Merge tag 'iomap-per-block-dirty-tracking' of https://github.com/riteshharjani/linux...

iomap: Add per-block dirty state tracking to iomap

iomap today only tracks per-block update state bitmap, this series extends
the support by adding per-block dirty state bitmap tracking to iomap buffered
I/O path. This helps in reducing the write amplification and improve
write performance for large folio writes and for platforms with higher
pagesize compared to blocksize.

We have seen ~83% performance improvement with these patches using
database benchmarking tests, with XFS on 64k pagesize.
fio benchmark (as shown in the last patch which adds dirty tracking
support) showed close to 16x performance improvement when tested with
64K pagesize on 4k blocksize XFS using nvme on Power.

* tag 'iomap-per-block-dirty-tracking' of https://github.com/riteshharjani/linux:
  iomap: Add per-block dirty state tracking to improve performance
  iomap: Allocate ifs in ->write_begin() early
  iomap: Refactor iomap_write_delalloc_punch() function out
  iomap: Use iomap_punch_t typedef
  iomap: Fix possible overflow condition in iomap_write_delalloc_scan
  iomap: Add some uptodate state handling helpers for ifs state bitmap
  iomap: Drop ifs argument from iomap_set_range_uptodate()
  iomap: Rename iomap_page to iomap_folio_state and others

[djwong: also yay to less write amplification!]

Signed-off-by: Darrick J. Wong <djwong@kernel.org>