latency: Update virsh command domblkstat to use new API

The modified function fallbacks to use virDomainBlockStats if
virDomainBlockStatsFlags is not supported by the hypervisor driver.
If the new API is supported, it will be invoked instead of the
old API.

tools/virsh.c

@@ -1070,6 +1070,9 @@ cmdDomblkstat (vshControl *ctl, const vshCmd *cmd)
     virDomainPtr dom;
     const char *name = NULL, *device = NULL;
     struct _virDomainBlockStats stats;
+    virTypedParameterPtr params = NULL;
+    int rc, nparams = 0;
+    bool ret = false;
 
     if (!vshConnectionUsability (ctl, ctl->conn))
         return false;
@@ -1077,34 +1080,95 @@ cmdDomblkstat (vshControl *ctl, const vshCmd *cmd)
     if (!(dom = vshCommandOptDomain (ctl, cmd, &name)))
         return false;
 
-    if (vshCommandOptString (cmd, "device", &device) <= 0) {
-        virDomainFree(dom);
-        return false;
-    }
+    if (vshCommandOptString (cmd, "device", &device) <= 0)
+        goto cleanup;
 
-    if (virDomainBlockStats (dom, device, &stats, sizeof stats) == -1) {
-        vshError(ctl, _("Failed to get block stats %s %s"), name, device);
-        virDomainFree(dom);
-        return false;
-    }
+    rc = virDomainBlockStatsFlags(dom, device, NULL, &nparams, 0);
 
-    if (stats.rd_req >= 0)
-        vshPrint (ctl, "%s rd_req %lld\n", device, stats.rd_req);
+    /* It might fail when virDomainBlockStatsFlags is not
+     * supported on older libvirt, fallback to use virDomainBlockStats
+     * then.
+     */
+    if (rc < 0) {
+        if (last_error->code != VIR_ERR_NO_SUPPORT) {
+            virshReportError(ctl);
+            goto cleanup;
+        } else {
+            virFreeError(last_error);
+            last_error = NULL;
 
-    if (stats.rd_bytes >= 0)
-        vshPrint (ctl, "%s rd_bytes %lld\n", device, stats.rd_bytes);
+            if (virDomainBlockStats (dom, device, &stats,
+                                     sizeof stats) == -1) {
+                vshError(ctl, _("Failed to get block stats %s %s"),
+                         name, device);
+                goto cleanup;
+            }
+
+            if (stats.rd_req >= 0)
+                vshPrint (ctl, "%s rd_req %lld\n", device, stats.rd_req);
 
-    if (stats.wr_req >= 0)
-        vshPrint (ctl, "%s wr_req %lld\n", device, stats.wr_req);
+            if (stats.rd_bytes >= 0)
+                vshPrint (ctl, "%s rd_bytes %lld\n", device, stats.rd_bytes);
 
-    if (stats.wr_bytes >= 0)
-        vshPrint (ctl, "%s wr_bytes %lld\n", device, stats.wr_bytes);
+            if (stats.wr_req >= 0)
+                vshPrint (ctl, "%s wr_req %lld\n", device, stats.wr_req);
 
-    if (stats.errs >= 0)
-        vshPrint (ctl, "%s errs %lld\n", device, stats.errs);
+            if (stats.wr_bytes >= 0)
+                vshPrint (ctl, "%s wr_bytes %lld\n", device, stats.wr_bytes);
 
+            if (stats.errs >= 0)
+                vshPrint (ctl, "%s errs %lld\n", device, stats.errs);
+        }
+    } else {
+        params = vshMalloc(ctl, sizeof(*params) * nparams);
+        memset(params, 0, sizeof(*params) * nparams);
+
+        if (virDomainBlockStatsFlags (dom, device, params, &nparams, 0) < 0) {
+            vshError(ctl, _("Failed to get block stats %s %s"), name, device);
+            goto cleanup;
+        }
+
+        int i;
+        /* XXX: The output sequence will be different. */
+        for (i = 0; i < nparams; i++) {
+            switch(params[i].type) {
+            case VIR_TYPED_PARAM_INT:
+                vshPrint (ctl, "%s %s %d\n", device,
+                          params[i].field, params[i].value.i);
+                break;
+            case VIR_TYPED_PARAM_UINT:
+                vshPrint (ctl, "%s %s %u\n", device,
+                          params[i].field, params[i].value.ui);
+                break;
+            case VIR_TYPED_PARAM_LLONG:
+                vshPrint (ctl, "%s %s %lld\n", device,
+                          params[i].field, params[i].value.l);
+                break;
+            case VIR_TYPED_PARAM_ULLONG:
+                vshPrint (ctl, "%s %s %llu\n", device,
+                          params[i].field, params[i].value.ul);
+                break;
+            case VIR_TYPED_PARAM_DOUBLE:
+                vshPrint (ctl, "%s %s %f\n", device,
+                          params[i].field, params[i].value.d);
+                break;
+            case VIR_TYPED_PARAM_BOOLEAN:
+                vshPrint (ctl, "%s %s %s\n", device,
+                          params[i].field, params[i].value.b ? _("yes") : _("no"));
+                break;
+            default:
+                vshError(ctl, _("unimplemented block statistics parameter type"));
+            }
+
+        }
+    }
+
+    ret = true;
+
+cleanup:
+    VIR_FREE(params);
     virDomainFree(dom);
-    return true;
+    return ret;
 }
 
 /* "domifstat" command