Asynchronous event for BlockPull completion

When an operation started by virDomainBlockPullAll completes (either with
success or with failure), raise an event to indicate the final status.  This
allows an API user to avoid polling on virDomainBlockPullInfo if they would
prefer to use the event mechanism.

* daemon/remote.c: Dispatch events to client
* include/libvirt/libvirt.h.in: Define event ID and callback signature
* src/conf/domain_event.c, src/conf/domain_event.h,
  src/libvirt_private.syms: Extend API to handle the new event
* src/qemu/qemu_driver.c: Connect to the QEMU monitor event
  for block_stream completion and emit a libvirt block pull event
* src/remote/remote_driver.c: Receive and dispatch events to application
* src/remote/remote_protocol.x: Wire protocol definition for the event
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor.h,
  src/qemu/qemu_monitor_json.c: Watch for BLOCK_STREAM_COMPLETED event
  from QEMU monitor

Signed-off-by: Adam Litke <agl@us.ibm.com>

daemon/remote.c

@@ -396,6 +396,37 @@ static int remoteRelayDomainEventGraphics(virConnectPtr conn ATTRIBUTE_UNUSED,
     return 0;
 }
 
+static int remoteRelayDomainEventBlockPull(virConnectPtr conn ATTRIBUTE_UNUSED,
+                                           virDomainPtr dom,
+                                           const char *path,
+                                           int status,
+                                           void *opaque)
+{
+    struct qemud_client *client = opaque;
+    remote_domain_event_block_pull_msg data;
+
+    if (!client)
+        return -1;
+
+    VIR_DEBUG("Relaying domain block pull event %s %d %s %i", dom->name, dom->id, path, status);
+
+    virMutexLock(&client->lock);
+
+    /* build return data */
+    memset(&data, 0, sizeof data);
+    make_nonnull_domain(&data.dom, dom);
+    data.path = (char*)path;
+    data.status = status;
+
+    remoteDispatchDomainEventSend(client,
+                                  REMOTE_PROC_DOMAIN_EVENT_BLOCK_PULL,
+                                  (xdrproc_t)xdr_remote_domain_event_block_pull_msg, &data);
+
+    virMutexUnlock(&client->lock);
+
+    return 0;
+}
+
 
 static int remoteRelayDomainEventControlError(virConnectPtr conn ATTRIBUTE_UNUSED,
                                               virDomainPtr dom,
@@ -434,6 +465,7 @@ static virConnectDomainEventGenericCallback domainEventCallbacks[] = {
     VIR_DOMAIN_EVENT_CALLBACK(remoteRelayDomainEventGraphics),
     VIR_DOMAIN_EVENT_CALLBACK(remoteRelayDomainEventIOErrorReason),
     VIR_DOMAIN_EVENT_CALLBACK(remoteRelayDomainEventControlError),
+    VIR_DOMAIN_EVENT_CALLBACK(remoteRelayDomainEventBlockPull),
 };
 
 verify(ARRAY_CARDINALITY(domainEventCallbacks) == VIR_DOMAIN_EVENT_ID_LAST);

include/libvirt/libvirt.h.in

@@ -2665,6 +2665,32 @@ typedef void (*virConnectDomainEventGraphicsCallback)(virConnectPtr conn,
                                                       virDomainEventGraphicsSubjectPtr subject,
                                                       void *opaque);
 
+/**
+ * virConnectDomainEventBlockPullStatus:
+ *
+ * The final status of a virDomainBlockPullAll() operation
+ */
+typedef enum {
+    VIR_DOMAIN_BLOCK_PULL_COMPLETED = 0,
+    VIR_DOMAIN_BLOCK_PULL_FAILED = 1,
+} virConnectDomainEventBlockPullStatus;
+
+/**
+ * virConnectDomainEventBlockPullCallback:
+ * @conn: connection object
+ * @dom: domain on which the event occurred
+ * @path: fully-qualified filename of the affected disk
+ * @status: final status of the operation (virConnectDomainEventBlockPullStatus)
+ *
+ * The callback signature to use when registering for an event of type
+ * VIR_DOMAIN_EVENT_ID_BLOCK_PULL with virConnectDomainEventRegisterAny()
+ */
+typedef void (*virConnectDomainEventBlockPullCallback)(virConnectPtr conn,
+                                                       virDomainPtr dom,
+                                                       const char *path,
+                                                       int status,
+                                                       void *opaque);
+
 /**
  * VIR_DOMAIN_EVENT_CALLBACK:
  *
@@ -2683,6 +2709,7 @@ typedef enum {
     VIR_DOMAIN_EVENT_ID_GRAPHICS = 5,        /* virConnectDomainEventGraphicsCallback */
     VIR_DOMAIN_EVENT_ID_IO_ERROR_REASON = 6, /* virConnectDomainEventIOErrorReasonCallback */
     VIR_DOMAIN_EVENT_ID_CONTROL_ERROR = 7,   /* virConnectDomainEventGenericCallback */
+    VIR_DOMAIN_EVENT_ID_BLOCK_PULL = 8,      /* virConnectDomainEventBlockPullCallback */
 
     /*
      * NB: this enum value will increase over time as new events are

python/libvirt-override-virConnect.py

@@ -124,6 +124,18 @@
         except AttributeError:
             pass
 
+    def dispatchDomainEventBlockPullCallback(self, dom, path, status, cbData):
+        """Dispatches events to python user domain blockPull event callbacks
+        """
+        try:
+            cb = cbData["cb"]
+            opaque = cbData["opaque"]
+
+            cb(self, virDomain(self, _obj=dom), path, status, opaque)
+            return 0
+        except AttributeError:
+            pass
+
     def domainEventDeregisterAny(self, callbackID):
         """Removes a Domain Event Callback. De-registering for a
            domain callback will disable delivery of this event type """

python/libvirt-override.c

@@ -3476,6 +3476,54 @@ libvirt_virConnectDomainEventGraphicsCallback(virConnectPtr conn ATTRIBUTE_UNUSE
     return ret;
 }
 
+static int
+libvirt_virConnectDomainEventBlockPullCallback(virConnectPtr conn ATTRIBUTE_UNUSED,
+                                               virDomainPtr dom,
+                                               const char *path,
+                                               int status,
+                                               void *opaque)
+{
+    PyObject *pyobj_cbData = (PyObject*)opaque;
+    PyObject *pyobj_dom;
+    PyObject *pyobj_ret;
+    PyObject *pyobj_conn;
+    PyObject *dictKey;
+    int ret = -1;
+
+    LIBVIRT_ENSURE_THREAD_STATE;
+
+    /* Create a python instance of this virDomainPtr */
+    virDomainRef(dom);
+    pyobj_dom = libvirt_virDomainPtrWrap(dom);
+    Py_INCREF(pyobj_cbData);
+
+    dictKey = libvirt_constcharPtrWrap("conn");
+    pyobj_conn = PyDict_GetItem(pyobj_cbData, dictKey);
+    Py_DECREF(dictKey);
+
+    /* Call the Callback Dispatcher */
+    pyobj_ret = PyObject_CallMethod(pyobj_conn,
+                                    (char*)"dispatchDomainEventBlockPullCallback",
+                                    (char*)"OsiO",
+                                    pyobj_dom, path, status, pyobj_cbData);
+
+    Py_DECREF(pyobj_cbData);
+    Py_DECREF(pyobj_dom);
+
+    if(!pyobj_ret) {
+#if DEBUG_ERROR
+        printf("%s - ret:%p\n", __FUNCTION__, pyobj_ret);
+#endif
+        PyErr_Print();
+    } else {
+        Py_DECREF(pyobj_ret);
+        ret = 0;
+    }
+
+    LIBVIRT_RELEASE_THREAD_STATE;
+    return ret;
+}
+
 static PyObject *
 libvirt_virConnectDomainEventRegisterAny(ATTRIBUTE_UNUSED PyObject * self,
                                          PyObject * args)
@@ -3534,6 +3582,9 @@ libvirt_virConnectDomainEventRegisterAny(ATTRIBUTE_UNUSED PyObject * self,
     case VIR_DOMAIN_EVENT_ID_CONTROL_ERROR:
         cb = VIR_DOMAIN_EVENT_CALLBACK(libvirt_virConnectDomainEventGenericCallback);
         break;
+    case VIR_DOMAIN_EVENT_ID_BLOCK_PULL:
+        cb = VIR_DOMAIN_EVENT_CALLBACK(libvirt_virConnectDomainEventBlockPullCallback);
+        break;
     }
 
     if (!cb) {

src/conf/domain_event.c

@@ -84,6 +84,10 @@ struct _virDomainEvent {
             char *authScheme;
             virDomainEventGraphicsSubjectPtr subject;
         } graphics;
+        struct {
+            char *path;
+            int status;
+        } blockPull;
     } data;
 };
 
@@ -500,6 +504,11 @@ void virDomainEventFree(virDomainEventPtr event)
             }
             VIR_FREE(event->data.graphics.subject);
         }
+        break;
+
+    case VIR_DOMAIN_EVENT_ID_BLOCK_PULL:
+        VIR_FREE(event->data.blockPull.path);
+        break;
     }
 
     VIR_FREE(event->dom.name);
@@ -875,6 +884,41 @@ virDomainEventPtr virDomainEventGraphicsNewFromObj(virDomainObjPtr obj,
     return ev;
 }
 
+static virDomainEventPtr
+virDomainEventBlockPullNew(int id, const char *name, unsigned char *uuid,
+                           const char *path, int status)
+{
+    virDomainEventPtr ev =
+        virDomainEventNewInternal(VIR_DOMAIN_EVENT_ID_BLOCK_PULL,
+                                  id, name, uuid);
+
+    if (ev) {
+        if (!(ev->data.blockPull.path = strdup(path))) {
+            virReportOOMError();
+            virDomainEventFree(ev);
+            return NULL;
+        }
+        ev->data.blockPull.status = status;
+    }
+
+    return ev;
+}
+
+virDomainEventPtr virDomainEventBlockPullNewFromObj(virDomainObjPtr obj,
+                                                    const char *path,
+                                                    int status)
+{
+    return virDomainEventBlockPullNew(obj->def->id, obj->def->name,
+                                                 obj->def->uuid, path, status);
+}
+
+virDomainEventPtr virDomainEventBlockPullNewFromDom(virDomainPtr dom,
+                                                    const char *path,
+                                                    int status)
+{
+    return virDomainEventBlockPullNew(dom->id, dom->name, dom->uuid,
+                                                 path, status);
+}
 
 virDomainEventPtr virDomainEventControlErrorNewFromDom(virDomainPtr dom)
 {
@@ -1028,6 +1072,13 @@ void virDomainEventDispatchDefaultFunc(virConnectPtr conn,
              cbopaque);
         break;
 
+    case VIR_DOMAIN_EVENT_ID_BLOCK_PULL:
+        ((virConnectDomainEventBlockPullCallback)cb)(conn, dom,
+                                                     event->data.blockPull.path,
+                                                     event->data.blockPull.status,
+                                                     cbopaque);
+        break;
+
     default:
         VIR_WARN("Unexpected event ID %d", event->eventID);
         break;

src/conf/domain_event.h

@@ -170,7 +170,12 @@ virDomainEventPtr virDomainEventGraphicsNewFromObj(virDomainObjPtr obj,
 virDomainEventPtr virDomainEventControlErrorNewFromDom(virDomainPtr dom);
 virDomainEventPtr virDomainEventControlErrorNewFromObj(virDomainObjPtr obj);
 
-
+virDomainEventPtr virDomainEventBlockPullNewFromObj(virDomainObjPtr obj,
+                                                    const char *path,
+                                                    int status);
+virDomainEventPtr virDomainEventBlockPullNewFromDom(virDomainPtr dom,
+                                                    const char *path,
+                                                    int status);
 
 int virDomainEventQueuePush(virDomainEventQueuePtr evtQueue,
                             virDomainEventPtr event);

src/libvirt_private.syms

@@ -377,6 +377,8 @@ virDomainWatchdogModelTypeToString;
 
 
 # domain_event.h
+virDomainEventBlockPullNewFromObj;
+virDomainEventBlockPullNewFromDom;
 virDomainEventCallbackListAdd;
 virDomainEventCallbackListAddID;
 virDomainEventCallbackListCount;

src/qemu/qemu_monitor.c

@@ -957,6 +957,18 @@ int qemuMonitorEmitGraphics(qemuMonitorPtr mon,
     return ret;
 }
 
+int qemuMonitorEmitBlockPull(qemuMonitorPtr mon,
+                             const char *diskAlias,
+                             int status)
+{
+    int ret = -1;
+    VIR_DEBUG("mon=%p", mon);
+
+    QEMU_MONITOR_CALLBACK(mon, ret, domainBlockPull, mon->vm,
+                          diskAlias, status);
+    return ret;
+}
+
 
 
 int qemuMonitorSetCapabilities(qemuMonitorPtr mon)

src/qemu/qemu_monitor.h

@@ -117,6 +117,10 @@ struct _qemuMonitorCallbacks {
                           const char *authScheme,
                           const char *x509dname,
                           const char *saslUsername);
+    int (*domainBlockPull)(qemuMonitorPtr mon,
+                           virDomainObjPtr vm,
+                           const char *diskAlias,
+                           int status);
 };
 
 
@@ -179,6 +183,10 @@ int qemuMonitorEmitGraphics(qemuMonitorPtr mon,
                             const char *authScheme,
                             const char *x509dname,
                             const char *saslUsername);
+int qemuMonitorEmitBlockPull(qemuMonitorPtr mon,
+                             const char *diskAlias,
+                             int status);
+
 
 
 int qemuMonitorStartCPUs(qemuMonitorPtr mon,

src/qemu/qemu_monitor_json.c

@@ -56,6 +56,7 @@ static void qemuMonitorJSONHandleIOError(qemuMonitorPtr mon, virJSONValuePtr dat
 static void qemuMonitorJSONHandleVNCConnect(qemuMonitorPtr mon, virJSONValuePtr data);
 static void qemuMonitorJSONHandleVNCInitialize(qemuMonitorPtr mon, virJSONValuePtr data);
 static void qemuMonitorJSONHandleVNCDisconnect(qemuMonitorPtr mon, virJSONValuePtr data);
+static void qemuMonitorJSONHandleBlockPull(qemuMonitorPtr mon, virJSONValuePtr data);
 
 struct {
     const char *type;
@@ -71,6 +72,7 @@ struct {
     { "VNC_CONNECTED", qemuMonitorJSONHandleVNCConnect, },
     { "VNC_INITIALIZED", qemuMonitorJSONHandleVNCInitialize, },
     { "VNC_DISCONNECTED", qemuMonitorJSONHandleVNCDisconnect, },
+    { "BLOCK_STREAM_COMPLETED", qemuMonitorJSONHandleBlockPull, },
 };
 
 
@@ -679,6 +681,34 @@ static void qemuMonitorJSONHandleVNCDisconnect(qemuMonitorPtr mon, virJSONValueP
     qemuMonitorJSONHandleVNC(mon, data, VIR_DOMAIN_EVENT_GRAPHICS_DISCONNECT);
 }
 
+static void qemuMonitorJSONHandleBlockPull(qemuMonitorPtr mon, virJSONValuePtr data)
+{
+    const char *device;
+    unsigned long long offset, len;
+    int status = VIR_DOMAIN_BLOCK_PULL_FAILED;
+
+    if ((device = virJSONValueObjectGetString(data, "device")) == NULL) {
+        VIR_WARN("missing device in disk io error event");
+        goto out;
+    }
+
+    if (virJSONValueObjectGetNumberUlong(data, "offset", &offset) < 0) {
+        VIR_WARN("missing offset in block pull event");
+        goto out;
+    }
+
+    if (virJSONValueObjectGetNumberUlong(data, "len", &len) < 0) {
+        VIR_WARN("missing len in block pull event");
+        goto out;
+    }
+
+    if (offset != 0 && offset == len)
+        status = VIR_DOMAIN_BLOCK_PULL_COMPLETED;
+
+out:
+    qemuMonitorEmitBlockPull(mon, device, status);
+}
+
 
 int
 qemuMonitorJSONHumanCommandWithFd(qemuMonitorPtr mon,

src/qemu/qemu_process.c

@@ -561,6 +561,35 @@ qemuProcessHandleIOError(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     return 0;
 }
 
+static int
+qemuProcessHandleBlockPull(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
+                           virDomainObjPtr vm,
+                           const char *diskAlias,
+                           int status)
+{
+    struct qemud_driver *driver = qemu_driver;
+    virDomainEventPtr event = NULL;
+    const char *path;
+    virDomainDiskDefPtr disk;
+
+    virDomainObjLock(vm);
+    disk = qemuProcessFindDomainDiskByAlias(vm, diskAlias);
+
+    if (disk) {
+        path = disk->src;
+        event = virDomainEventBlockPullNewFromObj(vm, path, status);
+    }
+
+    virDomainObjUnlock(vm);
+
+    if (event) {
+        qemuDriverLock(driver);
+        qemuDomainEventQueue(driver, event);
+        qemuDriverUnlock(driver);
+    }
+
+    return 0;
+}
 
 static int
 qemuProcessHandleGraphics(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
@@ -678,6 +707,7 @@ static qemuMonitorCallbacks monitorCallbacks = {
     .domainWatchdog = qemuProcessHandleWatchdog,
     .domainIOError = qemuProcessHandleIOError,
     .domainGraphics = qemuProcessHandleGraphics,
+    .domainBlockPull = qemuProcessHandleBlockPull,
 };
 
 static int

src/remote/remote_driver.c

@@ -3857,6 +3857,32 @@ remoteDomainReadEventIOErrorReason(virConnectPtr conn, XDR *xdr)
     return event;
 }
 
+static virDomainEventPtr
+remoteDomainReadEventBlockPull(virConnectPtr conn, XDR *xdr)
+{
+    remote_domain_event_block_pull_msg msg;
+    virDomainPtr dom;
+    virDomainEventPtr event = NULL;
+    memset (&msg, 0, sizeof msg);
+
+    /* unmarshall parameters, and process it*/
+    if (! xdr_remote_domain_event_block_pull_msg(xdr, &msg) ) {
+        remoteError(VIR_ERR_RPC, "%s",
+                    _("unable to demarshall block_pull event"));
+        return NULL;
+    }
+
+    dom = get_nonnull_domain(conn,msg.dom);
+    if (!dom)
+        return NULL;
+
+    event = virDomainEventBlockPullNewFromDom(dom, msg.path, msg.status);
+    xdr_free ((xdrproc_t) &xdr_remote_domain_event_block_pull_msg, (char *) &msg);
+
+    virDomainFree(dom);
+    return event;
+}
+
 
 static virDomainEventPtr
 remoteDomainReadEventGraphics(virConnectPtr conn, XDR *xdr)
@@ -5581,6 +5607,10 @@ processCallDispatchMessage(virConnectPtr conn, struct private_data *priv,
         event = remoteDomainReadEventControlError(conn, xdr);
         break;
 
+    case REMOTE_PROC_DOMAIN_EVENT_BLOCK_PULL:
+        event = remoteDomainReadEventBlockPull(conn, xdr);
+        break;
+
     default:
         VIR_DEBUG("Unexpected event proc %d", hdr->proc);
         break;

src/remote/remote_protocol.x

@@ -1923,6 +1923,12 @@ struct remote_domain_event_graphics_msg {
     remote_domain_event_graphics_identity subject<REMOTE_DOMAIN_EVENT_GRAPHICS_IDENTITY_MAX>;
 };
 
+struct remote_domain_event_block_pull_msg {
+    remote_nonnull_domain dom;
+    remote_nonnull_string path;
+    int status;
+};
+
 struct remote_domain_managed_save_args {
     remote_nonnull_domain dom;
     unsigned int flags;
@@ -2398,7 +2404,8 @@ enum remote_procedure {
     REMOTE_PROC_DOMAIN_BLOCK_PULL_ALL = 230, /* autogen autogen */
 
     REMOTE_PROC_DOMAIN_BLOCK_PULL_ABORT = 231, /* autogen autogen */
-    REMOTE_PROC_DOMAIN_GET_BLOCK_PULL_INFO = 232 /* skipgen skipgen */
+    REMOTE_PROC_DOMAIN_GET_BLOCK_PULL_INFO = 232, /* skipgen skipgen */
+    REMOTE_PROC_DOMAIN_EVENT_BLOCK_PULL = 233 /* skipgen skipgen */
 
     /*
      * Notice how the entries are grouped in sets of 10 ?

src/remote_protocol-structs

@@ -1421,6 +1421,11 @@ struct remote_domain_event_graphics_msg {
                 remote_domain_event_graphics_identity * subject_val;
         } subject;
 };
+struct remote_domain_event_block_pull_msg {
+        remote_nonnull_domain      dom;
+        remote_nonnull_string      path;
+        int                        status;
+};
 struct remote_domain_managed_save_args {
         remote_nonnull_domain      dom;
         u_int                      flags;