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Commit f164e690 authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
Browse files

dm btree: add dm_btree_find_lowest_key 



dm_btree_find_lowest_key is the reciprocal of dm_btree_find_highest_key.
Factor out common code for dm_btree_find_{highest,lowest}_key.

dm_btree_find_lowest_key is needed for an upcoming DM target, as such it
is best to get this interface in place.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 7e664b3d

drivers/md/persistent-data/dm-btree.c

+26 −7
Original line number Diff line number Diff line
@@ -770,7 +770,7 @@ EXPORT_SYMBOL_GPL(dm_btree_insert_notify); 


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



static int find_highest_key(struct ro_spine *s, dm_block_t block,

static int find_key(struct ro_spine *s, dm_block_t block, bool find_highest,

		    uint64_t *result_key, dm_block_t *next_block)

{

	int i, r;
@@ -788,7 +788,11 @@ static int find_highest_key(struct ro_spine *s, dm_block_t block, 
		else

			i--;



		if (find_highest)

			*result_key = le64_to_cpu(ro_node(s)->keys[i]);

		else

			*result_key = le64_to_cpu(ro_node(s)->keys[0]);



		if (next_block || flags & INTERNAL_NODE)

			block = value64(ro_node(s), i);
@@ -799,15 +803,15 @@ static int find_highest_key(struct ro_spine *s, dm_block_t block, 
	return 0;

}



int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,

			      uint64_t *result_keys)

static int dm_btree_find_key(struct dm_btree_info *info, dm_block_t root,

			     bool find_highest, uint64_t *result_keys)

{

	int r = 0, count = 0, level;

	struct ro_spine spine;



	init_ro_spine(&spine, info);

	for (level = 0; level < info->levels; level++) {

		r = find_highest_key(&spine, root, result_keys + level,

		r = find_key(&spine, root, find_highest, result_keys + level,

			     level == info->levels - 1 ? NULL : &root);

		if (r == -ENODATA) {

			r = 0;
@@ -822,8 +826,23 @@ int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root, 


	return r ? r : count;

}



int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,

			      uint64_t *result_keys)

{

	return dm_btree_find_key(info, root, true, result_keys);

}

EXPORT_SYMBOL_GPL(dm_btree_find_highest_key);



int dm_btree_find_lowest_key(struct dm_btree_info *info, dm_block_t root,

			     uint64_t *result_keys)

{

	return dm_btree_find_key(info, root, false, result_keys);

}

EXPORT_SYMBOL_GPL(dm_btree_find_lowest_key);



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



/*

 * FIXME: We shouldn't use a recursive algorithm when we have limited stack

 * space.  Also this only works for single level trees.

drivers/md/persistent-data/dm-btree.h

+8 −0
Original line number Diff line number Diff line
@@ -134,6 +134,14 @@ int dm_btree_insert_notify(struct dm_btree_info *info, dm_block_t root, 
int dm_btree_remove(struct dm_btree_info *info, dm_block_t root,

		    uint64_t *keys, dm_block_t *new_root);



/*

 * Returns < 0 on failure.  Otherwise the number of key entries that have

 * been filled out.  Remember trees can have zero entries, and as such have

 * no lowest key.

 */

int dm_btree_find_lowest_key(struct dm_btree_info *info, dm_block_t root,

			     uint64_t *result_keys);



/*

 * Returns < 0 on failure.  Otherwise the number of key entries that have

 * been filled out.  Remember trees can have zero entries, and as such have