From mboxrd@z Thu Jan  1 00:00:00 1970
From: Henry C Chang <henry.cy.chang@gmail.com>
Subject: output file not truncated
Date: Thu, 8 Sep 2011 12:13:57 +0800
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To: ceph-devel <ceph-devel@vger.kernel.org>

Hi,

Finally got some time to play around ceph.
I found that: when I dumped osd status by: ceph osd dump -o
/tmp/dump.json --format=json, I got some garbage data in the end of
file.
Thus, I checked the code. I noticed that the output file was not
truncated in ceph_tool_cli_input:

  // Write to a file. Don't truncate the file.
  int fd = TEMP_FAILURE_RETRY(::open(outfile, O_WRONLY|O_CREAT|O_TRUNC, 0644));

Since it seems intended, I was wondering why. After all, in my case, I
found it causing problems.

Henry