[PATCH v2 0/2] btrfs: migrate extent_buffer::pages[] to folio and more cleanups

[Qu Wenruo <wqu@suse.com>]

[CHANGELOG]
v2:
- Adda new patch to do more cleanups for metadata page pointers usage

This patchset would migrate extent_buffer::pages[] to folios[], then
cleanup the existing metadata page pointer usage to proper folios ones.

This cleanup would help future higher order folios usage for metadata in
the following aspects:

- No more need to iterate through the remaining pages for page flags
  We just call folio_set/mark/start_*() helpers, for the single folio.
  The helper would only set the flag (mostly for the leading page).

- Single bio_add_folio() call for the whole eb

- Better filio helpers naming
  PageUptodate() compared to folio_test_uptodate().

The first patch would do a very simple conversion, then the 2nd patch do
the prepartion for the higher order folio situation.

There are two locations which won't be converted to folios yet:

- Subpage code
  There is no meaning to support higher order folio for subpage.
  The two conditions are just conflicting with each other.

- Data page pointers
  That would be more useful in the future, before we going to support
  multi-page sectorsize.

However the 2nd one would also add a new corner case:

- Order mismatch in filemap and eb folios
  Unforatunately I don't have a better plan other than re-allocate the
  folios to the same order.
  Maybe in the future we would have better ways to handle it? Like
  migrating the pages to the higher order one?



Qu Wenruo (2):
  btrfs: migrate extent_buffer::pages[] to folio
  btrfs: cleanup metadata page pointer usage

 fs/btrfs/accessors.c             |  20 +-
 fs/btrfs/accessors.h             |   4 +-
 fs/btrfs/ctree.c                 |   2 +-
 fs/btrfs/disk-io.c               |  25 +-
 fs/btrfs/extent_io.c             | 402 ++++++++++++++++++-------------
 fs/btrfs/extent_io.h             |  21 +-
 fs/btrfs/inode.c                 |   2 +-
 fs/btrfs/subpage.c               |  60 ++---
 fs/btrfs/subpage.h               |  11 +-
 fs/btrfs/tests/extent-io-tests.c |   4 +-
 10 files changed, 322 insertions(+), 229 deletions(-)

-- 
2.43.0