On Friday 13 May 2016 07:28:29 Richard Sharpe wrote:

On Mon, May 9, 2016 at 6:09 AM, Arnd Bergmann [off-list ref] wrote:

quoted

On Thursday 05 May 2016 21:00:18 Steve French wrote:

quoted

On Thu, May 5, 2016 at 5:54 PM, Steve French [off-list ref] wrote:

quoted

On Wed, May 4, 2016 at 8:46 AM, Arnd Bergmann [off-list ref] wrote:

quoted

I've discussed this with Deepa in the past, as she is driving the
convertion of the inode timestamps to timespec64 now, and we will
need a new version of utimensat for her work as well. I can see good
reasons either way (allowing updates of btime or disallowing them).

It would help interop with Windows (and presumably Mac) if birth time can be
updated

Ok, thanks. That is certainly a good reason in favor.

If nothing else comes up, I guess we can prepare a patch for a new
utimensat variant to do this and wait for more comments on that.

In the meantime I found this LWN article at https://lwn.net/Articles/397442/
Apparently there was a discussion about 6 years ago, without a real
conclusion.

Isn't there also a strong case for a setattr call that allows us to
atomically set a collection of attributes from userspace?

It would seem that network file systems (the clients) could use such features.

I had not heard of this before, but that is obviously another option.
Most of the attributes returned by xstat are read-only, but I guess
this would include uid, gid, {a,b,c,m}time and mode (but not size)
along with a 'valid' mask that decides what to set (as in notify_change),
right?

	Arnd