geo-rep: Fix geo-rep for older versions of unshare

Geo-rep mounts are private to worker. It uses
mount namespace using unshare command to achieve
the same. Well, the unshare command has to support
'--propagation' option. So geo-rep breaks on the
systems with older unshare version. The patch
makes it fall back to lazy umount behaviour if
the unshare does not support propagation option.

Backport of:
 > BUG: 1589782
 > Change-Id: Ia614f068aede288d63ac62fea4461b1865066054
 > Signed-off-by: Kotresh HR <khiremat@redhat.com>

fixes: bz#1611111
Change-Id: Ia614f068aede288d63ac62fea4461b1865066054
Signed-off-by: Kotresh HR <khiremat@redhat.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/geo-replication/syncdaemon/syncdutils.py b/geo-replication/syncdaemon/syncdutils.py
index 1e40ff56858..ad923c3a53b 100644
--- a/geo-replication/syncdaemon/syncdutils.py
+++ b/geo-replication/syncdaemon/syncdutils.py
@@ -62,6 +62,7 @@ CHANGELOG_AGENT_SERVER_VERSION = 1.0
 CHANGELOG_AGENT_CLIENT_VERSION = 1.0
 NodeID = None
 rsync_version = None
+unshare_mnt_propagation = None
 SPACE_ESCAPE_CHAR = "%20"
 NEWLINE_ESCAPE_CHAR = "%0A"
 PERCENTAGE_ESCAPE_CHAR = "%25"
@@ -623,6 +624,22 @@ def get_master_and_slave_data_from_args(args):
 
     return (master_name, slave_data)
 
+def unshare_propagation_supported():
+    global unshare_mnt_propagation
+    if unshare_mnt_propagation is not None:
+        return unshare_mnt_propagation
+
+    unshare_mnt_propagation = False
+    p = subprocess.Popen(["unshare", "--help"],
+                         stderr=subprocess.PIPE,
+                         stdout=subprocess.PIPE)
+    out, err = p.communicate()
+    if p.returncode == 0:
+        if "propagation" in out:
+            unshare_mnt_propagation = True
+
+    return unshare_mnt_propagation
+
 
 def get_rsync_version(rsync_cmd):
     global rsync_version