On Thu, Apr 12, 2018 at 04:05:39PM -0400, Olga Kornievskaia wrote: > On Wed, Apr 11, 2018 at 1:33 PM, J. Bruce Fields <bfields@xxxxxxxxxx> wrote: > > On Tue, Apr 10, 2018 at 05:13:07PM -0400, J. Bruce Fields wrote: > >> On Tue, Apr 10, 2018 at 05:07:02PM -0400, Olga Kornievskaia wrote: > >> > On Tue, Apr 10, 2018 at 4:21 PM, J. Bruce Fields <bfields@xxxxxxxxxx> wrote: > >> > > 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. > > > > And come to think of it we should actually be adding that check to > > client_has_state()--it should return clientid_busy if there are any > > copies in progress. > > > >> > > So the server behavior you're seeing sounds correct to me--the client > >> > > should cancel any ongoing copies before calling DESTROY_CLIENTID. > >> > > >> > If the behavior of returning ERR_DELAY until the copy is done is > >> > correct one, then I don't think I need this patch at all. Since copy > >> > takes a reference on the nfs4_client structure, then in > >> > __destroy_client() where nfsd4_shutdown_copy() is called the list will > >> > always be empty. > >> > >> Actually I guess it should be returning CLIENTID_BUSY. Maybe that's a > >> preexisting bug. > > > > So the copy should be caught by the earlier client_has_state() check > > before it gets to the later mark_client_expired_locked(). > > > > And after reminding myself how this works.... We only hold references > > on clients temporarily such as while we're actually processing an RPC > > from a client. > > > > An elevated cl_refcount prevents the server from removing the client > > even after the lease expires, or after the client reboots and attempts > > to clear its old state with a new EXCHANGE_ID/CREATE_SESSION. I don't > > think that's what we want. Clients still need to renew their lease in > > the usual way, a long-running async copy doesn't keep the lease renewed > > automatically. > > > > So, the asynchronous copy shouldn't hold a reference on the client. > > > > The copy thread can still safely use the client while it's running, > > because it knows that anyone destroying the client will first cancel the > > copy and wait for the thread to die. > > Ok no reference on the client. I will add a check to > client_has_state() to check for on-going copies and then server would > return CLIENTID_BUSY. What was already in the patch was that during > client shutdown it would stop copies. I have tested for when the > server is expiring client's lease, it also shuts down any on-going > copies. I think I'm ready for the next version submission... OK, great.--b. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
