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Date: Thu, 22 Jul 2010 14:45:07 -0400
Message-ID: <AANLkTilU5QLBzOgwpmYRP5aZglOMta2iMCaNk62tiUIB@mail.gmail.com>
Subject: Re: [PATCH 02/18] xstat: Add a pair of system calls to make extended
	file stats available [ver #6]
From: Greg Freemyer <greg.freemyer@gmail.com>
To: Benny Halevy <bhalevy@panasas.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Jan Engelhardt <jengelh@medozas.de>, Jeremy Allison <jra@samba.org>,
        Volker.Lendecke@sernet.de, David Howells <dhowells@redhat.com>,
        linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org,
        samba-technical@lists.samba.org, linux-kernel@vger.kernel.org,
        viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org,
        linux-ext4@vger.kernel.org
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Sender: linux-nfs-owner@vger.kernel.org
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On Thu, Jul 22, 2010 at 2:21 PM, Benny Halevy <bhalevy@panasas.com> wrote:
> On Jul. 22, 2010, 20:24 +0300, Linus Torvalds <torvalds@linux-foundation.org> wrote:
>> On Thu, Jul 22, 2010 at 10:03 AM, Jan Engelhardt <jengelh@medozas.de> wrote:
>>>
>>> I beg to differ. ctime is not completely useless. It reflects changes on
>>> the inode for when you don't you change the content.
>>
>> Uh. Yes. Except that why is file metadata really different from file
>> data? Most people really don't care. And a lot of people have asked
>> for creation dates - and I seriously doubt that Windows people
>> complain a lot about the fact that there you have mtime for metadata
>> changes too.
>>
>> The point being that Unix ctime semantics certainly have well-defined
>> semantics, but they are in no way "better" than having a real creation
>> time, and are often worse.
>
> Yeah, having create time would be important.
> That said, having a non user-settable modify timestamp is crucial
> for quickly determining whether a file has changed.

How would "cp --archive" and a host of backup/restore tools work
without user-settable modify timestamps?

Or are you proposing another timestamp?  I do computer forensics, I
like timestamps, but enough is enough.

Greg