On 25/05/2020 13:27, David Sterba wrote:
>>> Suggested fix is to have a data block "header", with similar contents as
>>> the metadata blocks, eg.
>>>
>>> struct btrfs_hash_header {
>>> u8 fsid[BTRFS_FSID_SIZE];
>>> u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
>>> __le64 generation;
>>> };
>>>
>>> Perhaps also with some extra item for future extensions, set to zeros
>>> for now.
>>
>> This addition would be possible, yes. But if we'd add this header to every
>> checksum in the checksum tree it would be an incompatible on-disk format
>> change.
>
> No. It's only in-memory and is built from known pieces of information
> exactly to avoid storing it on disk.
>
Ah OK, now I get what you meant. This should then be only for the authenticated
FS I guess.
