1 files changed, 59 insertions, 0 deletions
diff --git a/src/librbd/cache/PassthroughImageCache.h b/src/librbd/cache/PassthroughImageCache.h
new file mode 100644
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+++ b/src/librbd/cache/PassthroughImageCache.h
@@ -0,0 +1,59 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#ifndef CEPH_LIBRBD_CACHE_PASSTHROUGH_IMAGE_CACHE
+#define CEPH_LIBRBD_CACHE_PASSTHROUGH_IMAGE_CACHE
+
+#include "ImageCache.h"
+#include "ImageWriteback.h"
+
+namespace librbd {
+
+struct ImageCtx;
+
+namespace cache {
+
+/**
+ * Example passthrough client-side, image extent cache
+ */
+template <typename ImageCtxT = librbd::ImageCtx>
+class PassthroughImageCache : public ImageCache {
+public:
+  explicit PassthroughImageCache(ImageCtx &image_ctx);
+
+  /// client AIO methods
+  void aio_read(Extents&& image_extents, ceph::bufferlist *bl,
+                int fadvise_flags, Context *on_finish) override;
+  void aio_write(Extents&& image_extents, ceph::bufferlist&& bl,
+                 int fadvise_flags, Context *on_finish) override;
+  void aio_discard(uint64_t offset, uint64_t length,
+                   uint32_t discard_granularity_bytes,
+                   Context *on_finish) override;
+  void aio_flush(Context *on_finish) override;
+  void aio_writesame(uint64_t offset, uint64_t length,
+                     ceph::bufferlist&& bl,
+                     int fadvise_flags, Context *on_finish) override;
+  void aio_compare_and_write(Extents&& image_extents,
+                             ceph::bufferlist&& cmp_bl, ceph::bufferlist&& bl,
+                             uint64_t *mismatch_offset,int fadvise_flags,
+                             Context *on_finish) override;
+
+  /// internal state methods
+  void init(Context *on_finish) override;
+  void shut_down(Context *on_finish) override;
+
+  void invalidate(Context *on_finish) override;
+  void flush(Context *on_finish) override;
+
+private:
+  ImageCtxT &m_image_ctx;
+  ImageWriteback<ImageCtxT> m_image_writeback;
+
+};
+
+} // namespace cache
+} // namespace librbd
+
+extern template class librbd::cache::PassthroughImageCache<librbd::ImageCtx>;
+
+#endif // CEPH_LIBRBD_CACHE_PASSTHROUGH_IMAGE_CACHE