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Subject: Re: [PATCH v3 2/3] nfsd: Initial implementation of NFSv4 Courteous
 Server
To:     "J. Bruce Fields" <bfields@fieldses.org>
Cc:     chuck.lever@oracle.com, linux-nfs@vger.kernel.org,
        linux-fsdevel@vger.kernel.org
References: <20210916182212.81608-1-dai.ngo@oracle.com>
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 <20210923013458.GE22937@fieldses.org>
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From:   dai.ngo@oracle.com
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Date:   Fri, 24 Sep 2021 13:53:13 -0700
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On 9/23/21 12:32 PM, J. Bruce Fields wrote:
> On Thu, Sep 23, 2021 at 10:09:35AM -0700, dai.ngo@oracle.com wrote:
>> On 9/22/21 6:34 PM, J. Bruce Fields wrote:
>>> On Thu, Sep 16, 2021 at 02:22:11PM -0400, Dai Ngo wrote:
>>>> +/*
>>>> + * If the conflict happens due to a NFSv4 request then check for
>>>> + * courtesy client and set rq_conflict_client so that upper layer
>>>> + * can destroy the conflict client and retry the call.
>>>> + */
>>> I think we need a different approach.
>> I think nfsd_check_courtesy_client is used to handle conflict with
>> delegation. So instead of using rq_conflict_client to let the caller
>> knows and destroy the courtesy client as the current patch does, we
>> can ask the laundromat thread to do the destroy.
> I can't see right now why that wouldn't work.
>
>> In that case,
>> nfs4_get_vfs_file in nfsd4_process_open2 will either return no error
>> since the the laufromat destroyed the courtesy client or it gets
>> get nfserr_jukebox which causes the NFS client to retry. By the time
>> the retry comes the courtesy client should already be destroyed.
> Make sure this works for local (non-NFS) lease breakers as well.  I
> think that mainly means making sure the !O_NONBLOCK case of
> __break_lease works.

Yes, local lease breakers use (!O_NONBLOCK). In this case __break_lease
will call lm_break then wait for all lease conflicts to be resolved
before returning to caller.

-Dai

>
> --b.