+size_t kblock_write(struct KBlock *b, block_idx_t idx, const void *buf, size_t offset, size_t size);
+
+/**
+ * Copy one block to another.
+ *
+ * This function will copy the content of block \a src to block \a dest.
+ *
+ * \note This function is available only on devices which support partial
+ * block write or are opened in buffered mode.
+ *
+ * \param b KBlock device.
+ * \param src source block number.
+ * \param dest destination block number.
+ *
+ * \return 0 if all is OK, EOF on errors.
+ */
+int kblock_copy(struct KBlock *b, block_idx_t src, block_idx_t dest);
+
+int kblock_swLoad(struct KBlock *b, block_idx_t index);
+int kblock_swStore(struct KBlock *b, block_idx_t index);
+size_t kblock_swReadBuf(struct KBlock *b, void *buf, size_t offset, size_t size);
+size_t kblock_swWriteBuf(struct KBlock *b, const void *buf, size_t offset, size_t size);
+int kblock_swClose(struct KBlock *b);