On Fri, Apr 05, 2019 at 01:33:19PM -0700, Darrick J. Wong wrote:
> On Thu, Apr 04, 2019 at 07:48:57AM -0400, Brian Foster wrote:
> > On Wed, Apr 03, 2019 at 09:11:06AM -0700, Darrick J. Wong wrote:
> > > On Wed, Apr 03, 2019 at 10:30:05AM -0400, Brian Foster wrote:
> > > > On Mon, Apr 01, 2019 at 10:10:52AM -0700, Darrick J. Wong wrote:
> > > > > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> > > > >
> > > > > Use the AG geometry info ioctl to report health status too.
> > > > >
> > > > > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> > > > > ---
> > > > > fs/xfs/libxfs/xfs_fs.h | 12 +++++++++++-
> > > > > fs/xfs/libxfs/xfs_health.h | 2 ++
> > > > > fs/xfs/xfs_health.c | 40 ++++++++++++++++++++++++++++++++++++++++
> > > > > fs/xfs/xfs_ioctl.c | 2 ++
> > > > > 4 files changed, 55 insertions(+), 1 deletion(-)
> > > > >
> > > > >
> > > > ...
> > > > > diff --git a/fs/xfs/xfs_health.c b/fs/xfs/xfs_health.c
> > > > > index 151c98693bef..5ca471bd41ad 100644
> > > > > --- a/fs/xfs/xfs_health.c
> > > > > +++ b/fs/xfs/xfs_health.c
> > > > > @@ -276,3 +276,43 @@ xfs_fsop_geom_health(
> > > > > if (sick & XFS_HEALTH_RT_SUMMARY)
> > > > > geo->health |= XFS_FSOP_GEOM_HEALTH_RT_SUMMARY;
> > > > > }
> > > > > +
> > > > > +/* Fill out ag geometry health info. */
> > > > > +void
> > > > > +xfs_ag_geom_health(
> > > > > + struct xfs_mount *mp,
> > > > > + xfs_agnumber_t agno,
> > > > > + struct xfs_ag_geometry *ageo)
> > > > > +{
> > > > > + struct xfs_perag *pag;
> > > > > + unsigned int sick;
> > > > > +
> > > > > + if (agno >= mp->m_sb.sb_agcount)
> > > > > + return;
> > > >
> > > > The call to xfs_ag_get_geometry() would have already returned an error
> > > > in the ioctl path for the above scenario. It might still make sense to
> > > > check here, but perhaps we could let this function also return an int
> > > > and return an error for consistency?
> > >
> > > Or maybe just ASSERT on the agno and add a note that the caller is
> > > required to pass in a valid ag number.
> > >
> > > > > +
> > > > > + ageo->ag_health = 0;
> > > > > +
> > > > > + pag = xfs_perag_get(mp, agno);
> > > > > + sick = xfs_ag_measure_sickness(pag);
> > > > > + if (sick & XFS_HEALTH_AG_SB)
> > > > > + ageo->ag_health |= XFS_AG_GEOM_HEALTH_AG_SB;
> > > >
> > > > I'm starting to wonder whether "health" is the best term to use for the
> > > > interface bits just because it reads a little weird to measure
> > > > "sickness" and then apply all the sick state to something called
> > > > "health." I don't have a better suggestion off the top of my head,
> > > > though. Just something to think about a bit more from an API
> > > > standpoint..
> > >
> > > I had the same conundrum. I guess we could start the bitset with -1 and
> > > clear bits when scrub says they've gone bad? That would be much clearer
> > > with regards to the names, but technically we don't know the health of a
> > > structure until we scan it, so I wouldn't want to represent the fs as
> > > being "healthy" having not actually looked for problems.
> > >
> > > What we /really/ need is a tri-state bitset[1]:
> > >
> > > enum Bool
> > > {
> > > True,
> > > False,
> > > FileNotFound
> > > };
> > >
> > > But maybe I will try renaming all this to "sick" again.
> > >
> > > if (sick & XFS_SICK_AG_AGF)
> > > ageo->ag_sick |= XFS_AG_GEOM_SICK_AG_AGF;
> > >
> > > Gosh. That second name is gross. XFS_AG_GEOM_SICK_AGF.
> > >
> > > Sick sick sick sick sick. Ok, I've convinced myself of the name change. :P
> > >
> >
> > Heh. I suppose we could either invert the logic or perhaps try to come
> > up with a better keyword than "health" for the exported bits (at least).
> > If I see ag_health in a data structure, for example, I'm assuming it's
> > telling me what is healthy. Of course we'll have documentation and
> > whatnot to clear that up..
> >
> > Another term that came to mind is "fault" or "faulted" as it has
> > precedent in storage contexts wrt to raid. I.e., ag_faults and
> > XFS_AG_GEOM_FAULT_AGF, etc. etc. To me it also kind of covers the angle
> > that we aren't necessarily stating a subset of the filesystem is healthy
> > due to lack of faults if we just haven't scrubbed/found anything. Hm? I
> > guess it could be confused with reporting underlying storage problems. I
> > dunno... it's more clear to me, but maybe others have ideas..
>
> I have a (not very strong) preference for 'sick' over 'fault' because
> there are other parts of xfs where we deal with (page) faults and I
> don't really want to get "file metadata faults" and "file page faults"
> confused.
>
> (I'm not sure anyone is really going to confuse them, though...)
>
Ok. Either way, I think a field/bit prefix name that reflects borkedness
over health is a bit more intuitive with the current semantics (i.e.,
bit set means something is borked).
Brian
> --D
>
> > Brian
> >
> > > --D
> > >
> > > [1] https://thedailywtf.com/articles/What_Is_Truth_0x3f_
> > >
> > > > Brian
> > > >
> > > > > + if (sick & XFS_HEALTH_AG_AGF)
> > > > > + ageo->ag_health |= XFS_AG_GEOM_HEALTH_AG_AGF;
> > > > > + if (sick & XFS_HEALTH_AG_AGFL)
> > > > > + ageo->ag_health |= XFS_AG_GEOM_HEALTH_AG_AGFL;
> > > > > + if (sick & XFS_HEALTH_AG_AGI)
> > > > > + ageo->ag_health |= XFS_AG_GEOM_HEALTH_AG_AGI;
> > > > > + if (sick & XFS_HEALTH_AG_BNOBT)
> > > > > + ageo->ag_health |= XFS_AG_GEOM_HEALTH_AG_BNOBT;
> > > > > + if (sick & XFS_HEALTH_AG_CNTBT)
> > > > > + ageo->ag_health |= XFS_AG_GEOM_HEALTH_AG_CNTBT;
> > > > > + if (sick & XFS_HEALTH_AG_INOBT)
> > > > > + ageo->ag_health |= XFS_AG_GEOM_HEALTH_AG_INOBT;
> > > > > + if (sick & XFS_HEALTH_AG_FINOBT)
> > > > > + ageo->ag_health |= XFS_AG_GEOM_HEALTH_AG_FINOBT;
> > > > > + if (sick & XFS_HEALTH_AG_RMAPBT)
> > > > > + ageo->ag_health |= XFS_AG_GEOM_HEALTH_AG_RMAPBT;
> > > > > + if (sick & XFS_HEALTH_AG_REFCNTBT)
> > > > > + ageo->ag_health |= XFS_AG_GEOM_HEALTH_AG_REFCNTBT;
> > > > > + xfs_perag_put(pag);
> > > > > +}
> > > > > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> > > > > index f9bf11b6a055..f1fc5e53cfc1 100644
> > > > > --- a/fs/xfs/xfs_ioctl.c
> > > > > +++ b/fs/xfs/xfs_ioctl.c
> > > > > @@ -853,6 +853,8 @@ xfs_ioc_ag_geometry(
> > > > > if (error)
> > > > > return error;
> > > > >
> > > > > + xfs_ag_geom_health(mp, ageo.ag_number, &ageo);
> > > > > +
> > > > > if (copy_to_user(arg, &ageo, sizeof(ageo)))
> > > > > return -EFAULT;
> > > > > return 0;
> > > > >
