Re: [PATCH 1/4] statx: Add a system call to make enhanced file info available [ver #3]

[Miklos Szeredi]

On Sun, Dec 4, 2016 at 6:33 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> On Sun, Dec 04, 2016 at 04:38:05AM +0000, Al Viro wrote:
>
>> I understand wanting to avoid extra arguments, but you are asking for trouble
>> with that sort of calling conventions.  Verifying that all call chains have
>> these fields initialized is bloody unpleasant and it *is* going to break,
>> especially since the rules are "you need to initialize it for vfs_xgetattr(),
>> but not for vfs_getattr()" - the names are similar enough for confusion,
>> and that's not the only such pair.
>
> FWIW, there's a bit of abuse of struct kstat in overlayfs object
> creation paths - for one thing, it ends up with a very small subset
> of struct kstat (mode + rdev), for another it also needs link in
> case of symlinks and ends up passing it separately.
>
> IMO it would be better to introduce a separate object for that; does anybody
> have objections to something like the patch below?  In principle, we might
> even lift that thing into general API and switch ->mkdir()/->mknod()/->symlink()
> to identical calling conventions.  Hell knows, perhaps ->create() as well...
> Comments?

Good cleanup.  Applied, thanks.

Miklos