+#define BLOCK_OPT_SIZE "size"
+#define BLOCK_OPT_ENCRYPT "encryption"
+#define BLOCK_OPT_COMPAT6 "compat6"
+#define BLOCK_OPT_BACKING_FILE "backing_file"
+#define BLOCK_OPT_BACKING_FMT "backing_fmt"
+#define BLOCK_OPT_CLUSTER_SIZE "cluster_size"
+#define BLOCK_OPT_PREALLOC "preallocation"
+
+typedef struct AIOPool {
+ void (*cancel)(BlockDriverAIOCB *acb);
+ int aiocb_size;
+ BlockDriverAIOCB *free_aiocb;
+} AIOPool;
+