Re: [PATCH v3 2/8] docs: document iomap writeback's iomap_finish_folio_write() requirement

["Darrick J. Wong" <djwong@kernel.org>]

On Tue, Nov 04, 2025 at 12:51:13PM -0800, Joanne Koong wrote:
> Document that iomap_finish_folio_write() must be called after writeback
> on the range completes.
> 
> Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Makes sense,
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  Documentation/filesystems/iomap/operations.rst | 3 +++
>  include/linux/iomap.h                          | 4 ++++
>  2 files changed, 7 insertions(+)
> 
> diff --git a/Documentation/filesystems/iomap/operations.rst b/Documentation/filesystems/iomap/operations.rst
> index c88205132039..4d30723be7fa 100644
> --- a/Documentation/filesystems/iomap/operations.rst
> +++ b/Documentation/filesystems/iomap/operations.rst
> @@ -361,6 +361,9 @@ The fields are as follows:
>      delalloc reservations to avoid having delalloc reservations for
>      clean pagecache.
>      This function must be supplied by the filesystem.
> +    If this succeeds, iomap_finish_folio_write() must be called once writeback
> +    completes for the range, regardless of whether the writeback succeeded or
> +    failed.
>  
>    - ``writeback_submit``: Submit the previous built writeback context.
>      Block based file systems should use the iomap_ioend_writeback_submit
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index 8b1ac08c7474..a5032e456079 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -435,6 +435,10 @@ struct iomap_writeback_ops {
>  	 * An existing mapping from a previous call to this method can be reused
>  	 * by the file system if it is still valid.
>  	 *
> +	 * If this succeeds, iomap_finish_folio_write() must be called once
> +	 * writeback completes for the range, regardless of whether the
> +	 * writeback succeeded or failed.
> +	 *
>  	 * Returns the number of bytes processed or a negative errno.
>  	 */
>  	ssize_t (*writeback_range)(struct iomap_writepage_ctx *wpc,
> -- 
> 2.47.3
> 
>