Re: [PATCH v1 05/16] iomap: propagate iomap_read_folio() error to caller

[Christoph Hellwig <hch@infradead.org>]

On Fri, Aug 29, 2025 at 04:56:16PM -0700, Joanne Koong wrote:
> Propagate any error encountered in iomap_read_folio() back up to its
> caller (otherwise a default -EIO will be passed up by
> filemap_read_folio() to callers). This is standard behavior for how
> other filesystems handle their ->read_folio() errors as well.

Is it?  As far as I remember we, or willy in particular has been
trying to kill this error return - it isn't very hepful when the
actually interesting real errors only happen on async completion
anyway.

> 
> Remove the out of date comment about setting the folio error flag.
> Folio error flags were removed in commit 1f56eedf7ff7 ("iomap:
> Remove calls to set and clear folio error flag").
> 
> Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
> ---
>  fs/iomap/buffered-io.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 9db233a4a82c..8dd26c50e5ea 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -495,12 +495,7 @@ int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops)
>  
>  	iomap_readfolio_complete(&iter, &ctx);
>  
> -	/*
> -	 * Just like mpage_readahead and block_read_full_folio, we always
> -	 * return 0 and just set the folio error flag on errors.  This
> -	 * should be cleaned up throughout the stack eventually.
> -	 */
> -	return 0;
> +	return ret;
>  }
>  EXPORT_SYMBOL_GPL(iomap_read_folio);
>  
> -- 
> 2.47.3
> 
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