From: bvanassche@acm.org (Bart Van Assche)
Subject: [PATCH v3 2/3] nvmet: Export NVMe namespace attributes
Date: Mon, 24 Jun 2019 16:51:39 -0700 [thread overview]
Message-ID: <062c6877-62e3-a37b-d2b2-ea35aadae912@acm.org> (raw)
In-Reply-To: <yq136jyo927.fsf@oracle.com>
On 6/24/19 4:30 PM, Martin K. Petersen wrote:
>
> Hi Bart,
>
>> As you must have noticed the patch at the start of this thread touches
>> both the bdev and the file backends. So I'm not sure what your
>> question is about?
>
> I was contemplating what the observed I/O atomicity would be for the
> initiator side when the target file backend is using buffered I/O.
Hi Martin,
My understanding is that after a completion has been reported for an
atomic NVMe write that the written data must survive a power cycle. As
you probably know all single logical block NVMe writes are atomic since
the AWUPF field is 0's based. So I don't think that it is possible to
implement a backend that uses buffered I/O in such a way that the
backend is NVMe compliant without using an uninterruptible power supply.
Bart.
next prev parent reply other threads:[~2019-06-24 23:51 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-17 16:12 [PATCH v3 0/3] NVMe 1.4 Identify Namespace Support Bart Van Assche
2019-06-17 16:12 ` [PATCH v3 1/3] nvme: Introduce NVMe 1.4 Identify Namespace fields in struct nvme_id_ns Bart Van Assche
2019-06-18 7:49 ` Hannes Reinecke
2019-06-17 16:12 ` [PATCH v3 2/3] nvmet: Export NVMe namespace attributes Bart Van Assche
2019-06-18 7:50 ` Hannes Reinecke
2019-06-19 4:13 ` Martin K. Petersen
2019-06-19 15:44 ` Bart Van Assche
2019-06-21 1:56 ` Martin K. Petersen
2019-06-21 15:19 ` Bart Van Assche
2019-06-24 23:30 ` Martin K. Petersen
2019-06-24 23:51 ` Bart Van Assche [this message]
2019-06-20 3:19 ` Chaitanya Kulkarni
2019-06-17 16:12 ` [PATCH v3 3/3] nvme: Set physical block size and optimal I/O size according to NVMe 1.4 Bart Van Assche
2019-06-18 7:51 ` Hannes Reinecke
2019-06-19 4:17 ` Martin K. Petersen
2019-06-18 7:52 ` [PATCH v3 0/3] NVMe 1.4 Identify Namespace Support Hannes Reinecke
2019-06-18 20:34 ` Bart Van Assche
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