kern/60806: zfs: can't change birthtime of file

["campbell+netbsd%mumble.net@localhost via gnats" <gnats-admin%NetBSD.org@localhost>]

>Number:         60806
>Category:       kern
>Synopsis:       zfs: can't change birthtime of file
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Sep 26 20:45:00 +0000 2026
>Originator:     Taylor R Campbell
>Release:        current, 11, 10, ...
>Organization:
The NetZFS Birthdation, Inc.
>Environment:
>Description:

	zfs appears to store birthtimes, and it can report them in
	stat(2), but utimes(2) doesn't appear to change them.

>How-To-Repeat:

	use utimes and stat

>Fix:

	Yes, please!