geo-rep: Fix upgrade issue

Cause and Analysis:
The last synced changelog for entry operations is
marked in current version to avoid re-processing
of already processed entry operations in a batch
during crash/restart of geo-rep. This was not
present in previous versoins.

The marker is maintained in the dictionary with the
key 'last_synced_entry' and dictionary is persisted
into status file. So upgrading to current version in
which the marker is present was failing with KeyError.

Solution:
Load the dictionary with default keys first which
contains all the keys including latest ones and then
load the values from status file instead of doing
otherwise.

Backport of
> patch: https://review.gluster.org/19969/
> Change-Id: Ic654e6f9a3c97f616761f1362f890352a2186fb4
> Signed-off-by: Kotresh HR <khiremat@redhat.com>
(cherry picked from commit 23c1385b5f6f6103e820d15ecfe1df31940fdb45)

fixes: bz#1577862
Change-Id: Ic654e6f9a3c97f616761f1362f890352a2186fb4
Signed-off-by: Kotresh HR <khiremat@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/geo-replication/syncdaemon/gsyncdstatus.py b/geo-replication/syncdaemon/gsyncdstatus.py
index 38ca92c73a9..909c6694bd8 100644
--- a/geo-replication/syncdaemon/gsyncdstatus.py
+++ b/geo-replication/syncdaemon/gsyncdstatus.py
@@ -152,11 +152,12 @@ class GeorepStatus(object):
                  **kwargs)
 
     def _update(self, mergerfunc):
+        data = self.default_values
         with LockedOpen(self.filename, 'r+') as f:
             try:
-                data = json.load(f)
+                data.update(json.load(f))
             except ValueError:
-                data = self.default_values
+                pass
 
             data = mergerfunc(data)
             # If Data is not changed by merger func