Re: [PATCH 06/22] xfs: add a repair helper to reset superblock counters

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Wed, May 16, 2018 at 02:29:27PM -0700, Allison Henderson wrote:
> On 05/15/2018 03:34 PM, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > Add a helper function to reset the superblock inode and block counters.
> > The AG rebuilding functions will need these to adjust the counts if they
> > need to change as a part of recovering from corruption.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> >   fs/xfs/scrub/repair.c |   79 +++++++++++++++++++++++++++++++++++++++++++++++++
> >   fs/xfs/scrub/repair.h |    7 ++++
> >   fs/xfs/scrub/scrub.c  |    2 +
> >   fs/xfs/scrub/scrub.h  |    1 +
> >   4 files changed, 89 insertions(+)
> > 
> > 
> > diff --git a/fs/xfs/scrub/repair.c b/fs/xfs/scrub/repair.c
> > index 06c84f76d7ff..1ca7e124e1a7 100644
> > --- a/fs/xfs/scrub/repair.c
> > +++ b/fs/xfs/scrub/repair.c
> > @@ -944,3 +944,82 @@ xfs_repair_find_ag_btree_roots(
> >   	return error;
> >   }
> > +
> > +/* Reset the superblock counters from the AGF/AGI. */
> > +int
> > +xfs_repair_reset_counters(
> > +	struct xfs_mount	*mp)
> > +{
> > +	struct xfs_buf		*agi_bp;
> > +	struct xfs_buf		*agf_bp;
> > +	struct xfs_agi		*agi;
> > +	struct xfs_agf		*agf;
> > +	xfs_agnumber_t		agno;
> > +	xfs_ino_t		icount = 0;
> > +	xfs_ino_t		ifree = 0;
> > +	xfs_filblks_t		fdblocks = 0;
> > +	int64_t			delta_icount;
> > +	int64_t			delta_ifree;
> > +	int64_t			delta_fdblocks;
> > +	int			error;
> > +
> > +	trace_xfs_repair_reset_counters(mp);
> > +
> > +	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
> > +		/* Count all the inodes... */
> > +		error = xfs_ialloc_read_agi(mp, NULL, agno, &agi_bp);
> > +		if (error)
> > +			return error;
> > +		agi = XFS_BUF_TO_AGI(agi_bp);
> > +		icount += be32_to_cpu(agi->agi_count);
> > +		ifree += be32_to_cpu(agi->agi_freecount);
> > +		xfs_buf_relse(agi_bp);
> > +
> > +		/* Add up the free/freelist/bnobt/cntbt blocks... */
> > +		error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agf_bp);
> > +		if (error)
> > +			return error;
> > +		if (!agf_bp)
> > +			return -ENOMEM;
> > +		agf = XFS_BUF_TO_AGF(agf_bp);
> > +		fdblocks += be32_to_cpu(agf->agf_freeblks);
> > +		fdblocks += be32_to_cpu(agf->agf_flcount);
> > +		fdblocks += be32_to_cpu(agf->agf_btreeblks);
> > +		xfs_buf_relse(agf_bp);
> > +	}
> > +
> > +	/*
> > +	 * Reinitialize the counters.  The on-disk and in-core counters differ
> > +	 * by the number of inodes/blocks reserved by the admin, the per-AG
> > +	 * reservation, and any transactions in progress, so we have to
> > +	 * account for that.  First we take the sb lock and update its
> > +	 * counters...
> > +	 */
> > +	spin_lock(&mp->m_sb_lock);
> > +	delta_icount = (int64_t)mp->m_sb.sb_icount - icount;
> > +	delta_ifree = (int64_t)mp->m_sb.sb_ifree - ifree;
> > +	delta_fdblocks = (int64_t)mp->m_sb.sb_fdblocks - fdblocks;
> > +	mp->m_sb.sb_icount = icount;
> > +	mp->m_sb.sb_ifree = ifree;
> > +	mp->m_sb.sb_fdblocks = fdblocks;
> > +	spin_unlock(&mp->m_sb_lock);
> > +
> > +	/* ...and then update the per-cpu counters. */
> > +	if (delta_icount) {
> > +		error = xfs_mod_icount(mp, delta_icount);
> > +		if (error)
> > +			return error;
> > +	}
> > +	if (delta_ifree) {
> > +		error = xfs_mod_ifree(mp, delta_ifree);
> > +		if (error)
> > +			return error;
> > +	}
> > +	if (delta_fdblocks) {
> > +		error = xfs_mod_fdblocks(mp, delta_fdblocks, false);
> > +		if (error)
> > +			return error;
> > +	}
> > +
> > +	return 0;
> > +}
> > diff --git a/fs/xfs/scrub/repair.h b/fs/xfs/scrub/repair.h
> > index 55441774e8e5..eea32a26f947 100644
> > --- a/fs/xfs/scrub/repair.h
> > +++ b/fs/xfs/scrub/repair.h
> > @@ -96,6 +96,7 @@ int xfs_repair_find_ag_btree_roots(struct xfs_scrub_context *sc,
> >   		struct xfs_buf *agf_bp,
> >   		struct xfs_repair_find_ag_btree *btree_info,
> >   		struct xfs_buf *agfl_bp);
> > +int xfs_repair_reset_counters(struct xfs_mount *mp);
> >   /* Metadata repairers */
> > @@ -121,6 +122,12 @@ xfs_repair_calc_ag_resblks(
> >   	return 0;
> >   }
> > +static inline int xfs_repair_reset_counters(struct xfs_mount *mp)
> > +{
> > +	ASSERT(0);
> > +	return -EIO;
> > +}
> > +
> >   #define xfs_repair_probe		xfs_repair_notsupported
> >   #endif /* CONFIG_XFS_ONLINE_REPAIR */
> > diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
> > index c5999c28c20c..bf5e8dd66133 100644
> > --- a/fs/xfs/scrub/scrub.c
> > +++ b/fs/xfs/scrub/scrub.c
> > @@ -200,6 +200,8 @@ xfs_scrub_teardown(
> >   		kmem_free(sc->buf);
> >   		sc->buf = NULL;
> >   	}
> > +	if (sc->reset_counters && !error)
> > +		error = xfs_repair_reset_counters(sc->mp);
> >   	return error;
> >   }
> > diff --git a/fs/xfs/scrub/scrub.h b/fs/xfs/scrub/scrub.h
> > index 2f89a84a0e10..1aaea393c2d1 100644
> > --- a/fs/xfs/scrub/scrub.h
> > +++ b/fs/xfs/scrub/scrub.h
> > @@ -77,6 +77,7 @@ struct xfs_scrub_context {
> >   	uint				ilock_flags;
> >   	bool				try_harder;
> >   	bool				has_quotaofflock;
> > +	bool				reset_counters;
> I noticed this bool is added here, and used in the conditional above,
> but I don't see where it gets set to anything?  Maybe it gets used later in
> the set?

Yeah, there are no callers of any of these helper functions until you
get to the part of the series where we actually start repairing
metadata.

--D

> Other than that looks good.  Thx!
> 
> Reviewed by: Allison Henderson <allison.henderson@oracle.com>
> 
> >   	/* State tracking for single-AG operations. */
> >   	struct xfs_scrub_ag		sa;
> > 
> > --
> > 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  https://urldefense.proofpoint.com/v2/url?u=http-3A__vger.kernel.org_majordomo-2Dinfo.html&d=DwICaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=LHZQ8fHvy6wDKXGTWcm97burZH5sQKHRDMaY1UthQxc&m=QJevHm77WCVmLISD9kjEPpN22CjDaymobWOYR-vTC2c&s=LEL8S70qR88zGjqrODTcuvE_OA75SuB5hdZ86g6FD70&e=
> > 
> --
> 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