RE: [PATCH v1] mm/memory: fix folio_set_dirty() vs. folio_mark_dirty() in zap_pte_range()

[Yuezhang.Mo@xxxxxxxx]

Reviewed-by: Yuezhang Mo <Yuezhang.Mo@xxxxxxxx>

Without this fix, testing the latest exfat with xfstests, test cases generic/029
and generic/030 will fail.

> -----Original Message-----
> From: owner-linux-mm@xxxxxxxxx <owner-linux-mm@xxxxxxxxx> On Behalf
> Of David Hildenbrand
> Sent: Tuesday, January 23, 2024 1:18 AM
> To: linux-kernel@xxxxxxxxxxxxxxx
> Cc: linux-mm@xxxxxxxxx; David Hildenbrand <david@xxxxxxxxxx>; Ryan
> Roberts <ryan.roberts@xxxxxxx>; Matthew Wilcox <willy@xxxxxxxxxxxxx>;
> Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Subject: [PATCH v1] mm/memory: fix folio_set_dirty() vs. folio_mark_dirty() in
> zap_pte_range()
> 
> The correct folio replacement for "set_page_dirty()" is
> "folio_mark_dirty()", not "folio_set_dirty()". Using the latter won't
> properly inform the FS using the dirty_folio() callback.
> 
> This has been found by code inspection, but likely this can result in
> some real trouble when zapping dirty PTEs that point at clean pagecache
> folios.
> 
> Reported-by: Ryan Roberts <ryan.roberts@xxxxxxx>
> Closes:
> https://lkml.kernel.org/r/2445cedb-61fb-422c-8bfb-caf0a2beed62@xxxxxxx
> Fixes: c46265030b0f ("mm/memory: page_remove_rmap() ->
> folio_remove_rmap_pte()")
> Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
> Reviewed-by: Ryan Roberts <ryan.roberts@xxxxxxx>
> ---
>  mm/memory.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/memory.c b/mm/memory.c
> index 7e1f4849463aa..89bcae0b224d6 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -1464,7 +1464,7 @@ static unsigned long zap_pte_range(struct
> mmu_gather *tlb,
>  			delay_rmap = 0;
>  			if (!folio_test_anon(folio)) {
>  				if (pte_dirty(ptent)) {
> -					folio_set_dirty(folio);
> +					folio_mark_dirty(folio);
>  					if (tlb_delay_rmap(tlb)) {
>  						delay_rmap = 1;
>  						force_flush = 1;