s390/dasd: add safe offline interface
The regular behavior of the DASD device driver when setting a device
offline is to return all outstanding I/O as failed. This behavior is
different from that of other System z operating systems and may lead
to unexpected data loss. Adding an explicit 'safe' offline function
will allow customers to use DASDs in the way they expect them to work.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c
index b2b8c18..4d12370 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -952,6 +952,39 @@
dasd_use_raw_store);
static ssize_t
+dasd_safe_offline_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct ccw_device *cdev = to_ccwdev(dev);
+ struct dasd_device *device;
+ int rc;
+
+ device = dasd_device_from_cdev(cdev);
+ if (IS_ERR(device)) {
+ rc = PTR_ERR(device);
+ goto out;
+ }
+
+ if (test_bit(DASD_FLAG_OFFLINE, &device->flags) ||
+ test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
+ /* Already doing offline processing */
+ dasd_put_device(device);
+ rc = -EBUSY;
+ goto out;
+ }
+
+ set_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags);
+ dasd_put_device(device);
+
+ rc = ccw_device_set_offline(cdev);
+
+out:
+ return rc ? rc : count;
+}
+
+static DEVICE_ATTR(safe_offline, 0200, NULL, dasd_safe_offline_store);
+
+static ssize_t
dasd_discipline_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
@@ -1320,6 +1353,7 @@
&dev_attr_expires.attr,
&dev_attr_reservation_policy.attr,
&dev_attr_last_known_reservation_state.attr,
+ &dev_attr_safe_offline.attr,
NULL,
};