong wrote:
> > On Wed, Oct 04, 2017 at 05:43:33PM +1100, Dave Chinner wrote:
> > > It seems to me that we're using the superblock 0 values as the
> > > golden master because it's a mounted filesystem, and then comparing
> > > everything else against it. Maybe we should at least check a couple
> > > of secondary superblocks to see that they match the primary
> > > superblock - that way we'll have some confidence that at least
> > > things like agcount, agblocks, dblocks, etc are valid before we go
> > > any further...
> >
> > xfs_scrub_superblock does check the secondary superblock geometry
> > against whatever's in mp->m_sb, which came from sb 0.
>
> /me smacks forehead
>
> The patch is even named "scrub the backup superblocks".
>
> Perhaps it didn't sink in because they are normally called
> "secondary superblocks". My bad....
Sometimes I think I still have ext4 on the brain. :(
--D
> > > BUt maybe all we need is comment in the overall scrub description -
> > > that we're pretty much assuming that sb 0 is intact because we write
> > > what is in memory back to it and so we can simply validate
> > > everything else against the primary superblock contents...
> >
> > Correct. Since scrub is run against a mounted live filesystem we assume
> > that the mount code fully validated sb 0 and therefore we can rely on it
> > not being wrong.
> >
> > If OTOH sb 0 *is* wrong then the admin is better off running xfs_repair
> > because there's too much whirring machinery to go changing fundamental
> > geometry.
>
> Yup, that makes sense.
>
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@fromorbit.com
> --
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next prev parent reply other threads:[~2017-10-04 23:12 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-03 20:40 [PATCH v11 00/25] xfs: online scrub support Darrick J. Wong
2017-10-03 20:40 ` [PATCH 01/25] xfs: create an ioctl to scrub AG metadata Darrick J. Wong
2017-10-03 20:41 ` [PATCH 02/25] xfs: dispatch metadata scrub subcommands Darrick J. Wong
2017-10-03 20:41 ` [PATCH 03/25] xfs: probe the scrub ioctl Darrick J. Wong
2017-10-03 23:32 ` Dave Chinner
2017-10-04 0:02 ` Darrick J. Wong
2017-10-04 1:56 ` Dave Chinner
2017-10-04 3:14 ` Darrick J. Wong
2017-10-03 20:41 ` [PATCH 04/25] xfs: create helpers to record and deal with scrub problems Darrick J. Wong
2017-10-03 23:44 ` Dave Chinner
2017-10-04 0:56 ` Darrick J. Wong
2017-10-03 20:41 ` [PATCH 05/25] xfs: create helpers to scrub a metadata btree Darrick J. Wong
2017-10-03 23:49 ` Dave Chinner
2017-10-04 0:13 ` Darrick J. Wong
2017-10-03 20:41 ` [PATCH 06/25] xfs: scrub the shape of " Darrick J. Wong
2017-10-04 0:15 ` Dave Chinner
2017-10-04 3:51 ` Darrick J. Wong
2017-10-04 5:48 ` Dave Chinner
2017-10-04 17:48 ` Darrick J. Wong
2017-10-03 20:41 ` [PATCH 07/25] xfs: scrub btree keys and records Darrick J. Wong
2017-10-04 20:52 ` Darrick J. Wong
2017-10-03 20:41 ` [PATCH 08/25] xfs: create helpers to scan an allocation group Darrick J. Wong
2017-10-04 0:46 ` Dave Chinner
2017-10-04 3:58 ` Darrick J. Wong
2017-10-04 5:59 ` Dave Chinner
2017-10-04 17:51 ` Darrick J. Wong
2017-10-03 20:41 ` [PATCH 09/25] xfs: scrub the backup superblocks Darrick J. Wong
2017-10-04 0:57 ` Dave Chinner
2017-10-04 4:06 ` Darrick J. Wong
2017-10-04 6:13 ` Dave Chinner
2017-10-04 17:56 ` Darrick J. Wong
2017-10-03 20:41 ` [PATCH 10/25] xfs: scrub AGF and AGFL Darrick J. Wong
2017-10-04 1:31 ` Dave Chinner
2017-10-04 4:21 ` Darrick J. Wong
2017-10-04 6:28 ` Dave Chinner
2017-10-04 17:57 ` Darrick J. Wong
2017-10-03 20:41 ` [PATCH 11/25] xfs: scrub the AGI Darrick J. Wong
2017-10-04 1:43 ` Dave Chinner
2017-10-04 4:25 ` Darrick J. Wong
2017-10-04 6:43 ` Dave Chinner
2017-10-04 18:02 ` Darrick J. Wong
2017-10-04 22:16 ` Dave Chinner
2017-10-04 23:12 ` Darrick J. Wong [this message]
2017-10-03 20:42 ` [PATCH 12/25] xfs: scrub free space btrees Darrick J. Wong
2017-10-05 0:59 ` Dave Chinner
2017-10-05 1:13 ` Darrick J. Wong
2017-10-03 20:42 ` [PATCH 13/25] xfs: scrub inode btrees Darrick J. Wong
2017-10-05 2:08 ` Dave Chinner
2017-10-05 5:47 ` Darrick J. Wong
2017-10-05 7:22 ` Dave Chinner
2017-10-05 18:26 ` Darrick J. Wong
2017-10-03 20:42 ` [PATCH 14/25] xfs: scrub rmap btrees Darrick J. Wong
2017-10-05 2:56 ` Dave Chinner
2017-10-05 5:02 ` Darrick J. Wong
2017-10-03 20:42 ` [PATCH 15/25] xfs: scrub refcount btrees Darrick J. Wong
2017-10-05 2:59 ` Dave Chinner
2017-10-05 5:02 ` Darrick J. Wong
2017-10-03 20:42 ` [PATCH 16/25] xfs: scrub inodes Darrick J. Wong
2017-10-05 4:04 ` Dave Chinner
2017-10-05 5:22 ` Darrick J. Wong
2017-10-05 7:13 ` Dave Chinner
2017-10-05 19:56 ` Darrick J. Wong
2017-10-03 20:42 ` [PATCH 17/25] xfs: scrub inode block mappings Darrick J. Wong
2017-10-06 2:51 ` Dave Chinner
2017-10-06 17:00 ` Darrick J. Wong
2017-10-07 23:10 ` Dave Chinner
2017-10-08 3:54 ` Darrick J. Wong
2017-10-03 20:42 ` [PATCH 18/25] xfs: scrub directory/attribute btrees Darrick J. Wong
2017-10-06 5:07 ` Dave Chinner
2017-10-06 18:30 ` Darrick J. Wong
2017-10-03 20:42 ` [PATCH 19/25] xfs: scrub directory metadata Darrick J. Wong
2017-10-06 7:07 ` Dave Chinner
2017-10-06 19:45 ` Darrick J. Wong
2017-10-06 22:16 ` Dave Chinner
2017-10-03 20:42 ` [PATCH 20/25] xfs: scrub directory freespace Darrick J. Wong
2017-10-09 1:44 ` Dave Chinner
2017-10-09 22:54 ` Darrick J. Wong
2017-10-03 20:43 ` [PATCH 21/25] xfs: scrub extended attributes Darrick J. Wong
2017-10-09 2:13 ` Dave Chinner
2017-10-09 21:14 ` Darrick J. Wong
2017-10-03 20:43 ` [PATCH 22/25] xfs: scrub symbolic links Darrick J. Wong
2017-10-09 2:17 ` Dave Chinner
2017-10-03 20:43 ` [PATCH 23/25] xfs: scrub parent pointers Darrick J. Wong
2017-10-03 20:43 ` [PATCH 24/25] xfs: scrub realtime bitmap/summary Darrick J. Wong
2017-10-09 2:28 ` Dave Chinner
2017-10-09 20:24 ` Darrick J. Wong
2017-10-03 20:43 ` [PATCH 25/25] xfs: scrub quota information Darrick J. Wong
2017-10-09 2:51 ` Dave Chinner
2017-10-09 20:03 ` Darrick J. Wong
2017-10-09 22:17 ` Dave Chinner
2017-10-09 23:08 ` Darrick J. Wong
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