Merge patch series "fs: refactor write_begin/write_end and add ext4 IOCB_DONTCACHE support"

陈涛涛 Taotao Chen <chentaotao@didiglobal.com> says:

This patch series refactors the address_space_operations write_begin()
and write_end() callbacks to take const struct kiocb * as their first
argument, allowing IOCB flags such as IOCB_DONTCACHE to propagate to the
filesystem's buffered I/O path.

Ext4 is updated to implement handling of the IOCB_DONTCACHE flag and
advertises support via the FOP_DONTCACHE file operation flag.

Additionally, the i915 driver's shmem write paths are updated to bypass
the legacy write_begin/write_end interface in favor of directly
calling write_iter() with a constructed synchronous kiocb. Another i915
change replaces a manual write loop with kernel_write() during GEM shmem
object creation.

Tested with ext4 and i915 GEM workloads.

* patches from https://lore.kernel.org/20250716093559.217344-1-chentaotao@didiglobal.com:
  ext4: support uncached buffered I/O
  mm/pagemap: add write_begin_get_folio() helper function
  fs: change write_begin/write_end interface to take struct kiocb *
  drm/i915: Refactor shmem_pwrite() to use kiocb and write_iter
  drm/i915: Use kernel_write() in shmem object create

Link: https://lore.kernel.org/20250716093559.217344-1-chentaotao@didiglobal.com


Signed-off-by: Christian Brauner <brauner@kernel.org>