Re: [PATCH 2/8] xfs: calculate inode cluster geometry once during inobt scrub

[Dave Chinner <david@fromorbit.com>]

On Mon, Nov 05, 2018 at 08:08:18PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Hoist all the inode cluster geometry information into struct
> xchk_iallocbt instead of recomputing them over and over.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  fs/xfs/scrub/ialloc.c |   42 ++++++++++++++++++++++++++++--------------
>  1 file changed, 28 insertions(+), 14 deletions(-)
> 
> 
> diff --git a/fs/xfs/scrub/ialloc.c b/fs/xfs/scrub/ialloc.c
> index 76ae8338a42e..3c12a0fe3b38 100644
> --- a/fs/xfs/scrub/ialloc.c
> +++ b/fs/xfs/scrub/ialloc.c
> @@ -45,8 +45,18 @@ xchk_setup_ag_iallocbt(
>  /* Inode btree scrubber. */
>  
>  struct xchk_iallocbt {
> +	/* owner info for inode blocks */
> +	struct xfs_owner_info	oinfo;
> +
>  	/* Number of inodes we see while scanning inobt. */
>  	unsigned long long	inodes;
> +
> +	/* Blocks and inodes per inode cluster. */
> +	unsigned int		blocks_per_cluster;
> +	unsigned int		inodes_per_cluster;
> +
> +	/* Block alignment of inode clusters. */
> +	unsigned int		cluster_align;
>  };
>  
>  /*
> @@ -189,32 +199,30 @@ xchk_iallocbt_check_cluster_freemask(
>  STATIC int
>  xchk_iallocbt_check_freemask(
>  	struct xchk_btree		*bs,
> +	struct xchk_iallocbt		*iabt,
>  	struct xfs_inobt_rec_incore	*irec)
>  {
> -	struct xfs_owner_info		oinfo;
>  	struct xfs_imap			imap;
>  	struct xfs_mount		*mp = bs->cur->bc_mp;
>  	struct xfs_dinode		*dip;
>  	struct xfs_buf			*bp;
>  	xfs_ino_t			fsino;
> -	xfs_agino_t			nr_inodes;
> +	unsigned int			nr_inodes;
>  	xfs_agino_t			agino;
>  	xfs_agino_t			chunkino;
>  	xfs_agino_t			clusterino;
>  	xfs_agblock_t			agbno;
> -	int				blks_per_cluster;
>  	uint16_t			holemask;
>  	uint16_t			ir_holemask;
>  	int				error = 0;
>  
>  	/* Make sure the freemask matches the inode records. */
> -	blks_per_cluster = xfs_icluster_size_fsb(mp);
> -	nr_inodes = XFS_OFFBNO_TO_AGINO(mp, blks_per_cluster, 0);
> -	xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_INODES);
> +	nr_inodes = min_t(unsigned int, iabt->inodes_per_cluster,
> +			XFS_INODES_PER_CHUNK);

That's a bug fix not just a mechanical change, right? Can you either
call it out in the commit message, or put it in a separate patch?

Apart from that, the patch is good.

Reviewed-by: Dave Chinner <dchinner@redhat.com>

> @@ -440,9 +448,15 @@ xchk_iallocbt(
>  	struct xfs_owner_info	oinfo;
>  	struct xchk_iallocbt	iabt = {
>  		.inodes		= 0,
> +		.cluster_align	= xfs_ialloc_cluster_alignment(sc->mp),
> +		.blocks_per_cluster = xfs_icluster_size_fsb(sc->mp),
>  	};
>  	int			error;
>  
> +	xfs_rmap_ag_owner(&iabt.oinfo, XFS_RMAP_OWN_INODES);
> +	iabt.inodes_per_cluster = XFS_OFFBNO_TO_AGINO(sc->mp,
> +			iabt.blocks_per_cluster, 0);

As an aside, this Seems like an obtuse way to calculate inodes per
cluster. It is just:

	inodes_per_cluster = blocks_per_cluster << mp->m_sb.sb_inopblog;

I guess that's exactly what the macro degenerates to, but there's
lots of code with that exact open coded calculation for inodes per
cluster.

/me wonders if we should just calculate these two values at mount
time and stuff them in the struct xfs_mount...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com