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Date:   Wed, 24 May 2023 11:05:07 -0700
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Subject: Re: [PATCH v5 3/3] locks: allow support for write delegation
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To:     Chuck Lever III <chuck.lever@oracle.com>,
        Jeff Layton <jlayton@kernel.org>
Cc:     Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
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On 5/24/23 10:41 AM, Chuck Lever III wrote:
>
>> On May 24, 2023, at 12:55 PM, Jeff Layton <jlayton@kernel.org> wrote:
>>
>> On Wed, 2023-05-24 at 15:09 +0000, Chuck Lever III wrote:
>>>> On May 24, 2023, at 11:08 AM, Jeff Layton <jlayton@kernel.org> wrote:
>>>>
>>>> On Mon, 2023-05-22 at 16:52 -0700, Dai Ngo wrote:
>>>>> Remove the check for F_WRLCK in generic_add_lease to allow file_lock
>>>>> to be used for write delegation.
>>>>>
>>>>> First consumer is NFSD.
>>>>>
>>>>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>>>>> ---
>>>>> fs/locks.c | 7 -------
>>>>> 1 file changed, 7 deletions(-)
>>>>>
>>>>> diff --git a/fs/locks.c b/fs/locks.c
>>>>> index df8b26a42524..08fb0b4fd4f8 100644
>>>>> --- a/fs/locks.c
>>>>> +++ b/fs/locks.c
>>>>> @@ -1729,13 +1729,6 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr
>>>>> if (is_deleg && !inode_trylock(inode))
>>>>> return -EAGAIN;
>>>>>
>>>>> - if (is_deleg && arg == F_WRLCK) {
>>>>> - /* Write delegations are not currently supported: */
>>>>> - inode_unlock(inode);
>>>>> - WARN_ON_ONCE(1);
>>>>> - return -EINVAL;
>>>>> - }
>>>>> -
>>>>> percpu_down_read(&file_rwsem);
>>>>> spin_lock(&ctx->flc_lock);
>>>>> time_out_leases(inode, &dispose);
>>>> I'd probably move this back to the first patch in the series.
>>>>
>>>> Reviewed-by: Jeff Layton <jlayton@kernel.org>
>>> I asked him to move it to the end. Is it safe to take out this
>>> check before write delegation is actually implemented?
>>>
>> I think so, but it don't think it doesn't make much difference either
>> way. The only real downside of putting it at the end is that you might
>> have to contend with a WARN_ON_ONCE if you're bisecting.
> My main concern is in fact preventing problems during bisection.
> I can apply 3/3 and then 1/3, if you're good with that.

I'm good with that. You can apply 3/3 then 1/3 and drop 2/3 so I
don't have to send out v6.

-Dai

>
>
> --
> Chuck Lever
>
>