[dm-devel] dm-mq and end_clone_request()
Mike Snitzer
snitzer at redhat.com
Tue Jul 26 01:16:07 UTC 2016
On Mon, Jul 25 2016 at 6:00P -0400,
Bart Van Assche <bart.vanassche at sandisk.com> wrote:
> On 07/25/2016 02:23 PM, Mike Snitzer wrote:
> >So I'd be curious to know if your debugging has enabled you to identify
> >exactly where in the dm-mapth.c code the -EIO return is being
> >established. do_end_io() is the likely candidate -- but again the
> >__must_push_back() check should prevent it and DM_ENDIO_REQUEUE should
> >be returned.
>
> Hello Mike,
>
> Thanks for looking further into this. The pr_info() statement that I had
> added in the following code block in __multipath_map() fired what told me
> that the following code block triggered the -EIO return:
>
> if (!pgpath) {
> if (!must_push_back(m))
> r = -EIO; /* Failed */
> pr_info("%s(): (a) returning %d\n", __func__, r);
> return r;
> }
>
> From the system log:
>
> kernel: mpath 254:0: queue_if_no_path 1 -> 0
> kernel: __multipath_map(): (a) returning -5
>
> The code that I had added in queue_if_no_path() is as follows:
>
> old = test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags);
> [ ... ]
> pr_info("mpath %s: queue_if_no_path %d -> %d\n",
> dm_device_name(dm_table_get_md(m->ti->table)), old,
> queue_if_no_path);
Hi Bart,
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;
}
/*
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