title: git forces refresh index after switching between Windows and Linux
body: <p>I have a disk partition (format: NTFS) shared by Windows and Linux. It contains a git repository (about 6.7 GB).
  If I <strong>only use Windows</strong> or <strong>only use Linux</strong> to manipulate the git repository everything is okay.
  But everytime I switch the system, the <code>git status</code> command will refresh the index, which takes about 1 minute. If I run the <code>git status</code> in the same system again, it only take less than 1 second. Here is the result</p>
  <pre class="lang-none prettyprint-override"><code># Just after switch from windows
  [#5#wangx@manjaro:duishang_design] git status  # this command takes more than 60s
  Refresh index: 100% (2751/2751), done.
  On branch master
  nothing to commit, working tree clean
  
  [#10#wangx@manjaro:duishang_design] git status  # this time the command takes less than 1s
  On branch master
  nothing to commit, working tree clean
  
  [#11#wangx@manjaro:duishang_design] git status  # this time the command takes less than 1s
  On branch master
  nothing to commit, working tree clean
  </code></pre>
  <p>I guess there is some problem with the git cache. For example: Windows and Linux all use the <code>.git/index</code> file as cache file, but the git in Linux system can't recognize the <code>.git/index</code> changed by Windows. So it can only refresh the index and replace the <code>.git/index</code> file, which makes the next <code>git status</code> super fast and <code>git status</code> in Windows very slow (because the Windows system will refresh the index file again).</p>
  <p>Is my guess correct? If so, how can I set the index file for different system? How can I solve the problem?</p>