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Commit 4ec331c3 authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
Browse files

dm btree: add dm_btree_remove_leaves() 



Removes a range of leaf values from the tree.

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 0f24b79b

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

+127 −0
Original line number Diff line number Diff line
@@ -590,3 +590,130 @@ int dm_btree_remove(struct dm_btree_info *info, dm_block_t root, 
	return r;

}

EXPORT_SYMBOL_GPL(dm_btree_remove);



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



static int remove_nearest(struct shadow_spine *s, struct dm_btree_info *info,

			  struct dm_btree_value_type *vt, dm_block_t root,

			  uint64_t key, int *index)

{

	int i = *index, r;

	struct btree_node *n;



	for (;;) {

		r = shadow_step(s, root, vt);

		if (r < 0)

			break;



		/*

		 * We have to patch up the parent node, ugly, but I don't

		 * see a way to do this automatically as part of the spine

		 * op.

		 */

		if (shadow_has_parent(s)) {

			__le64 location = cpu_to_le64(dm_block_location(shadow_current(s)));

			memcpy(value_ptr(dm_block_data(shadow_parent(s)), i),

			       &location, sizeof(__le64));

		}



		n = dm_block_data(shadow_current(s));



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

			*index = lower_bound(n, key);

			return 0;

		}



		r = rebalance_children(s, info, vt, key);

		if (r)

			break;



		n = dm_block_data(shadow_current(s));

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

			*index = lower_bound(n, key);

			return 0;

		}



		i = lower_bound(n, key);



		/*

		 * We know the key is present, or else

		 * rebalance_children would have returned

		 * -ENODATA

		 */

		root = value64(n, i);

	}



	return r;

}



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

		      uint64_t *keys, uint64_t end_key,

		      dm_block_t *new_root, unsigned *nr_removed)

{

	unsigned level, last_level = info->levels - 1;

	int index = 0, r = 0;

	struct shadow_spine spine;

	struct btree_node *n;

	uint64_t k;



	init_shadow_spine(&spine, info);

	for (level = 0; level < last_level; level++) {

		r = remove_raw(&spine, info, &le64_type,

			       root, keys[level], (unsigned *) &index);

		if (r < 0)

			goto out;



		n = dm_block_data(shadow_current(&spine));

		root = value64(n, index);

	}



	r = remove_nearest(&spine, info, &info->value_type,

			   root, keys[last_level], &index);

	if (r < 0)

		goto out;



	n = dm_block_data(shadow_current(&spine));



	if (index < 0)

		index = 0;



	if (index >= le32_to_cpu(n->header.nr_entries)) {

		r = -ENODATA;

		goto out;

	}



	k = le64_to_cpu(n->keys[index]);

	if (k >= keys[last_level] && k < end_key) {

		if (info->value_type.dec)

			info->value_type.dec(info->value_type.context,

					     value_ptr(n, index));



		delete_at(n, index);



	} else

		r = -ENODATA;



out:

	*new_root = shadow_root(&spine);

	exit_shadow_spine(&spine);



	return r;

}



int dm_btree_remove_leaves(struct dm_btree_info *info, dm_block_t root,

			   uint64_t *first_key, uint64_t end_key,

			   dm_block_t *new_root, unsigned *nr_removed)

{

	int r;



	*nr_removed = 0;

	do {

		r = remove_one(info, root, first_key, end_key, &root, nr_removed);

		if (!r)

			(*nr_removed)++;

	} while (!r);



	*new_root = root;

	return r == -ENODATA ? 0 : r;

}

EXPORT_SYMBOL_GPL(dm_btree_remove_leaves);

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

+9 −0
Original line number Diff line number Diff line
@@ -134,6 +134,15 @@ 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);



/*

 * Removes values between 'keys' and keys2, where keys2 is keys with the

 * final key replaced with 'end_key'.  'end_key' is the one-past-the-end

 * value.  'keys' may be altered.

 */

int dm_btree_remove_leaves(struct dm_btree_info *info, dm_block_t root,

			   uint64_t *keys, uint64_t end_key,

			   dm_block_t *new_root, unsigned *nr_removed);



/*

 * 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