From: Sage Weil <sage@redhat.com>
Date: Tue, 3 Oct 2017 21:48:37 +0000 (-0500)
Subject: os/bluestore: use normal Context for async deferred_try_submit
X-Git-Tag: v12.2.2~170^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=7986d4566a1f6d8e22a9acd19608530ce64cbfa1;p=ceph.git

os/bluestore: use normal Context for async deferred_try_submit

I'm not quite sure why the FunctionContext did not ever execute on the
finisher thread (perhaps the [&] captured some state on the stack that it
shouldn't have?).  In any case, using a traditional Context here appears
to resolve the problem (of the async deferred_try_submit() never executing,
leading to a bluestore stall/deadlock).

Fixes: http://tracker.ceph.com/issues/21470
Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 67ec75805787ed63b35f8d70478a7a2cd785df06)
---

diff --git a/src/os/bluestore/BlueStore.cc b/src/os/bluestore/BlueStore.cc
index b46b06ae410a..a28efdcd90c4 100644
--- a/src/os/bluestore/BlueStore.cc
+++ b/src/os/bluestore/BlueStore.cc
@@ -8707,6 +8707,14 @@ void BlueStore::_deferred_submit_unlock(OpSequencer *osr)
   bdev->aio_submit(&b->ioc);
 }
 
+struct C_DeferredTrySubmit : public Context {
+  BlueStore *store;
+  C_DeferredTrySubmit(BlueStore *s) : store(s) {}
+  void finish(int r) {
+    store->deferred_try_submit();
+  }
+};
+
 void BlueStore::_deferred_aio_finish(OpSequencer *osr)
 {
   dout(10) << __func__ << " osr " << osr << dendl;
@@ -8723,9 +8731,7 @@ void BlueStore::_deferred_aio_finish(OpSequencer *osr)
       deferred_queue.erase(q);
     } else if (deferred_aggressive) {
       dout(20) << __func__ << " queuing async deferred_try_submit" << dendl;
-      deferred_finisher.queue(new FunctionContext([&](int) {
-	    deferred_try_submit();
-	  }));
+      deferred_finisher.queue(new C_DeferredTrySubmit(this));
     } else {
       dout(20) << __func__ << " leaving queued, more pending" << dendl;
     }
diff --git a/src/os/bluestore/BlueStore.h b/src/os/bluestore/BlueStore.h
index 102c1e215557..311107c18b40 100644
--- a/src/os/bluestore/BlueStore.h
+++ b/src/os/bluestore/BlueStore.h
@@ -2036,7 +2036,9 @@ private:
 
   bluestore_deferred_op_t *_get_deferred_op(TransContext *txc, OnodeRef o);
   void _deferred_queue(TransContext *txc);
+public:
   void deferred_try_submit();
+private:
   void _deferred_submit_unlock(OpSequencer *osr);
   void _deferred_aio_finish(OpSequencer *osr);
   int _deferred_replay();