Date: Fri, 21 Aug 2015 08:59:54 +0200
From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <keith.busch@intel.com>
Cc: Jens Axboe <axboe@fb.com>, linux-api@vger.kernel.org, dm-devel@redhat.com,
        linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: Persistent Reservation API V2
Message-ID: <20150821065954.GA14559@lst.de>
References: <1439360604-16192-1-git-send-email-hch@lst.de> <alpine.LNX.2.00.1508202317270.15930@localhost.lm.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <alpine.LNX.2.00.1508202317270.15930@localhost.lm.intel.com>
User-Agent: Mutt/1.5.17 (2007-11-01)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1038
Lines: 25

On Thu, Aug 20, 2015 at 11:56:36PM +0000, Keith Busch wrote:

> NVMe can also specify
> if whether or not a reservation should persist through power-loss.

SCSI does as well, it's the APTPL flag.  However reservations not persistent
through a power loss are basically useless, so I decided to force them on
in the API.  From the documentation:

"All implementations are expected to ensure the reservations survive
 a power loss"

So I would prefer not to add it, or if we really have to as a negative flag
to specifically opt out of the APTPL behavior.

> with it. For example, NVMe can ignore existing keys when acquiring a
> reservation in addition to registering a new key.

This sounds like a sensible addition to me, and I wouldn't be surprised
if future SPC versions will add this flag.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/