From: IvanGuan <yunfei.guan@xtaotech.com>
Date: Fri, 4 Jan 2019 04:22:27 +0000 (+0800)
Subject: client: fix fuse client hang because its pipe to mds is not ok
X-Git-Tag: v12.2.11~15^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=refs%2Fpull%2F25904%2Fhead;p=ceph.git

client: fix fuse client hang because its pipe to mds is not ok

If fuse client session had been killed by mds and the mds daemon restart
or hot-standby switch happens right away but the client did not receive
any message from monitor due to network or other whatever reason untill
the mds become active again.Thus cause client didn't do closed_mds_session
lead the seession still is STATE_OPEN but client can't send any message to
mds because its pipe is not ok.So we should close the stale session so that
it can be reopened again.

Fixes: http://tracker.ceph.com/issues/36079
Signed-off-by: Guan yunfei <yunfei.guan@xtaotech.com>
(cherry picked from commit 0e137de26e85942f8b40f7b13e564bd4c31b37f9)

Conflicts:
	src/client/Client.cc : Resolved in handle_mds_map
---

diff --git a/src/client/Client.cc b/src/client/Client.cc
index f756d188a59c..2d89b1f4127e 100644
--- a/src/client/Client.cc
+++ b/src/client/Client.cc
@@ -2618,13 +2618,14 @@ void Client::handle_fs_map_user(MFSMapUser *m)
 
 void Client::handle_mds_map(MMDSMap* m)
 {
+  mds_gid_t old_inc, new_inc;
   if (m->get_epoch() <= mdsmap->get_epoch()) {
     ldout(cct, 1) << "handle_mds_map epoch " << m->get_epoch()
                   << " is identical to or older than our "
                   << mdsmap->get_epoch() << dendl;
     m->put();
     return;
-  }  
+  }
 
   ldout(cct, 1) << "handle_mds_map epoch " << m->get_epoch() << dendl;
 
@@ -2671,6 +2672,13 @@ void Client::handle_mds_map(MMDSMap* m)
     if (!mdsmap->is_up(mds)) {
       session->con->mark_down();
     } else if (mdsmap->get_inst(mds) != session->inst) {
+      old_inc = oldmap->get_incarnation(mds);
+      new_inc = mdsmap->get_incarnation(mds);
+      if (old_inc != new_inc) {
+        ldout(cct, 1) << "mds incarnation changed from "
+		      << old_inc << " to " << new_inc << dendl;
+        oldstate = MDSMap::STATE_NULL;
+      }
       session->con->mark_down();
       session->inst = mdsmap->get_inst(mds);
       // When new MDS starts to take over, notify kernel to trim unused entries
@@ -2681,6 +2689,11 @@ void Client::handle_mds_map(MMDSMap* m)
       continue;  // no change
     
     session->mds_state = newstate;
+    if (old_inc != new_inc && newstate > MDSMap::STATE_RECONNECT) {
+      // missed reconnect close the session so that it can be reopened
+      _closed_mds_session(session);
+      continue;
+    }
     if (newstate == MDSMap::STATE_RECONNECT) {
       session->con = messenger->get_connection(session->inst);
       send_reconnect(session);
diff --git a/src/mds/MDSMap.h b/src/mds/MDSMap.h
index 86a538ce476e..f9ab4f5a82cd 100644
--- a/src/mds/MDSMap.h
+++ b/src/mds/MDSMap.h
@@ -635,6 +635,16 @@ public:
     }
   }
 
+  /**
+   * Get MDS rank incarnation if the rank is up, else -1
+   */
+  mds_gid_t get_incarnation(mds_rank_t m) const {
+    std::map<mds_rank_t, mds_gid_t>::const_iterator u = up.find(m);
+    if (u == up.end())
+      return MDS_GID_NONE;
+    return (mds_gid_t)get_inc_gid(u->second);
+  }
+
   int get_inc_gid(mds_gid_t gid) const {
     auto mds_info_entry = mds_info.find(gid);
     if (mds_info_entry != mds_info.end())