Frankly I still think this does not solve anything. Concurrent write access from two sources to a single page is simply wrong. You cannot make this right by allowing long term RDMA pins in a filesystem and thus the filesystem can never update part of its files on disk.
Can we just disable RDMA to regular filesystems? Regular filesystems should have full control of the write back and dirty status of their pages. Special filesystems that do not actually do write back (like hugetlbfs), mmaped raw device files and anonymous allocations are fine.
