On 4/7/21 3:14 PM, J. Bruce Fields wrote: > On Fri, Mar 19, 2021 at 05:09:22PM -0400, J. Bruce Fields wrote: >> On Sat, Mar 20, 2021 at 07:48:44AM +1100, NeilBrown wrote: >>> On Fri, Mar 19 2021, J. Bruce Fields wrote: >>> >>>> On Fri, Mar 19, 2021 at 02:36:24PM +1100, NeilBrown wrote: >>>>> On Mon, Mar 01 2021, J. Bruce Fields wrote: >>>>> >>>>>> On Tue, Mar 02, 2021 at 02:01:36PM +1100, NeilBrown wrote: >>>>>>> On Mon, Mar 01 2021, J. Bruce Fields wrote: >>>>>>> >>>>>>>> I've gotten requests for similar functionality, and intended to >>>>>>>> implement it using directory notifications on /proc/fs/nfsd/clients. >>>>>>> >>>>>>> I've been exploring this a bit. >>>>>>> When I mount a filesystem, 2 clients get created. >>>>>>> With NFSv4.0, the second client is immediately deleted, and the first >>>>>>> client is deleted one grace period after the filesystem is unmounted. >>>>>>> With NFSv4.1 and 4.2, the first client is immediately deleted, and the >>>>>>> second client is deleted immediately after the unmount. >>>>>> >>>>>> Yeah, internally it's creating an "unconfirmed client" on SETCLIENTID >>>>>> (or EXCHANGE_ID) and then a new "confirmed client" on >>>>>> SETCLIENTID_CONFIRM (or CREATE_SESSION). >>>>>> >>>>>> I'm not sure why the ordering's a little different between the 4.0/4.1+ >>>>>> cases. >>>>> >>>>> The multiple clients are not really nfsd's "fault". The Linux NFS >>>>> client sends multiple EXCHANGE_ID or SET_CLIENT_ID requests, so NFSD >>>>> really does need to create multiple clients. >>>>> >>>>> For NFSv4.0, when nfsd gets a repeat SET_CLIENT_ID, it keeps the old one >>>>> and discards the new. >>>>> For NFSv4.1, the spec requires that it keep the new one and discard the >>>>> old. >>>>> This explains the different ordering. >>>> >>>> Hm, is this the client's trunking-detection logic? >>> >>> Yes. >>> >>>> >>>> In which case, it's not just unconfirmed clients. >>> >>> For NFSv4.1, only the EXCHANGE_ID is duplicate. There is only one >>> CREATE_SESSION, and that is where the client is confirmed. So only one >>> confirmed client. >>> >>> For NFSv4.0 bother SETCLIENTID and SETCLIENDID_CONFIRM are duplicate. >>> So maybe both clients get confirmed. I should check that. >> >> Drifting off topic, but I don't see how this client behavior makes >> sense. Mount is chatty enough without the unnecessary duplication. >> Looking at the code.... > > I never sorted this out, by the way. I think there must be a bug, > though. My bad... I didn't realize you had concern with the patch... What needs to happen... to figure this out? steved.
