Re: [PATCH 2/3] uapi: get rid of STATX_ALL

* Amir Goldstein:

On Thu, Oct 18, 2018 at 4:11 PM Miklos Szeredi [off-list ref] wrote:

quoted

Constants of the *_ALL type can be actively harmful due to the fact that
developers will usually fail to consider the possible effects of future
changes to the definition.

Remove STATX_ALL from the uapi, while no damage has been done yet.

Look. When Linus says "let's see if somebody notices" and referring to ABI
it means sooner or later someone will upgrade to newer kernel and complain
if something breaks.

But what does it mean with UAPI change?  How often do people
re-build existing programs?  I, for one, build master for my
testing, but never install uapi headers from master.  I just can't
wrap my head around the backward compatibiltiy nightmare a change
like this could create.

So it appears that people use #ifdef STATX_ALL to check for struct
statx availability.  So the backwards compatibility impact is that you
silently lose features in a consistent manner, which is very hard to
spot. 8-(

Probably not a good idea, then.