vircgroup: introduce virCgroupV2GetBlkioIoServiced

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>

src/util/vircgroupv2.c

@@ -566,6 +566,70 @@ virCgroupV2GetBlkioWeight(virCgroupPtr group,
 }
 
 
+static int
+virCgroupV2GetBlkioIoServiced(virCgroupPtr group,
+                              long long *bytes_read,
+                              long long *bytes_write,
+                              long long *requests_read,
+                              long long *requests_write)
+{
+    long long stats_val;
+    VIR_AUTOFREE(char *) str1 = NULL;
+    char *p1;
+    size_t i;
+
+    const char *value_names[] = {
+        "rbytes=",
+        "wbytes=",
+        "rios=",
+        "wios=",
+    };
+    long long *value_ptrs[] = {
+        bytes_read,
+        bytes_write,
+        requests_read,
+        requests_write
+    };
+
+    *bytes_read = 0;
+    *bytes_write = 0;
+    *requests_read = 0;
+    *requests_write = 0;
+
+    if (virCgroupGetValueStr(group,
+                             VIR_CGROUP_CONTROLLER_BLKIO,
+                             "io.stat", &str1) < 0) {
+        return -1;
+    }
+
+    /* sum up all entries of the same kind, from all devices */
+    for (i = 0; i < ARRAY_CARDINALITY(value_names); i++) {
+        p1 = str1;
+
+        while ((p1 = strstr(p1, value_names[i]))) {
+            p1 += strlen(value_names[i]);
+            if (virStrToLong_ll(p1, &p1, 10, &stats_val) < 0) {
+                virReportError(VIR_ERR_INTERNAL_ERROR,
+                               _("Cannot parse byte '%s' stat '%s'"),
+                               value_names[i], p1);
+                return -1;
+            }
+
+            if (stats_val < 0 ||
+                (stats_val > 0 && *value_ptrs[i] > (LLONG_MAX - stats_val))) {
+                virReportError(VIR_ERR_OVERFLOW,
+                               _("Sum of byte '%s' stat overflows"),
+                               value_names[i]);
+                return -1;
+            }
+            *value_ptrs[i] += stats_val;
+        }
+    }
+
+    return 0;
+}
+
+
 virCgroupBackend virCgroupV2Backend = {
     .type = VIR_CGROUP_BACKEND_TYPE_V2,
 
@@ -590,6 +654,7 @@ virCgroupBackend virCgroupV2Backend = {
 
     .setBlkioWeight = virCgroupV2SetBlkioWeight,
     .getBlkioWeight = virCgroupV2GetBlkioWeight,
+    .getBlkioIoServiced = virCgroupV2GetBlkioIoServiced,
 };