diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
index c9018c0360..c910b31f91 100644
--- a/include/libvirt/libvirt.h.in
+++ b/include/libvirt/libvirt.h.in
@@ -4884,6 +4884,12 @@ typedef void (*virConnectDomainEventIOErrorCallback)(virConnectPtr conn,
  * The callback signature to use when registering for an event of type
  * VIR_DOMAIN_EVENT_ID_IO_ERROR_REASON with virConnectDomainEventRegisterAny()
  *
+ * If the I/O error is known to be caused by an ENOSPC condition in
+ * the host (where resizing the disk to be larger will allow the guest
+ * to be resumed as if nothing happened), @reason will be "enospc".
+ * Otherwise, @reason will be "", although future strings may be added
+ * if determination of other error types becomes possible.
+ *
  */
 typedef void (*virConnectDomainEventIOErrorReasonCallback)(virConnectPtr conn,
                                                            virDomainPtr dom,
diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
index 90a125faa6..6504d15605 100644
--- a/src/qemu/qemu_monitor_json.c
+++ b/src/qemu/qemu_monitor_json.c
@@ -739,11 +739,13 @@ VIR_ENUM_IMPL(qemuMonitorIOErrorAction, VIR_DOMAIN_EVENT_IO_ERROR_LAST,
               "ignore", "stop", "report");
 
 
-static void qemuMonitorJSONHandleIOError(qemuMonitorPtr mon, virJSONValuePtr data)
+static void
+qemuMonitorJSONHandleIOError(qemuMonitorPtr mon, virJSONValuePtr data)
 {
     const char *device;
     const char *action;
-    const char *reason;
+    const char *reason = "";
+    bool nospc = false;
     int actionID;
 
     /* Throughout here we try our best to carry on upon errors,
@@ -759,14 +761,8 @@ static void qemuMonitorJSONHandleIOError(qemuMonitorPtr mon, virJSONValuePtr dat
         VIR_WARN("missing device in disk io error event");
     }
 
-#if 0
-    if ((reason = virJSONValueObjectGetString(data, "reason")) == NULL) {
-        VIR_WARN("missing reason in disk io error event");
-        reason = "";
-    }
-#else
-    reason = "";
-#endif
+    if (virJSONValueObjectGetBoolean(data, "nospace", &nospc) == 0 && nospc)
+        reason = "enospc";
 
     if ((actionID = qemuMonitorIOErrorActionTypeFromString(action)) < 0) {
         VIR_WARN("unknown disk io error action '%s'", action);