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Commit 4e7f1f90 authored by Joe Thornber's avatar Joe Thornber Committed by Alasdair G Kergon
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dm persistent data: add btree_walk 



Add dm_btree_walk to iterate through the contents of a btree.
This will be used by the dm cache target.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent b0d8ed4d

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

+1 −0
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ struct ro_spine { 
void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info);

int exit_ro_spine(struct ro_spine *s);

int ro_step(struct ro_spine *s, dm_block_t new_child);

void ro_pop(struct ro_spine *s);

struct btree_node *ro_node(struct ro_spine *s);



struct shadow_spine {

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

+7 −0
Original line number Diff line number Diff line
@@ -164,6 +164,13 @@ int ro_step(struct ro_spine *s, dm_block_t new_child) 
	return r;

}



void ro_pop(struct ro_spine *s)

{

	BUG_ON(!s->count);

	--s->count;

	unlock_block(s->info, s->nodes[s->count]);

}



struct btree_node *ro_node(struct ro_spine *s)

{

	struct dm_block *block;

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

+52 −0
Original line number Diff line number Diff line
@@ -807,3 +807,55 @@ int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root, 
	return r ? r : count;

}

EXPORT_SYMBOL_GPL(dm_btree_find_highest_key);



/*

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

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

 */

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

		     int (*fn)(void *context, uint64_t *keys, void *leaf),

		     void *context)

{

	int r;

	unsigned i, nr;

	struct btree_node *n;

	uint64_t keys;



	r = ro_step(s, block);

	n = ro_node(s);



	nr = le32_to_cpu(n->header.nr_entries);

	for (i = 0; i < nr; i++) {

		if (le32_to_cpu(n->header.flags) & INTERNAL_NODE) {

			r = walk_node(s, value64(n, i), fn, context);

			if (r)

				goto out;

		} else {

			keys = le64_to_cpu(*key_ptr(n, i));

			r = fn(context, &keys, value_ptr(n, i));

			if (r)

				goto out;

		}

	}



out:

	ro_pop(s);

	return r;

}



int dm_btree_walk(struct dm_btree_info *info, dm_block_t root,

		  int (*fn)(void *context, uint64_t *keys, void *leaf),

		  void *context)

{

	int r;

	struct ro_spine spine;



	BUG_ON(info->levels > 1);



	init_ro_spine(&spine, info);

	r = walk_node(&spine, root, fn, context);

	exit_ro_spine(&spine);



	return r;

}

EXPORT_SYMBOL_GPL(dm_btree_walk);

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

+9 −0
Original line number Diff line number Diff line
@@ -142,4 +142,13 @@ int dm_btree_remove(struct dm_btree_info *info, dm_block_t root, 
int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,

			      uint64_t *result_keys);



/*

 * Iterate through the a btree, calling fn() on each entry.

 * It only works for single level trees and is internally recursive, so

 * monitor stack usage carefully.

 */

int dm_btree_walk(struct dm_btree_info *info, dm_block_t root,

		  int (*fn)(void *context, uint64_t *keys, void *leaf),

		  void *context);



#endif	/* _LINUX_DM_BTREE_H */