[dm-devel] dm-mq and end_clone_request()

[Bart Van Assche]

On 07/25/2016 06:15 PM, Mike Snitzer wrote:
> Please try this patch to see if it fixes your issue, thanks.
> 
> diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
> index 52baf8a..287caa7 100644
> --- a/drivers/md/dm-mpath.c
> +++ b/drivers/md/dm-mpath.c
> @@ -433,10 +433,17 @@ failed:
>   */
>  static int must_push_back(struct multipath *m)
>  {
> -	return (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) ||
> -		((test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) !=
> -		  test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) &&
> -		 dm_noflush_suspending(m->ti)));
> +	bool r;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&m->lock, flags);
> +	r = (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) ||
> +	     ((test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) !=
> +	       test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) &&
> +	      dm_noflush_suspending(m->ti)));
> +	spin_unlock_irqrestore(&m->lock, flags);
> +
> +	return r;
>  }
>  
>  /*
 
Hello Mike,

Thank you for having made this patch available. Unfortunately even
with this patch applied I still see fio reporting I/O errors and the
following text still appears in the system log immediately before the
I/O errors are reported (due to debug statements I added in the device
mapper; mpath 254:0 and mpathbe refer to the same dm device):

Jul 26 15:40:37 ion-dev-ib-ini kernel: mpath 254:0: queue_if_no_path 0 -> 1
Jul 26 15:40:37 ion-dev-ib-ini kernel: executing DM ioctl DEV_SUSPEND on mpathbe
Jul 26 15:40:37 ion-dev-ib-ini kernel: mpath 254:0: queue_if_no_path 1 -> 0

BTW, I have not yet been able to determine which user space code
triggers the DEV_SUSPEND ioctl. A condlog() call I had added just
above dm_simplecmd_flush(DM_DEVICE_SUSPEND, mapname, 0) call in
multipathd did not produce any output.

Bart.