From: Jason Dillaman <dillaman@redhat.com>
Date: Wed, 14 Jun 2017 13:56:58 +0000 (-0400)
Subject: librbd: convert ImageRequestWQ to template
X-Git-Tag: v12.1.1~185^2~10
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=b9569585fab5654b6c29552c5eb009dcddfaaa3b;p=ceph.git

librbd: convert ImageRequestWQ to template

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

diff --git a/src/librbd/ImageCtx.cc b/src/librbd/ImageCtx.cc
index fd2333ee105e..ed27beda2e53 100644
--- a/src/librbd/ImageCtx.cc
+++ b/src/librbd/ImageCtx.cc
@@ -210,7 +210,7 @@ struct C_InvalidateCache : public Context {
 
     ThreadPool *thread_pool;
     get_thread_pool_instance(cct, &thread_pool, &op_work_queue);
-    io_work_queue = new io::ImageRequestWQ(
+    io_work_queue = new io::ImageRequestWQ<>(
       this, "librbd::io_work_queue", cct->_conf->rbd_op_thread_timeout,
       thread_pool);
 
diff --git a/src/librbd/ImageCtx.h b/src/librbd/ImageCtx.h
index 99a02748ef66..2bda521f1542 100644
--- a/src/librbd/ImageCtx.h
+++ b/src/librbd/ImageCtx.h
@@ -52,7 +52,7 @@ namespace librbd {
   namespace io {
   class AioCompletion;
   class AsyncOperation;
-  class ImageRequestWQ;
+  template <typename> class ImageRequestWQ;
   class CopyupRequest;
   }
   namespace journal { struct Policy; }
@@ -154,7 +154,7 @@ namespace librbd {
 
     xlist<operation::ResizeRequest<ImageCtx>*> resize_reqs;
 
-    io::ImageRequestWQ *io_work_queue;
+    io::ImageRequestWQ<ImageCtx> *io_work_queue;
     xlist<io::AioCompletion*> completed_reqs;
     EventSocket event_socket;
 
diff --git a/src/librbd/io/ImageRequestWQ.cc b/src/librbd/io/ImageRequestWQ.cc
index 2758790eb087..7b8d47d39001 100644
--- a/src/librbd/io/ImageRequestWQ.cc
+++ b/src/librbd/io/ImageRequestWQ.cc
@@ -21,11 +21,12 @@
 namespace librbd {
 namespace io {
 
-ImageRequestWQ::ImageRequestWQ(ImageCtx *image_ctx, const string &name,
-                               time_t ti, ThreadPool *tp)
-  : ThreadPool::PointerWQ<ImageRequest<> >(name, ti, 0, tp),
+template <typename I>
+ImageRequestWQ<I>::ImageRequestWQ(I *image_ctx, const string &name,
+				  time_t ti, ThreadPool *tp)
+  : ThreadPool::PointerWQ<ImageRequest<I> >(name, ti, 0, tp),
     m_image_ctx(*image_ctx),
-    m_lock(util::unique_lock_name("ImageRequestWQ::m_lock", this)),
+    m_lock(util::unique_lock_name("ImageRequestWQ<I>::m_lock", this)),
     m_write_blockers(0), m_in_progress_writes(0), m_queued_reads(0),
     m_queued_writes(0), m_in_flight_ops(0), m_refresh_in_progress(false),
     m_shutdown(false), m_on_shutdown(nullptr) {
@@ -34,8 +35,9 @@ ImageRequestWQ::ImageRequestWQ(ImageCtx *image_ctx, const string &name,
   tp->add_work_queue(this);
 }
 
-ssize_t ImageRequestWQ::read(uint64_t off, uint64_t len,
-                             ReadResult &&read_result, int op_flags) {
+template <typename I>
+ssize_t ImageRequestWQ<I>::read(uint64_t off, uint64_t len,
+				ReadResult &&read_result, int op_flags) {
   CephContext *cct = m_image_ctx.cct;
   ldout(cct, 20) << "ictx=" << &m_image_ctx << ", off=" << off << ", "
                  << "len = " << len << dendl;
@@ -46,8 +48,9 @@ ssize_t ImageRequestWQ::read(uint64_t off, uint64_t len,
   return cond.wait();
 }
 
-ssize_t ImageRequestWQ::write(uint64_t off, uint64_t len,
-                              bufferlist &&bl, int op_flags) {
+template <typename I>
+ssize_t ImageRequestWQ<I>::write(uint64_t off, uint64_t len,
+				 bufferlist &&bl, int op_flags) {
   CephContext *cct = m_image_ctx.cct;
   ldout(cct, 20) << "ictx=" << &m_image_ctx << ", off=" << off << ", "
                  << "len = " << len << dendl;
@@ -71,7 +74,9 @@ ssize_t ImageRequestWQ::write(uint64_t off, uint64_t len,
   return len;
 }
 
-ssize_t ImageRequestWQ::discard(uint64_t off, uint64_t len, bool skip_partial_discard) {
+template <typename I>
+ssize_t ImageRequestWQ<I>::discard(uint64_t off, uint64_t len,
+				   bool skip_partial_discard) {
   CephContext *cct = m_image_ctx.cct;
   ldout(cct, 20) << "ictx=" << &m_image_ctx << ", off=" << off << ", "
                  << "len = " << len << dendl;
@@ -95,8 +100,9 @@ ssize_t ImageRequestWQ::discard(uint64_t off, uint64_t len, bool skip_partial_di
   return len;
 }
 
-ssize_t ImageRequestWQ::writesame(uint64_t off, uint64_t len, bufferlist &&bl,
-                                  int op_flags) {
+template <typename I>
+ssize_t ImageRequestWQ<I>::writesame(uint64_t off, uint64_t len,
+				     bufferlist &&bl, int op_flags) {
   CephContext *cct = m_image_ctx.cct;
   ldout(cct, 20) << "ictx=" << &m_image_ctx << ", off=" << off << ", "
                  << "len = " << len << ", data_len " << bl.length() << dendl;
@@ -120,9 +126,10 @@ ssize_t ImageRequestWQ::writesame(uint64_t off, uint64_t len, bufferlist &&bl,
   return len;
 }
 
-void ImageRequestWQ::aio_read(AioCompletion *c, uint64_t off, uint64_t len,
-                              ReadResult &&read_result, int op_flags,
-                              bool native_async) {
+template <typename I>
+void ImageRequestWQ<I>::aio_read(AioCompletion *c, uint64_t off, uint64_t len,
+				 ReadResult &&read_result, int op_flags,
+				 bool native_async) {
   CephContext *cct = m_image_ctx.cct;
   ZTracer::Trace trace;
   if (cct->_conf->rbd_blkin_trace_all) {
@@ -155,20 +162,21 @@ void ImageRequestWQ::aio_read(AioCompletion *c, uint64_t off, uint64_t len,
 
   if (m_image_ctx.non_blocking_aio || writes_blocked() || !writes_empty() ||
       lock_required) {
-    queue(new ImageReadRequest<>(m_image_ctx, c, {{off, len}},
-                                 std::move(read_result), op_flags, trace));
+    queue(new ImageReadRequest<I>(m_image_ctx, c, {{off, len}},
+				  std::move(read_result), op_flags, trace));
   } else {
     c->start_op();
-    ImageRequest<>::aio_read(&m_image_ctx, c, {{off, len}},
-                             std::move(read_result), op_flags, trace);
+    ImageRequest<I>::aio_read(&m_image_ctx, c, {{off, len}},
+			      std::move(read_result), op_flags, trace);
     finish_in_flight_op();
   }
   trace.event("finish");
 }
 
-void ImageRequestWQ::aio_write(AioCompletion *c, uint64_t off, uint64_t len,
-                               bufferlist &&bl, int op_flags,
-                               bool native_async) {
+template <typename I>
+void ImageRequestWQ<I>::aio_write(AioCompletion *c, uint64_t off, uint64_t len,
+				  bufferlist &&bl, int op_flags,
+				  bool native_async) {
   CephContext *cct = m_image_ctx.cct;
   ZTracer::Trace trace;
   if (cct->_conf->rbd_blkin_trace_all) {
@@ -191,20 +199,21 @@ void ImageRequestWQ::aio_write(AioCompletion *c, uint64_t off, uint64_t len,
 
   RWLock::RLocker owner_locker(m_image_ctx.owner_lock);
   if (m_image_ctx.non_blocking_aio || writes_blocked()) {
-    queue(new ImageWriteRequest<>(m_image_ctx, c, {{off, len}},
-                                  std::move(bl), op_flags, trace));
+    queue(new ImageWriteRequest<I>(m_image_ctx, c, {{off, len}},
+				   std::move(bl), op_flags, trace));
   } else {
     c->start_op();
-    ImageRequest<>::aio_write(&m_image_ctx, c, {{off, len}},
-                              std::move(bl), op_flags, trace);
+    ImageRequest<I>::aio_write(&m_image_ctx, c, {{off, len}},
+			       std::move(bl), op_flags, trace);
     finish_in_flight_op();
   }
   trace.event("finish");
 }
 
-void ImageRequestWQ::aio_discard(AioCompletion *c, uint64_t off,
-                                 uint64_t len, bool skip_partial_discard,
-                                 bool native_async) {
+template <typename I>
+void ImageRequestWQ<I>::aio_discard(AioCompletion *c, uint64_t off,
+				    uint64_t len, bool skip_partial_discard,
+				    bool native_async) {
   CephContext *cct = m_image_ctx.cct;
   ZTracer::Trace trace;
   if (cct->_conf->rbd_blkin_trace_all) {
@@ -227,18 +236,19 @@ void ImageRequestWQ::aio_discard(AioCompletion *c, uint64_t off,
 
   RWLock::RLocker owner_locker(m_image_ctx.owner_lock);
   if (m_image_ctx.non_blocking_aio || writes_blocked()) {
-    queue(new ImageDiscardRequest<>(m_image_ctx, c, off, len,
-				    skip_partial_discard, trace));
+    queue(new ImageDiscardRequest<I>(m_image_ctx, c, off, len,
+				     skip_partial_discard, trace));
   } else {
     c->start_op();
-    ImageRequest<>::aio_discard(&m_image_ctx, c, off, len,
-				skip_partial_discard, trace);
+    ImageRequest<I>::aio_discard(&m_image_ctx, c, off, len,
+				 skip_partial_discard, trace);
     finish_in_flight_op();
   }
   trace.event("finish");
 }
 
-void ImageRequestWQ::aio_flush(AioCompletion *c, bool native_async) {
+template <typename I>
+void ImageRequestWQ<I>::aio_flush(AioCompletion *c, bool native_async) {
   CephContext *cct = m_image_ctx.cct;
   ZTracer::Trace trace;
   if (cct->_conf->rbd_blkin_trace_all) {
@@ -260,17 +270,18 @@ void ImageRequestWQ::aio_flush(AioCompletion *c, bool native_async) {
 
   RWLock::RLocker owner_locker(m_image_ctx.owner_lock);
   if (m_image_ctx.non_blocking_aio || writes_blocked() || !writes_empty()) {
-    queue(new ImageFlushRequest<>(m_image_ctx, c, trace));
+    queue(new ImageFlushRequest<I>(m_image_ctx, c, trace));
   } else {
-    ImageRequest<>::aio_flush(&m_image_ctx, c, trace);
+    ImageRequest<I>::aio_flush(&m_image_ctx, c, trace);
     finish_in_flight_op();
   }
   trace.event("finish");
 }
 
-void ImageRequestWQ::aio_writesame(AioCompletion *c, uint64_t off, uint64_t len,
-                                   bufferlist &&bl, int op_flags,
-                                   bool native_async) {
+template <typename I>
+void ImageRequestWQ<I>::aio_writesame(AioCompletion *c, uint64_t off,
+				      uint64_t len, bufferlist &&bl,
+				      int op_flags, bool native_async) {
   CephContext *cct = m_image_ctx.cct;
   ZTracer::Trace trace;
   if (cct->_conf->rbd_blkin_trace_all) {
@@ -294,18 +305,19 @@ void ImageRequestWQ::aio_writesame(AioCompletion *c, uint64_t off, uint64_t len,
 
   RWLock::RLocker owner_locker(m_image_ctx.owner_lock);
   if (m_image_ctx.non_blocking_aio || writes_blocked()) {
-    queue(new ImageWriteSameRequest<>(m_image_ctx, c, off, len, std::move(bl),
-                                      op_flags, trace));
+    queue(new ImageWriteSameRequest<I>(m_image_ctx, c, off, len, std::move(bl),
+				       op_flags, trace));
   } else {
     c->start_op();
-    ImageRequest<>::aio_writesame(&m_image_ctx, c, off, len, std::move(bl),
-                                  op_flags, trace);
+    ImageRequest<I>::aio_writesame(&m_image_ctx, c, off, len, std::move(bl),
+				   op_flags, trace);
     finish_in_flight_op();
   }
   trace.event("finish");
 }
 
-void ImageRequestWQ::shut_down(Context *on_shutdown) {
+template <typename I>
+void ImageRequestWQ<I>::shut_down(Context *on_shutdown) {
   assert(m_image_ctx.owner_lock.is_locked());
 
   {
@@ -326,19 +338,22 @@ void ImageRequestWQ::shut_down(Context *on_shutdown) {
   m_image_ctx.flush(on_shutdown);
 }
 
-bool ImageRequestWQ::is_lock_request_needed() const {
+template <typename I>
+bool ImageRequestWQ<I>::is_lock_request_needed() const {
   RWLock::RLocker locker(m_lock);
   return (m_queued_writes > 0 ||
           (m_require_lock_on_read && m_queued_reads > 0));
 }
 
-int ImageRequestWQ::block_writes() {
+template <typename I>
+int ImageRequestWQ<I>::block_writes() {
   C_SaferCond cond_ctx;
   block_writes(&cond_ctx);
   return cond_ctx.wait();
 }
 
-void ImageRequestWQ::block_writes(Context *on_blocked) {
+template <typename I>
+void ImageRequestWQ<I>::block_writes(Context *on_blocked) {
   assert(m_image_ctx.owner_lock.is_locked());
   CephContext *cct = m_image_ctx.cct;
 
@@ -357,7 +372,8 @@ void ImageRequestWQ::block_writes(Context *on_blocked) {
   m_image_ctx.flush(on_blocked);
 }
 
-void ImageRequestWQ::unblock_writes() {
+template <typename I>
+void ImageRequestWQ<I>::unblock_writes() {
   CephContext *cct = m_image_ctx.cct;
 
   bool wake_up = false;
@@ -374,11 +390,12 @@ void ImageRequestWQ::unblock_writes() {
   }
 
   if (wake_up) {
-    signal();
+    this->signal();
   }
 }
 
-void ImageRequestWQ::set_require_lock_on_read() {
+template <typename I>
+void ImageRequestWQ<I>::set_require_lock_on_read() {
   CephContext *cct = m_image_ctx.cct;
   ldout(cct, 20) << dendl;
 
@@ -386,7 +403,8 @@ void ImageRequestWQ::set_require_lock_on_read() {
   m_require_lock_on_read = true;
 }
 
-void ImageRequestWQ::clear_require_lock_on_read() {
+template <typename I>
+void ImageRequestWQ<I>::clear_require_lock_on_read() {
   CephContext *cct = m_image_ctx.cct;
   ldout(cct, 20) << dendl;
 
@@ -398,11 +416,12 @@ void ImageRequestWQ::clear_require_lock_on_read() {
 
     m_require_lock_on_read = false;
   }
-  signal();
+  this->signal();
 }
 
-void *ImageRequestWQ::_void_dequeue() {
-  ImageRequest<> *peek_item = front();
+template <typename I>
+void *ImageRequestWQ<I>::_void_dequeue() {
+  ImageRequest<I> *peek_item = this->front();
 
   // no IO ops available or refresh in-progress (IO stalled)
   if (peek_item == nullptr || m_refresh_in_progress) {
@@ -426,8 +445,8 @@ void *ImageRequestWQ::_void_dequeue() {
     }
   }
 
-  ImageRequest<> *item = reinterpret_cast<ImageRequest<> *>(
-    ThreadPool::PointerWQ<ImageRequest<> >::_void_dequeue());
+  ImageRequest<I> *item = reinterpret_cast<ImageRequest<I> *>(
+    ThreadPool::PointerWQ<ImageRequest<I> >::_void_dequeue());
   assert(peek_item == item);
 
   if (refresh_required) {
@@ -437,9 +456,9 @@ void *ImageRequestWQ::_void_dequeue() {
     // stall IO until the refresh completes
     m_refresh_in_progress = true;
 
-    get_pool_lock().Unlock();
+    this->get_pool_lock().Unlock();
     m_image_ctx.state->refresh(new C_RefreshFinish(this, item));
-    get_pool_lock().Lock();
+    this->get_pool_lock().Lock();
     return nullptr;
   }
 
@@ -447,7 +466,8 @@ void *ImageRequestWQ::_void_dequeue() {
   return item;
 }
 
-void ImageRequestWQ::process(ImageRequest<> *req) {
+template <typename I>
+void ImageRequestWQ<I>::process(ImageRequest<I> *req) {
   CephContext *cct = m_image_ctx.cct;
   ldout(cct, 20) << "ictx=" << &m_image_ctx << ", "
                  << "req=" << req << dendl;
@@ -463,7 +483,8 @@ void ImageRequestWQ::process(ImageRequest<> *req) {
   finish_in_flight_op();
 }
 
-void ImageRequestWQ::finish_queued_op(ImageRequest<> *req) {
+template <typename I>
+void ImageRequestWQ<I>::finish_queued_op(ImageRequest<I> *req) {
   RWLock::RLocker locker(m_lock);
   if (req->is_write_op()) {
     assert(m_queued_writes > 0);
@@ -474,7 +495,8 @@ void ImageRequestWQ::finish_queued_op(ImageRequest<> *req) {
   }
 }
 
-void ImageRequestWQ::finish_in_progress_write() {
+template <typename I>
+void ImageRequestWQ<I>::finish_in_progress_write() {
   bool writes_blocked = false;
   {
     RWLock::RLocker locker(m_lock);
@@ -490,7 +512,8 @@ void ImageRequestWQ::finish_in_progress_write() {
   }
 }
 
-int ImageRequestWQ::start_in_flight_op(AioCompletion *c) {
+template <typename I>
+int ImageRequestWQ<I>::start_in_flight_op(AioCompletion *c) {
   RWLock::RLocker locker(m_lock);
 
   if (m_shutdown) {
@@ -505,7 +528,8 @@ int ImageRequestWQ::start_in_flight_op(AioCompletion *c) {
   return true;
 }
 
-void ImageRequestWQ::finish_in_flight_op() {
+template <typename I>
+void ImageRequestWQ<I>::finish_in_flight_op() {
   Context *on_shutdown;
   {
     RWLock::RLocker locker(m_lock);
@@ -522,7 +546,8 @@ void ImageRequestWQ::finish_in_flight_op() {
   m_image_ctx.flush(on_shutdown);
 }
 
-bool ImageRequestWQ::is_lock_required() const {
+template <typename I>
+bool ImageRequestWQ<I>::is_lock_required() const {
   assert(m_image_ctx.owner_lock.is_locked());
   if (m_image_ctx.exclusive_lock == NULL) {
     return false;
@@ -531,7 +556,8 @@ bool ImageRequestWQ::is_lock_required() const {
   return (!m_image_ctx.exclusive_lock->is_lock_owner());
 }
 
-void ImageRequestWQ::queue(ImageRequest<> *req) {
+template <typename I>
+void ImageRequestWQ<I>::queue(ImageRequest<I> *req) {
   CephContext *cct = m_image_ctx.cct;
   ldout(cct, 20) << "ictx=" << &m_image_ctx << ", "
                  << "req=" << req << dendl;
@@ -556,19 +582,20 @@ void ImageRequestWQ::queue(ImageRequest<> *req) {
     m_queued_reads++;
   }
 
-  ThreadPool::PointerWQ<ImageRequest<> >::queue(req);
+  ThreadPool::PointerWQ<ImageRequest<I> >::queue(req);
 
   if (lock_required) {
     m_image_ctx.exclusive_lock->acquire_lock(nullptr);
   }
 }
 
-void ImageRequestWQ::handle_refreshed(int r, ImageRequest<> *req) {
+template <typename I>
+void ImageRequestWQ<I>::handle_refreshed(int r, ImageRequest<I> *req) {
   CephContext *cct = m_image_ctx.cct;
   ldout(cct, 15) << "resuming IO after image refresh: r=" << r << ", "
                  << "req=" << req << dendl;
   if (r < 0) {
-    process_finish();
+    this->process_finish();
     req->fail(r);
     finish_queued_op(req);
     delete req;
@@ -576,11 +603,11 @@ void ImageRequestWQ::handle_refreshed(int r, ImageRequest<> *req) {
   } else {
     // since IO was stalled for refresh -- original IO order is preserved
     // if we requeue this op for work queue processing
-    requeue(req);
+    this->requeue(req);
   }
 
   m_refresh_in_progress = false;
-  signal();
+  this->signal();
 
   // refresh might have enabled exclusive lock -- IO stalled until
   // we acquire the lock
@@ -590,7 +617,8 @@ void ImageRequestWQ::handle_refreshed(int r, ImageRequest<> *req) {
   }
 }
 
-void ImageRequestWQ::handle_blocked_writes(int r) {
+template <typename I>
+void ImageRequestWQ<I>::handle_blocked_writes(int r) {
   Contexts contexts;
   {
     RWLock::WLocker locker(m_lock);
@@ -602,5 +630,7 @@ void ImageRequestWQ::handle_blocked_writes(int r) {
   }
 }
 
+template class librbd::io::ImageRequestWQ<librbd::ImageCtx>;
+
 } // namespace io
 } // namespace librbd
diff --git a/src/librbd/io/ImageRequestWQ.h b/src/librbd/io/ImageRequestWQ.h
index 0ed843dafebd..3f162fede50e 100644
--- a/src/librbd/io/ImageRequestWQ.h
+++ b/src/librbd/io/ImageRequestWQ.h
@@ -21,9 +21,11 @@ class AioCompletion;
 template <typename> class ImageRequest;
 class ReadResult;
 
-class ImageRequestWQ : protected ThreadPool::PointerWQ<ImageRequest<ImageCtx> > {
+template <typename ImageCtxT = librbd::ImageCtx>
+class ImageRequestWQ
+  : protected ThreadPool::PointerWQ<ImageRequest<ImageCtxT> > {
 public:
-  ImageRequestWQ(ImageCtx *image_ctx, const string &name, time_t ti,
+  ImageRequestWQ(ImageCtxT *image_ctx, const string &name, time_t ti,
                  ThreadPool *tp);
 
   ssize_t read(uint64_t off, uint64_t len, ReadResult &&read_result,
@@ -42,9 +44,9 @@ public:
   void aio_writesame(AioCompletion *c, uint64_t off, uint64_t len,
                      bufferlist &&bl, int op_flags, bool native_async=true);
 
-  using ThreadPool::PointerWQ<ImageRequest<ImageCtx> >::drain;
+  using ThreadPool::PointerWQ<ImageRequest<ImageCtxT> >::drain;
 
-  using ThreadPool::PointerWQ<ImageRequest<ImageCtx> >::empty;
+  using ThreadPool::PointerWQ<ImageRequest<ImageCtxT> >::empty;
 
   void shut_down(Context *on_shutdown);
 
@@ -65,17 +67,17 @@ public:
 
 protected:
   void *_void_dequeue() override;
-  void process(ImageRequest<ImageCtx> *req) override;
+  void process(ImageRequest<ImageCtxT> *req) override;
 
 private:
   typedef std::list<Context *> Contexts;
 
   struct C_RefreshFinish : public Context {
     ImageRequestWQ *aio_work_queue;
-    ImageRequest<ImageCtx> *aio_image_request;
+    ImageRequest<ImageCtxT> *aio_image_request;
 
     C_RefreshFinish(ImageRequestWQ *aio_work_queue,
-                    ImageRequest<ImageCtx> *aio_image_request)
+                    ImageRequest<ImageCtxT> *aio_image_request)
       : aio_work_queue(aio_work_queue), aio_image_request(aio_image_request) {
     }
     void finish(int r) override {
@@ -94,7 +96,7 @@ private:
     }
   };
 
-  ImageCtx &m_image_ctx;
+  ImageCtxT &m_image_ctx;
   mutable RWLock m_lock;
   Contexts m_write_blocker_contexts;
   uint32_t m_write_blockers;
@@ -114,19 +116,21 @@ private:
     return (m_queued_writes == 0);
   }
 
-  void finish_queued_op(ImageRequest<ImageCtx> *req);
+  void finish_queued_op(ImageRequest<ImageCtxT> *req);
   void finish_in_progress_write();
 
   int start_in_flight_op(AioCompletion *c);
   void finish_in_flight_op();
 
-  void queue(ImageRequest<ImageCtx> *req);
+  void queue(ImageRequest<ImageCtxT> *req);
 
-  void handle_refreshed(int r, ImageRequest<ImageCtx> *req);
+  void handle_refreshed(int r, ImageRequest<ImageCtxT> *req);
   void handle_blocked_writes(int r);
 };
 
 } // namespace io
 } // namespace librbd
 
+extern template class librbd::io::ImageRequestWQ<librbd::ImageCtx>;
+
 #endif // CEPH_LIBRBD_IO_IMAGE_REQUEST_WQ_H