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Date:   Thu, 23 Sep 2021 17:51:13 -0700
From:   Jeremy Allison <jra@samba.org>
To:     dai.ngo@oracle.com
Cc:     Bruce Fields <bfields@fieldses.org>,
        "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
        CIFS <linux-cifs@vger.kernel.org>
Subject: Re: Locking issue between NFSv4 and SMB client
Message-ID: <YU0hAYLow+8n8siT@jeremy-acer>
Reply-To: Jeremy Allison <jra@samba.org>
References: <5b7be2c0-95a6-048c-581f-17e5e3750daa@oracle.com>
 <20210923215056.GH18334@fieldses.org>
 <90a8f89b-e8ac-2187-2926-d723ebbcb839@oracle.com>
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On Thu, Sep 23, 2021 at 03:39:52PM -0700, dai.ngo@oracle.com wrote:
>
>On 9/23/21 2:50 PM, Bruce Fields wrote:
>>On Thu, Jul 15, 2021 at 04:45:22PM -0700, dai.ngo@oracle.com wrote:
>>>Hi Bruce,
>>Oops, sorry for neglecting this.
>>
>>>I'm doing some locking testing between NFSv4 and SMB client and
>>>think there are some issues on the server that allows both clients
>>>to lock the same file at the same time.
>>It's not too surprising to me that getting consistent locks between the
>>two would be hard.
>>
>>Did you get any review from a Samba expert?  I seem to recall it having
>>a lot of options, and I wonder if it's configured correctly for this
>>case.
>
>No, I have not heard from any Samba expert.
>
>>
>>It sounds like Samba may be giving out oplocks without getting a lease
>>from the kernel.
>
>I will have to circle back to this when we're done with the 1st
>phase of courteous server.
>
>-Dai
>
>>
>>--b.
>>
>>>Here is what I did:
>>>
>>>NOTE: lck is a simple program that use lockf(3) to lock a file from
>>>offset 0 to the length specified by '-l'.

What does lockf map to in NFS ?

Samba only uses posix fcntl byte range locks (and only when
told to map SMB locks onto underlying posix locks), we don't use
lockf at all.