Re: [PATCH v2 0/8] btrfs: separate/simplify/unify subpage handling

[David Sterba <dsterba@suse.cz>]

On Fri, Feb 07, 2025 at 02:55:59PM +1030, Qu Wenruo wrote:
> [CHANGELOG]
> v2:
> - Fix a crash in 4K page sized system caused by
>   btrfs_clear_buffer_dirty()
>   It looks like using btrfs_meta_folio_set_writeback() and
>   btrfs_meta_folio_clear_writeback() is screwing up the btree inode map.
>   
>   Fix it by reverting to the old manually clearing of
>   PAGECACHE_DIRTY_TAG.
> 
> [METADATA SUBPAGE CHECKS]
> Currently we only have one btrfs_is_subpage() check, utilized by data
> and metadata.
> 
> But the truth is, btrfs_is_subpage() can return incorrect result if the
> target folio belongs to a dummy extent buffer.
> 
> This means we have quite some metadata call sites doing their own
> metadata specific subpage check.
> 
> [SUBPAGE SPECIFIC HANDLINGS]
> There are several functions that split the metadata subpage handling
> into a dedicated path.
> 
> But the truth is, a lot of such paths only have minor differences
> compared to the regular routine.
> 
> [THIS SERIES]
> This series address the above problems and prepare for the incoming data
> larger folio support by:
> 
> - Remove btrfs_fs_info::sectors_per_page
>   This is mostly a preparation for the future data larger folio support.
> 
> - Introduce a dedicated metadata specific subpage check
> 
> - Unify/simplify metadata subpage handling
>   So that we have a single unified path for metadata
> 
> Qu Wenruo (8):
>   btrfs: remove btrfs_fs_info::sectors_per_page
>   btrfs: extract metadata subpage detection into a dedicated helper
>   btrfs: make subpage attach and detach to handle metadata properly
>   btrfs: use metadata specific helpers to simplify extent buffer helpers
>   btrfs: simplify btrfs_clear_buffer_dirty()
>   btrfs: simplify write_one_eb()
>   btrfs: simplify read_extent_buffer_pages_nowait()
>   btrfs: require strict data/metadata split for subpage check

All look good to me.

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

Please update the subjects in the simplify patches in what regard they
simplify the functions. For example "sipmlify subpage handling in ...".
Thanks.