On Tue, 2019-04-30 at 14:58 -0400, Scott Mayhew wrote: > On Thu, 18 Apr 2019, J. Bruce Fields wrote: > > > On Thu, Apr 18, 2019 at 04:50:24PM -0400, Scott Mayhew wrote: > > > On Thu, 18 Apr 2019, J. Bruce Fields wrote: > > > > > > > On Thu, Apr 18, 2019 at 09:24:00AM -0400, Scott Mayhew wrote: > > > > > While trying to track down some issues involving large > > > > > numbers of > > > > > delegations being recalled/revoked, I caught the server > > > > > setting > > > > > SEQ4_STATUS_CB_PATH_DOWN while the client was actively > > > > > responding to > > > > > CB_RECALLs. It turns out that the client had already done a > > > > > TEST_STATEID and FREE_STATEID for a delegation being recalled > > > > > by the > > > > > time it received the CB_RECALL. > > > > > > > > That's interesting, thanks! > > > > > > > > This exception seems awfully narrow, though. > > > > > > > > If we get back any NFS-level error at all, then I think the > > > > callback > > > > channel is working (am I wrong?) > > > > > > Correct, if the client replies with either NFS4ERR_DELAY or > > > NFS4ERR_BAD_STATEID, the server will retry 1 time (see > > > dl_retries). > > > After that, we fall thru and nfsd4_cb_recall_done() returns -1 > > > which > > > causes the SEQ4_STATUS_CB_PATH_DOWN flag to be set. > > > > > > > and telling the client to set up a new > > > > one is probably not going to help. The best we can do is > > > > probably just > > > > give up > > > > > > That's what the patch is essentially doing. Or are you saying > > > don't > > > even bother with the checks but still return 1 so we don't set > > > the > > > SEQ4_STATUS_CB_PATH_DOWN flag? > > > > Right, I don't see any point returning -1 (which ends up setting > > CB_PATH_DOWN) in any case where we get an nfs-level error. If the > > client got so far as returning an error, then the callback path is > > working. > > > > I'm not sure exactly what errors *should* result in CB_PATH_DOWN, > > though. ETIMEDOUT, ENOTCONN, EIO? > > I'm not sure either. Looking at > call_status/call_timeout/rpc_check_timeout, it looks to me like > ENOTCONN > will be translated to ETIMEDOUT because nfsd4_run_cb_work sets the > RPC_TASK_SOFTCONN flag in the call to rpc_call_async. > > It looks like call_status can return EHOSTDOWN, ENETDOWN, > EHOSTUNREACH, > ENETUNREACH, and EPERM... should those be handled as well? Those errors should never be passed back to applications. -- Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@xxxxxxxxxxxxxxx
