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: Fri, 7 May 2021 19:02:52 +0200 [thread overview]
Message-ID: <4fd33328-9060-6e95-dd26-ab013e44c07a@suse.de> (raw)
In-Reply-To: <20210507064656.GA24437@lst.de>
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).
This can be easily demonstrated on qemu; just set the 'subsys' parameter
for the nvme device.
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@suse.de +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer
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next prev parent reply other threads:[~2021-05-07 17:03 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 [this message]
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
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