config: Introduce ThrottleFilter and corresponding XML parsing

Introduce throttle filter along with corresponding operations.

* Define new struct 'virDomainThrottleFilterDef' and corresponding destructor
* Update _virDomainDiskDef to include virDomainThrottleFilterDef
* Support throttle filter "Parse" and "Format" for operations between DOM XML
  and structs. Note, this commit just contains parse/format of group name for
  throttle filter in domain_conf.c, there is other commit to handle throttle
  filter nodename parse/format between throttlefilter and diskPrivateData for
  statusxml in qemu_domain.c when processing qemuDomainDiskPrivate and
  qemuDomainDiskPrivate

Signed-off-by: Chun Feng Wu <danielwuwy@163.com>

* Error handling for null throttle group.
* Update of code documentation comments.
* Apply suggested coding style changes.

Signed-off-by: Harikumar Rajkumar <harirajkumar230@gmail.com>

* Fixed naming of virDomainThrottleFilterDefClear to ...Free
* Fixed memleak of the throttle filter definitions

Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

src/conf/domain_conf.c

@@ -2438,6 +2438,15 @@ virDomainDiskDefFree(virDomainDiskDef *def)
     virObjectUnref(def->privateData);
     g_slist_free_full(def->iothreads, (GDestroyNotify) virDomainIothreadMappingDefFree);
 
+    if (def->throttlefilters) {
+        size_t i;
+
+        for (i = 0; i < def->nthrottlefilters; i++)
+            virDomainThrottleFilterDefFree(def->throttlefilters[i]);
+
+        g_free(def->throttlefilters);
+    }
+
     g_free(def);
 }
 
@@ -3837,6 +3846,17 @@ virDomainThrottleGroupDefArrayFree(virDomainThrottleGroupDef **def,
 }
 
 
+void
+virDomainThrottleFilterDefFree(virDomainThrottleFilterDef *def)
+{
+    if (!def)
+        return;
+    g_free(def->group_name);
+    g_free(def->nodename);
+    g_free(def);
+}
+
+
 void
 virDomainResourceDefFree(virDomainResourceDef *resource)
 {
@@ -8001,6 +8021,50 @@ virDomainDefThrottleGroupsParse(virDomainDef *def,
 }
 
 
+static virDomainThrottleFilterDef *
+virDomainDiskThrottleFilterDefParse(xmlNodePtr node)
+{
+    g_autoptr(virDomainThrottleFilterDef) filter = g_new0(virDomainThrottleFilterDef, 1);
+
+    filter->group_name = virXMLPropStringRequired(node, "group");
+
+    return g_steal_pointer(&filter);
+}
+
+
+static int
+virDomainDiskDefThrottleFiltersParse(virDomainDiskDef *def,
+                                     xmlXPathContextPtr ctxt)
+{
+    size_t i;
+    int n = 0;
+    g_autofree xmlNodePtr *nodes = NULL;
+
+    if ((n = virXPathNodeSet("./throttlefilters/throttlefilter", ctxt, &nodes)) < 0)
+        return -1;
+
+    if (n)
+        def->throttlefilters = g_new0(virDomainThrottleFilterDef *, n);
+
+    for (i = 0; i < n; i++) {
+        g_autoptr(virDomainThrottleFilterDef) filter = NULL;
+
+        if (!(filter = virDomainDiskThrottleFilterDefParse(nodes[i]))) {
+            return -1;
+        }
+
+        if (virDomainThrottleFilterFind(def, filter->group_name)) {
+            virReportError(VIR_ERR_XML_ERROR,
+                           _("duplicate filter name '%1$s' found"),
+                           filter->group_name);
+            return -1;
+        }
+        def->throttlefilters[def->nthrottlefilters++] = g_steal_pointer(&filter);
+    }
+    return 0;
+}
+
+
 static int
 virDomainDiskDefMirrorParse(virDomainDiskDef *def,
                             xmlNodePtr cur,
@@ -8503,6 +8567,9 @@ virDomainDiskDefParseXML(virDomainXMLOption *xmlopt,
     if (virDomainDiskDefIotuneParse(def, ctxt) < 0)
         return NULL;
 
+    if (virDomainDiskDefThrottleFiltersParse(def, ctxt) < 0)
+        return NULL;
+
     def->domain_name = virXPathString("string(./backenddomain/@name)", ctxt);
     def->serial = virXPathString("string(./serial)", ctxt);
     def->wwn = virXPathString("string(./wwn)", ctxt);
@@ -22745,6 +22812,31 @@ virDomainThrottleGroupDel(virDomainDef *def,
 }
 
 
+/**
+ * virDomainThrottleFilterFind:
+ * @def: domain disk definition
+ * @name: throttle group name
+ *
+ * Search domain disk to find throttle filter referencing
+ * throttle group with name @name.
+ *
+ * Return a pointer to throttle filter found
+ */
+virDomainThrottleFilterDef *
+virDomainThrottleFilterFind(const virDomainDiskDef *def,
+                            const char *name)
+{
+    size_t i;
+
+    for (i = 0; i < def->nthrottlefilters; i++) {
+        if (STREQ(name, def->throttlefilters[i]->group_name))
+            return def->throttlefilters[i];
+    }
+
+    return NULL;
+}
+
+
 static int
 virDomainEventActionDefFormat(virBuffer *buf,
                               int type,
@@ -23426,6 +23518,21 @@ virDomainIothreadMappingDefFormat(virBuffer *buf,
 }
 
 
+static void
+virDomainDiskDefFormatThrottleFilters(virBuffer *buf,
+                                      virDomainDiskDef *disk)
+{
+    size_t i;
+    g_auto(virBuffer) throttleChildBuf = VIR_BUFFER_INIT_CHILD(buf);
+    for (i = 0; i < disk->nthrottlefilters; i++) {
+        g_auto(virBuffer) throttleAttrBuf = VIR_BUFFER_INITIALIZER;
+        virBufferEscapeString(&throttleAttrBuf, " group='%s'", disk->throttlefilters[i]->group_name);
+        virXMLFormatElement(&throttleChildBuf, "throttlefilter", &throttleAttrBuf, NULL);
+    }
+    virXMLFormatElement(buf, "throttlefilters", NULL, &throttleChildBuf);
+}
+
+
 static void
 virDomainDiskDefFormatDriver(virBuffer *buf,
                              virDomainDiskDef *disk)
@@ -23690,6 +23797,8 @@ virDomainDiskDefFormat(virBuffer *buf,
 
     virDomainDiskDefFormatIotune(&childBuf, def);
 
+    virDomainDiskDefFormatThrottleFilters(&childBuf, def);
+
     if (def->src->readonly)
         virBufferAddLit(&childBuf, "<readonly/>\n");
     if (def->src->shared)

src/conf/domain_conf.h

@@ -520,6 +520,15 @@ void virDomainIothreadMappingDefFree(virDomainIothreadMappingDef *def);
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(virDomainIothreadMappingDef, virDomainIothreadMappingDefFree);
 
 
+/* Stores information related to a ThrottleFilter resource. */
+struct _virDomainThrottleFilterDef {
+    char *group_name;
+    char *nodename;  /* node name of throttle filter object */
+    /* node name is a qemu driver implementation
+       detail and not a configuration field */
+};
+
+
 /* Stores the virtual disk configuration */
 struct _virDomainDiskDef {
     virStorageSource *src; /* non-NULL.  XXX Allow NULL for empty cdrom? */
@@ -552,6 +561,9 @@ struct _virDomainDiskDef {
 
     virDomainBlockIoTuneInfo blkdeviotune;
 
+    size_t nthrottlefilters;
+    virDomainThrottleFilterDef **throttlefilters;
+
     char *driverName;
 
     char *serial;
@@ -4663,3 +4675,11 @@ virDomainThrottleGroupByName(const virDomainDef *def,
 void
 virDomainThrottleGroupDefCopy(const virDomainThrottleGroupDef *src,
                               virDomainThrottleGroupDef *dst);
+
+void
+virDomainThrottleFilterDefFree(virDomainThrottleFilterDef *def);
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(virDomainThrottleFilterDef, virDomainThrottleFilterDefFree);
+
+virDomainThrottleFilterDef *
+virDomainThrottleFilterFind(const virDomainDiskDef *def,
+                            const char *name);

src/conf/virconftypes.h

@@ -82,6 +82,8 @@ typedef struct _virDomainBlockIoTuneInfo virDomainBlockIoTuneInfo;
 
 typedef struct _virDomainBlockIoTuneInfo  virDomainThrottleGroupDef;
 
+typedef struct _virDomainThrottleFilterDef  virDomainThrottleFilterDef;
+
 typedef struct _virDomainCheckpointDef virDomainCheckpointDef;
 
 typedef struct _virDomainCheckpointObj virDomainCheckpointObj;

src/libvirt_private.syms

@@ -682,6 +682,8 @@ virDomainTaintMessageTypeFromString;
 virDomainTaintMessageTypeToString;
 virDomainTaintTypeFromString;
 virDomainTaintTypeToString;
+virDomainThrottleFilterDefFree;
+virDomainThrottleFilterFind;
 virDomainThrottleGroupAdd;
 virDomainThrottleGroupByName;
 virDomainThrottleGroupDefCopy;