[PATCH 0/2] btrfs: convert btrfs_buffered_write() to folio interface

[Qu Wenruo <wqu@suse.com>]

Inspired by generic_perform_write(), convert btrfs_buffered_write() to
go a page-by-page iteration, then convert it to use folio interface.

This should provide the basis for use to go
address_operations->write_begin() and write_end() callbacks.

There is a tiny timing change.
Before this patchset we wait for the page writeback after we get an
uptodate or no need to read the page.

But now we follow the regular FGP_WRITEBEGIN, which implies FGP_STABLE
and will wait for writeback before reading the page.

Qu Wenruo (2):
  btrfs: make buffered write to copy one page a time
  btrfs: convert btrfs_buffered_write() to use folio interface

 fs/btrfs/file.c             | 259 +++++++++++++-----------------------
 fs/btrfs/file.h             |   2 +-
 fs/btrfs/free-space-cache.c |  15 ++-
 3 files changed, 102 insertions(+), 174 deletions(-)

-- 
2.46.2