From: xiexingguo <258156334@qq.com>
Date: Thu, 29 Oct 2015 12:04:11 +0000 (+0800)
Subject: Objecter: pool_op callback may hang forever.
X-Git-Tag: v0.94.6~61^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=refs%2Fpull%2F6588%2Fhead;p=ceph.git

Objecter: pool_op callback may hang forever.

pool_op callback may hang forever due to osdmap update during reply handling.
Fixes: #13642
Signed-off-by: xie xingguo <xie.xingguo@zte.com.cn>

(cherry picked from commit 00c6fa9e31975a935ed2bb33a099e2b4f02ad7f2)
---

diff --git a/src/osdc/Objecter.cc b/src/osdc/Objecter.cc
index 9f35ffdda753c..faddcd4fc1db3 100644
--- a/src/osdc/Objecter.cc
+++ b/src/osdc/Objecter.cc
@@ -3626,12 +3626,24 @@ void Objecter::handle_pool_op_reply(MPoolOpReply *m)
     if (osdmap->get_epoch() < m->epoch) {
       rwlock.unlock();
       rwlock.get_write();
+      // recheck op existence since we have let go of rwlock
+      // (for promotion) above.
+      iter = pool_ops.find(tid);
+      if (iter == pool_ops.end())
+        goto done; // op is gone.
       if (osdmap->get_epoch() < m->epoch) {
         ldout(cct, 20) << "waiting for client to reach epoch " << m->epoch << " before calling back" << dendl;
         _wait_for_new_map(op->onfinish, m->epoch, m->replyCode);
+      } else {
+	// map epoch changed, probably because a MOSDMap message
+	// sneaked in. Do caller-specified callback now or else
+	// we lose it forever.
+	assert(op->onfinish);
+	op->onfinish->complete(m->replyCode);	
       }
     }
     else {
+      assert(op->onfinish);
       op->onfinish->complete(m->replyCode);
     }
     op->onfinish = NULL;
@@ -3646,6 +3658,8 @@ void Objecter::handle_pool_op_reply(MPoolOpReply *m)
   } else {
     ldout(cct, 10) << "unknown request " << tid << dendl;
   }
+
+done:
   rwlock.unlock();
 
   ldout(cct, 10) << "done" << dendl;