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, 11 insertions, 4 deletions

diff --git a/geo-replication/syncdaemon/monitor.py b/geo-replication/syncdaemon/monitor.py
index 0d1423aca9f..40818427bfe 100644
--- a/geo-replication/syncdaemon/monitor.py
+++ b/geo-replication/syncdaemon/monitor.py
@@ -26,7 +26,7 @@ from syncdutils import set_term_handler, GsyncdError
 from syncdutils import Thread, finalize, Volinfo, VolinfoFromGconf
 from syncdutils import gf_event, EVENT_GEOREP_FAULTY, get_up_nodes
 from gsyncdstatus import GeorepStatus, set_monitor_status
-
+from syncdutils import unshare_propagation_supported
 
 ParseError = XET.ParseError if hasattr(XET, 'ParseError') else SyntaxError
 
@@ -225,9 +225,16 @@ class Monitor(object):
                 if access_mount:
                     os.execv(sys.executable, args_to_worker)
                 else:
-                    unshare_cmd = ['unshare', '-m', '--propagation', 'private']
-                    cmd = unshare_cmd + args_to_worker
-                    os.execvp("unshare", cmd)
+                    if unshare_propagation_supported():
+                        logging.debug("Worker would mount volume privately")
+                        unshare_cmd = ['unshare', '-m', '--propagation',
+                                       'private']
+                        cmd = unshare_cmd + args_to_worker
+                        os.execvp("unshare", cmd)
+                    else:
+                        logging.debug("Mount is not private. It would be lazy"
+                                      " umounted")
+                        os.execv(sys.executable, args_to_worker)
 
             cpids.add(cpid)
             agents.add(apid)