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Commit 2fc48021 authored by Joe Thornber's avatar Joe Thornber Committed by Alasdair G Kergon
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dm persistent metadata: add space map threshold callback 



Add a threshold callback to dm persistent data space maps.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 7c3d3f2a

drivers/md/persistent-data/dm-space-map-metadata.c

+76 −1
Original line number Diff line number Diff line
@@ -16,6 +16,55 @@ 


/*----------------------------------------------------------------*/



/*

 * An edge triggered threshold.

 */

struct threshold {

	bool threshold_set;

	bool value_set;

	dm_block_t threshold;

	dm_block_t current_value;

	dm_sm_threshold_fn fn;

	void *context;

};



static void threshold_init(struct threshold *t)

{

	t->threshold_set = false;

	t->value_set = false;

}



static void set_threshold(struct threshold *t, dm_block_t value,

			  dm_sm_threshold_fn fn, void *context)

{

	t->threshold_set = true;

	t->threshold = value;

	t->fn = fn;

	t->context = context;

}



static bool below_threshold(struct threshold *t, dm_block_t value)

{

	return t->threshold_set && value <= t->threshold;

}



static bool threshold_already_triggered(struct threshold *t)

{

	return t->value_set && below_threshold(t, t->current_value);

}



static void check_threshold(struct threshold *t, dm_block_t value)

{

	if (below_threshold(t, value) &&

	    !threshold_already_triggered(t))

		t->fn(t->context);



	t->value_set = true;

	t->current_value = value;

}



/*----------------------------------------------------------------*/



/*

 * Space map interface.

 *
@@ -54,6 +103,8 @@ struct sm_metadata { 
	unsigned allocated_this_transaction;

	unsigned nr_uncommitted;

	struct block_op uncommitted[MAX_RECURSIVE_ALLOCATIONS];



	struct threshold threshold;

};



static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b)
@@ -329,9 +380,19 @@ static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b) 


static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)

{

	dm_block_t count;

	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);



	int r = sm_metadata_new_block_(sm, b);

	if (r)

		DMERR("unable to allocate new metadata block");



	r = sm_metadata_get_nr_free(sm, &count);

	if (r)

		DMERR("couldn't get free block count");



	check_threshold(&smm->threshold, count);



	return r;

}
@@ -351,6 +412,18 @@ static int sm_metadata_commit(struct dm_space_map *sm) 
	return 0;

}



static int sm_metadata_register_threshold_callback(struct dm_space_map *sm,

						   dm_block_t threshold,

						   dm_sm_threshold_fn fn,

						   void *context)

{

	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);



	set_threshold(&smm->threshold, threshold, fn, context);



	return 0;

}



static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result)

{

	*result = sizeof(struct disk_sm_root);
@@ -392,7 +465,7 @@ static struct dm_space_map ops = { 
	.commit = sm_metadata_commit,

	.root_size = sm_metadata_root_size,

	.copy_root = sm_metadata_copy_root,

	.register_threshold_callback = NULL

	.register_threshold_callback = sm_metadata_register_threshold_callback

};



/*----------------------------------------------------------------*/
@@ -577,6 +650,7 @@ int dm_sm_metadata_create(struct dm_space_map *sm, 
	smm->recursion_count = 0;

	smm->allocated_this_transaction = 0;

	smm->nr_uncommitted = 0;

	threshold_init(&smm->threshold);



	memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
@@ -618,6 +692,7 @@ int dm_sm_metadata_open(struct dm_space_map *sm, 
	smm->recursion_count = 0;

	smm->allocated_this_transaction = 0;

	smm->nr_uncommitted = 0;

	threshold_init(&smm->threshold);



	memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));

	return 0;