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

[dai.ngo@oracle.com]

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.
>>