From: Dave Chinner <david@fromorbit.com>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: linux-xfs@vger.kernel.org
Subject: Re: [PATCH 03/25] xfs: probe the scrub ioctl
Date: Wed, 4 Oct 2017 12:56:06 +1100 [thread overview]
Message-ID: <20171004015606.GY3666@dastard> (raw)
In-Reply-To: <20171004000209.GG6503@magnolia>
On Tue, Oct 03, 2017 at 05:02:09PM -0700, Darrick J. Wong wrote:
> On Wed, Oct 04, 2017 at 10:32:47AM +1100, Dave Chinner wrote:
> > On Tue, Oct 03, 2017 at 01:41:08PM -0700, Darrick J. Wong wrote:
> > > +/*
> > > + * Scrub probe -- userspace uses this to probe if we're willing to
> > > + * scrub or repair a given mountpoint.
> > > + */
> > > +int
> > > +xfs_scrub_probe(
> > > + struct xfs_scrub_context *sc)
> > > +{
> > > + if (sc->sm->sm_ino || sc->sm->sm_agno)
> > > + return -EINVAL;
> > > + if (sc->sm->sm_gen & ~XFS_SCRUB_FLAGS_OUT)
> >
> > sm_flags?
>
> sm_gen is correct because in xfs_scrub_probe we reflect back to
> userspace any valid scrub outflags that were passed in via sm_gen.
> Therefore we have to check sm_gen for unknown output flags so that we
> can error out on any invalid inputs from userland.
Hmmm - seeing sm_ino and sm_gen in the same structure immediately
makes me think {inode number, generation} tuple for uniquely
identifying inodes from userspace. What on earth would scrub output
flags be doing in a generation number? Indeed, from the first patch:
+struct xfs_scrub_metadata {
+ __u32 sm_type; /* What to check? */
+ __u32 sm_flags; /* flags; see below. */
+ __u64 sm_ino; /* inode number. */
+ __u32 sm_gen; /* inode generation. */
+ __u32 sm_agno; /* ag number. */
+ __u64 sm_reserved[5]; /* pad to 64 bytes */
....
It is an inode generation number?
So I'm somewhat confused by flags appearing in the generation
number...
> xfs_scrub_metadata() unconditionally clears all the out flags from
> sm_flags on its way in, prior to any of the scrub handlers being called.
>
> (It's possible I'm misunderstanding your question.)
What has tripped me up is that the probe function sm_gen abuse isn't
documented in this patch, so I had no idea why oflags were in
sm_gen. Maybe you explained it previously, but I don't remember
that detail and there's nothing in the patch to remind me....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2017-10-04 1:56 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 [this message]
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
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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