From: Josh Durgin <josh.durgin@inktank.com>
Date: Fri, 10 May 2013 00:05:20 +0000 (-0700)
Subject: librbd: only send non-zero copyup data
X-Git-Tag: v0.63~39^2~4
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=bfa106694dc4db97f58c623eafc3c2d0f9a8bff1;p=ceph.git

librbd: only send non-zero copyup data

If the parent image is logically zero for the range of a child object,
it's equivalent to the object not existing. Save some I/O and network
bandwidth and don't send the useless zeroes.

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
---

diff --git a/src/librbd/AioRequest.cc b/src/librbd/AioRequest.cc
index 8d4d98c0bd0f..83e19272f8d2 100644
--- a/src/librbd/AioRequest.cc
+++ b/src/librbd/AioRequest.cc
@@ -234,7 +234,8 @@ namespace librbd {
   }
 
   void AbstractWrite::send_copyup() {
-    m_copyup.exec("rbd", "copyup", m_read_data);
+    if (!m_read_data.is_zero())
+      m_copyup.exec("rbd", "copyup", m_read_data);
     add_copyup_ops();
 
     librados::AioCompletion *rados_completion =