Date: Tue, 14 Apr 2015 23:31:29 +0000 (UTC) From: Benjamin Kaduk <bjk@FreeBSD.org> 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 Message-ID: <201504142331.t3ENVUB6072451@svn.freebsd.org>
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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</pre> </task> </help> </project> + + <project cat='kern'> + <title>Nanosecond file timestamps</title> + + <contact> + <person> + <name> + <given>Jilles</given> + <common>Tjoelker</common> + </name> + <email>jilles@FreeBSD.org</email> + </person> + + <person> + <name> + <given>Sergey</given> + <common>Kandaurov</common> + </name> + <email>pluknet@FreeBSD.org</email> + </person> + </contact> + + <body> + <p>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.</p> + + <p>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.</p> + + <p>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.</p> + </body> + + <help> + <task> + <p>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.</p> + </task> + </help> + </project> </report>
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