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

Greg Freemyer greg.freemyer at gmail.com
Thu Jul 22 10:07:05 MDT 2010

On Thu, Jul 22, 2010 at 12:06 PM, Greg Freemyer <greg.freemyer at gmail.com> wrote:
> On Thu, Jul 22, 2010 at 11:47 AM, Linus Torvalds
> <torvalds at linux-foundation.org> wrote:
>> On Thu, Jul 22, 2010 at 8:36 AM, Volker Lendecke
>> <Volker.Lendecke at sernet.de> wrote:
>>> The nice thing about this is also that if this is supposed
>>> to be fully usable for Windows clients, the birthtime needs
>>> to be changeable. That's what NTFS semantics gives you, thus
>>> Windows clients tend to require it.
>> Ok. So it's not really a creation date, exactly the same way ctime
>> isn't at all a creation date.
>> And maybe that actually hints at a better solution: maybe a better
>> model is to create a new per-thread flag that says "do ctime updates
>> the way windows does them".
>> So instead of adding another "btime" - which isn't actually what even
>> windows does - just admit that the _real_ issue is that Unix and
>> Windows semantics are different for the pre-existing "ctime".
>> The fact is, windows has "access time", "modification time" and
>> "creation time" _exactly_ like UNIX. It's just that the ctime has
>> slightly different semantics in windows vs unix. So quite frankly,
>> it's totally insane to introduce a "birthtime", when that isn't even
>> what windows wants, just because people cannot face the actual real
>> difference.
>> Tell me why we shouldn't just do this right?
>>                Linus
> I haven't been keeping up with this thread, but I believe NTFS has a
> number of timestamps, not just 3.
> This blog post references 8 in the left hand column.
> The 4 standard (most common) ones are:
> File last access
> File last modified
> File created
> MFT last modified
> My understanding is that "MFT last modified" has semantics very
> similar to Linux ctime.
> But there is not a generic equivalent to NTFS created.
> Thus if trying to have the Linux kernel match NTFS semantics for the
> benefit of Samba is the goal, it seems a new field should be preferred
> instead of having linux ctime try to do different jobs.
> Greg

I forgot the blog post url:


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