[PATCH v10.1 8/9] xfs: Implement ->notify_failure() for XFS

v10.1 update: - Handle the error code returns by dax_register_holder() - In v10.1, dax_register_holder() will hold a write lock so XFS doesn't need to hold a lock - Fix the mistake in failure notification over two AGs - Fix the year in copyright message Introduce xfs_notify_failure.c to

[PATCH v10.1 1/9] dax: Introduce holder for dax_device

v10.1 update: - Fix build error reported by kernel test robot - Add return code to dax_register_holder() - Add write lock to prevent concurrent registrations - Rename dax_get_holder() to dax_holder() - Add kernel doc for new added functions To easily track filesystem from a pmem device, we