[PATCH v3 0/2] btrfs: fixes related to btrfs_folio_start_writer_lock()

[Qu Wenruo <wqu@suse.com>]

[Changelog]
v2:
- Remove the unused btrfs_folio_start_writer_lock()

v3:
- Split out the btrfs_folio_start_writer_lock() removal
  As the initial fix needs to go backported to 5.15+, keeps the
  modification as small as possible

The function lacks the proper folio->mapping check, thus we can even get
a folio not belonging to btrfs, and cause unexpeceted folio->private
updates.

Fix the only caller of btrfs_folio_start_writer_lock() inside
lock_delalloc_folios() and other sector size < page size handling of
lock_delalloc_folios().

Then finally remove btrfs_folio_start_writer_lock()

Qu Wenruo (2):
  btrfs: fix the delalloc range locking if sector size < page size
  btrfs: remove unused btrfs_folio_start_writer_lock()

 fs/btrfs/extent_io.c | 17 ++++++++--------
 fs/btrfs/subpage.c   | 47 --------------------------------------------
 fs/btrfs/subpage.h   |  2 --
 3 files changed, 9 insertions(+), 57 deletions(-)

-- 
2.46.2