[libvirt] [PATCH RFC 34/39] qemu: monitor: Add APIs for refreshing disk capacity when using -blockdev

[Peter Krempa]

Disk image size data are not contained in the reply of query-blockstats
but need to be gathered from query-block. For use with -blockdev we
really need to call 'query-named-block-nodes' and process it to retrieve
the correct data.

This patch introduces qemuMonitorBlockStatsUpdateCapacityBlockdev which
updates the capacity data by nodename rather than device name.

Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
 src/qemu/qemu_monitor.c      | 11 +++++++++++
 src/qemu/qemu_monitor.h      |  4 ++++
 src/qemu/qemu_monitor_json.c | 46 ++++++++++++++++++++++++++++++++++++++++++++
 src/qemu/qemu_monitor_json.h |  2 ++
 4 files changed, 63 insertions(+)

diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
index bc9c7d53b0..a69fbb0749 100644
--- a/src/qemu/qemu_monitor.c
+++ b/src/qemu/qemu_monitor.c
@@ -2339,6 +2339,17 @@ qemuMonitorBlockStatsUpdateCapacity(qemuMonitorPtr mon,
 }


+int
+qemuMonitorBlockStatsUpdateCapacityBlockdev(qemuMonitorPtr mon,
+                                            virHashTablePtr stats)
+{
+    VIR_DEBUG("stats=%p", stats);
+
+    QEMU_CHECK_MONITOR(mon);
+
+    return qemuMonitorJSONBlockStatsUpdateCapacityBlockdev(mon, stats);
+}
+
 int
 qemuMonitorBlockResize(qemuMonitorPtr mon,
                        const char *device,
diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h
index 8ede11c82c..d1a8f899d7 100644
--- a/src/qemu/qemu_monitor.h
+++ b/src/qemu/qemu_monitor.h
@@ -603,6 +603,10 @@ int qemuMonitorBlockStatsUpdateCapacity(qemuMonitorPtr mon,
                                         bool backingChain)
     ATTRIBUTE_NONNULL(2);

+int qemuMonitorBlockStatsUpdateCapacityBlockdev(qemuMonitorPtr mon,
+                                            virHashTablePtr stats)
+    ATTRIBUTE_NONNULL(2);
+
 int qemuMonitorBlockResize(qemuMonitorPtr mon,
                            const char *dev_name,
                            unsigned long long size);
diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
index 02a3f09a8b..820e669d16 100644
--- a/src/qemu/qemu_monitor_json.c
+++ b/src/qemu/qemu_monitor_json.c
@@ -2639,6 +2639,52 @@ qemuMonitorJSONBlockStatsUpdateCapacity(qemuMonitorPtr mon,
 }


+static int
+qemuMonitorJSONBlockStatsUpdateCapacityBlockdevWorker(size_t pos ATTRIBUTE_UNUSED,
+                                                      virJSONValuePtr val,
+                                                      void *opaque)
+{
+    virHashTablePtr stats = opaque;
+    virJSONValuePtr image;
+    const char *nodename;
+
+    if (!(nodename = virJSONValueObjectGetString(val, "node-name")) ||
+        !(image = virJSONValueObjectGetObject(val, "image"))) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("query-named-block-nodes entry was not in expected format"));
+        return -1;
+    }
+
+    if (qemuMonitorJSONBlockStatsUpdateCapacityData(image, nodename, stats) < 0)
+        return -1;
+
+    return 1; /* we don't want to steal the value from the JSON array */
+}
+
+
+int
+qemuMonitorJSONBlockStatsUpdateCapacityBlockdev(qemuMonitorPtr mon,
+                                                virHashTablePtr stats)
+{
+    virJSONValuePtr nodes;
+    int ret = -1;
+
+    if (!(nodes = qemuMonitorJSONQueryNamedBlockNodes(mon)))
+        return -1;
+
+    if (virJSONValueArrayForeachSteal(nodes,
+                                      qemuMonitorJSONBlockStatsUpdateCapacityBlockdevWorker,
+                                      stats) < 0)
+        goto cleanup;
+
+    ret = 0;
+
+ cleanup:
+    virJSONValueFree(nodes);
+    return ret;
+}
+
+
 /* Return 0 on success, -1 on failure, or -2 if not supported.  Size
  * is in bytes.  */
 int qemuMonitorJSONBlockResize(qemuMonitorPtr mon,
diff --git a/src/qemu/qemu_monitor_json.h b/src/qemu/qemu_monitor_json.h
index 6042f7161f..ebf4d4e78b 100644
--- a/src/qemu/qemu_monitor_json.h
+++ b/src/qemu/qemu_monitor_json.h
@@ -95,6 +95,8 @@ int qemuMonitorJSONGetAllBlockStatsInfo(qemuMonitorPtr mon,
 int qemuMonitorJSONBlockStatsUpdateCapacity(qemuMonitorPtr mon,
                                             virHashTablePtr stats,
                                             bool backingChain);
+int qemuMonitorJSONBlockStatsUpdateCapacityBlockdev(qemuMonitorPtr mon,
+                                                    virHashTablePtr stats);
 int qemuMonitorJSONGetBlockStatsInfo(qemuMonitorPtr mon,
                                      virHashTablePtr hash,
                                      int *nstats);
-- 
2.16.2