Merge remote-tracking branch 'aosp/upstream-f2fs-stable-linux-4.19.y' into android-4.19-stable

This series addressed merge conflicts based on pa/c/1664425/15, mainly
integrated with a patch "f2fs: Handle casefolding with Encryption" for
casefolding support in ACK only.

* aosp/upstream-f2fs-stable-linux-4.19.y:
  f2fs: flush dirty meta pages when flushing them
  f2fs: fix checkpoint=disable:%u%%
  f2fs: rework filename handling
  f2fs: split f2fs_d_compare() from f2fs_match_name()
  f2fs: don't leak filename in f2fs_try_convert_inline_dir()
  f2fs: fix missing check for f2fs_unlock_op

Conflicts:
	fs/f2fs/dir.c
	fs/f2fs/f2fs.h
	fs/f2fs/hash.c
	fs/f2fs/inline.c
	fs/f2fs/namei.c

Change-Id: Ib5ceb0f2f076d6c215d4c0c6262f3c1d41cde7c8
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>