On 2018/10/12 下午2:31, Nikolay Borisov wrote:
>
>
> On 12.10.2018 09:26, Qu Wenruo wrote:
>> The member log_root_transid is never used.
>> It's always kept untouched even when updating log tree root.
>>
>> And populating it without introducing new incompat flags could easily
>> cause back-compatibility problems.
>> So just mark it unused.
>>
>> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
>> ---
>> fs/btrfs/ctree.h | 6 ++----
>> 1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
>> index 53af9f5253f4..9adc53db679a 100644
>> --- a/fs/btrfs/ctree.h
>> +++ b/fs/btrfs/ctree.h
>> @@ -214,8 +214,8 @@ struct btrfs_super_block {
>> __le64 chunk_root;
>> __le64 log_root;
>>
>> - /* this will help find the new super based on the log root */
>> - __le64 log_root_transid;
>> + /* This member is never touched, should always be 0 */
>> + __le64 __unused_log_root_transid;
>
> no need to be that descriptive, that's the whole idea of switching the
> parameter's name. Just use "reserved1" or "unused" or "padding", also
> the name is eloquent enough that the comment is redundant.
Indeed, that comment will be gone.
Thanks,
Qu
>
>> __le64 total_bytes;
>> __le64 bytes_used;
>> __le64 root_dir_objectid;
>> @@ -2317,8 +2317,6 @@ BTRFS_SETGET_STACK_FUNCS(super_chunk_root_level, struct btrfs_super_block,
>> chunk_root_level, 8);
>> BTRFS_SETGET_STACK_FUNCS(super_log_root, struct btrfs_super_block,
>> log_root, 64);
>> -BTRFS_SETGET_STACK_FUNCS(super_log_root_transid, struct btrfs_super_block,
>> - log_root_transid, 64);
>> BTRFS_SETGET_STACK_FUNCS(super_log_root_level, struct btrfs_super_block,
>> log_root_level, 8);
>> BTRFS_SETGET_STACK_FUNCS(super_total_bytes, struct btrfs_super_block,
>>
