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:   Mon, 29 Jun 2020 09:09:47 +0100
From:   Christoph Hellwig <hch@infradead.org>
To:     Simon Arlott <simon@octiron.net>
Cc:     "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-scsi@vger.kernel.org, linux-doc@vger.kernel.org,
        Bart Van Assche <bvanassche@acm.org>,
        Christoph Hellwig <hch@infradead.org>,
        Damien Le Moal <Damien.LeMoal@wdc.com>,
        Pavel Machek <pavel@ucw.cz>,
        Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Subject: Re: [PATCH (v2)] scsi: sd: add parameter to stop disks before reboot
Message-ID: <20200629080947.GA28551@infradead.org>
References: <e726ffd8-8897-4a79-c3d6-6271eda8aebb@0882a8b5-c6c3-11e9-b005-00805fc181fe>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <e726ffd8-8897-4a79-c3d6-6271eda8aebb@0882a8b5-c6c3-11e9-b005-00805fc181fe>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Sun, Jun 28, 2020 at 07:32:51PM +0100, Simon Arlott wrote:
> I need to use "reboot=p" on my desktop because one of the PCIe devices
> does not appear after a warm boot. This results in a very cold boot
> because the BIOS turns the PSU off and on.
> 
> The scsi sd shutdown process does not send a stop command to disks
> before the reboot happens (stop commands are only sent for a shutdown).
> 
> The result is that all of my SSDs experience a sudden power loss on
> every reboot, which is undesirable behaviour because it could cause data
> to be corrupted. These events are recorded in the SMART attributes.
> 
> Add a "stop_before_reboot" module parameter that can be used to control
> the shutdown behaviour of disks before a reboot. The default will be
> the existing behaviour (disks are not stopped).
> 
>   sd_mod.stop_before_reboot=<integer>
>     0 = disabled (default)
>     1 = enabled
> 
> The behaviour on shutdown is unchanged: all disks are unconditionally
> stopped.

What happened to the suggestion to treat reboot=p like a poweroff
instead?  That seems to be fundamentally the right thing to do.