mon/OSDMonitor: fix safety/idempotency of {set,rm}-device-class

If the command is resent (e.g., due to network reconnect), the second
instance may find that the pending crush map already has the changes
and not wait for it to commit.

Note that the stderr message will be misleading in this case; that is a
problem with most of our mon commands.  :(

Fixes: https://tracker.ceph.com/issues/49212
Signed-off-by: Sage Weil <sage@newdream.net>
(cherry picked from commit db6c8f9ab32a7bc0dc8bca94f79812bfb9e7b123)

diff --git a/src/mon/OSDMonitor.cc b/src/mon/OSDMonitor.cc
index 7bf8a2d76b0cc42eb07730e156f22228c29a6f62..dbb4ed317fd767b028dede8a50cb07e1c1bf5f1f 100644 (file)
--- a/src/mon/OSDMonitor.cc
+++ b/src/mon/OSDMonitor.cc
@@ -9931,16 +9931,14 @@ bool OSDMonitor::prepare_command_impl(MonOpRequestRef op,
       }
     }
 
-    if (!updated.empty()) {
-      pending_inc.crush.clear();
-      newcrush.encode(pending_inc.crush, mon.get_quorum_con_features());
-      ss << "set osd(s) " << updated << " to class '" << device_class << "'";
-      getline(ss, rs);
-      wait_for_finished_proposal(op,
-        new Monitor::C_Command(mon,op, 0, rs, get_last_committed() + 1));
-      return true;
-    }
-
+    pending_inc.crush.clear();
+    newcrush.encode(pending_inc.crush, mon.get_quorum_con_features());
+    ss << "set osd(s) " << updated << " to class '" << device_class << "'";
+    getline(ss, rs);
+    wait_for_finished_proposal(
+      op,
+      new Monitor::C_Command(mon,op, 0, rs, get_last_committed() + 1));
+    return true;
  } else if (prefix == "osd crush rm-device-class") {
     bool stop = false;
     vector<string> idvec;
@@ -9993,15 +9991,14 @@ bool OSDMonitor::prepare_command_impl(MonOpRequestRef op,
       }
     }
 
-    if (!updated.empty()) {
-      pending_inc.crush.clear();
-      newcrush.encode(pending_inc.crush, mon.get_quorum_con_features());
-      ss << "done removing class of osd(s): " << updated;
-      getline(ss, rs);
-      wait_for_finished_proposal(op,
-        new Monitor::C_Command(mon,op, 0, rs, get_last_committed() + 1));
-      return true;
-    }
+    pending_inc.crush.clear();
+    newcrush.encode(pending_inc.crush, mon.get_quorum_con_features());
+    ss << "done removing class of osd(s): " << updated;
+    getline(ss, rs);
+    wait_for_finished_proposal(
+      op,
+      new Monitor::C_Command(mon,op, 0, rs, get_last_committed() + 1));
+    return true;
   } else if (prefix == "osd crush class create") {
     string device_class;
     if (!cmd_getval(cmdmap, "class", device_class)) {