Re: [PATCH 00/46] btrfs: convert most of the data path to use folios

[David Sterba <dsterba@suse.cz>]

On Fri, Jul 26, 2024 at 03:35:47PM -0400, Josef Bacik wrote:
> Hello,
> 
> Willy indicated that he wants to get rid of page->index in the next merge
> window, so I went to look at what that would entail for btrfs, and I got a
> little carried away.
> 
> This patch series does in fact accomplish that, but it takes almost the entirety
> of the data write path and makes it work with only folios.  I was going to
> convert everything, but there's some weird gaps that need to be handled in their
> own chunk.
> 
> 1. Scrub.  We're still passing around page pointers.  Not a huge deal, it was
>    just another 10ish patches just for that work, so I decided against it.
> 
> 2. Buffered writes.  Again, I did most of this work and it wasn't bad, but then
>    I realized that the free space cache uses some of this code, and I really
>    don't want to convert that code, I want to delete it, so I'll do that first.
> 
> 3. Metadata.  Qu has been doing this consistently and I didn't want to get in
>    the way of his work so I just left most of that.
> 
> This has run through the CI and didn't cause any issues.  I've made everything
> as easy to review as possible and as small as possible.  My eyes started to
> glaze over a little bit with the changelogs, so let me know if there's anything
> you want changed.  Thanks,

I did two passes, most of the conversions are straightforward, the API
changes seem OK. There are some local variable referring to page, like
page_start but initialized from folios. Not a big problem for now, we'll
keep removing references to pages, this can be done later.

Reviewed-by: David Sterba <dsterba@suse.com>