From: Andreas Dilger Subject: Re: creation time stamps for ext4 ? Date: Thu, 5 Oct 2006 14:07:26 -0600 Message-ID: <20061005200726.GW22010@schatzie.adilger.int> References: <20061005151937.GV22010@schatzie.adilger.int> <20061005165504.GA23727@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: =?utf-8?B?Qmrvv71ybg==?= JACKE , ext3-users@redhat.com, linux-ext4@vger.kernel.org Return-path: Received: from mail.clusterfs.com ([206.168.112.78]:61361 "EHLO mail.clusterfs.com") by vger.kernel.org with ESMTP id S1751146AbWJEUH2 (ORCPT ); Thu, 5 Oct 2006 16:07:28 -0400 To: Theodore Tso Content-Disposition: inline In-Reply-To: <20061005165504.GA23727@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Oct 05, 2006 12:55 -0400, Theodore Tso wrote: > > I've given this some thought for adding creation time as part of the nsec > > timestamp patch. That is more feasable if we move the nsec ctime into > > the main inode to double as the version field. > > Shoehorning an extra creation time field into the inode is relatively > easy, but it's also necessary to have system calls to get and set the > creation time. The stat structure doesn't have room for the creation > time, so that means a new version of the stat structure exported the > kernel, and a new version of the stat structure exported by glibc. For Lustre and NFSv4, an in-kernel interface is sufficient. I was thinking that as a preliminary userspace interface we can use getxattr with a standard name like user.crtime. Storing the crtime directly in the inode is more efficient than a separate EA, but it would also be compatible if Samba wanted to use real EAs to store this in the absence of large inodes. Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc.