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From: Mike Christie <mchristi@redhat.com>
To: Josef Bacik <josef@toxicpanda.com>, Hou Pu <houpu.main@gmail.com>,
	axboe@kernel.dk
Cc: linux-block@vger.kernel.org, nbd@other.debian.org,
	Hou Pu <houpu@bytedance.com>
Subject: Re: [PATCH 1/2] nbd: enable replace socket if only one connection is configured
Date: Tue, 3 Mar 2020 15:48:47 -0600	[thread overview]
Message-ID: <5E5ED0BF.7030407@redhat.com> (raw)
In-Reply-To: <3b6ae210-f942-b74d-1e53-768c7e8c3675@toxicpanda.com>

On 03/03/2020 03:12 PM, Josef Bacik wrote:
> On 2/28/20 1:40 AM, Hou Pu wrote:
>> Nbd server with multiple connections could be upgraded since
>> 560bc4b (nbd: handle dead connections). But if only one conncection
>> is configured, after we take down nbd server, all inflight IO
>> would finally timeout and return error. We could requeue them
>> like what we do with multiple connections and wait for new socket
>> in submit path.
>>
>> Signed-off-by: Hou Pu <houpu@bytedance.com>
>> ---
>>   drivers/block/nbd.c | 17 +++++++++--------
>>   1 file changed, 9 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
>> index 78181908f0df..83070714888b 100644
>> --- a/drivers/block/nbd.c
>> +++ b/drivers/block/nbd.c
>> @@ -395,16 +395,19 @@ static enum blk_eh_timer_return
>> nbd_xmit_timeout(struct request *req,
>>       }
>>       config = nbd->config;
>>   -    if (config->num_connections > 1) {
>> +    if (config->num_connections > 1 ||
>> +        (config->num_connections == 1 && nbd->tag_set.timeout)) {
> 
> This is every connection, do you mean to couple this with
> dead_conn_timeout? Thanks,
> 

In

commit 2da22da573481cc4837e246d0eee4d518b3f715e
Author: Mike Christie <mchristi@redhat.com>
Date:   Tue Aug 13 11:39:52 2019 -0500

    nbd: fix zero cmd timeout handling v2

we can set tag_set.timeout=0 again.

So if timeout != 0 and num_connections = 1, we requeue here and let
nbd_handle_cmd->wait_for_reconnect decide to wait or fail the command if
dead_conn_timeout is not set.

If timeout = 0, then we give it more time because it might have just
been a slow server or connection. I think this behavior is wrong for the
case Hou is fixing. See comment in the next patch.


  reply	other threads:[~2020-03-03 21:48 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-28  6:40 [PATCH v2 0/2] nbd: requeue request if only one connection is configured Hou Pu
2020-02-28  6:40 ` [PATCH 1/2] nbd: enable replace socket " Hou Pu
2020-03-03 21:12   ` Josef Bacik
2020-03-03 21:48     ` Mike Christie [this message]
2020-03-04  5:41       ` Hou Pu
2020-03-04 18:48   ` Josef Bacik
2020-02-28  6:40 ` [PATCH 2/2] nbd: requeue command if the soecket is changed Hou Pu
2020-03-03 21:13   ` Josef Bacik
2020-03-03 22:06     ` Mike Christie
2020-03-03 22:21       ` Mike Christie
2020-03-04  7:13         ` Hou Pu
2020-03-04 18:48   ` Josef Bacik
2020-03-12 13:59 ` [PATCH v2 0/2] nbd: requeue request if only one connection is configured Jens Axboe
2020-03-13 11:29   ` Hou Pu
  -- strict thread matches above, loose matches on Subject: below --
2020-02-19  6:31 [PATCH 0/2] " Hou Pu
2020-02-19  6:31 ` [PATCH 1/2] nbd: enable replace socket " Hou Pu
2020-02-25  6:32   ` Mike Christie
2020-02-25 14:10     ` Hou Pu

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