On Tue, Apr 06, 2021 at 04:05:50PM +0100, Christoph Hellwig wrote: > On Tue, Apr 06, 2021 at 03:55:11PM +0100, Matthew Wilcox wrote: > > Assuming we're getting rid of them all though, we have to include: > > > > $ git grep 'page->mapping' fs |wc -l > > 358 > > $ git grep 'page->index' fs |wc -l > > 355 > > Are they all going to stay? Or are we going to clean up some of that > mess. A lot of ->index should be page_offet, and on the mapping side > the page_mapping and page_file_mapping mess is also waiting to be > sorted.. About a third of ->index can be folio_offset(), based on a crude: $ git grep 'page->index.*PAGE_' |wc -l 101 and I absolutely don't mind cleaning that up as part of the folio work, but that still leaves 200-250 instances that would need to be changed later. I don't want to change the page->mapping to calls to folio_mapping(). That's a lot of extra work for a page which the filesystem knows belongs to it. folio_mapping() only needs to be used for pages which might not belong to a filesystem. page_file_mapping() absolutely needs to go away. The way to do that is to change swap-over-nfs to use direct IO, and then NFS can use folio->mapping like all other filesystems. f2fs is just terminally confused and shouldn't be using page_file_mapping at all. I'll fix that as part of the folio work.
