From d07dc5d8ab6f15353c866e2768c389abdc1faba6 Mon Sep 17 00:00:00 2001 From: Stefan Haberland Date: Wed, 28 Nov 2012 13:43:38 +0100 Subject: 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 Signed-off-by: Martin Schwidefsky --- drivers/s390/block/dasd.c | 97 +++++++++++++++++++++++++++++++++------- drivers/s390/block/dasd_devmap.c | 34 ++++++++++++++ drivers/s390/block/dasd_int.h | 2 + 3 files changed, 116 insertions(+), 17 deletions(-) diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c index 0595c763daf..29225e1c159 100644 --- a/drivers/s390/block/dasd.c +++ b/drivers/s390/block/dasd.c @@ -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; diff --git a/drivers/s390/block/dasd_devmap.c b/drivers/s390/block/dasd_devmap.c index b2b8c18eece..4d12370337a 100644 --- a/drivers/s390/block/dasd_devmap.c +++ b/drivers/s390/block/dasd_devmap.c @@ -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, }; diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h index 7ff93eea673..899e3f5a56e 100644 --- a/drivers/s390/block/dasd_int.h +++ b/drivers/s390/block/dasd_int.h @@ -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 *); 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