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From: hch@lst.de (hch@lst.de)
Subject: [PATCH] nvme-fabrics -in case of REQ_NVME_MPATH we should return BLK_STS_RESOURCE
Date: Thu, 20 Sep 2018 08:39:24 +0200	[thread overview]
Message-ID: <20180920063924.GG12913@lst.de> (raw)
In-Reply-To: <19b26262-686c-c778-7e01-488917537636@broadcom.com>

On Tue, Sep 18, 2018@12:43:30PM -0700, James Smart wrote:
> The issue that I believe exists is that the multipath driver/core knows how 
> to retry on a different path when the request is accepted then the 
> nvme_complete_rq() is called. But it doesn't know how to retry on a 
> different path when the initial transport:queue_rq() fails - the io ends up 
> failing completely.?? I think we need to fix that code path, not "busy" 
> requeue the mpath io.

The multipath code handles failures from nvme_complete_rq just fine,
in fact even with this patch we still don't accept the command into
queue_rq.  It is just that BLK_STS_RESOURCE is a magic indicator
for the blk-mq core to retry internally and not hand it back to the
next higher level (which would be the multipath code, either nvme
or dm for that matter).

  reply	other threads:[~2018-09-20  6:39 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CY4PR17MB1368DE7C1E52DF30E17060BBE61D0@CY4PR17MB1368.namprd17.prod.outlook.com>
2018-09-18 16:25 ` [PATCH] nvme-fabrics -in case of REQ_NVME_MPATH we should return BLK_STS_RESOURCE hch
2018-09-18 18:37   ` James Smart
2018-09-18 19:08     ` Keith Busch
2018-09-18 19:43       ` James Smart
2018-09-20  6:39         ` hch [this message]
2018-09-20 23:39           ` James Smart
2018-09-21  7:05             ` hch
2018-09-21 18:21               ` James Smart
     [not found]           ` <CY4PR17MB1368B68A2FC010C1A8CED289E6120@CY4PR17MB1368.namprd17.prod.outlook.com>
2018-09-21  8:19             ` hch

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