alloc_dummy_extent_buffer
eb = alloc_dummy_extent_buffer(fs_info, start);
struct extent_buffer *alloc_dummy_extent_buffer(struct btrfs_fs_info *fs_info,
eb = alloc_dummy_extent_buffer(fs_info, nodesize);
eb = alloc_dummy_extent_buffer(fs_info, 0);
eb = alloc_dummy_extent_buffer(fs_info, sectorsize);
eb = alloc_dummy_extent_buffer(fs_info, SZ_1M);
root->node = alloc_dummy_extent_buffer(fs_info, nodesize);
root->node = alloc_dummy_extent_buffer(fs_info, nodesize);
ctx->scratch_eb = alloc_dummy_extent_buffer(inode->root->fs_info, 0);
eb = alloc_dummy_extent_buffer(fs_info, logical);
eb_rewin = alloc_dummy_extent_buffer(fs_info, eb->start);
sb = alloc_dummy_extent_buffer(fs_info, BTRFS_SUPER_INFO_OFFSET);