Re: [PATCH RFC 00/10] RDMA/FS DAX truncate proposal

Jason Gunthorpe
2019-06-13T15:13:57Z

On Wed, Jun 12, 2019 at 06:14:46PM -0700, Dan Williams wrote:
> > Effectively, we would need a way for an admin to close a specific file
> > descriptor (or set of fds) which point to that file. AFAIK there is no way to
> > do that at all, is there?
>
> Even if there were that gets back to my other question, does RDMA
> teardown happen at close(fd), or at final fput() of the 'struct
> file'?

AFAIK there is no kernel side driver hook for close(fd).

rdma uses a normal chardev so it's lifetime is linked to the file_ops
release, which is called on last fput. So all the mmaps, all the dups,
everything must go before it releases its resources.

Jason