linux-kernel - Re: [PATCH] nbd: ratelimit error msgs after socket close

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Date:	Fri, 05 Feb 2016 08:59:50 +0100
From:	Markus Pargmann <mpa@...gutronix.de>
To:	Dan Streetman <dan.streetman@...onical.com>
Cc:	Jens Axboe <axboe@...com>, nbd-general@...ts.sourceforge.net,
	linux-kernel@...r.kernel.org, Dan Streetman <ddstreet@...e.org>
Subject: Re: [PATCH] nbd: ratelimit error msgs after socket close

Hi Dan,

On Tuesday, February 02, 2016 12:07:04 PM Dan Streetman wrote:
> Hi Markus,
> 
> just checking if you had any comments on this patch?
> 
> On Thu, Jan 14, 2016 at 1:42 PM, Dan Streetman
> <dan.streetman@...onical.com> wrote:
> > Make the "Attempted send on closed socket" error messages generated in
> > nbd_request_handler() ratelimited.
> >
> > When the nbd socket is shutdown, the nbd_request_handler() function emits
> > an error message for every request remaining in its queue.  If the queue
> > is large, this will spam a large amount of messages to the log.  There's
> > no need for a separate error message for each request, so this patch
> > ratelimits it.
> >
> > In the specific case this was found, the system was virtual and the error
> > messages were logged to the serial port, which overwhelmed it.
> >
> > Fixes: 4d48a542b427 ("nbd: fix I/O hang on disconnected nbds")
> > Signed-off-by: Dan Streetman <dan.streetman@...onical.com>

Sorry for the delay. I applied the patch.

Thanks,

Markus

> > ---
> >  drivers/block/nbd.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> > index e4c5cc1..c65d41f 100644
> > --- a/drivers/block/nbd.c
> > +++ b/drivers/block/nbd.c
> > @@ -618,8 +618,8 @@ static void nbd_request_handler(struct request_queue *q)
> >                         req, req->cmd_type);
> >
> >                 if (unlikely(!nbd->sock)) {
> > -                       dev_err(disk_to_dev(nbd->disk),
> > -                               "Attempted send on closed socket\n");
> > +                       dev_err_ratelimited(disk_to_dev(nbd->disk),
> > +                                           "Attempted send on closed socket\n");
> >                         req->errors++;
> >                         nbd_end_request(nbd, req);
> >                         spin_lock_irq(q->queue_lock);
> > --
> > 2.5.0
> >
> 

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