Merge patch series "vfs: preparatory changes to centralize locking of create/remove/rename"

NeilBrown <neilb@ownmail.net> says:

This is a re-re-revised selection of cleanups and API renaming which
continues my work to centralise locking of create/remove/rename
operations.

* patches from https://lore.kernel.org/20250922043121.193821-2-neilb@ownmail.net

:
  debugfs: rename start_creating() to debugfs_start_creating()
  VFS: rename kern_path_locked() and related functions.
  VFS/audit: introduce kern_path_parent() for audit
  VFS: unify old_mnt_idmap and new_mnt_idmap in renamedata
  VFS: discard err2 in filename_create()
  VFS/ovl: add lookup_one_positive_killable()

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