Re: [PATCH RESEND v6 9/9] fsdax: add exception for reflinked files

[Jane Chu]

On 7/30/2021 3:01 AM, Shiyang Ruan wrote:
> For reflinked files, one dax page may be associated more than once with
> different fime mapping and index.  It will report warning.  Now, since             ^^^typo here?

> we have introduced dax-RMAP for this case and also have to keep its
> functionality for other filesystems who are not support rmap, I add this
> exception here.
>
> Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
> ---
>   fs/dax.c | 14 ++++++++------
>   1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index dce6307a12eb..f5910d178695 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -352,9 +352,10 @@ static void dax_associate_entry(void *entry, struct address_space *mapping,
>   	for_each_mapped_pfn(entry, pfn) {
>   		struct page *page = pfn_to_page(pfn);
>   
> -		WARN_ON_ONCE(page->mapping);
> -		page->mapping = mapping;
> -		page->index = index + i++;
> +		if (!page->mapping) {
> +			page->mapping = mapping;
> +			page->index = index + i++;
> +		}
>   	}
>   }
>   
> @@ -370,9 +371,10 @@ static void dax_disassociate_entry(void *entry, struct address_space *mapping,
>   		struct page *page = pfn_to_page(pfn);
>   
>   		WARN_ON_ONCE(trunc && page_ref_count(page) > 1);
> -		WARN_ON_ONCE(page->mapping && page->mapping != mapping);
> -		page->mapping = NULL;
> -		page->index = 0;
> +		if (page->mapping == mapping) {
> +			page->mapping = NULL;
> +			page->index = 0;
> +		}
>   	}
>   }
>