Re: [PATCH 10/12] xfs: move xfs_inode_ag_iterator to be closer to the perag walking code

From: Brian Foster <bfoster@redhat.com>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 10/12] xfs: move xfs_inode_ag_iterator to be closer to the perag walking code
Date: Fri, 22 May 2020 08:23:44 -0400	[thread overview]
Message-ID: <20200522122344.GK50656@bfoster> (raw)
In-Reply-To: <159011607216.77079.15513788306075418133.stgit@magnolia>

On Thu, May 21, 2020 at 07:54:32PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Move the xfs_inode_ag_iterator function to be nearer xfs_inode_ag_walk
> so that we don't have to scroll back and forth to figure out how the
> incore inode walking function works.  No functional changes.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  fs/xfs/xfs_icache.c |   88 ++++++++++++++++++++++++++++-----------------------
>  1 file changed, 48 insertions(+), 40 deletions(-)
> 
> 
> diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
> index 791544a1d54c..0e25d50372e2 100644
> --- a/fs/xfs/xfs_icache.c
> +++ b/fs/xfs/xfs_icache.c
> @@ -791,6 +791,10 @@ xfs_inode_ag_walk_grab(
>  	return false;
>  }
>  
> +/*
> + * For a given per-AG structure @pag, grab, @execute, and rele all incore
> + * inodes with the given radix tree @tag.
> + */
>  STATIC int
>  xfs_inode_ag_walk(
>  	struct xfs_mount	*mp,
> @@ -896,6 +900,50 @@ xfs_inode_ag_walk(
>  	return last_error;
>  }
>  
> +/* Fetch the next (possibly tagged) per-AG structure. */
> +static inline struct xfs_perag *
> +xfs_inode_walk_get_perag(
> +	struct xfs_mount	*mp,
> +	xfs_agnumber_t		agno,
> +	int			tag)
> +{
> +	if (tag == XFS_ICI_NO_TAG)
> +		return xfs_perag_get(mp, agno);
> +	return xfs_perag_get_tag(mp, agno, tag);
> +}
> +
> +/*
> + * Call the @execute function on all incore inodes matching the radix tree
> + * @tag.
> + */
> +int
> +xfs_inode_ag_iterator(
> +	struct xfs_mount	*mp,
> +	int			iter_flags,
> +	int			(*execute)(struct xfs_inode *ip, void *args),
> +	void			*args,
> +	int			tag)
> +{
> +	struct xfs_perag	*pag;
> +	int			error = 0;
> +	int			last_error = 0;
> +	xfs_agnumber_t		ag;
> +
> +	ag = 0;
> +	while ((pag = xfs_inode_walk_get_perag(mp, ag, tag))) {
> +		ag = pag->pag_agno + 1;
> +		error = xfs_inode_ag_walk(mp, pag, execute, args, tag,
> +				iter_flags);
> +		xfs_perag_put(pag);
> +		if (error) {
> +			last_error = error;
> +			if (error == -EFSCORRUPTED)
> +				break;
> +		}
> +	}
> +	return last_error;
> +}
> +
>  /*
>   * Background scanning to trim post-EOF preallocated space. This is queued
>   * based on the 'speculative_prealloc_lifetime' tunable (5m by default).
> @@ -959,46 +1007,6 @@ xfs_cowblocks_worker(
>  	xfs_queue_cowblocks(mp);
>  }
>  
> -/* Fetch the next (possibly tagged) per-AG structure. */
> -static inline struct xfs_perag *
> -xfs_inode_walk_get_perag(
> -	struct xfs_mount	*mp,
> -	xfs_agnumber_t		agno,
> -	int			tag)
> -{
> -	if (tag == XFS_ICI_NO_TAG)
> -		return xfs_perag_get(mp, agno);
> -	return xfs_perag_get_tag(mp, agno, tag);
> -}
> -
> -int
> -xfs_inode_ag_iterator(
> -	struct xfs_mount	*mp,
> -	int			iter_flags,
> -	int			(*execute)(struct xfs_inode *ip, void *args),
> -	void			*args,
> -	int			tag)
> -{
> -	struct xfs_perag	*pag;
> -	int			error = 0;
> -	int			last_error = 0;
> -	xfs_agnumber_t		ag;
> -
> -	ag = 0;
> -	while ((pag = xfs_inode_walk_get_perag(mp, ag, tag))) {
> -		ag = pag->pag_agno + 1;
> -		error = xfs_inode_ag_walk(mp, pag, execute, args, tag,
> -				iter_flags);
> -		xfs_perag_put(pag);
> -		if (error) {
> -			last_error = error;
> -			if (error == -EFSCORRUPTED)
> -				break;
> -		}
> -	}
> -	return last_error;
> -}
> -
>  /*
>   * Grab the inode for reclaim exclusively.
>   * Return 0 if we grabbed it, non-zero otherwise.
> 