qemu: block: Don't query monitor in qemuBlockStorageSourceCreateDetectSize

Calling the monitor was convenient for the implementation in
qemuDomainBlockCopyCommon, but causes the snapshot code to call
query-named-block-nodes for every disk.

Fix this by removing the monitor call from
qemuBlockStorageSourceCreateDetectSize so that the data can be reused in
loops.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
ACKed-by: NEric Blake <eblake@redhat.com>

src/qemu/qemu_block.c

@@ -2566,10 +2566,9 @@ qemuBlockStorageSourceCreate(virDomainObjPtr vm,
 
 /**
  * qemuBlockStorageSourceCreateDetectSize:
- * @vm: domain object
+ * @blockNamedNodeData: hash table filled with qemuBlockNamedNodeData
  * @src: storage source to update size/capacity on
  * @templ: storage source template
- * @asyncJob: qemu asynchronous job type
  *
  * When creating a storage source via blockdev-create we need to know the size
  * and capacity of the original volume (e.g. when creating a snapshot or copy).
@@ -2577,28 +2576,13 @@ qemuBlockStorageSourceCreate(virDomainObjPtr vm,
  * to the detected sizes from @templ.
  */
 int
-qemuBlockStorageSourceCreateDetectSize(virDomainObjPtr vm,
+qemuBlockStorageSourceCreateDetectSize(virHashTablePtr blockNamedNodeData,
                                        virStorageSourcePtr src,
-                                       virStorageSourcePtr templ,
-                                       qemuDomainAsyncJob asyncJob)
+                                       virStorageSourcePtr templ)
 {
-    qemuDomainObjPrivatePtr priv = vm->privateData;
-    g_autoptr(virHashTable) stats = NULL;
-    qemuBlockStatsPtr entry;
-    int rc;
-
-    if (!(stats = virHashCreate(10, virHashValueFree)))
-        return -1;
-
-    if (qemuDomainObjEnterMonitorAsync(priv->driver, vm, asyncJob) < 0)
-        return -1;
-
-    rc = qemuMonitorBlockStatsUpdateCapacityBlockdev(priv->mon, stats);
-
-    if (qemuDomainObjExitMonitor(priv->driver, vm) < 0 || rc < 0)
-        return -1;
+    qemuBlockNamedNodeDataPtr entry;
 
-    if (!(entry = virHashLookup(stats, templ->nodeformat))) {
+    if (!(entry = virHashLookup(blockNamedNodeData, templ->nodeformat))) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
                        _("failed to update capacity data for block node '%s'"),
                        templ->nodeformat);

src/qemu/qemu_block.h

@@ -194,7 +194,6 @@ qemuBlockStorageSourceCreate(virDomainObjPtr vm,
                              qemuDomainAsyncJob asyncJob);
 
 int
-qemuBlockStorageSourceCreateDetectSize(virDomainObjPtr vm,
+qemuBlockStorageSourceCreateDetectSize(virHashTablePtr blockNamedNodeData,
                                        virStorageSourcePtr src,
-                                       virStorageSourcePtr templ,
-                                       qemuDomainAsyncJob asyncJob);
+                                       virStorageSourcePtr templ);

src/qemu/qemu_driver.c

@@ -15246,6 +15246,7 @@ qemuDomainSnapshotDiskPrepareOne(virQEMUDriverPtr driver,
                                  virDomainDiskDefPtr disk,
                                  virDomainSnapshotDiskDefPtr snapdisk,
                                  qemuDomainSnapshotDiskDataPtr dd,
+                                 virHashTablePtr blockNamedNodeData,
                                  bool reuse,
                                  bool blockdev,
                                  qemuDomainAsyncJob asyncJob)
@@ -15349,8 +15350,8 @@ qemuDomainSnapshotDiskPrepareOne(virQEMUDriverPtr driver,
             if (qemuDomainObjExitMonitor(driver, vm) < 0 || rc < 0)
                 return -1;
         } else {
-            if (qemuBlockStorageSourceCreateDetectSize(vm, dd->src, dd->disk->src,
-                                                       asyncJob) < 0)
+            if (qemuBlockStorageSourceCreateDetectSize(blockNamedNodeData,
+                                                       dd->src, dd->disk->src) < 0)
                 return -1;
 
             if (qemuBlockStorageSourceCreate(vm, dd->src, dd->disk->src,
@@ -15379,6 +15380,7 @@ qemuDomainSnapshotDiskPrepare(virQEMUDriverPtr driver,
                               virQEMUDriverConfigPtr cfg,
                               bool reuse,
                               bool blockdev,
+                              virHashTablePtr blockNamedNodeData,
                               qemuDomainAsyncJob asyncJob,
                               qemuDomainSnapshotDiskDataPtr *rdata,
                               size_t *rndata)
@@ -15398,7 +15400,9 @@ qemuDomainSnapshotDiskPrepare(virQEMUDriverPtr driver,
 
         if (qemuDomainSnapshotDiskPrepareOne(driver, vm, cfg, vm->def->disks[i],
                                              snapdef->disks + i,
-                                             data + ndata++, reuse, blockdev,
+                                             data + ndata++,
+                                             blockNamedNodeData,
+                                             reuse, blockdev,
                                              asyncJob) < 0)
             goto cleanup;
     }
@@ -15489,6 +15493,7 @@ qemuDomainSnapshotCreateDiskActive(virQEMUDriverPtr driver,
     qemuDomainSnapshotDiskDataPtr diskdata = NULL;
     size_t ndiskdata = 0;
     bool blockdev =  virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV);
+    g_autoptr(virHashTable) blockNamedNodeData = NULL;
 
     if (virDomainObjCheckActive(vm) < 0)
         return -1;
@@ -15496,10 +15501,21 @@ qemuDomainSnapshotCreateDiskActive(virQEMUDriverPtr driver,
     if (!(actions = virJSONValueNewArray()))
         return -1;
 
+    if (blockdev) {
+        if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
+            return -1;
+
+        blockNamedNodeData = qemuMonitorBlockGetNamedNodeData(priv->mon);
+
+        if (qemuDomainObjExitMonitor(driver, vm) < 0 || !blockNamedNodeData)
+            return -1;
+    }
+
     /* prepare a list of objects to use in the vm definition so that we don't
      * have to roll back later */
     if (qemuDomainSnapshotDiskPrepare(driver, vm, snap, cfg, reuse, blockdev,
-                                      asyncJob, &diskdata, &ndiskdata) < 0)
+                                      blockNamedNodeData, asyncJob,
+                                      &diskdata, &ndiskdata) < 0)
         goto cleanup;
 
     /* check whether there's anything to do */
@@ -18008,6 +18024,7 @@ qemuDomainBlockCopyCommon(virDomainObjPtr vm,
     g_autoptr(qemuBlockStorageSourceChainData) crdata = NULL;
     virStorageSourcePtr n;
     virStorageSourcePtr mirrorBacking = NULL;
+    g_autoptr(virHashTable) blockNamedNodeData = NULL;
     int rc = 0;
 
     /* Preliminaries: find the disk we are editing, sanity checks */
@@ -18169,7 +18186,13 @@ qemuDomainBlockCopyCommon(virDomainObjPtr vm,
                                                                           priv->qemuCaps)))
                 goto endjob;
         } else {
-            if (qemuBlockStorageSourceCreateDetectSize(vm, mirror, disk->src, QEMU_ASYNC_JOB_NONE) < 0)
+            qemuDomainObjEnterMonitor(driver, vm);
+            blockNamedNodeData = qemuMonitorBlockGetNamedNodeData(priv->mon);
+            if (qemuDomainObjExitMonitor(driver, vm) < 0 || !blockNamedNodeData)
+                goto endjob;
+
+            if (qemuBlockStorageSourceCreateDetectSize(blockNamedNodeData,
+                                                       mirror, disk->src))
                 goto endjob;
 
             if (mirror_shallow) {