Re: [PATCH v3 05/16] iomap: add public helpers for uptodate state manipulation

Darrick J. Wong
2025-07-02T17:39:08Z

On Mon, Jun 23, 2025 at 07:21:24PM -0700, Joanne Koong wrote:
> Add a new iomap_start_folio_write helper to abstract away the
> write_bytes_pending handling, and export it and the existing
> iomap_finish_folio_write for non-iomap writeback in fuse.
>
> Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
> [hch: split from a larger patch]
> Signed-off-by: Christoph Hellwig <hch@lst.de>

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

--D

> ---
> fs/iomap/buffered-io.c | 20 +++++++++++++++-----
> include/linux/iomap.h | 5 +++++
> 2 files changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 50cfddff1393..b4a8d2241d70 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -1535,7 +1535,18 @@ vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops,
> }
> EXPORT_SYMBOL_GPL(iomap_page_mkwrite);
>
> -static void iomap_finish_folio_write(struct inode *inode, struct folio *folio,
> +void iomap_start_folio_write(struct inode *inode, struct folio *folio,
> + size_t len)
> +{
> + struct iomap_folio_state *ifs = folio->private;
> +
> + WARN_ON_ONCE(i_blocks_per_folio(inode, folio) > 1 && !ifs);
> + if (ifs)
> + atomic_add(len, &ifs->write_bytes_pending);
> +}
> +EXPORT_SYMBOL_GPL(iomap_start_folio_write);
> +
> +void iomap_finish_folio_write(struct inode *inode, struct folio *folio,
> size_t len)
> {
> struct iomap_folio_state *ifs = folio->private;
> @@ -1546,6 +1557,7 @@ static void iomap_finish_folio_write(struct inode *inode, struct folio *folio,
> if (!ifs || atomic_sub_and_test(len, &ifs->write_bytes_pending))
> folio_end_writeback(folio);
> }
> +EXPORT_SYMBOL_GPL(iomap_finish_folio_write);
>
> /*
> * We're now finished for good with this ioend structure. Update the page
> @@ -1668,7 +1680,6 @@ ssize_t iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, struct folio *folio,
> loff_t pos, loff_t end_pos, unsigned int dirty_len)
> {
> struct iomap_ioend *ioend = wpc->wb_ctx;
> - struct iomap_folio_state *ifs = folio->private;
> size_t poff = offset_in_folio(folio, pos);
> unsigned int ioend_flags = 0;
> unsigned int map_len = min_t(u64, dirty_len,
> @@ -1711,8 +1722,7 @@ ssize_t iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, struct folio *folio,
> if (!bio_add_folio(&ioend->io_bio, folio, map_len, poff))
> goto new_ioend;
>
> - if (ifs)
> - atomic_add(map_len, &ifs->write_bytes_pending);
> + iomap_start_folio_write(wpc->inode, folio, map_len);
>
> /*
> * Clamp io_offset and io_size to the incore EOF so that ondisk
> @@ -1880,7 +1890,7 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc,
> * all blocks.
> */
> WARN_ON_ONCE(atomic_read(&ifs->write_bytes_pending) != 0);
> - atomic_inc(&ifs->write_bytes_pending);
> + iomap_start_folio_write(inode, folio, 1);
> }
>
> /*
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index 047100f94092..bfd178fb7cfc 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -460,6 +460,11 @@ void iomap_sort_ioends(struct list_head *ioend_list);
> ssize_t iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, struct folio *folio,
> loff_t pos, loff_t end_pos, unsigned int dirty_len);
> int ioend_writeback_submit(struct iomap_writepage_ctx *wpc, int error);
> +
> +void iomap_start_folio_write(struct inode *inode, struct folio *folio,
> + size_t len);
> +void iomap_finish_folio_write(struct inode *inode, struct folio *folio,
> + size_t len);
> int iomap_writepages(struct iomap_writepage_ctx *wpc);
>
> /*
> --
> 2.47.1
>
>