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From: Hannes Reinecke <hare@suse.de>
To: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>,
	Keith Busch <keith.busch@wdc.com>,
	linux-nvme@lists.infradead.org, Keith Busch <kbusch@kernel.org>,
	Daniel Wagner <daniel.wagner@suse.de>
Subject: Re: [PATCHv3] nvme-mpath: delete disk after last connection
Date: Mon, 10 May 2021 16:48:36 +0200	[thread overview]
Message-ID: <deb2beb3-5aec-b439-3ce3-6c04f7badc45@suse.de> (raw)
In-Reply-To: <20210510062346.GA30116@lst.de>

On 5/10/21 8:23 AM, Christoph Hellwig wrote:
> On Fri, May 07, 2021 at 07:02:52PM +0200, Hannes Reinecke wrote:
>> On 5/7/21 8:46 AM, Christoph Hellwig wrote:
>>> On Thu, May 06, 2021 at 05:54:29PM +0200, Hannes Reinecke wrote:
>>>> PCI and fabrics have different defaults; for PCI the device goes away if
>>>> the last path (ie the controller) goes away, for fabrics it doesn't if the
>>>> device is mounted.
>>>
>>> Err, no.  For fabrics we reconnect a while, but otherwise the behavior
>>> is the same right now.
>>>
>> No, that is not the case.
>>
>> When a PCI nvme device with CMIC=0 is removed (via pci hotplug, say), the 
>> nvme device is completely removed, irrespective on whether it's mounted or 
>> not.
>> When the _same_ PCI device with CMIC=1 is removed, the nvme device (ie the 
>> nsnhead) will _stay_ when mounted (as the refcount is not zero).
> 
> Yes.  But that has nothing to do with fabrics as you claimed above, but
> with the fact if the subsystem supports multiple controller (and thus
> shared namespaces) or not.
> 
So, I seem to have reproduced the issue with latest nvme-5.13.
The failure pattern is slightly different, so I think I've been able to
solve is in a slightly less controversial manner.

Patch to follow.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		        Kernel Storage Architect
hare@suse.de			               +49 911 74053 688
SUSE Software Solutions Germany GmbH, 90409 Nürnberg
GF: F. Imendörffer, HRB 36809 (AG Nürnberg)

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      parent reply	other threads:[~2021-05-10 14:49 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-01 12:04 [PATCHv3] nvme-mpath: delete disk after last connection Hannes Reinecke
2021-05-04  8:54 ` Christoph Hellwig
2021-05-04 13:40   ` Hannes Reinecke
2021-05-04 19:54     ` Sagi Grimberg
2021-05-05 15:26       ` Keith Busch
2021-05-05 16:15         ` Hannes Reinecke
2021-05-05 20:40           ` Sagi Grimberg
2021-05-06  2:50             ` Keith Busch
2021-05-06  6:13             ` Hannes Reinecke
2021-05-06  7:43       ` Christoph Hellwig
2021-05-06  8:42         ` Hannes Reinecke
2021-05-06  9:47           ` Sagi Grimberg
2021-05-06 12:08             ` Christoph Hellwig
2021-05-06 15:54               ` Hannes Reinecke
2021-05-07  6:46                 ` Christoph Hellwig
2021-05-07 17:02                   ` Hannes Reinecke
2021-05-07 17:20                     ` Sagi Grimberg
2021-05-10  6:23                     ` Christoph Hellwig
2021-05-10 13:01                       ` Hannes Reinecke
2021-05-10 13:57                         ` Hannes Reinecke
2021-05-10 14:48                       ` Hannes Reinecke [this message]

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