Re: [RFCv5 5/5] iomap: Add per-block dirty state tracking to improve performance

[Christoph Hellwig <hch@infradead.org>]

On Wed, May 17, 2023 at 02:48:12PM -0400, Brian Foster wrote:
> But I also wonder.. if we can skip the iop alloc on full folio buffered
> overwrites, isn't that also true of mapped writes to folios that don't
> already have an iop?

Yes.

> I.e., I think what I was trying to do in the
> previous diff was actually something like this:
> 
> bool iomap_dirty_folio(struct address_space *mapping, struct folio *folio)
> {
>         iop_set_range_dirty(mapping->host, folio, 0, folio_size(folio));
>         return filemap_dirty_folio(mapping, folio);
> }
> 
> ... which would only dirty the full iop if it already exists. Thoughts?

That does sound pretty good to me, and I can't think of any obvious
pitfall.