From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from szxga01-in.huawei.com ([119.145.14.64]:42807 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751156Ab2GEBKe (ORCPT ); Wed, 4 Jul 2012 21:10:34 -0400 Message-ID: <4FF4E8C5.4030507@huawei.com> Date: Thu, 5 Jul 2012 09:07:17 +0800 From: Li Zefan MIME-Version: 1.0 To: Alexander Block CC: chandan r , Subject: Re: [PATCH] Btrfs: Add code to support file creation time. References: <87ipe43sgg.fsf@gmail.com> <4FF3F740.3070601@huawei.com> In-Reply-To: Content-Type: text/plain; charset="ISO-8859-1" Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 2012/7/4 19:04, Alexander Block wrote: > On Wed, Jul 4, 2012 at 9:56 AM, Li Zefan wrote: >> On 2012/7/4 15:18, chandan r wrote: >> >>> This patch adds a new member to the 'struct btrfs_inode' structure to hold >>> the file creation time. >>> >> >> >> Well, how do users use this file creation time? There's no syscall and there's >> no ioctl that exports this information. That xstat syscall hasn't been accepted, >> so you can revise and repost the patch when you see it happens. > In my opinion we should still include this patch. Currently, otime is never even > initialized, having undefined values. If it ever gets possible to > access otime, we > would at least have some inodes with valid otime fields. otime (on disk) is initialized to 0, not some undefined value. But yeah, your point makes some sense, that with this patch we can access valid otime in an old filesystem once we update to a new kernel which has otime support.