Re: [PATCH] jfs: implement migrate_folio for jfs_metapage_aops

[Matthew Wilcox <willy@infradead.org>]

On Sun, Apr 13, 2025 at 05:23:57PM +0000, Shivank Garg wrote:
> +++ b/fs/jfs/jfs_metapage.c
> @@ -570,6 +570,7 @@ const struct address_space_operations jfs_metapage_aops = {
>  	.release_folio	= metapage_release_folio,
>  	.invalidate_folio = metapage_invalidate_folio,
>  	.dirty_folio	= filemap_dirty_folio,
> +	.migrate_folio	= filemap_migrate_folio,
>  };

Ooh, damn, I think we're going to need more than this ;-(

static inline struct metapage *folio_to_mp(struct folio *folio, int offset)
{
        return folio->private;
}

struct metapage {
...
        void *data;             /* Data pointer */

So we're going to need something like buffer_migrate_folio(), but
specialised to jfs metadata.  And when we come up with it, that'll
be Fixes: 35474d52c605