btrfs_tree_lock_nested
btrfs_tree_lock_nested(left, BTRFS_NESTING_LEFT);
btrfs_tree_lock_nested(right, BTRFS_NESTING_RIGHT);
btrfs_tree_lock_nested(right, BTRFS_NESTING_RIGHT);
btrfs_tree_lock_nested(left, BTRFS_NESTING_LEFT);
btrfs_tree_lock_nested(left, BTRFS_NESTING_LEFT);
btrfs_tree_lock_nested(right, BTRFS_NESTING_RIGHT);
btrfs_tree_lock_nested(buf, nest);
void btrfs_tree_lock_nested(struct extent_buffer *eb, enum btrfs_lock_nesting nest);
btrfs_tree_lock_nested(eb, BTRFS_NESTING_NORMAL);