Re: [PATCH v2 1/7] iomap: Remove large folio handling in iomap_invalidate_folio()

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

On Fri, Jun 02, 2023 at 11:24:38PM +0100, Matthew Wilcox (Oracle) wrote:
> We do not need to release the iomap_page in iomap_invalidate_folio()
> to allow the folio to be split.  The splitting code will call
> ->release_folio() if there is still per-fs private data attached to
> the folio.  At that point, we will check if the folio is still dirty
> and decline to release the iomap_page.  It is possible to trigger the
> warning in perfectly legitimate circumstances (eg if a disk read fails,
> we do a partial write to the folio, then we truncate the folio), which
> will cause those writes to be lost.
> 
> Fixes: 60d8231089f0 ("iomap: Support large folios in invalidatepage")
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Sounds reasonable to me...
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/iomap/buffered-io.c | 5 -----
>  1 file changed, 5 deletions(-)
> 
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 063133ec77f4..08ee293c4117 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -508,11 +508,6 @@ void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len)
>  		WARN_ON_ONCE(folio_test_writeback(folio));
>  		folio_cancel_dirty(folio);
>  		iomap_page_release(folio);
> -	} else if (folio_test_large(folio)) {
> -		/* Must release the iop so the page can be split */
> -		WARN_ON_ONCE(!folio_test_uptodate(folio) &&
> -			     folio_test_dirty(folio));
> -		iomap_page_release(folio);
>  	}
>  }
>  EXPORT_SYMBOL_GPL(iomap_invalidate_folio);
> -- 
> 2.39.2
>