Re: [PATCH v7 10/10] NFSD stop queued async copies on client shutdown

["J. Bruce Fields" <bfields@redhat.com>]

On Tue, Apr 10, 2018 at 04:09:09PM -0400, Olga Kornievskaia wrote:
> I have a question. I’m testing how the code works in
> nfsd4_shutdown_copy. I have disabled canceling the copy (just
> returning ok) and so then the client can stop its copy and do the
> close and then I can issue an unmount. What I see is that the server
> returns “err_delay” until the copy finishes. That’s because in
> nfsd4_destroy_clientid() it calls mark_client_expired_locked() which
> checks the refcount on the client structure and since copy holds a
> reference server returns err_delay. Once the copy finished and
> decrements the reference, and nfsd4_destroy_clientid() gets past that
> then calling nfsd4_shutdown_copy() doesn’t find any copies.
> 
> Should the logic of nfsd4_destroy_clientid() be changed to stop copies
> then instead of during destruction of the client structure?

Oh, good question, I don't know.  Thinking about it....

DESTROY_CLIENTID doesn't throw away all the client's state for it, it's
only meant to be called after the client has already cleaned up
everything else.  So:

	https://tools.ietf.org/html/rfc5661#section-18.50.3

	If there are sessions (both idle and non-idle), opens, locks,
	delegations, layouts, and/or wants (Section 18.49) associated
	with the unexpired lease of the client ID, the server MUST
	return NFS4ERR_CLIENTID_BUSY.

My feeling is that "ongoing copies" also belongs on that list.

So the server behavior you're seeing sounds correct to me--the client
should cancel any ongoing copies before calling DESTROY_CLIENTID.

--b.