qemu: hotplug: Allow specifying explicit source for disk backend hotplug code

Since the code is also used when changing media we need to allow
specifying explicit source for which we are going to prepare. With this
change callers don't have to replace disk->src with the new source
definition for generating these.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

src/qemu/qemu_hotplug.c

@@ -458,6 +458,7 @@ qemuHotplugRemoveStorageSourcePrepareData(virStorageSourcePtr src,
 
 static qemuHotplugDiskSourceDataPtr
 qemuHotplugDiskSourceRemovePrepare(virDomainDiskDefPtr disk,
+                                   virStorageSourcePtr src,
                                    virQEMUCapsPtr qemuCaps)
 {
     qemuDomainDiskPrivatePtr diskPriv = QEMU_DOMAIN_DISK_PRIVATE(disk);
@@ -474,7 +475,7 @@ qemuHotplugDiskSourceRemovePrepare(virDomainDiskDefPtr disk,
         if (VIR_STRDUP(data->corAlias, diskPriv->nodeCopyOnRead) < 0)
             goto cleanup;
 
-        for (n = disk->src; virStorageSourceIsBacking(n); n = n->backingStore) {
+        for (n = src; virStorageSourceIsBacking(n); n = n->backingStore) {
             if (!(backend = qemuHotplugRemoveStorageSourcePrepareData(n, NULL)))
                 goto cleanup;
 
@@ -485,7 +486,7 @@ qemuHotplugDiskSourceRemovePrepare(virDomainDiskDefPtr disk,
         if (!(drivealias = qemuAliasDiskDriveFromDisk(disk)))
             goto cleanup;
 
-        if (!(backend = qemuHotplugRemoveStorageSourcePrepareData(disk->src,
+        if (!(backend = qemuHotplugRemoveStorageSourcePrepareData(src,
                                                                   drivealias)))
             goto cleanup;
 
@@ -505,6 +506,7 @@ qemuHotplugDiskSourceRemovePrepare(virDomainDiskDefPtr disk,
 /**
  * qemuHotplugDiskSourceAttachPrepare:
  * @disk: disk to generate attachment data for
+ * @src: disk source to prepare attachment
  * @qemuCaps: capabilities of the qemu process
  *
  * Prepares and returns qemuHotplugDiskSourceData structure filled with all data
@@ -512,11 +514,13 @@ qemuHotplugDiskSourceRemovePrepare(virDomainDiskDefPtr disk,
  */
 static qemuHotplugDiskSourceDataPtr
 qemuHotplugDiskSourceAttachPrepare(virDomainDiskDefPtr disk,
+                                   virStorageSourcePtr src,
                                    virQEMUCapsPtr qemuCaps)
 {
     qemuBlockStorageSourceAttachDataPtr backend = NULL;
     qemuHotplugDiskSourceDataPtr data;
     qemuHotplugDiskSourceDataPtr ret = NULL;
+    virStorageSourcePtr savesrc = NULL;
     virStorageSourcePtr n;
 
     if (VIR_ALLOC(data) < 0)
@@ -527,7 +531,7 @@ qemuHotplugDiskSourceAttachPrepare(virDomainDiskDefPtr disk,
             !(data->corProps = qemuBlockStorageGetCopyOnReadProps(disk)))
             goto cleanup;
 
-        for (n = disk->src; virStorageSourceIsBacking(n); n = n->backingStore) {
+        for (n = src; virStorageSourceIsBacking(n); n = n->backingStore) {
             if (!(backend = qemuBlockStorageSourceAttachPrepareBlockdev(n)))
                 goto cleanup;
 
@@ -538,10 +542,15 @@ qemuHotplugDiskSourceAttachPrepare(virDomainDiskDefPtr disk,
                 goto cleanup;
         }
     } else {
+        VIR_STEAL_PTR(savesrc, disk->src);
+        disk->src = src;
+
         if (!(backend = qemuBuildStorageSourceAttachPrepareDrive(disk, qemuCaps)))
             goto cleanup;
 
-        if (qemuBuildStorageSourceAttachPrepareCommon(disk->src, backend, qemuCaps) < 0)
+        VIR_STEAL_PTR(disk->src, savesrc);
+
+        if (qemuBuildStorageSourceAttachPrepareCommon(src, backend, qemuCaps) < 0)
             goto cleanup;
 
         if (VIR_APPEND_ELEMENT(data->backends, data->nbackends, backend) < 0)
@@ -551,6 +560,9 @@ qemuHotplugDiskSourceAttachPrepare(virDomainDiskDefPtr disk,
     VIR_STEAL_PTR(ret, data);
 
  cleanup:
+    if (savesrc)
+        VIR_STEAL_PTR(disk->src, savesrc);
+
     qemuBlockStorageSourceAttachDataFree(backend);
     qemuHotplugDiskSourceDataFree(data);
     return ret;
@@ -640,12 +652,13 @@ qemuDomainChangeMediaBlockdev(virQEMUDriverPtr driver,
     int ret = -1;
 
     if (!virStorageSourceIsEmpty(disk->src) &&
-        !(oldbackend = qemuHotplugDiskSourceRemovePrepare(disk, priv->qemuCaps)))
+        !(oldbackend = qemuHotplugDiskSourceRemovePrepare(disk, disk->src,
+                                                          priv->qemuCaps)))
         goto cleanup;
 
     disk->src = newsrc;
     if (!virStorageSourceIsEmpty(disk->src)) {
-        if (!(newbackend = qemuHotplugDiskSourceAttachPrepare(disk,
+        if (!(newbackend = qemuHotplugDiskSourceAttachPrepare(disk, disk->src,
                                                               priv->qemuCaps)))
             goto cleanup;
 
@@ -782,7 +795,8 @@ qemuDomainAttachDiskGeneric(virQEMUDriverPtr driver,
     if (qemuDomainPrepareDiskSource(disk, priv, cfg) < 0)
         goto error;
 
-    if (!(diskdata = qemuHotplugDiskSourceAttachPrepare(disk, priv->qemuCaps)))
+    if (!(diskdata = qemuHotplugDiskSourceAttachPrepare(disk, disk->src,
+                                                        priv->qemuCaps)))
         goto error;
 
     if (!(devstr = qemuBuildDiskDeviceStr(vm->def, disk, 0, priv->qemuCaps)))
@@ -4159,7 +4173,8 @@ qemuDomainRemoveDiskDevice(virQEMUDriverPtr driver,
     VIR_DEBUG("Removing disk %s from domain %p %s",
               disk->info.alias, vm, vm->def->name);
 
-    if (!(diskbackend = qemuHotplugDiskSourceRemovePrepare(disk, priv->qemuCaps)))
+    if (!(diskbackend = qemuHotplugDiskSourceRemovePrepare(disk, disk->src,
+                                                           priv->qemuCaps)))
         return -1;
 
     for (i = 0; i < vm->def->ndisks; i++) {