Merge patch series "vfs: if RESOLVE_NO_XDEV passed to openat2, don't *trigger* automounts"

Askar Safin <safinaskar@zohomail.com> says:

openat2 had a bug: if we pass RESOLVE_NO_XDEV, then openat2
doesn't traverse through automounts, but may still trigger them.
See this link for full bug report with reproducer:
https://lore.kernel.org/linux-fsdevel/20250817075252.4137628-1-safinaskar@zohomail.com/

This patchset fixes the bug.

RESOLVE_NO_XDEV logic hopefully becomes more clear:
now we immediately fail when we cross mountpoints.

* patches from https://lore.kernel.org/20250825181233.2464822-1-safinaskar@zohomail.com:
  openat2: don't trigger automounts with RESOLVE_NO_XDEV
  namei: move cross-device check to __traverse_mounts
  namei: remove LOOKUP_NO_XDEV check from handle_mounts
  namei: move cross-device check to traverse_mounts

Link: https://lore.kernel.org/20250825181233.2464822-1-safinaskar@zohomail.com


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