Re: [PATCH 20/21] iomap: Support multi-page folios in invalidatepage

Darrick J. Wong
2021-11-03T16:03:26Z

On Mon, Nov 01, 2021 at 08:39:28PM +0000, Matthew Wilcox (Oracle) wrote:
> If we're punching a hole in a multi-page folio, we need to remove the
> per-folio iomap data as the folio is about to be split and each page will
> need its own. If a dirty folio is only partially-uptodate, the iomap
> data contains the information about which blocks cannot be written back,
> so assert that a dirty folio is fully uptodate.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Looks good to me,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
> fs/iomap/buffered-io.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 3b93fdfedb72..9d7c91f9ec1d 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -470,13 +470,18 @@ void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len)
> trace_iomap_invalidatepage(folio->mapping->host, offset, len);
>
> /*
> - * If we're invalidating the entire page, clear the dirty state from it
> - * and release it to avoid unnecessary buildup of the LRU.
> + * If we're invalidating the entire folio, clear the dirty state
> + * from it and release it to avoid unnecessary buildup of the LRU.
> */
> if (offset == 0 && len == folio_size(folio)) {
> WARN_ON_ONCE(folio_test_writeback(folio));
> folio_cancel_dirty(folio);
> iomap_page_release(folio);
> + } else if (folio_test_multi(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);
> --
> 2.33.0
>