[libvirt] [PATCH 3/3] qemu: stats: Display the block threshold size in bulk stats

[Peter Krempa]

Management tools may want to check whether the threshold is still set if
they missed an event. Add the data to the bulk stats API where they can
also query the current backing size at the same time.
---
 src/libvirt-domain.c   |  4 ++++
 src/qemu/qemu_driver.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++---
 tools/virsh.pod        |  3 +++
 3 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
index fd367bcb0..815cbb1e1 100644
--- a/src/libvirt-domain.c
+++ b/src/libvirt-domain.c
@@ -11206,6 +11206,10 @@ virConnectGetDomainCapabilities(virConnectPtr conn,
  *                              backing image as unsigned long long.
  *     "block.<num>.physical" - physical size in bytes of the container of the
  *                              backing image as unsigned long long.
+ *     "block.<num>.threshold.storage - current threshold for delivering the
+ *                                      VIR_DOMAIN_EVENT_ID_BLOCK_THRESHOLD
+ *                                      event in bytes.
+ *                                      See virDomainSetBlockThreshold.
  *
  * VIR_DOMAIN_STATS_PERF:
  *     Return perf event statistics.
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 22cf866cd..a541b671d 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -19186,6 +19186,32 @@ qemuDomainGetStatsOneBlockFallback(virQEMUDriverPtr driver,


 static int
+qemuDomainGetStatsOneBlockNode(virDomainStatsRecordPtr record,
+                               int *maxparams,
+                               virStorageSourcePtr src,
+                               size_t block_idx,
+                               virHashTablePtr nodedata)
+{
+    virJSONValuePtr data;
+    unsigned long long tmp;
+    int ret = -1;
+
+    if (src->nodebacking &&
+        (data = virHashLookup(nodedata, src->nodebacking))) {
+        if (virJSONValueObjectGetNumberUlong(data, "write_threshold", &tmp) == 0 &&
+            tmp > 0)
+            QEMU_ADD_BLOCK_PARAM_ULL(record, maxparams, block_idx,
+                                     "threshold.storage", tmp);
+    }
+
+    ret = 0;
+
+ cleanup:
+    return ret;
+}
+
+
+static int
 qemuDomainGetStatsOneBlock(virQEMUDriverPtr driver,
                            virQEMUDriverConfigPtr cfg,
                            virDomainObjPtr dom,
@@ -19195,7 +19221,8 @@ qemuDomainGetStatsOneBlock(virQEMUDriverPtr driver,
                            virStorageSourcePtr src,
                            size_t block_idx,
                            unsigned int backing_idx,
-                           virHashTablePtr stats)
+                           virHashTablePtr stats,
+                           virHashTablePtr nodedata)
 {
     qemuBlockStats *entry;
     int ret = -1;
@@ -19264,6 +19291,10 @@ qemuDomainGetStatsOneBlock(virQEMUDriverPtr driver,
         }
     }

+    if (qemuDomainGetStatsOneBlockNode(record, maxparams, src, block_idx,
+                                       nodedata) < 0)
+        goto cleanup;
+
     ret = 0;
  cleanup:
     VIR_FREE(alias);
@@ -19282,8 +19313,12 @@ qemuDomainGetStatsBlock(virQEMUDriverPtr driver,
     int ret = -1;
     int rc;
     virHashTablePtr stats = NULL;
+    virHashTablePtr nodestats = NULL;
+    virJSONValuePtr nodedata = NULL;
     qemuDomainObjPrivatePtr priv = dom->privateData;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
+    bool fetchnodedata = virQEMUCapsGet(priv->qemuCaps,
+                                        QEMU_CAPS_QUERY_NAMED_BLOCK_NODES);
     int count_index = -1;
     size_t visited = 0;
     bool visitBacking = !!(privflags & QEMU_DOMAIN_STATS_BACKING);
@@ -19295,14 +19330,22 @@ qemuDomainGetStatsBlock(virQEMUDriverPtr driver,
         if (rc >= 0)
             ignore_value(qemuMonitorBlockStatsUpdateCapacity(priv->mon, stats,
                                                              visitBacking));
+
+        if (fetchnodedata)
+            nodedata = qemuMonitorQueryNamedBlockNodes(priv->mon);
+
         if (qemuDomainObjExitMonitor(driver, dom) < 0)
             goto cleanup;

         /* failure to retrieve stats is fine at this point */
-        if (rc < 0)
+        if (rc < 0 || (fetchnodedata && !nodedata))
             virResetLastError();
     }

+    if (nodedata &&
+        !(nodestats = qemuBlockGetNodeData(nodedata)))
+        goto cleanup;
+
     /* When listing backing chains, it's easier to fix up the count
      * after the iteration than it is to iterate twice; but we still
      * want count listed first.  */
@@ -19317,7 +19360,7 @@ qemuDomainGetStatsBlock(virQEMUDriverPtr driver,
         while (src && (backing_idx == 0 || visitBacking)) {
             if (qemuDomainGetStatsOneBlock(driver, cfg, dom, record, maxparams,
                                            disk, src, visited, backing_idx,
-                                           stats) < 0)
+                                           stats, nodestats) < 0)
                 goto cleanup;
             visited++;
             backing_idx++;
@@ -19330,6 +19373,8 @@ qemuDomainGetStatsBlock(virQEMUDriverPtr driver,

  cleanup:
     virHashFree(stats);
+    virHashFree(nodestats);
+    virJSONValueFree(nodedata);
     virObjectUnref(cfg);
     return ret;
 }
diff --git a/tools/virsh.pod b/tools/virsh.pod
index 48be19234..c2a70f07f 100644
--- a/tools/virsh.pod
+++ b/tools/virsh.pod
@@ -1005,6 +1005,9 @@ Information listed includes:
  "block.<num>.allocation" - offset of highest written sector in bytes
  "block.<num>.capacity" - logical size of source file in bytes
  "block.<num>.physical" - physical size of source file in bytes
+ "block.<num>.threshold.storage" - threshold (in bytes) for delivering the
+                                   VIR_DOMAIN_EVENT_ID_BLOCK_THRESHOLD event
+                                   See domblkthreshold.

 Selecting a specific statistics groups doesn't guarantee that the
 daemon supports the selected group of stats. Flag I<--enforce>
-- 
2.12.0