On Tue, Oct 19, 2021 at 07:29:25PM +0800, Qu Wenruo wrote:

Due to the fact that btrfs_tree.h contains all the info for
BTRFS_IOC_TREE_SEARCH, it's almost the perfect location of btrfs on-disk
schema.

So let's move struct btrfs_super_block to uapi/linux/btrfs_tree.h,
further reducing the size of ctree.h.

The definitions of tree items are in the public header due to the search
tree ioctl, but why do you want to make superblock public? Ie. what user
space tool is going to use it?