librbd: allocate the asio strands directly on the heap

This will assist with potential race condition debugging since the
stand pointer will be invalidated by the time the strand has been
destructed and shut down.

Signed-off-by: Jason Dillaman <dillaman@redhat.com>

diff --git a/src/librbd/AsioEngine.cc b/src/librbd/AsioEngine.cc
index d8cf48d3969085b9b19c2d05fdb5f4ef23e9f00f..1a46b590479d69fa27a3db2f0266b087f5d2446e 100644 (file)
--- a/src/librbd/AsioEngine.cc
+++ b/src/librbd/AsioEngine.cc
@@ -21,7 +21,8 @@ AsioEngine::AsioEngine(std::shared_ptr<librados::Rados> rados)
       neorados::RADOS::make_with_librados(*rados))),
     m_cct(m_rados_api->cct()),
     m_io_context(m_rados_api->get_io_context()),
-    m_api_strand(m_io_context),
+    m_api_strand(std::make_unique<boost::asio::io_context::strand>(
+      m_io_context)),
     m_context_wq(std::make_unique<asio::ContextWQ>(m_cct, m_io_context)) {
   ldout(m_cct, 20) << dendl;
 
@@ -40,6 +41,7 @@ AsioEngine::AsioEngine(librados::IoCtx& io_ctx)
 
 AsioEngine::~AsioEngine() {
   ldout(m_cct, 20) << dendl;
+  m_api_strand.reset();
 }
 
 void AsioEngine::dispatch(Context* ctx, int r) {

diff --git a/src/librbd/AsioEngine.h b/src/librbd/AsioEngine.h
index 00cb7f7f8a102f339b1a50d978e6bd86f1df4684..d2730fd98804ab215263124d06099d191125dbec 100644 (file)
--- a/src/librbd/AsioEngine.h
+++ b/src/librbd/AsioEngine.h
@@ -45,7 +45,7 @@ public:
 
   inline boost::asio::io_context::strand& get_api_strand() {
     // API client callbacks should never fire concurrently
-    return m_api_strand;
+    return *m_api_strand;
   }
 
   inline asio::ContextWQ* get_work_queue() {
@@ -69,7 +69,7 @@ private:
   CephContext* m_cct;
 
   boost::asio::io_context& m_io_context;
-  boost::asio::io_context::strand m_api_strand;
+  std::unique_ptr<boost::asio::io_context::strand> m_api_strand;
   std::unique_ptr<asio::ContextWQ> m_context_wq;
 };
 

diff --git a/src/librbd/asio/ContextWQ.cc b/src/librbd/asio/ContextWQ.cc
index 2d12d5080fd1dec294e8aa0d946a88fc305ad8d1..4f6c7277080621ebe4f485c256a39629432e1772 100644 (file)
--- a/src/librbd/asio/ContextWQ.cc
+++ b/src/librbd/asio/ContextWQ.cc
@@ -15,7 +15,8 @@ namespace librbd {
 namespace asio {
 
 ContextWQ::ContextWQ(CephContext* cct, boost::asio::io_context& io_context)
-  : m_cct(cct), m_io_context(io_context), m_strand(io_context),
+  : m_cct(cct), m_io_context(io_context),
+    m_strand(std::make_unique<boost::asio::io_context::strand>(io_context)),
     m_queued_ops(0) {
   ldout(m_cct, 20) << dendl;
 }
@@ -23,6 +24,7 @@ ContextWQ::ContextWQ(CephContext* cct, boost::asio::io_context& io_context)
 ContextWQ::~ContextWQ() {
   ldout(m_cct, 20) << dendl;
   drain();
+  m_strand.reset();
 }
 
 void ContextWQ::drain() {
@@ -40,7 +42,7 @@ void ContextWQ::drain_handler(Context* ctx) {
 
   // new items might be queued while we are trying to drain, so we
   // might need to post the handler multiple times
-  boost::asio::post(m_strand, [this, ctx]() { drain_handler(ctx); });
+  boost::asio::post(*m_strand, [this, ctx]() { drain_handler(ctx); });
 }
 
 } // namespace asio

diff --git a/src/librbd/asio/ContextWQ.h b/src/librbd/asio/ContextWQ.h
index 3197756205d338b2b34d65a6fb78204b27e0151d..85c254161213770c50749e355c651f863b0ed774 100644 (file)
--- a/src/librbd/asio/ContextWQ.h
+++ b/src/librbd/asio/ContextWQ.h
@@ -7,6 +7,7 @@
 #include "include/common_fwd.h"
 #include "include/Context.h"
 #include <atomic>
+#include <memory>
 #include <boost/asio/io_context.hpp>
 #include <boost/asio/io_context_strand.hpp>
 #include <boost/asio/post.hpp>
@@ -26,7 +27,7 @@ public:
 
     // ensure all legacy ContextWQ users are dispatched sequentially for
     // backwards compatibility (i.e. might not be concurrent thread-safe)
-    boost::asio::post(m_strand, [this, ctx, r]() {
+    boost::asio::post(*m_strand, [this, ctx, r]() {
       ctx->complete(r);
 
       ceph_assert(m_queued_ops > 0);
@@ -37,7 +38,7 @@ public:
 private:
   CephContext* m_cct;
   boost::asio::io_context& m_io_context;
-  boost::asio::io_context::strand m_strand;
+  std::unique_ptr<boost::asio::io_context::strand> m_strand;
 
   std::atomic<uint64_t> m_queued_ops;