From: Patrick Donnelly <pdonnell@redhat.com>
Date: Thu, 30 Jul 2020 02:36:28 +0000 (-0700)
Subject: mds: resolve SIGSEGV in waiting for uncommitted fragments
X-Git-Tag: v14.2.12~23^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=993528a0d7a53422ef6643830dfc03aedbaaffa7;p=ceph.git

mds: resolve SIGSEGV in waiting for uncommitted fragments

The MDSGatherBuilder was not correctly used / wired up.

Fixes: https://tracker.ceph.com/issues/46765
Fixes: 77eb368d2d35f2418875227fff9a34b5ef15a290
Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>
(cherry picked from commit f9e58687612d60a416dd32c321069060244ce07e)
---

diff --git a/src/mds/MDCache.cc b/src/mds/MDCache.cc
index f771ca545562..70aacf5d33fd 100644
--- a/src/mds/MDCache.cc
+++ b/src/mds/MDCache.cc
@@ -11985,10 +11985,13 @@ void MDCache::rollback_uncommitted_fragment(dirfrag_t basedirfrag, frag_vec_t&&
   }
 }
 
-void MDCache::wait_for_uncommitted_fragments(MDSGather *gather)
+void MDCache::wait_for_uncommitted_fragments(MDSContext* finisher)
 {
-  for (auto& p : uncommitted_fragments)
-    p.second.waiters.push_back(gather->new_sub());
+  MDSGatherBuilder gather(g_ceph_context, finisher);
+  for (auto& p : uncommitted_fragments) {
+    p.second.waiters.push_back(gather.new_sub());
+  }
+  gather.activate();
 }
 
 void MDCache::rollback_uncommitted_fragments()
diff --git a/src/mds/MDCache.h b/src/mds/MDCache.h
index 40d449fa685d..ab5adb68d58e 100644
--- a/src/mds/MDCache.h
+++ b/src/mds/MDCache.h
@@ -1254,7 +1254,7 @@ public:
   bool is_any_uncommitted_fragment() const {
     return !uncommitted_fragments.empty();
   }
-  void wait_for_uncommitted_fragments(MDSGather *gather);
+  void wait_for_uncommitted_fragments(MDSContext* finisher);
   void rollback_uncommitted_fragments();
 
   void split_dir(CDir *dir, int byn);
diff --git a/src/mds/MDSRank.cc b/src/mds/MDSRank.cc
index 9ddd1246af04..4997daacba9a 100644
--- a/src/mds/MDSRank.cc
+++ b/src/mds/MDSRank.cc
@@ -1918,9 +1918,7 @@ void MDSRank::rejoin_done()
 
   if (mdcache->is_any_uncommitted_fragment()) {
     dout(1) << " waiting for uncommitted fragments" << dendl;
-    MDSGatherBuilder gather(g_ceph_context, new C_MDS_VoidFn(this, &MDSRank::rejoin_done));
-    mdcache->wait_for_uncommitted_fragments(gather.get());
-    gather.activate();
+    mdcache->wait_for_uncommitted_fragments(new C_MDS_VoidFn(this, &MDSRank::rejoin_done));
     return;
   }