Add fchmodat2() - or add a more general syscall?

[Eric Biggers]

On Tue, Jul 25, 2023 at 04:58:34PM +0100, David Howells wrote:
> Rather than adding a fchmodat2() syscall, should we add a "set_file_attrs()"
> syscall that takes a mask and allows you to set a bunch of stuff all in one
> go?  Basically, an interface to notify_change() in the kernel that would allow
> several stats to be set atomically.  This might be of particular interest to
> network filesystems.
> 
> David
> 

fchmodat2() is a simple addition that fits well with the existing syscalls.
It fixes an oversight in fchmodat().

IMO we should just add fchmodat2(), and not get sidetracked by trying to add
some super-generalized syscall instead.  That can always be done later.

- Eric