Merge patch series "Filesystem page flags cleanup"

Matthew Wilcox (Oracle) <[email protected]> says:

The first four patches continue the work begun in 02e1960aafac to make
the mappedtodisk/owner_2 flag available to filesystems which don't use
buffer heads. The last two remove uses of Private2 (we're achingly close
to being rid of it entirely, but that doesn't seem like it'll land this
merge window).

* patches from https://lore.kernel.org/r/20241002040111.1023018[email protected]:
  migrate: Remove references to Private2
  ceph: Remove call to PagePrivate2()
  btrfs: Switch from using the private_2 flag to owner_2
  mm: Remove PageMappedToDisk
  nilfs2: Convert nilfs_copy_buffer() to use folios
  fs: Move clearing of mappedtodisk to buffer.c

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Christian Brauner <[email protected]>