+ return ret;
+}
+
+struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
+ u64 bytenr, u32 blocksize)
+{
+ struct inode *btree_inode = root->fs_info->btree_inode;
+ struct extent_buffer *eb;
+ eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
+ bytenr, blocksize, GFP_NOFS);
+ return eb;
+}
+
+struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
+ u64 bytenr, u32 blocksize)
+{
+ struct inode *btree_inode = root->fs_info->btree_inode;
+ struct extent_buffer *eb;
+
+ eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
+ bytenr, blocksize, NULL, GFP_NOFS);
+ return eb;
+}
+
+
+struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
+ u32 blocksize)
+{
+ struct extent_buffer *buf = NULL;
+ struct inode *btree_inode = root->fs_info->btree_inode;
+ struct extent_io_tree *io_tree;
+ int ret;
+
+ io_tree = &BTRFS_I(btree_inode)->io_tree;
+
+ buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
+ if (!buf)
+ return NULL;
+ read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree, buf, 0, 1,
+ btree_get_extent);
+
+ ret = btrfs_verify_block_csum(root, buf);