[Virtio-fs] [PATCH 4/5] fuse: For sending setattr in case of open(O_TRUNC)

[Miklos Szeredi]

On Fri, Jul 24, 2020 at 8:38 PM Vivek Goyal <vgoyal at redhat.com> wrote:
>
> open(O_TRUNC) will not kill suid/sgid on server and fuse_open_in does not
> have information if caller has CAP_FSETID or not.
>
> So force sending setattr() which is called after open(O_TRUNC) so that
> server clears setuid/setgid.

I don't really like the fact that we lose atomicity if
handle_killpriv_v2 is enabled.

Let's just add a new flag to open as well.  If a filesystem doesn't
want to add the complexity of handling that it can still just disable
atomic_o_trunc.

Thanks,
Miklos