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s390/dasd: add safe offline interface

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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>
This commit is contained in:
Stefan Haberland 2012-11-28 13:43:38 +01:00 committed by Martin Schwidefsky
parent 55d3a85cd2
commit d07dc5d8ab
3 changed files with 116 additions and 17 deletions
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97
drivers/s390/block/dasd.c
View File

@ -349,6 +349,16 @@ static int dasd_state_basic_to_ready(struct dasd_device *device)
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 @@ static void __dasd_device_check_expire(struct dasd_device *device)
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 @@ void dasd_generic_remove(struct ccw_device *cdev)
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 @@ void dasd_generic_remove(struct ccw_device *cdev)
*/
if (block)
dasd_free_block(block);
dasd_remove_sysfs_files(cdev);
}
/*
@ -3126,16 +3145,13 @@ int dasd_generic_set_offline(struct ccw_device *cdev)
{
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 @@ int dasd_generic_set_offline(struct ccw_device *cdev)
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 @@ int dasd_generic_set_offline(struct ccw_device *cdev)
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 @@ char *dasd_get_sense(struct irb *irb)
}
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;

34
drivers/s390/block/dasd_devmap.c
View File

@ -951,6 +951,39 @@ dasd_use_raw_store(struct device *dev, struct device_attribute *attr,
static DEVICE_ATTR(raw_track_access, 0644, dasd_use_raw_show,
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 @@ static struct attribute * dasd_attrs[] = {
&dev_attr_expires.attr,
&dev_attr_reservation_policy.attr,
&dev_attr_last_known_reservation_state.attr,
&dev_attr_safe_offline.attr,
NULL,
};

2
drivers/s390/block/dasd_int.h
View File

@ -516,6 +516,8 @@ struct dasd_block {
#define DASD_FLAG_IS_RESERVED 7 /* The device is reserved */
#define DASD_FLAG_LOCK_STOLEN 8 /* The device lock was stolen */
#define DASD_FLAG_SUSPENDED 9 /* The device was suspended */
#define DASD_FLAG_SAFE_OFFLINE 10 /* safe offline processing requested*/
#define DASD_FLAG_SAFE_OFFLINE_RUNNING 11 /* safe offline running */
void dasd_put_device_wake(struct dasd_device *);