1 files changed, 49 insertions, 0 deletions
diff --git a/src/librbd/asio/ContextWQ.cc b/src/librbd/asio/ContextWQ.cc
new file mode 100644
index 000000000..4f6c72770
--- /dev/null
+++ b/src/librbd/asio/ContextWQ.cc
@@ -0,0 +1,49 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "librbd/asio/ContextWQ.h"
+#include "include/Context.h"
+#include "common/Cond.h"
+#include "common/dout.h"
+
+#define dout_subsys ceph_subsys_rbd
+#undef dout_prefix
+#define dout_prefix *_dout << "librbd::asio::ContextWQ: " \
+                           << this << " " << __func__ << ": "
+
+namespace librbd {
+namespace asio {
+
+ContextWQ::ContextWQ(CephContext* cct, boost::asio::io_context& 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;
+}
+
+ContextWQ::~ContextWQ() {
+  ldout(m_cct, 20) << dendl;
+  drain();
+  m_strand.reset();
+}
+
+void ContextWQ::drain() {
+  ldout(m_cct, 20) << dendl;
+  C_SaferCond ctx;
+  drain_handler(&ctx);
+  ctx.wait();
+}
+
+void ContextWQ::drain_handler(Context* ctx) {
+  if (m_queued_ops == 0) {
+    ctx->complete(0);
+    return;
+  }
+
+  // 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); });
+}
+
+} // namespace asio
+} // namespace librbd