qemu: monitor: Open-code retrieval of wr_highest_offset

Instead of using qemuMonitorJSONDevGetBlockExtent (which I plan to
remove later) extract the data in place.

Additionally add a flag that will be set when the wr_highest_offset was
extracted correctly so that callers can act according to that.

The test case addition should help make sure that everything works.

src/qemu/qemu_monitor.h

@@ -378,7 +378,11 @@ struct _qemuBlockStats {
     long long flush_total_times;
     unsigned long long capacity;
     unsigned long long physical;
+
+    /* value of wr_highest_offset is valid if it's non 0 or
+     * if wr_highest_offset_valid is true */
     unsigned long long wr_highest_offset;
+    bool wr_highest_offset_valid;
 };
 
 int qemuMonitorGetAllBlockStatsInfo(qemuMonitorPtr mon,

src/qemu/qemu_monitor_json.c

@@ -1699,6 +1699,8 @@ qemuMonitorJSONGetOneBlockStatsInfo(virJSONValuePtr dev,
 {
     qemuBlockStatsPtr bstats = NULL;
     virJSONValuePtr stats;
+    virJSONValuePtr parent;
+    virJSONValuePtr parentstats;
     int ret = -1;
     int nstats = 0;
     char *entry_name = qemuDomainStorageAlias(dev_name, depth);
@@ -1735,8 +1737,12 @@ qemuMonitorJSONGetOneBlockStatsInfo(virJSONValuePtr dev,
     QEMU_MONITOR_BLOCK_STAT_GET("flush_total_time_ns", bstats->flush_total_times, false);
 #undef QEMU_MONITOR_BLOCK_STAT_GET
 
-    /* it's ok to not have this information here. Just skip silently. */
-    qemuMonitorJSONDevGetBlockExtent(dev, &bstats->wr_highest_offset);
+    if ((parent = virJSONValueObjectGetObject(dev, "parent")) &&
+        (parentstats = virJSONValueObjectGetObject(parent, "stats"))) {
+        if (virJSONValueObjectGetNumberUlong(parentstats, "wr_highest_offset",
+                                             &bstats->wr_highest_offset) == 0)
+            bstats->wr_highest_offset_valid = true;
+    }
 
     if (virHashAddEntry(hash, entry_name, bstats) < 0)
         goto cleanup;

tests/qemumonitorjsontest.c

@@ -1538,16 +1538,20 @@ testQemuMonitorJSONqemuMonitorJSONGetBlockStatsInfo(const void *data)
         qemuMonitorTestAddItem(test, "query-blockstats", reply) < 0)
         goto cleanup;
 
-#define CHECK0(var, value) \
+#define CHECK0FULL(var, value, varformat, valformat) \
     if (stats->var != value) { \
         virReportError(VIR_ERR_INTERNAL_ERROR, \
-                       "Invalid " #var " value: %lld, expected %d", \
+                       "Invalid " #var " value: " varformat \
+                       ", expected " valformat, \
                        stats->var, value); \
         goto cleanup; \
     }
 
+#define CHECK0(var, value) CHECK0FULL(var, value, "%lld", "%d")
+
 #define CHECK(NAME, RD_REQ, RD_BYTES, RD_TOTAL_TIMES, WR_REQ, WR_BYTES,        \
-              WR_TOTAL_TIMES, FLUSH_REQ, FLUSH_TOTAL_TIMES)                    \
+              WR_TOTAL_TIMES, FLUSH_REQ, FLUSH_TOTAL_TIMES,                    \
+              WR_HIGHEST_OFFSET, WR_HIGHEST_OFFSET_VALID)                      \
     if (!(stats = virHashLookup(blockstats, NAME))) {                          \
         virReportError(VIR_ERR_INTERNAL_ERROR,                                 \
                        "block stats for device '%s' is missing", NAME);        \
@@ -1560,7 +1564,9 @@ testQemuMonitorJSONqemuMonitorJSONGetBlockStatsInfo(const void *data)
     CHECK0(wr_bytes, WR_BYTES) \
     CHECK0(wr_total_times, WR_TOTAL_TIMES) \
     CHECK0(flush_req, FLUSH_REQ) \
-    CHECK0(flush_total_times, FLUSH_TOTAL_TIMES)
+    CHECK0(flush_total_times, FLUSH_TOTAL_TIMES) \
+    CHECK0FULL(wr_highest_offset, WR_HIGHEST_OFFSET, "%llu", "%llu") \
+    CHECK0FULL(wr_highest_offset_valid, WR_HIGHEST_OFFSET_VALID, "%d", "%d")
 
     if (qemuMonitorGetAllBlockStatsInfo(qemuMonitorTestGetMonitor(test),
                                         &blockstats, false) < 0)
@@ -1572,9 +1578,9 @@ testQemuMonitorJSONqemuMonitorJSONGetBlockStatsInfo(const void *data)
         goto cleanup;
     }
 
-    CHECK("virtio-disk0", 1279, 28505088, 640616474, 174, 2845696, 530699221, 0, 0)
-    CHECK("virtio-disk1", 85, 348160, 8232156, 0, 0, 0, 0, 0)
-    CHECK("ide0-1-0", 16, 49250, 1004952, 0, 0, 0, 0, 0)
+    CHECK("virtio-disk0", 1279, 28505088, 640616474, 174, 2845696, 530699221, 0, 0, 5256018944ULL, true)
+    CHECK("virtio-disk1", 85, 348160, 8232156, 0, 0, 0, 0, 0, 0ULL, true)
+    CHECK("ide0-1-0", 16, 49250, 1004952, 0, 0, 0, 0, 0, 0ULL, true)
 
     if (qemuMonitorJSONGetBlockExtent(qemuMonitorTestGetMonitor(test), "virtio-disk0",
                                       &extent) < 0)
@@ -1613,6 +1619,7 @@ testQemuMonitorJSONqemuMonitorJSONGetBlockStatsInfo(const void *data)
 
 #undef CHECK
 #undef CHECK0
+#undef CHECK0FULL
 
  cleanup:
     qemuMonitorTestFree(test);

tests/qemumonitortest.c

@@ -93,12 +93,14 @@ struct blockInfoData {
 
 static const struct blockInfoData testBlockInfoData[] =
 {
-/* NAME, rd_req, rd_bytes, wr_req, wr_bytes, rd_total_time, wr_total_time, flush_req, flush_total_time */
-    {"vda", {11, 12, 13, 14, 15, 16, 17, 18, 0, 0, 0}},
-    {"vdb", {21, 22, 23, 24, 25, 26, 27, 28, 0, 0, 0}},
-    {"vdc", {31, 32, 33, -1, 35, 36, 37, 38, 0, 0, 0}},
-    {"vdd", {-1, -1, -1, -1, -1, -1, -1, -1, 0, 0, 0}},
-    {"vde", {41, 42, 43, 44, 45, 46, 47, 48, 0, 0, 0}}
+/* NAME, rd_req, rd_bytes, wr_req, wr_bytes, rd_total_time, wr_total_time,
+ * flush_req, flush_total_time, capacity, physical, wr_highest_offset,
+ * wr_highest_offset_valid*/
+    {"vda", {11, 12, 13, 14, 15, 16, 17, 18, 0, 0, 0, false}},
+    {"vdb", {21, 22, 23, 24, 25, 26, 27, 28, 0, 0, 0, false}},
+    {"vdc", {31, 32, 33, -1, 35, 36, 37, 38, 0, 0, 0, false}},
+    {"vdd", {-1, -1, -1, -1, -1, -1, -1, -1, 0, 0, 0, false}},
+    {"vde", {41, 42, 43, 44, 45, 46, 47, 48, 0, 0, 0, false}}
 };
 
 static const char testBlockInfoReply[] =