[S390] dasd: Improve handling of stolen DASD reservation
If a DASD device has been reserved by a Linux system, and later
this reservation is ‘stolen’ by a second system by means of an
unconditional reserve, then the first system receives a
notification about this fact. With this patch such an event can
be either ignored, as before, or it can be used to let the device
fail all I/O request, so that the device will not block anymore.
Signed-off-by: Stefan Weinhuber <wein@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 0001df8..47fc886 100644
--- a/drivers/s390/block/dasd_devmap.c
+++ b/drivers/s390/block/dasd_devmap.c
@@ -1127,6 +1127,103 @@
static DEVICE_ATTR(expires, 0644, dasd_expires_show, dasd_expires_store);
+static ssize_t dasd_reservation_policy_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct dasd_devmap *devmap;
+ int rc = 0;
+
+ devmap = dasd_find_busid(dev_name(dev));
+ if (IS_ERR(devmap)) {
+ rc = snprintf(buf, PAGE_SIZE, "ignore\n");
+ } else {
+ spin_lock(&dasd_devmap_lock);
+ if (devmap->features & DASD_FEATURE_FAILONSLCK)
+ rc = snprintf(buf, PAGE_SIZE, "fail\n");
+ else
+ rc = snprintf(buf, PAGE_SIZE, "ignore\n");
+ spin_unlock(&dasd_devmap_lock);
+ }
+ return rc;
+}
+
+static ssize_t dasd_reservation_policy_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct dasd_devmap *devmap;
+ int rc;
+
+ devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
+ if (IS_ERR(devmap))
+ return PTR_ERR(devmap);
+ rc = 0;
+ spin_lock(&dasd_devmap_lock);
+ if (sysfs_streq("ignore", buf))
+ devmap->features &= ~DASD_FEATURE_FAILONSLCK;
+ else if (sysfs_streq("fail", buf))
+ devmap->features |= DASD_FEATURE_FAILONSLCK;
+ else
+ rc = -EINVAL;
+ if (devmap->device)
+ devmap->device->features = devmap->features;
+ spin_unlock(&dasd_devmap_lock);
+ if (rc)
+ return rc;
+ else
+ return count;
+}
+
+static DEVICE_ATTR(reservation_policy, 0644,
+ dasd_reservation_policy_show, dasd_reservation_policy_store);
+
+static ssize_t dasd_reservation_state_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct dasd_device *device;
+ int rc = 0;
+
+ device = dasd_device_from_cdev(to_ccwdev(dev));
+ if (IS_ERR(device))
+ return snprintf(buf, PAGE_SIZE, "none\n");
+
+ if (test_bit(DASD_FLAG_IS_RESERVED, &device->flags))
+ rc = snprintf(buf, PAGE_SIZE, "reserved\n");
+ else if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags))
+ rc = snprintf(buf, PAGE_SIZE, "lost\n");
+ else
+ rc = snprintf(buf, PAGE_SIZE, "none\n");
+ dasd_put_device(device);
+ return rc;
+}
+
+static ssize_t dasd_reservation_state_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct dasd_device *device;
+ int rc = 0;
+
+ device = dasd_device_from_cdev(to_ccwdev(dev));
+ if (IS_ERR(device))
+ return -ENODEV;
+ if (sysfs_streq("reset", buf))
+ clear_bit(DASD_FLAG_LOCK_STOLEN, &device->flags);
+ else
+ rc = -EINVAL;
+ dasd_put_device(device);
+
+ if (rc)
+ return rc;
+ else
+ return count;
+}
+
+static DEVICE_ATTR(last_known_reservation_state, 0644,
+ dasd_reservation_state_show, dasd_reservation_state_store);
+
static struct attribute * dasd_attrs[] = {
&dev_attr_readonly.attr,
&dev_attr_discipline.attr,
@@ -1139,6 +1236,8 @@
&dev_attr_erplog.attr,
&dev_attr_failfast.attr,
&dev_attr_expires.attr,
+ &dev_attr_reservation_policy.attr,
+ &dev_attr_last_known_reservation_state.attr,
NULL,
};