Re: [PATCH RFC v5 0/2] nfsd: Initial implementation of NFSv4 Courteous Server

From: dai.ngo@oracle.com
To: "J. Bruce Fields" <bfields@fieldses.org>
Cc: chuck.lever@oracle.com, linux-nfs@vger.kernel.org,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH RFC v5 0/2] nfsd: Initial implementation of NFSv4 Courteous Server
Date: Tue, 16 Nov 2021 15:06:32 -0800	[thread overview]
Message-ID: <33c8ea5a-4187-a9fa-d507-a2dcec06416c@oracle.com> (raw)
In-Reply-To: <a6c9ba13-43d7-4ea9-e05d-f454c2c9f4c2@oracle.com>

Hi Bruce,

Just a reminder that this patch is still waiting for your review.

Thanks,
-Dai

On 10/1/21 2:41 PM, dai.ngo@oracle.com wrote:
>
> On 10/1/21 1:53 PM, J. Bruce Fields wrote:
>> On Tue, Sep 28, 2021 at 08:56:39PM -0400, Dai Ngo wrote:
>>> Hi Bruce,
>>>
>>> This series of patches implement the NFSv4 Courteous Server.
>> Apologies, I keep meaning to get back to this and haven't yet.
>>
>> I do notice I'm seeing a timeout on pynfs 4.0 test OPEN18.
>
> It's weird, this test passes on my system:
>
>
> [root@nfsvmf25 nfs4.0]# ./testserver.py $server --rundeps -v OPEN18
> INIT     st_setclientid.testValid : RUNNING
> INIT     st_setclientid.testValid : PASS
> MKFILE   st_open.testOpen : RUNNING
> MKFILE   st_open.testOpen : PASS
> OPEN18   st_open.testShareConflict1 : RUNNING
> OPEN18   st_open.testShareConflict1 : PASS
> **************************************************
> INIT     st_setclientid.testValid : PASS
> OPEN18   st_open.testShareConflict1 : PASS
> MKFILE   st_open.testOpen : PASS
> **************************************************
> Command line asked for 3 of 673 tests
> Of those: 0 Skipped, 0 Failed, 0 Warned, 3 Passed
> [root@nfsvmf25 nfs4.0]#
>
> Do you have a network trace?
>
> -Dai
>
>>
>> --b.
>>
>>> A server which does not immediately expunge the state on lease 
>>> expiration
>>> is known as a Courteous Server.  A Courteous Server continues to 
>>> recognize
>>> previously generated state tokens as valid until conflict arises 
>>> between
>>> the expired state and the requests from another client, or the server
>>> reboots.
>>>
>>> The v2 patch includes the following:
>>>
>>> . add new callback, lm_expire_lock, to lock_manager_operations to
>>>    allow the lock manager to take appropriate action with conflict 
>>> lock.
>>>
>>> . handle conflicts of NFSv4 locks with NFSv3/NLM and local locks.
>>>
>>> . expire courtesy client after 24hr if client has not reconnected.
>>>
>>> . do not allow expired client to become courtesy client if there are
>>>    waiters for client's locks.
>>>
>>> . modify client_info_show to show courtesy client and seconds from
>>>    last renew.
>>>
>>> . fix a problem with NFSv4.1 server where the it keeps returning
>>>    SEQ4_STATUS_CB_PATH_DOWN in the successful SEQUENCE reply, after
>>>    the courtesy client re-connects, causing the client to keep sending
>>>    BCTS requests to server.
>>>
>>> The v3 patch includes the following:
>>>
>>> . modified posix_test_lock to check and resolve conflict locks
>>>    to handle NLM TEST and NFSv4 LOCKT requests.
>>>
>>> . separate out fix for back channel stuck in SEQ4_STATUS_CB_PATH_DOWN.
>>>
>>> The v4 patch includes:
>>>
>>> . rework nfsd_check_courtesy to avoid dead lock of fl_lock and 
>>> client_lock
>>>    by asking the laudromat thread to destroy the courtesy client.
>>>
>>> . handle NFSv4 share reservation conflicts with courtesy client. This
>>>    includes conflicts between access mode and deny mode and vice versa.
>>>
>>> . drop the patch for back channel stuck in SEQ4_STATUS_CB_PATH_DOWN.
>>>
>>> The v5 patch includes:
>>>
>>> . fix recursive locking of file_rwsem from posix_lock_file.
>>>
>>> . retest with LOCKDEP enabled.
>>>
>>> NOTE: I will submit pynfs tests for courteous server including tests
>>> for share reservation conflicts in a separate patch.
>>>