Re: [RFC 08/23] filemap: align the index to mapping_min_order in filemap_get_folios_tag()

[Matthew Wilcox]

On Fri, Sep 15, 2023 at 08:38:33PM +0200, Pankaj Raghav wrote:
> From: Luis Chamberlain <mcgrof@xxxxxxxxxx>
> 
> Align the index to the mapping_min_order number of pages while setting
> the XA_STATE in filemap_get_folios_tag().

... because?  It should already search backwards in the page cache,
otherwise calling sync_file_range() would skip the start if it landed
in a tail page of a folio.