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.c b/drivers/s390/block/dasd.c
index 0595c76..29225e1c 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -349,6 +349,16 @@
return rc;
}
+static inline
+int _wait_for_empty_queues(struct dasd_device *device)
+{
+ if (device->block)
+ return list_empty(&device->ccw_queue) &&
+ list_empty(&device->block->ccw_queue);
+ else
+ return list_empty(&device->ccw_queue);
+}
+
/*
* Remove device from block device layer. Destroy dirty buffers.
* Forget format information. Check if the target level is basic
@@ -1841,6 +1851,13 @@
cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
if ((cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) &&
(time_after_eq(jiffies, cqr->expires + cqr->starttime))) {
+ if (test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
+ /*
+ * IO in safe offline processing should not
+ * run out of retries
+ */
+ cqr->retries++;
+ }
if (device->discipline->term_IO(cqr) != 0) {
/* Hmpf, try again in 5 sec */
dev_err(&device->cdev->dev,
@@ -3024,11 +3041,11 @@
cdev->handler = NULL;
- dasd_remove_sysfs_files(cdev);
device = dasd_device_from_cdev(cdev);
if (IS_ERR(device))
return;
- if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
+ if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags) &&
+ !test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
/* Already doing offline processing */
dasd_put_device(device);
return;
@@ -3048,6 +3065,8 @@
*/
if (block)
dasd_free_block(block);
+
+ dasd_remove_sysfs_files(cdev);
}
/*
@@ -3126,16 +3145,13 @@
{
struct dasd_device *device;
struct dasd_block *block;
- int max_count, open_count;
+ int max_count, open_count, rc;
+ rc = 0;
device = dasd_device_from_cdev(cdev);
if (IS_ERR(device))
return PTR_ERR(device);
- if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
- /* Already doing offline processing */
- dasd_put_device(device);
- return 0;
- }
+
/*
* We must make sure that this device is currently not in use.
* The open_count is increased for every opener, that includes
@@ -3159,6 +3175,54 @@
return -EBUSY;
}
}
+
+ if (test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
+ /*
+ * safe offline allready running
+ * could only be called by normal offline so safe_offline flag
+ * needs to be removed to run normal offline and kill all I/O
+ */
+ if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
+ /* Already doing normal offline processing */
+ dasd_put_device(device);
+ return -EBUSY;
+ } else
+ clear_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags);
+
+ } else
+ if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) {
+ /* Already doing offline processing */
+ dasd_put_device(device);
+ return -EBUSY;
+ }
+
+ /*
+ * if safe_offline called set safe_offline_running flag and
+ * clear safe_offline so that a call to normal offline
+ * can overrun safe_offline processing
+ */
+ if (test_and_clear_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags) &&
+ !test_and_set_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
+ /*
+ * If we want to set the device safe offline all IO operations
+ * should be finished before continuing the offline process
+ * so sync bdev first and then wait for our queues to become
+ * empty
+ */
+ /* sync blockdev and partitions */
+ rc = fsync_bdev(device->block->bdev);
+ if (rc != 0)
+ goto interrupted;
+
+ /* schedule device tasklet and wait for completion */
+ dasd_schedule_device_bh(device);
+ rc = wait_event_interruptible(shutdown_waitq,
+ _wait_for_empty_queues(device));
+ if (rc != 0)
+ goto interrupted;
+ }
+
+ set_bit(DASD_FLAG_OFFLINE, &device->flags);
dasd_set_target_state(device, DASD_STATE_NEW);
/* dasd_delete_device destroys the device reference. */
block = device->block;
@@ -3170,6 +3234,14 @@
if (block)
dasd_free_block(block);
return 0;
+
+interrupted:
+ /* interrupted by signal */
+ clear_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags);
+ clear_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags);
+ clear_bit(DASD_FLAG_OFFLINE, &device->flags);
+ dasd_put_device(device);
+ return rc;
}
int dasd_generic_last_path_gone(struct dasd_device *device)
@@ -3489,15 +3561,6 @@
}
EXPORT_SYMBOL_GPL(dasd_get_sense);
-static inline int _wait_for_empty_queues(struct dasd_device *device)
-{
- if (device->block)
- return list_empty(&device->ccw_queue) &&
- list_empty(&device->block->ccw_queue);
- else
- return list_empty(&device->ccw_queue);
-}
-
void dasd_generic_shutdown(struct ccw_device *cdev)
{
struct dasd_device *device;