Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Tue, 2 Mar 2021 01:05:47 +0900
From:   Keith Busch <kbusch@kernel.org>
To:     Hannes Reinecke <hare@suse.de>
Cc:     Daniel Wagner <dwagner@suse.de>, Sagi Grimberg <sagi@grimberg.me>,
        Jens Axboe <axboe@fb.com>, Christoph Hellwig <hch@lst.de>,
        linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] nvme-tcp: Check if request has started before processing
 it
Message-ID: <20210301160547.GB17228@redsun51.ssa.fujisawa.hgst.com>
References: <73e4914e-f867-c899-954d-4b61ae2b4c33@suse.de>
 <20210215104020.yyithlo2hkxqvguj@beryllium.lan>
 <a2064070-b511-ba6d-bd64-0b3abc208356@grimberg.me>
 <20210226123534.4oovbzk4wrnfjp64@beryllium.lan>
 <9e209b12-3771-cdca-2c9d-50451061bd2a@suse.de>
 <20210226161355.GG31593@redsun51.ssa.fujisawa.hgst.com>
 <a42d6285-ff32-3e16-b2b1-808d29f2a743@suse.de>
 <20210226171901.GA3949@redsun51.ssa.fujisawa.hgst.com>
 <20210301132639.n3eowtvkms2n5mog@beryllium.lan>
 <786dcef5-148d-ff34-590c-804b331ac519@suse.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <786dcef5-148d-ff34-590c-804b331ac519@suse.de>
User-Agent: Mutt/1.12.1 (2019-06-15)
Precedence: bulk

On Mon, Mar 01, 2021 at 02:55:30PM +0100, Hannes Reinecke wrote:
> On 3/1/21 2:26 PM, Daniel Wagner wrote:
> > On Sat, Feb 27, 2021 at 02:19:01AM +0900, Keith Busch wrote:
> >> Crashing is bad, silent data corruption is worse. Is there truly no
> >> defense against that? If not, why should anyone rely on this?
> > 
> > If we receive an response for which we don't have a started request, we
> > know that something is wrong. Couldn't we in just reset the connection
> > in this case? We don't have to pretend nothing has happened and
> > continuing normally. This would avoid a host crash and would not create
> > (more) data corruption. Or I am just too naive?
> > 
> This is actually a sensible solution.
> Please send a patch for that.

Is a bad frame a problem that can be resolved with a reset?

Even if so, the reset doesn't indicate to the user if previous commands
completed with bad data, so it still seems unreliable.