Merge tag 'ceph-for-4.15-rc4' of git://github.com/ceph/ceph-client

Pull ceph fix from Ilya Dryomov:
 "CephFS inode trimming fix from Zheng, marked for stable"

* tag 'ceph-for-4.15-rc4' of git://github.com/ceph/ceph-client:
  ceph: drop negative child dentries before try pruning inode's alias