On Tue 22-05-18 07:39:57, Dan Williams wrote:
> In support of enabling memory_failure() handling for filesystem-dax
> mappings, set ->index to the pgoff of the page. The rmap implementation
> requires ->index to bound the search through the vma interval tree. The
> index is set and cleared at dax_associate_entry() and
> dax_disassociate_entry() time respectively.
>
> Cc: Jan Kara <jack@xxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
> Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> ---
> fs/dax.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index aaec72ded1b6..2e4682cd7c69 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -319,18 +319,22 @@ static unsigned long dax_radix_end_pfn(void *entry)
> for (pfn = dax_radix_pfn(entry); \
> pfn < dax_radix_end_pfn(entry); pfn++)
>
> -static void dax_associate_entry(void *entry, struct address_space *mapping)
> +static void dax_associate_entry(void *entry, struct address_space *mapping,
> + struct vm_area_struct *vma, unsigned long address)
> {
> - unsigned long pfn;
> + unsigned long size = dax_entry_size(entry), pfn, index;
> + int i = 0;
>
> if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
> return;
>
> + index = linear_page_index(vma, address & ~(size - 1));
> 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++;
> }
> }
Hum, this just made me think: How is this going to work with XFS reflink?
In fact is not the page->mapping association already broken by XFS reflink?
Because with reflink we can have two or more mappings pointing to the same
physical blocks (i.e., pages in DAX case)...
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
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