[RFC PATCH V3 0/9] Introduce attach/detach_page_private to cleanup code

[Guoqing Jiang]

Hi,

Based on the previous thread [1], this patchset introduces attach_page_private
and detach_page_private to replace attach_page_buffers and __clear_page_buffers.
Thanks a lot for the constructive suggestions and comments from Christoph,
Matthew and Dave.

And sorry for cross post to different lists since it modifies different subsystems.

RFC V2 -> RFC V3:
1. rename clear_page_private to detach_page_private.
2. Update the comments for attach/detach_page_private from Mattew.
3. add one patch to call new function in mm/migrate.c as suggested by Mattew, but
   use the conservative way to keep the orginal semantics [2].


RFC -> RFC V2:
1. rename the new functions and add comments for them.
2. change the return type of attach_page_private.
3. call attach_page_private(newpage, clear_page_private(page)) to cleanup code further.
4. avoid potential use-after-free in orangefs.

[1]. https://lore.kernel.org/linux-fsdevel/20200420221424.GH5820@xxxxxxxxxxxxxxxxxxxxxx/
[2]. https://lore.kernel.org/lkml/e4d5ddc0-877f-6499-f697-2b7c0ddbf386@xxxxxxxxxxxxxxx/

Thanks,
Guoqing

Guoqing Jiang (10):
  include/linux/pagemap.h: introduce attach/detach_page_private
  md: remove __clear_page_buffers and use attach/detach_page_private
  btrfs: use attach/detach_page_private
  fs/buffer.c: use attach/detach_page_private
  f2fs: use attach/detach_page_private
  iomap: use attach/detach_page_private
  ntfs: replace attach_page_buffers with attach_page_private
  orangefs: use attach/detach_page_private
  buffer_head.h: remove attach_page_buffers
  mm/migrate.c: call detach_page_private to cleanup code

 drivers/md/md-bitmap.c      | 12 ++----------
 fs/btrfs/disk-io.c          |  4 +---
 fs/btrfs/extent_io.c        | 21 ++++++---------------
 fs/btrfs/inode.c            | 23 +++++------------------
 fs/buffer.c                 | 16 ++++------------
 fs/f2fs/f2fs.h              | 11 ++---------
 fs/iomap/buffered-io.c      | 19 ++++---------------
 fs/ntfs/aops.c              |  2 +-
 fs/ntfs/mft.c               |  2 +-
 fs/orangefs/inode.c         | 32 ++++++--------------------------
 include/linux/buffer_head.h |  8 --------
 include/linux/pagemap.h     | 37 +++++++++++++++++++++++++++++++++++++
 mm/migrate.c                |  5 +----
 13 files changed, 70 insertions(+), 122 deletions(-)

-- 
2.17.1