[PATCH 02/18] xstat: Add a pair of system calls to make extended file stats available [ver #6]

[Jeremy Allison]

On Thu, Jul 22, 2010 at 10:24:17AM -0700, Linus Torvalds wrote:
> 
> And yes, I am also sure that there are applications that do depend on
> ctime semantics. Trond mentioned NFS serving, and that's unfortunate.
> I bet there are others. That's inevitable when you have 40 years of
> history. So I'm not claiming that re-using ctime is painfree, but for
> somebody that cares about samba a lot, I bet it's a _lot_ better than
> adding a new time that almost nobody actually supports as things stand
> now.

Samba mostly ignores ctime, for just the reasons you mention.
But re-using ctime as create time will lead to more horrible
confusion (IMHO).

Easier to add a btime field to stat (or whatever you want to
call it), especially as some of the filesystems already support it,
the code for it exists inside Samba and is working on other UNIX-style
OS'es, and for filesystems that don't support it, just return
zero or -1 in that field (which we already ignore).

> Of people can just use xattrs and do it all entirely in user space. I
> assume that's what samba does now, even outside of birthtime.

Yep. We even have to do that on systems with an immutable
btime to get Windows semantics.

Jeremy.