Re: [PATCH] iomap: wait for batched folios to be stable in __iomap_get_folio

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

On Tue, Jan 13, 2026 at 04:39:17PM +0100, Christoph Hellwig wrote:
> __iomap_get_folio needs to wait for writeback to finish if the file
> requires folios to be stable for writes.  For the regular path this is
> taken care of by __filemap_get_folio, but for the newly added batch
> lookup it has to be done manually.
> 
> This fixes xfs/131 failures when running on PI-capable hardware.
> 
> Fixes: 395ed1ef0012 ("iomap: optional zero range dirty folio processing")
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/iomap/buffered-io.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index fd9a2cf95620..6beb876658c0 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -851,6 +851,7 @@ static struct folio *__iomap_get_folio(struct iomap_iter *iter,
>  		}
>  
>  		folio_get(folio);
> +		folio_wait_stable(folio);

Heh, oops.  That's a little too easy to miss. :(

I wonder if we ought to have a filemap_fbatch_next() that would take
care of the relocking, revalidation, and stabilization... but this spot
fix is good as-is.

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

--D

>  		return folio;
>  	}
>  
> -- 
> 2.47.3
>