setfacl fails with older kernels (4.x 3.x)

[abbbi]

Module includes all required function definitions to build with ACL support on older kernels but attempting to set acl information fails with:

setfacl -m u:root:r /mnt/file
setfacl: /mnt/file: Operation not supported

Probably a few things are missing here which are handled by the generic_acl_access_handler functions exported
by newer kernel versions. I could not make it work, help welcome (if required)