> Yes we knew this changes the semantics of file creates, but we did not take into account that semantics of deletes/renames will change too.
How not? The semantics for delete and rename for files that are being written are consistent with the semantics of delete and rename for files that are in the namespace and that have been completed and closed. If a client is reading a 'complete' file and that file gets deleted or renamed then the reader will fail. Arguably, this is a flaw in the filesystem, but addressing that is a different discussion.
All this issue does is make files visible in the namespace as they are created and while they are being written. Delete and rename semantics for these files are the same as for all other files.
> Would it be more consistent to forbid deletion of files that have active leases.
It might be, but the change should apply to all files that are being written or read. I guess that is what you mean by files with active leases. It might be better to fix it so that files can be deleted and renamed as they are being operated on, with POSIX semantics. We should file a different JIRA issue for this.