From: John Spray <john.spray@redhat.com>
Date: Wed, 20 Jan 2016 11:19:33 +0000 (+0000)
Subject: mds: Fix lock ordering around asok registration
X-Git-Tag: v10.0.4~137^2^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=9588efe2bb72c320c1567d5e69147bb01f2fb431;p=ceph.git

mds: Fix lock ordering around asok registration

Because we acquire mds_lock inside asok handlers,
we must not hold mds_lock while registering our commands.

Fixes: #14374
Signed-off-by: John Spray <john.spray@redhat.com>
---

diff --git a/src/mds/MDSDaemon.cc b/src/mds/MDSDaemon.cc
index d38db5b70249..b38b6c9a6cc4 100644
--- a/src/mds/MDSDaemon.cc
+++ b/src/mds/MDSDaemon.cc
@@ -226,6 +226,7 @@ void MDSDaemon::set_up_admin_socket()
 {
   int r;
   AdminSocket *admin_socket = g_ceph_context->get_admin_socket();
+  assert(asok_hook == nullptr);
   asok_hook = new MDSSocketHook(this);
   r = admin_socket->register_command("status", "status", asok_hook,
 				     "high-level status of MDS");
@@ -472,6 +473,10 @@ int MDSDaemon::init(MDSMap::DaemonState wanted_state)
     sleep(10);
   }
 
+  // Set up admin socket before taking mds_lock, so that ordering
+  // is consistent (later we take mds_lock within asok callbacks)
+  set_up_admin_socket();
+
   mds_lock.Lock();
   if (beacon.get_want_state() == MDSMap::STATE_DNE) {
     suicide();  // we could do something more graceful here
@@ -520,7 +525,6 @@ int MDSDaemon::init(MDSMap::DaemonState wanted_state)
   // schedule tick
   reset_tick();
 
-  set_up_admin_socket();
   g_conf->add_observer(this);
 
   mds_lock.Unlock();