On 6/17/19 5:18 PM, Bart Van Assche wrote:
> The ability to modify the SCSI device state was introduced by commit
> 638127e579a4 ("[PATCH] Fix error handler offline behaviour"; v2.6.12). That
> same commit introduced the following device states:
>
> { SDEV_CREATED, "created" },
> { SDEV_RUNNING, "running" },
> { SDEV_CANCEL, "cancel" },
> { SDEV_DEL, "deleted" },
> { SDEV_QUIESCE, "quiesce" },
> { SDEV_OFFLINE, "offline" },
>
> The SDEV_BLOCK state was introduced later to avoid that an FC cable pull
> would immediately result in an I/O error (commit 1094e682310e; "[PATCH]
> suspending I/Os to a device"; v2.6.12). That same patch introduced the
> ability to set the SDEV_BLOCK state from user space. I'm not sure whether
> that ability was introduced on purpose or accidentally.
>
> Since there is agreement that only writing "running" or "offline" into
> the SCSI sysfs device state attribute makes sense, restrict sysfs writes
> to these values.
>
> This patch makes sure that SDEV_BLOCK is only used for its original
> purpose, namely to allow transport drivers and LLDs to block further
> .queuecommand() calls while transport layer or adapter recovery is in
> progress.
>
> Note: a web search for "/sys/class/scsi_device" AND "device/state"
> revealed several storage configuration guides. The instructions I found
> in these guides tell users to write the value "running" or "offline" in
> the SCSI device state sysfs attribute and no other values.
>
> Cc: Christoph Hellwig <h...@lst.de>
> Cc: Ming Lei <ming....@redhat.com>
> Cc: Hannes Reinecke <h...@suse.de>
> Cc: Johannes Thumshirn <jthumsh...@suse.de>
> Cc: James Smart <james.sm...@broadcom.com>
> Cc: Ewan D. Milne <emi...@redhat.com>
> Cc: Laurence Oberman <lober...@redhat.com>
> Signed-off-by: Bart Van Assche <bvanass...@acm.org>
> ---
> drivers/scsi/scsi_sysfs.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
> index 3b119ca0cc0c..850cdc731a1f 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -766,8 +766,13 @@ store_state_field(struct device *dev, struct
> device_attribute *attr,
> break;
> }
> }
> - if (!state)
> + switch (state) {
> + case SDEV_RUNNING:
> + case SDEV_OFFLINE:
> + break;
> + default:
> return -EINVAL;
> + }
>
> mutex_lock(&sdev->state_mutex);
> ret = scsi_device_set_state(sdev, state);
>
Reviewed-by: Hannes Reinecke <h...@suse.com>
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
h...@suse.com +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
