[Cluster-devel] [PATCH 21/30] iomap: switch iomap_seek_data to use iomap_iter

[Darrick J. Wong]

On Mon, Aug 09, 2021 at 08:12:35AM +0200, Christoph Hellwig wrote:
> Rewrite iomap_seek_data to use iomap_iter.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>

Nice cleanup,
Reviewed-by: Darrick J. Wong <djwong at kernel.org>

--D

> ---
>  fs/iomap/seek.c | 47 ++++++++++++++++++++++++-----------------------
>  1 file changed, 24 insertions(+), 23 deletions(-)
> 
> diff --git a/fs/iomap/seek.c b/fs/iomap/seek.c
> index fed8f9005f9e46..a845c012b50c67 100644
> --- a/fs/iomap/seek.c
> +++ b/fs/iomap/seek.c
> @@ -56,47 +56,48 @@ iomap_seek_hole(struct inode *inode, loff_t pos, const struct iomap_ops *ops)
>  }
>  EXPORT_SYMBOL_GPL(iomap_seek_hole);
>  
> -static loff_t
> -iomap_seek_data_actor(struct inode *inode, loff_t start, loff_t length,
> -		      void *data, struct iomap *iomap, struct iomap *srcmap)
> +static loff_t iomap_seek_data_iter(const struct iomap_iter *iter,
> +		loff_t *hole_pos)
>  {
> -	loff_t offset = start;
> +	loff_t length = iomap_length(iter);
>  
> -	switch (iomap->type) {
> +	switch (iter->iomap.type) {
>  	case IOMAP_HOLE:
>  		return length;
>  	case IOMAP_UNWRITTEN:
> -		offset = mapping_seek_hole_data(inode->i_mapping, start,
> -				start + length, SEEK_DATA);
> -		if (offset < 0)
> +		*hole_pos = mapping_seek_hole_data(iter->inode->i_mapping,
> +				iter->pos, iter->pos + length, SEEK_DATA);
> +		if (*hole_pos < 0)
>  			return length;
> -		fallthrough;
> +		return 0;
>  	default:
> -		*(loff_t *)data = offset;
> +		*hole_pos = iter->pos;
>  		return 0;
>  	}
>  }
>  
>  loff_t
> -iomap_seek_data(struct inode *inode, loff_t offset, const struct iomap_ops *ops)
> +iomap_seek_data(struct inode *inode, loff_t pos, const struct iomap_ops *ops)
>  {
>  	loff_t size = i_size_read(inode);
> -	loff_t ret;
> +	struct iomap_iter iter = {
> +		.inode	= inode,
> +		.pos	= pos,
> +		.flags	= IOMAP_REPORT,
> +	};
> +	int ret;
>  
>  	/* Nothing to be found before or beyond the end of the file. */
> -	if (offset < 0 || offset >= size)
> +	if (pos < 0 || pos >= size)
>  		return -ENXIO;
>  
> -	while (offset < size) {
> -		ret = iomap_apply(inode, offset, size - offset, IOMAP_REPORT,
> -				  ops, &offset, iomap_seek_data_actor);
> -		if (ret < 0)
> -			return ret;
> -		if (ret == 0)
> -			return offset;
> -		offset += ret;
> -	}
> -
> +	iter.len = size - pos;
> +	while ((ret = iomap_iter(&iter, ops)) > 0)
> +		iter.processed = iomap_seek_data_iter(&iter, &pos);
> +	if (ret < 0)
> +		return ret;
> +	if (iter.len) /* found data before EOF */
> +		return pos;
>  	/* We've reached the end of the file without finding data */
>  	return -ENXIO;
>  }
> -- 
> 2.30.2
>