Merge patch series "Add and use folio_next_pos()"

Matthew Wilcox (Oracle) <willy@infradead.org> says:

It's relatively common in filesystems to want to know the end of the
current folio we're looking at.  So common in fact that btrfs has its own
helper for that.  Lift that helper to filemap and use it everywhere that
I've noticed it could be used.  This actually fixes a long-standing bug
in ocfs2 on 32-bit systems with files larger than 2GiB.  Presumably this
is not a common configuration, but I've marked it for backport anyway.

The other filesystems are all fine; none of them have a bug, they're
just mildly inefficient.  I think this should all go in via Christian's
tree, ideally with acks from the various fs maintainers (cc'd on their
individual patches).

* patches from https://patch.msgid.link/20251024170822.1427218-1-willy@infradead.org:
  mm: Use folio_next_pos()
  xfs: Use folio_next_pos()
  netfs: Use folio_next_pos()
  iomap: Use folio_next_pos()
  gfs2: Use folio_next_pos()
  f2fs: Use folio_next_pos()
  ext4: Use folio_next_pos()
  buffer: Use folio_next_pos()
  btrfs: Use folio_next_pos()
  filemap: Add folio_next_pos()

Link: https://patch.msgid.link/20251024170822.1427218-1-willy@infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>