From owner-svn-doc-head@FreeBSD.ORG Tue Apr 14 23:31:30 2015 Return-Path: Delivered-To: svn-doc-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id AE47170E; Tue, 14 Apr 2015 23:31:30 +0000 (UTC) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 801292D7; Tue, 14 Apr 2015 23:31:30 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.9/8.14.9) with ESMTP id t3ENVUgY072454; Tue, 14 Apr 2015 23:31:30 GMT (envelope-from bjk@FreeBSD.org) Received: (from bjk@localhost) by svn.freebsd.org (8.14.9/8.14.9/Submit) id t3ENVUB6072451; Tue, 14 Apr 2015 23:31:30 GMT (envelope-from bjk@FreeBSD.org) Message-Id: <201504142331.t3ENVUB6072451@svn.freebsd.org> X-Authentication-Warning: svn.freebsd.org: bjk set sender to bjk@FreeBSD.org using -f From: Benjamin Kaduk Date: Tue, 14 Apr 2015 23:31:29 +0000 (UTC) To: doc-committers@freebsd.org, svn-doc-all@freebsd.org, svn-doc-head@freebsd.org Subject: svn commit: r46547 - head/en_US.ISO8859-1/htdocs/news/status X-SVN-Group: doc-head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-doc-head@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: SVN commit messages for the doc tree for head List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 14 Apr 2015 23:31:30 -0000 Author: bjk Date: Tue Apr 14 23:31:28 2015 New Revision: 46547 URL: https://svnweb.freebsd.org/changeset/doc/46547 Log: Add report on nanosecond file timestamps Approved by: hrs (mentor, implicit) Modified: head/en_US.ISO8859-1/htdocs/news/status/report-2015-01-2015-03.xml Modified: head/en_US.ISO8859-1/htdocs/news/status/report-2015-01-2015-03.xml ============================================================================== --- head/en_US.ISO8859-1/htdocs/news/status/report-2015-01-2015-03.xml Tue Apr 14 23:26:24 2015 (r46546) +++ head/en_US.ISO8859-1/htdocs/news/status/report-2015-01-2015-03.xml Tue Apr 14 23:31:28 2015 (r46547) @@ -1475,4 +1475,56 @@ WITHOUT_FORTH=y + + + Nanosecond file timestamps + + + + + Jilles + Tjoelker + + jilles@FreeBSD.org + + + + + Sergey + Kandaurov + + pluknet@FreeBSD.org + + + + +

Two new system calls, futimens() and utimensat(), were + added, making it possible to set file timestamps with nanosecond + accuracy. Various utilities like cp, mv and touch were changed + to use the new calls to preserve and set timestamps with + full precision.

+ +

The stat() and related system calls have returned file + timestamps with nanosecond accuracy for a long time, but there + was no way to set a timestamp more accurately than + microseconds.

+ +

With these changes, it will be possible to use more + accurate timestamps (sysctl vfs.timestamp_precision=3) without + anomalies such as a copy of a file (from cp -p) appearing older + than the original. This is particularly useful for NFS servers, + which use file timestamps for cache invalidation.

+ + + + +

Where possible, fix code that still sets inaccurate + timestamps on files, typically by calling futimes(), + futimesat(), lutimes(), utime() or utimes() with a non-null + times pointer. There may be a reason for this such as a limited + network protocol or file format, but there is some code left + that can be fixed.

+ + +