On Fri, Oct 12, 2018 at 05:57:29PM +0800, Qu Wenruo wrote:
> >>>> + printf("log_root_transid (deprecated)\t%llu\n",
> >>>> + le64_to_cpu(sb->__unused_log_root_transid));
> >>>
> >>> This should be entirely removed.
> >>
> >> It looks OK to me.
> >> Just like the old leafsize.
> >>
> >> And if we try to use this member again, even old progs could show it
> >> without problem.
> >
> > But what is the point of having something which always shows 0 and is
> > essentially unused?
>
> Personally speaking, even it's in fact never used, it is still part of
> the specification of btrfs super blocks.
>
> Even it's a bad decision we made a long time ago, we still need to mark
> it as unused, other than converting it back to "reserved".
>
> To make it short and clear, if some member is specified in early
> specification, even it's never used, we still need to mark it unused and
> keep part of naming.
Agreed, follows the same patern as the leafsize. The superblock dump is
a debugging and bug report tool, the full output is desirable.
