As i see, HSM patch have a land LL_IOC_SET_LEASE support.
but it's support invalid and don't supported NFS v4 lease functionality and clustered samba.

first of all, if lease conflict found - we need notify an application via sending an signal to release a lease, but implementation do NOTHING in that area.
second, lease lock should be released after some timeout unconditionally and take to new owner.

current implementation do NOTHING for both, so broke both NFS v4 and clustered samba.