Import all this stuff into a single repo called Serenity.

VirtualFileSystem/DeviceBackedFileSystem.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include "FileSystem.h"
+#include <AK/ByteBuffer.h>
+
+class DeviceBackedFileSystem : public FileSystem {
+public:
+    virtual ~DeviceBackedFileSystem() override;
+
+    BlockDevice& device() { return *m_device; }
+    const BlockDevice& device() const { return *m_device; }
+
+    unsigned blockSize() const { return m_blockSize; }
+
+protected:
+    explicit DeviceBackedFileSystem(RetainPtr<BlockDevice>&&);
+
+    void setBlockSize(unsigned);
+    void invalidateCaches();
+
+    ByteBuffer readBlock(unsigned index) const;
+    ByteBuffer readBlocks(unsigned index, unsigned count) const;
+
+    bool writeBlock(unsigned index, const ByteBuffer&);
+    bool writeBlocks(unsigned index, unsigned count, const ByteBuffer&);
+
+private:
+    unsigned m_blockSize { 0 };
+    RetainPtr<BlockDevice> m_device;
+};