Re: [PATCH v3 1/3] iomap: Permit pages without an iop to enter writeback

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

On Wed, Jul 07, 2021 at 01:55:22PM +0200, Andreas Gruenbacher wrote:
> Create an iop in the writeback path if one doesn't exist.  This allows us
> to avoid creating the iop in some cases.  We'll initially do that for pages
> with inline data, but it can be extended to pages which are entirely within
> an extent.  It also allows for an iop to be removed from pages in the
> future (eg page split).
> 
> Co-developed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Seems simple enough...
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/iomap/buffered-io.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 9023717c5188..598fcfabc337 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -1334,14 +1334,13 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc,
>  		struct writeback_control *wbc, struct inode *inode,
>  		struct page *page, u64 end_offset)
>  {
> -	struct iomap_page *iop = to_iomap_page(page);
> +	struct iomap_page *iop = iomap_page_create(inode, page);
>  	struct iomap_ioend *ioend, *next;
>  	unsigned len = i_blocksize(inode);
>  	u64 file_offset; /* file offset of page */
>  	int error = 0, count = 0, i;
>  	LIST_HEAD(submit_list);
>  
> -	WARN_ON_ONCE(i_blocks_per_page(inode, page) > 1 && !iop);
>  	WARN_ON_ONCE(iop && atomic_read(&iop->write_bytes_pending) != 0);
>  
>  	/*
> -- 
> 2.26.3
>