librbd: skeleton implementation of image snap list dispatch hooks

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

src/librbd/exclusive_lock/ImageDispatch.h

@@ -89,6 +89,16 @@ public:
       io::DispatchResult* dispatch_result, Context** on_finish,
       Context* on_dispatched) override;
 
+  bool list_snaps(
+      io::AioCompletion* aio_comp, io::Extents&& image_extents,
+      io::SnapIds&& snap_ids, int list_snaps_flags,
+      io::SnapshotDelta* snapshot_delta, const ZTracer::Trace &parent_trace,
+      uint64_t tid, std::atomic<uint32_t>* image_dispatch_flags,
+      io::DispatchResult* dispatch_result, Context** on_finish,
+      Context* on_dispatched) override {
+    return false;
+  }
+
 private:
   typedef std::list<Context*> Contexts;
   typedef std::unordered_set<uint64_t> Tids;

src/librbd/io/ImageDispatch.cc

@@ -145,6 +145,27 @@ bool ImageDispatch<I>::flush(
   return true;
 }
 
+template <typename I>
+bool ImageDispatch<I>::list_snaps(
+    AioCompletion* aio_comp, Extents&& image_extents, SnapIds&& snap_ids,
+    int list_snaps_flags, SnapshotDelta* snapshot_delta,
+    const ZTracer::Trace &parent_trace, uint64_t tid,
+    std::atomic<uint32_t>* image_dispatch_flags,
+    DispatchResult* dispatch_result, Context** on_finish,
+    Context* on_dispatched) {
+  auto cct = m_image_ctx->cct;
+  ldout(cct, 20) << dendl;
+
+  start_in_flight_io(aio_comp);
+
+  *dispatch_result = DISPATCH_RESULT_COMPLETE;
+  ImageListSnapsRequest<I> req(
+    *m_image_ctx, aio_comp, std::move(image_extents), std::move(snap_ids),
+    list_snaps_flags, snapshot_delta, parent_trace);
+  req.send();
+  return true;
+}
+
 } // namespace io
 } // namespace librbd
 

src/librbd/io/ImageDispatch.h

@@ -73,6 +73,14 @@ public:
       DispatchResult* dispatch_result, Context** on_finish,
       Context* on_dispatched) override;
 
+  bool list_snaps(
+      AioCompletion* aio_comp, Extents&& image_extents, SnapIds&& snap_ids,
+      int list_snaps_flags, SnapshotDelta* snapshot_delta,
+      const ZTracer::Trace &parent_trace, uint64_t tid,
+      std::atomic<uint32_t>* image_dispatch_flags,
+      DispatchResult* dispatch_result, Context** on_finish,
+      Context* on_dispatched) override;
+
 private:
   ImageCtxT* m_image_ctx;
 

src/librbd/io/ImageDispatchInterface.h

@@ -71,6 +71,14 @@ struct ImageDispatchInterface {
       DispatchResult* dispatch_result, Context** on_finish,
       Context* on_dispatched) = 0;
 
+  virtual bool list_snaps(
+      AioCompletion* aio_comp, Extents&& image_extents, SnapIds&& snap_ids,
+      int list_snaps_flags, SnapshotDelta* snapshot_delta,
+      const ZTracer::Trace &parent_trace, uint64_t tid,
+      std::atomic<uint32_t>* image_dispatch_flags,
+      DispatchResult* dispatch_result, Context** on_finish,
+      Context* on_dispatched) = 0;
+
 };
 
 } // namespace io

src/librbd/io/ImageDispatchSpec.h

@@ -85,12 +85,25 @@ public:
     }
   };
 
+  struct ListSnaps {
+    SnapIds snap_ids;
+    int list_snaps_flags;
+    SnapshotDelta* snapshot_delta;
+
+    ListSnaps(SnapIds&& snap_ids, int list_snaps_flags,
+              SnapshotDelta* snapshot_delta)
+      : snap_ids(std::move(snap_ids)), list_snaps_flags(list_snaps_flags),
+        snapshot_delta(snapshot_delta) {
+    }
+  };
+
   typedef boost::variant<Read,
                          Discard,
                          Write,
                          WriteSame,
                          CompareAndWrite,
-                         Flush> Request;
+                         Flush,
+                         ListSnaps> Request;
 
   C_Dispatcher dispatcher_ctx;
 
@@ -181,6 +194,20 @@ public:
                                  Flush{flush_source}, {}, 0, parent_trace);
   }
 
+  template <typename ImageCtxT = ImageCtx>
+  static ImageDispatchSpec* create_list_snaps(
+      ImageCtxT &image_ctx, ImageDispatchLayer image_dispatch_layer,
+      AioCompletion *aio_comp, Extents &&image_extents, SnapIds&& snap_ids,
+      int list_snaps_flags, SnapshotDelta* snapshot_delta,
+      const ZTracer::Trace &parent_trace) {
+    return new ImageDispatchSpec(image_ctx.io_image_dispatcher,
+                                 image_dispatch_layer, aio_comp,
+                                 std::move(image_extents),
+                                 ListSnaps{std::move(snap_ids),
+                                           list_snaps_flags, snapshot_delta},
+                                 {}, 0, parent_trace);
+  }
+
   ~ImageDispatchSpec() {
     aio_comp->put();
   }

src/librbd/io/ImageDispatcher.cc

@@ -108,6 +108,18 @@ struct ImageDispatcher<I>::SendVisitor : public boost::static_visitor<bool> {
       &image_dispatch_spec->aio_comp->image_dispatcher_ctx,
       &image_dispatch_spec->dispatcher_ctx);
   }
+
+  bool operator()(ImageDispatchSpec::ListSnaps& list_snaps) const {
+    return image_dispatch->list_snaps(
+      image_dispatch_spec->aio_comp,
+      std::move(image_dispatch_spec->image_extents),
+      std::move(list_snaps.snap_ids), list_snaps.list_snaps_flags,
+      list_snaps.snapshot_delta, image_dispatch_spec->parent_trace,
+      image_dispatch_spec->tid, &image_dispatch_spec->image_dispatch_flags,
+      &image_dispatch_spec->dispatch_result,
+      &image_dispatch_spec->aio_comp->image_dispatcher_ctx,
+      &image_dispatch_spec->dispatcher_ctx);
+  }
 };
 
 template <typename I>

src/librbd/io/QosImageDispatch.h

@@ -90,6 +90,16 @@ public:
       DispatchResult* dispatch_result, Context** on_finish,
       Context* on_dispatched) override;
 
+  bool list_snaps(
+      AioCompletion* aio_comp, Extents&& image_extents, SnapIds&& snap_ids,
+      int list_snaps_flags, SnapshotDelta* snapshot_delta,
+      const ZTracer::Trace &parent_trace, uint64_t tid,
+      std::atomic<uint32_t>* image_dispatch_flags,
+      DispatchResult* dispatch_result, Context** on_finish,
+      Context* on_dispatched) override {
+    return false;
+  }
+
 private:
   ImageCtxT* m_image_ctx;
 

src/librbd/io/QueueImageDispatch.h

@@ -77,6 +77,16 @@ public:
       DispatchResult* dispatch_result, Context** on_finish,
       Context* on_dispatched) override;
 
+  bool list_snaps(
+      AioCompletion* aio_comp, Extents&& image_extents, SnapIds&& snap_ids,
+      int list_snaps_flags, SnapshotDelta* snapshot_delta,
+      const ZTracer::Trace &parent_trace, uint64_t tid,
+      std::atomic<uint32_t>* image_dispatch_flags,
+      DispatchResult* dispatch_result, Context** on_finish,
+      Context* on_dispatched) override {
+    return false;
+  }
+
 private:
   ImageCtxT* m_image_ctx;
 

src/librbd/io/RefreshImageDispatch.h

@@ -73,6 +73,16 @@ public:
       DispatchResult* dispatch_result, Context** on_finish,
       Context* on_dispatched) override;
 
+  bool list_snaps(
+      AioCompletion* aio_comp, Extents&& image_extents, SnapIds&& snap_ids,
+      int list_snaps_flags, SnapshotDelta* snapshot_delta,
+      const ZTracer::Trace &parent_trace, uint64_t tid,
+      std::atomic<uint32_t>* image_dispatch_flags,
+      DispatchResult* dispatch_result, Context** on_finish,
+      Context* on_dispatched) override {
+    return false;
+  }
+
 private:
   ImageCtxT* m_image_ctx;
 

src/librbd/io/WriteBlockImageDispatch.h

@@ -88,6 +88,16 @@ public:
       DispatchResult* dispatch_result, Context** on_finish,
       Context* on_dispatched) override;
 
+  bool list_snaps(
+      AioCompletion* aio_comp, Extents&& image_extents, SnapIds&& snap_ids,
+      int list_snaps_flags, SnapshotDelta* snapshot_delta,
+      const ZTracer::Trace &parent_trace, uint64_t tid,
+      std::atomic<uint32_t>* image_dispatch_flags,
+      DispatchResult* dispatch_result, Context** on_finish,
+      Context* on_dispatched) override {
+    return false;
+  }
+
 private:
   struct C_BlockedWrites;
 

src/test/librbd/mock/io/MockImageDispatch.h

@@ -77,6 +77,16 @@ public:
     return false;
   }
 
+  bool list_snaps(
+      AioCompletion* aio_comp, Extents&& image_extents, SnapIds&& snap_ids,
+      int list_snaps_flags, SnapshotDelta* snapshot_delta,
+      const ZTracer::Trace &parent_trace, uint64_t tid,
+      std::atomic<uint32_t>* image_dispatch_flags,
+      DispatchResult* dispatch_result, Context** on_finish,
+      Context* on_dispatched) override {
+    return false;
+  }
+
 };
 
 } // namespace io