mds: warn on unconnected snap realms

When there are more than one active MDS, restarting MDS triggers
assertion "reconnected_snaprealms.empty()" quite often. If there
is no snapshot in the FS, the items left in reconnected_snaprealms
should be other MDS' mdsdir. I think it's harmless.

If there are snapshots in the FS, the assertion probably can catch
real bugs. But at present, snapshot feature is broken, fixing it is
non-trivial. So replace the assertion with a warning.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/src/mds/MDCache.cc b/src/mds/MDCache.cc
index a67f605efd9..8fc1ab83d11 100644
--- a/src/mds/MDCache.cc
+++ b/src/mds/MDCache.cc
@@ -5213,9 +5213,22 @@ void MDCache::open_snap_parents()
     gather.set_finisher(new C_MDC_OpenSnapParents(this));
     gather.activate();
   } else {
+    if (!reconnected_snaprealms.empty()) {
+      stringstream warn_str;
+      for (map<inodeno_t,map<client_t,snapid_t> >::iterator p = reconnected_snaprealms.begin();
+	   p != reconnected_snaprealms.end();
+	   ++p) {
+	warn_str << " unconnected snaprealm " << p->first << "\n";
+	for (map<client_t,snapid_t>::iterator q = p->second.begin();
+	     q != p->second.end();
+	     ++q)
+	  warn_str << "  client." << q->first << " snapid " << q->second << "\n";
+      }
+      mds->clog.warn() << "open_snap_parents has:" << "\n";
+      mds->clog.warn(warn_str);
+    }
     assert(rejoin_waiters.empty());
     assert(missing_snap_parents.empty());
-    assert(reconnected_snaprealms.empty());
     dout(10) << "open_snap_parents - all open" << dendl;
     do_delayed_cap_imports();