Commit 20524f02 authored by Chris Mason's avatar Chris Mason Committed by David Woodhouse
Browse files

Btrfs: recursion free-first pass 



Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 0579da42

fs/btrfs/extent-tree.c

+96 −2
Original line number Diff line number Diff line
@@ -50,7 +50,7 @@ static int inc_block_ref(struct ctree_root *root, u64 blocknr) 
	return 0;

}



static int lookup_block_ref(struct ctree_root *root, u64 blocknr, int *refs)

static int lookup_block_ref(struct ctree_root *root, u64 blocknr, u32 *refs)

{

	struct ctree_path path;

	int ret;
@@ -415,6 +415,100 @@ struct tree_buffer *alloc_free_block(struct ctree_root *root) 
	return buf;

}



int walk_down_tree(struct ctree_root *root, struct ctree_path *path, int *level)

{

	struct tree_buffer *next;

	struct tree_buffer *cur;

	u64 blocknr;

	int ret;

	u32 refs;



	ret = lookup_block_ref(root, path->nodes[*level]->blocknr, &refs);

	BUG_ON(ret);

	if (refs > 1)

		goto out;

	while(*level > 0) {

		cur = path->nodes[*level];

		if (path->slots[*level] >= cur->node.header.nritems)

			break;

		blocknr = cur->node.blockptrs[path->slots[*level]];

		ret = lookup_block_ref(root, blocknr, &refs);

		if (refs != 1 || *level == 1) {

			path->slots[*level]++;

			ret = free_extent(root, blocknr, 1);

			BUG_ON(ret);

			continue;

		}

		BUG_ON(ret);

		next = read_tree_block(root, blocknr);

		if (path->nodes[*level-1]) {

			tree_block_release(root, path->nodes[*level-1]);

		}

		path->nodes[*level-1] = next;

		*level = node_level(next->node.header.flags);

		path->slots[*level] = 0;

	}

out:

	ret = free_extent(root, path->nodes[*level]->blocknr, 1);

	path->nodes[*level] = NULL;

	*level += 1;

	BUG_ON(ret);

	return 0;

}



int walk_up_tree(struct ctree_root *root, struct ctree_path *path, int *level)

{

	int i;

	int slot;

	int ret;

	for(i = *level; i < MAX_LEVEL - 1 && path->nodes[i]; i++) {

		slot = path->slots[i];

		if (slot < path->nodes[i]->node.header.nritems - 1) {

			path->slots[i]++;

			*level = i;

			return 0;

		} else {

			ret = free_extent(root,

					  path->nodes[*level]->blocknr, 1);

			*level = i + 1;

			BUG_ON(ret);

		}

	}

	return 1;

}



int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap)

{

	int ret;

	int level;

	struct ctree_path path;

	int i;

	int orig_level;



	init_path(&path);



	level = node_level(snap->node.header.flags);

	orig_level = level;

	path.nodes[level] = snap;

	path.slots[level] = 0;

	while(1) {

		ret = walk_down_tree(root, &path, &level);

		if (ret > 0)

			break;

		ret = walk_up_tree(root, &path, &level);

		if (ret > 0)

			break;

	}

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

		if (path.nodes[i])

			tree_block_release(root, path.nodes[i]);

	}



	return 0;

}





#if 0

int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap)

{

	int ret;
@@ -441,4 +535,4 @@ int btrfs_drop_snapshot(struct ctree_root *root, struct tree_buffer *snap) 
	BUG_ON(ret);

	return 0;

}

#endif

fs/btrfs/quick-test.c

+4 −1
Original line number Diff line number Diff line
@@ -44,6 +44,9 @@ int main(int ac, char **av) { 
		if (!ret)

			tree_size++;

		free(buf);

		if (i == run_size - 5) {

			commit_transaction(root, &super);

		}



	}

	close_ctree(root, &super);