Add a pausable property to the sync drivers

Drivers handling hardware-assisted disks replication are set non-pausable,
other drivers default to pausable.

If pausable and the aggregated service status is not up, the resource status
is n/a.

If not pausable, always evaluate the real resource status.

This patch fixes the undue failback for a service with rollback=false an
instance of which failed to start in the resource just next after a
srdf resource. In this situation, the instance availstatus is still down
because the srdf resource status is n/a due to the paused mecanism, instead
of up.

lib/resSync.py

@@ -33,6 +33,7 @@ def __init__(self,
                  sync_max_delay=None,
                  schedule=None,
                  **kwargs):
+        self.pausable = True
         if sync_max_delay is None:
             self.sync_max_delay = 1500
         else:
@@ -170,6 +171,19 @@ def sync_status(self, *args, **kwargs):
         return rcStatus.UNDEF
 
     def _status(self, **kwargs):
+        if self.paused():
+            return rcStatus.NA
+        return self.sync_status(**kwargs)
+
+    def paused(self):
+        """
+        Return True if the aggregated service status is not up, in which
+        case we don't care about computing a status for the sync resource.
+
+        Drivers with pausable=False are never paused.
+        """
+        if self.pausable:
+            return False
         try:
             data = self.svc.node._daemon_status()
         except Exception:
@@ -178,13 +192,13 @@ def _status(self, **kwargs):
             svcnames = data["monitor"]["services"]
         except (KeyError, TypeError):
             # the daemon is not returning proper status data
-            svcnames = []
+            svcnames = {}
         if self.svc.svcname in svcnames:
-            avail = data["monitor"]["services"][self.svc.svcname]["avail"]
+            avail = svcnames[self.svc.svcname]["avail"]
             if avail != "up":
                 self.status_log("paused, service not up", "info")
-                return rcStatus.NA
-        return self.sync_status(**kwargs)
+                return True
+        return False
 
     @lazy
     def last_stats_file(self):

lib/resSyncHp3par.py

@@ -20,6 +20,7 @@ def __init__(self,
                               rid=rid,
                               type="sync.hp3par",
                               **kwargs)
+        self.pausable = False
         self.array = array
         self.rcg_names = rcg_names
         self.rcg = rcg_names[array]

lib/resSyncNetapp.py

@@ -279,6 +279,7 @@ def __init__(self,
                               rid=rid,
                               type="sync.netapp",
                               **kwargs)
+        self.pausable = False
         self.label = "netapp %s on %s"%(path, ', '.join(filers.values()))
         self.filers = filers
         self.path = path

lib/resSyncNexenta.py

@@ -230,6 +230,7 @@ def __init__(self,
                               rid=rid,
                               type="sync.nexenta",
                               **kwargs)
+        self.pausable = False
         self.label = "nexenta autosync %s"%name
         self.autosync = name
         self.filers = filers

lib/resSyncSymSrdfS.py

@@ -582,6 +582,7 @@ def __init__(self,
                               type="sync.symsrdfs",
                               **kwargs)
 
+        self.pausable = False
         self.label = "srdf/s symdg %s"%(symdg)
         self.symid = symid