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Commit 80c57893 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm thin: add 'no_space_timeout' dm-thin-pool module param 



Commit 85ad643b ("dm thin: add timeout to stop out-of-data-space mode
holding IO forever") introduced a fixed 60 second timeout.  Users may
want to either disable or modify this timeout.

Allow the out-of-data-space timeout to be configured using the
'no_space_timeout' dm-thin-pool module param.  Setting it to 0 will
disable the timeout, resulting in IO being queued until more data space
is added to the thin-pool.

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.14+
parent 4cdd2ad7

Documentation/device-mapper/thin-provisioning.txt

+4 −1
Original line number Diff line number Diff line
@@ -309,7 +309,10 @@ ii) Status 
    error_if_no_space|queue_if_no_space

	If the pool runs out of data or metadata space, the pool will

	either queue or error the IO destined to the data device.  The

	default is to queue the IO until more space is added.

	default is to queue the IO until more space is added or the

	'no_space_timeout' expires.  The 'no_space_timeout' dm-thin-pool

	module parameter can be used to change this timeout -- it

	defaults to 60 seconds but may be disabled using a value of 0.



iii) Messages

drivers/md/dm-thin.c

+9 −3
Original line number Diff line number Diff line
@@ -27,7 +27,9 @@ 
#define MAPPING_POOL_SIZE 1024

#define PRISON_CELLS 1024

#define COMMIT_PERIOD HZ

#define NO_SPACE_TIMEOUT (HZ * 60)

#define NO_SPACE_TIMEOUT_SECS 60



static unsigned no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS;



DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,

		"A percentage of time allocated for copy on write");
@@ -1670,6 +1672,7 @@ static void set_pool_mode(struct pool *pool, enum pool_mode new_mode) 
	struct pool_c *pt = pool->ti->private;

	bool needs_check = dm_pool_metadata_needs_check(pool->pmd);

	enum pool_mode old_mode = get_pool_mode(pool);

	unsigned long no_space_timeout = ACCESS_ONCE(no_space_timeout_secs) * HZ;



	/*

	 * Never allow the pool to transition to PM_WRITE mode if user
@@ -1732,8 +1735,8 @@ static void set_pool_mode(struct pool *pool, enum pool_mode new_mode) 
		pool->process_prepared_mapping = process_prepared_mapping;

		pool->process_prepared_discard = process_prepared_discard_passdown;



		if (!pool->pf.error_if_no_space)

			queue_delayed_work(pool->wq, &pool->no_space_timeout, NO_SPACE_TIMEOUT);

		if (!pool->pf.error_if_no_space && no_space_timeout)

			queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);

		break;



	case PM_WRITE:
@@ -3508,6 +3511,9 @@ static void dm_thin_exit(void) 
module_init(dm_thin_init);

module_exit(dm_thin_exit);



module_param_named(no_space_timeout, no_space_timeout_secs, uint, S_IRUGO | S_IWUSR);

MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");



MODULE_DESCRIPTION(DM_NAME " thin provisioning target");

MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");

MODULE_LICENSE("GPL");