glusterd/geo-rep: Handle empty monitor.status during upgrade

Problem:
Consider geo-replication is in Stopped state.
Following which, glusterfs is upgraded (where monitor.status is the 
new status file).

Now, When geo-replication status command is run,
empty monitor status file gets created.

Now, if glusterd is restarted, it reads empty monitor status
and  starts geo-replication session. This is incorrect as session
was in Stopped state earlier.

Solution:
If monitor status is empty, error out and avoid
starting geo-replication session.

Note: if monitor status is empty, geo-rep session is displayed
as Stopped state.

Change-Id: Ifb3db896e5ed92b927764cf1163503765cb08bb4
BUG: 1368053
Signed-off-by: Saravanakumar Arumugam <sarumuga@redhat.com>
> Reviewed-on: http://review.gluster.org/14830
> Smoke: Gluster Build System <jenkins@build.gluster.org>
> CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
> Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
(cherry picked from commit f938b3a26ffab9482d5f910ee76d2bb2b370517f)
Reviewed-on: http://review.gluster.org/15196
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Smoke: Gluster Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Aravinda VK <avishwan@redhat.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-geo-rep.c b/xlators/mgmt/glusterd/src/glusterd-geo-rep.c
index 1b0af527897..e7afb9b599d 100644
--- a/xlators/mgmt/glusterd/src/glusterd-geo-rep.c
+++ b/xlators/mgmt/glusterd/src/glusterd-geo-rep.c
@@ -4281,7 +4281,10 @@ glusterd_gsync_read_frm_status (char *path, char *buf, size_t blen)
                         while (isspace (*p))
                                 *p-- = '\0';
                 }
-        } else if (ret < 0)
+        } else if (ret == 0)
+                gf_msg (this->name, GF_LOG_ERROR, 0, GD_MSG_GSYNCD_ERROR,
+                        "Status file of gsyncd is empty");
+        else /* ret < 0 */
                 gf_msg (this->name, GF_LOG_ERROR, 0, GD_MSG_GSYNCD_ERROR,
                         "Status file of gsyncd is corrupt");