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Subject: Re: [PATCH V2 0/6]nvme-pci: fixes on nvme_timeout and
 nvme_dev_disable
To:     Keith Busch <keith.busch@intel.com>
Cc:     axboe@fb.com, linux-kernel@vger.kernel.org,
        Sagi Grimberg <sagi@grimberg.me>,
        linux-nvme@lists.infradead.org, hch@lst.de
References: <1517822415-11710-1-git-send-email-jianchao.w.wang@oracle.com>
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From:   "jianchao.wang" <jianchao.w.wang@oracle.com>
Message-ID: <de6fd2ac-fc69-1b3b-c206-7abfce24ac70@oracle.com>
Date:   Sat, 10 Feb 2018 10:32:27 +0800
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Hi Keith

Thanks for your kindly response here.
That's really appreciated.

On 02/10/2018 01:12 AM, Keith Busch wrote:
> On Fri, Feb 09, 2018 at 09:50:58AM +0800, jianchao.wang wrote:
>>
>> if we set NVME_REQ_CANCELLED and return BLK_EH_HANDLED as the RESETTING case,
>> nvme_reset_work will hang forever, because no one could complete the entered requests.
> 
> Except it's no longer in the "RESETTING" case since you added the
> "CONNECTING" state, so that's already broken for other reasons...
> 

Yes, but as your patch, we have to fail the IOs and even kill the controller.
In fact, up to nvme_wait_freeze in nvme_reset_work, the RECONNECTING state has been completed.
We even could say it is in LIVE state. Maybe we should recover the controller again instead
of fail the IOs and kill the controller.

On the other hand, can you share with me why we cannot use blk_set_preempt_only to replace
blk_freeze_queue ? we just want to gate the new bios out of generic_make_request and we 
needn't use the preempt requests.

Looking forward your advice and directive.

Thanks
Jianchao


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