Pull iomap updates from Christian Brauner:
 "This contains some minor work for the iomap subsystem:

   - Add documentation on the design of iomap and how to port to it

   - Optimize iomap_read_folio()

   - Bring back the change to iomap_write_end() to no increase i_size.

     This is accompanied by a change to xfs to reserve blocks for
     truncating large realtime inodes to avoid exposing stale data when
     iomap_write_end() stops increasing i_size"

* tag 'vfs-6.11.iomap' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  iomap: don't increase i_size in iomap_write_end()
  xfs: reserve blocks for truncating large realtime inode
  Documentation: the design of iomap and how to port
  iomap: Optimize iomap_read_folio