From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steve French Subject: Re: ext4 - getting at birth time (file create time) and getting/setting nanosecond time stamps and utime Date: Tue, 20 Oct 2009 16:11:15 -0500 Message-ID: <524f69650910201411j3dc4897bic8a042cb17fcede8@mail.gmail.com> References: <524f69650910191017j7883ed7bvdb0329d1a73f34e4@mail.gmail.com> <524f69650910191245t2eb7ffb2r770a7373ec2ba1e3@mail.gmail.com> <5715838A-4568-4273-B1C1-983B348580B6@sun.com> <524f69650910191524k5c9d766fu430c4f7b17d86952@mail.gmail.com> <890110E9-FA69-4356-9BEB-925F98487C52@sun.com> <4ADDB09D.5000707@hp.com> <6E5D19DA-64C5-4A44-9DF4-BEF2AA8DD8AB@sun.com> <524f69650910201349w20a3145cm6b88cd4029912b6b@mail.gmail.com> <4ADE24C2.20009@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: Andreas Dilger , jim owens , linux-fsdevel , samba-technical To: Sunil Mushran Return-path: Received: from mail-px0-f171.google.com ([209.85.216.171]:47392 "EHLO mail-px0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751419AbZJTVLL (ORCPT ); Tue, 20 Oct 2009 17:11:11 -0400 Received: by pxi1 with SMTP id 1so1695072pxi.33 for ; Tue, 20 Oct 2009 14:11:16 -0700 (PDT) In-Reply-To: <4ADE24C2.20009@oracle.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, Oct 20, 2009 at 3:59 PM, Sunil Mushran wrote: > Steve French wrote: >> >> So, are we ready for Mingming or one of the ext4 developers to propose >> a patch for this via xattrs (I can do a similar one for cifs). >> Sounds like various have said: >> >> 1) xattrs instead of ioctl >> 2) get of create time allowed by default, but set of create time limited >> >> But for the second part of this - how should we set nanosecond >> timestamps for the others (or in Samba's case, rounded to 100 >> nanoseconds for DCE time) ... a millisecond granularity for utimes is >> a very long time these days. > > What's wrong with stat(2)? AFAIK, it supports nanoseconds. An earlier post from Mingming IIRC noted that utimes does not support setting nanosecond timestamps (e.g. write time). "The function utime() allows specification of time stamps with a resolution of 1 second. ... The function utimes() is similar, but the times argument allows a reso lution of 1 microsecond for the timestamps. " 1 millisecond is not sufficient, and as a result Samba has to store duplicate time stamps (in Samba specific xattrs) which we would like to avoid wherever possible -- Thanks, Steve