Re: [PATCH 2/2] btrfs: move btrfs_super_block to uapi/linux/btrfs_tree.h

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

On 2021/10/21 01:13, David Sterba wrote:
> On Wed, Oct 20, 2021 at 08:19:30AM +0800, Qu Wenruo wrote:
>>
>>
>> On 2021/10/20 00:10, David Sterba wrote:
>>> 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?
>>>
>>
>> Well, for super block I'd say any user space tool can directly see it.
>>
>> My main objective here is to move all on-disk format to uapi.
>
> Why? You sent such patches in the past, I need to read again what we
> discussed but I don't think we should put everything to the UAPI
> headers.
>
Then we need a new header for on-disk format that is not exposed through
tree search API.

It's definitely not ideal to put everything into ctree.h.

This is especially useful when someone is crafting a new btrfs
implementation, no matter if it's something like winBtrfs or BSD (if
they really want) or something else.

In fact when I am trying to create the btrfs-fuse, one of the things I'm
doing is separating things from ctree.h.

Thanks,
Qu