Re: RFC: reject unknown open flags

[Christoph Hellwig]

On Thu, Mar 30, 2017 at 10:08:10AM -0700, Linus Torvalds wrote:
> What kind of new flag did you even have in mind that would have such
> broken semantics that it would completely change the other flags?
> Becuase now I'm starting to think that the whole series has an even
> deeper bug: stupid new features that were badly thought out and not
> even described.

Failure atomic file updates, aka O_ATOMIC:

	https://lwn.net/Articles/573092/

Currently the way to probe for it is a new ioctl to check if atomicy
is offered.  This should work, but it's rather fragile..