nvme: provide UUID value to userspace

Now that we have a way for getting the UUID from a target, provide it
to userspace as well.

Unfortunately there is already a sysfs attribute called UUID which is
a misnomer as it holds the NGUID value. So instead of creating yet
another wrong name, create a new 'nguid' sysfs attribute for the
NGUID. For the UUID attribute add a check wheter the namespace has a
UUID assigned to it and return this or return the NGUID to maintain
backwards compatibility. This should give userspace a chance to catch
up.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Sagi Grimberg <sagi@rimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Johannes Thumshirn 2017-06-07 11:45:35 +02:00 committed by Christoph Hellwig
parent 3b22ba2682
commit d934f9848a

View File

@ -1879,11 +1879,28 @@ static ssize_t wwid_show(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR(wwid, S_IRUGO, wwid_show, NULL);
static ssize_t nguid_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct nvme_ns *ns = nvme_get_ns_from_dev(dev);
return sprintf(buf, "%pU\n", ns->nguid);
}
static DEVICE_ATTR(nguid, S_IRUGO, nguid_show, NULL);
static ssize_t uuid_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct nvme_ns *ns = nvme_get_ns_from_dev(dev);
return sprintf(buf, "%pU\n", ns->nguid);
/* For backward compatibility expose the NGUID to userspace if
* we have no UUID set
*/
if (uuid_is_null(&ns->uuid)) {
printk_ratelimited(KERN_WARNING
"No UUID available providing old NGUID\n");
return sprintf(buf, "%pU\n", ns->nguid);
}
return sprintf(buf, "%pU\n", &ns->uuid);
}
static DEVICE_ATTR(uuid, S_IRUGO, uuid_show, NULL);
@ -1906,6 +1923,7 @@ static DEVICE_ATTR(nsid, S_IRUGO, nsid_show, NULL);
static struct attribute *nvme_ns_attrs[] = {
&dev_attr_wwid.attr,
&dev_attr_uuid.attr,
&dev_attr_nguid.attr,
&dev_attr_eui.attr,
&dev_attr_nsid.attr,
NULL,
@ -1918,6 +1936,11 @@ static umode_t nvme_ns_attrs_are_visible(struct kobject *kobj,
struct nvme_ns *ns = nvme_get_ns_from_dev(dev);
if (a == &dev_attr_uuid.attr) {
if (uuid_is_null(&ns->uuid) ||
!memchr_inv(ns->nguid, 0, sizeof(ns->nguid)))
return 0;
}
if (a == &dev_attr_nguid.attr) {
if (!memchr_inv(ns->nguid, 0, sizeof(ns->nguid)))
return 0;
}