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From:   Chuck Lever III <chuck.lever@oracle.com>
To:     Dai Ngo <dai.ngo@oracle.com>
CC:     Bruce Fields <bfields@fieldses.org>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH RFC 1/1] nfsd: Initial implementation of NFSv4 Courteous
 Server
Thread-Topic: [PATCH RFC 1/1] nfsd: Initial implementation of NFSv4 Courteous
 Server
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Date:   Wed, 16 Jun 2021 19:29:37 +0000
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> On Jun 16, 2021, at 3:25 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>=20
> On 6/16/21 9:32 AM, Chuck Lever III wrote:
>>> On Jun 16, 2021, at 12:02 PM, J. Bruce Fields <bfields@fieldses.org> wr=
ote:
>>>=20
>>> On Thu, Jun 03, 2021 at 02:14:38PM -0400, Dai Ngo wrote:
>>>> . instead of destroy the client anf all its state on conflict, only de=
stroy
>>>> the state that is conflicted with the current request.
>>> The other todos I think have to be done before we merge, but this one I
>>> think can wait.
>> I agree on both points: this one can wait, but the others
>> should be done before merge.
>=20
> yes, will do.
>=20
>>=20
>>=20
>>>> . destroy the COURTESY_CLIENT either after a fixed period of time to r=
elease
>>>> resources or as reacting to memory pressure.
>>> I think we need something here, but it can be pretty simple.
>> We should work out a policy now.
>>=20
>> A lower bound is good to have. Keep courtesy clients at least
>> this long. Average network partition length times two as a shot
>> in the dark. Or it could be N times the lease expiry time.
>>=20
>> An upper bound is harder to guess at. Obviously these things
>> will go away when the server reboots. The laundromat could
>> handle this sooner. However using a shrinker might be nicer and
>> more Linux-y, keeping the clients as long as practical, without
>> the need for adding another administrative setting.
>=20
> Can we start out with a simple 12 or 24 hours to accommodate long
> network outages for this phase?

Sure. Let's go with 24 hours.

Bill suggested adding a "clear_locks" like mechanism that could be
used to throw out all courteous clients at once. Maybe another
phase 2 project!


--
Chuck Lever