From: Sage Weil <sage@inktank.com>
Date: Sat, 19 May 2012 20:54:13 +0000 (-0700)
Subject: osd: only (re)write_meta files if old content is incorrect
X-Git-Tag: v0.48argonaut~151^2~26^2~19
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=17c4624e9398cdadd8822dc1eef28ea601e08bc0;p=ceph.git

osd: only (re)write_meta files if old content is incorrect

Do nothing if the file already exists with the correct content.

Signed-off-by: Sage Weil <sage@inktank.com>
---

diff --git a/src/osd/OSD.cc b/src/osd/OSD.cc
index cebf502c7bcc..39d14ab10542 100644
--- a/src/osd/OSD.cc
+++ b/src/osd/OSD.cc
@@ -428,6 +428,12 @@ int OSD::write_meta(const std::string &base, const std::string &file,
   char tmp[PATH_MAX];
   int fd;
 
+  // does the file already have correct content?
+  char oldval[80];
+  ret = read_meta(base, file, oldval, sizeof(oldval));
+  if (ret == (int)vallen && memcmp(oldval, val, vallen) == 0)
+    return 0;  // yes.
+
   snprintf(fn, sizeof(fn), "%s/%s", base.c_str(), file.c_str());
   snprintf(tmp, sizeof(tmp), "%s/%s.tmp", base.c_str(), file.c_str());
   fd = ::open(tmp, O_WRONLY|O_CREAT|O_TRUNC, 0644);