diff --git a/iocore/aio/I_AIO.h b/iocore/aio/I_AIO.h
index 8618e59da37..6144e188f6e 100644
--- a/iocore/aio/I_AIO.h
+++ b/iocore/aio/I_AIO.h
@@ -67,7 +67,7 @@ typedef struct io_event ink_io_event_t;
 #else
 
 struct ink_aiocb {
-  int aio_fildes    = 0;
+  int aio_fildes    = -1;      /* file descriptor or status: AIO_NOT_IN_PROGRESS */
   void *aio_buf     = nullptr; /* buffer location */
   size_t aio_nbytes = 0;       /* length of transfer */
   off_t aio_offset  = 0;       /* file offset */
diff --git a/iocore/aio/P_AIO.h b/iocore/aio/P_AIO.h
index 95534c9821b..b0c6b21c495 100644
--- a/iocore/aio/P_AIO.h
+++ b/iocore/aio/P_AIO.h
@@ -95,10 +95,10 @@ struct AIO_Reqs {
   ASLL(AIOCallbackInternal, alink) aio_temp_list;
   ink_mutex aio_mutex;
   ink_cond aio_cond;
-  int index           = 0; /* position of this struct in the aio_reqs array */
-  int pending         = 0; /* number of outstanding requests on the disk */
-  int queued          = 0; /* total number of aio_todo requests */
-  int filedes         = 0; /* the file descriptor for the requests */
+  int index           = 0;  /* position of this struct in the aio_reqs array */
+  int pending         = 0;  /* number of outstanding requests on the disk */
+  int queued          = 0;  /* total number of aio_todo requests */
+  int filedes         = -1; /* the file descriptor for the requests or status IO_NOT_IN_PROGRESS */
   int requests_queued = 0;
 };
 
diff --git a/iocore/cache/P_CacheVol.h b/iocore/cache/P_CacheVol.h
index a51d245e585..b9009d8a9b7 100644
--- a/iocore/cache/P_CacheVol.h
+++ b/iocore/cache/P_CacheVol.h
@@ -51,8 +51,8 @@
 #define LOOKASIDE_SIZE 256
 #define EVACUATION_BUCKET_SIZE (2 * EVACUATION_SIZE) // 16MB
 #define RECOVERY_SIZE EVACUATION_SIZE                // 8MB
-#define AIO_NOT_IN_PROGRESS 0
-#define AIO_AGG_WRITE_IN_PROGRESS -1
+#define AIO_NOT_IN_PROGRESS -1
+#define AIO_AGG_WRITE_IN_PROGRESS -2
 #define AUTO_SIZE_RAM_CACHE -1                               // 1-1 with directory size
 #define DEFAULT_TARGET_FRAGMENT_SIZE (1048576 - sizeof(Doc)) // 1MB