qemu: domain: don't loop through images in qemuDomainPrepareDiskSourceChain

Convert the function to just prepare data for the disk. Callers need to
do the looping since there's more to do than just copy the data around.

The code path in qemuDomainPrepareDiskSource doesn't need to loop over
the chain yet, since there currently is no chain at this point. This
will be addressed later in the blockdev series where we will setup much
more stuff.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

src/qemu/qemu_domain.c

@@ -8034,6 +8034,7 @@ qemuDomainDetermineDiskChain(virQEMUDriverPtr driver,
 {
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
     virStorageSourcePtr src = disk->src;
+    virStorageSourcePtr n;
     qemuDomainObjPrivatePtr priv = vm->privateData;
     int ret = -1;
     uid_t uid;
@@ -8116,9 +8117,10 @@ qemuDomainDetermineDiskChain(virQEMUDriverPtr driver,
                                   report_broken) < 0)
         goto cleanup;
 
-    /* fill in data for the rest of the chain */
-    if (qemuDomainPrepareDiskSourceChain(disk, src, cfg, priv->qemuCaps) < 0)
-        goto cleanup;
+    for (n = src; virStorageSourceIsBacking(n); n = n->backingStore) {
+        if (qemuDomainPrepareDiskSourceData(disk, n, cfg, priv->qemuCaps) < 0)
+            goto cleanup;
+    }
 
     ret = 0;
 
@@ -12399,51 +12401,44 @@ qemuDomainCheckCCWS390AddressSupport(const virDomainDef *def,
 
 
 /**
- * qemuDomainPrepareDiskSourceChain:
+ * qemuDomainPrepareDiskSourceData:
  *
  * @disk: Disk config object
  * @src: source to start from
  * @cfg: qemu driver config object
  *
- * Prepares various aspects of the disk source and it's backing chain. This
- * function should be also called for detected backing chains. If @src is NULL
- * the root source is used.
+ * Prepares various aspects of a storage source belonging to a disk backing
+ * chain. This function should be also called for detected backing chain
+ * members.
  */
 int
-qemuDomainPrepareDiskSourceChain(virDomainDiskDefPtr disk,
-                                 virStorageSourcePtr src,
-                                 virQEMUDriverConfigPtr cfg,
-                                 virQEMUCapsPtr qemuCaps)
+qemuDomainPrepareDiskSourceData(virDomainDiskDefPtr disk,
+                                virStorageSourcePtr src,
+                                virQEMUDriverConfigPtr cfg,
+                                virQEMUCapsPtr qemuCaps)
 {
-    virStorageSourcePtr n;
-
-    if (!src)
-        src = disk->src;
-
     /* transfer properties valid only for the top level image */
     if (src == disk->src)
         src->detect_zeroes = disk->detect_zeroes;
 
-    for (n = src; virStorageSourceIsBacking(n); n = n->backingStore) {
-        if (cfg &&
-            n->type == VIR_STORAGE_TYPE_NETWORK &&
-            n->protocol == VIR_STORAGE_NET_PROTOCOL_GLUSTER &&
-            virQEMUCapsGet(qemuCaps, QEMU_CAPS_GLUSTER_DEBUG_LEVEL)) {
-            n->debug = true;
-            n->debugLevel = cfg->glusterDebugLevel;
-        }
+    if (cfg &&
+        src->type == VIR_STORAGE_TYPE_NETWORK &&
+        src->protocol == VIR_STORAGE_NET_PROTOCOL_GLUSTER &&
+        virQEMUCapsGet(qemuCaps, QEMU_CAPS_GLUSTER_DEBUG_LEVEL)) {
+        src->debug = true;
+        src->debugLevel = cfg->glusterDebugLevel;
+    }
 
-        if (qemuDomainValidateStorageSource(n, qemuCaps) < 0)
-            return -1;
+    if (qemuDomainValidateStorageSource(src, qemuCaps) < 0)
+        return -1;
 
-        /* transfer properties valid for the full chain */
-        n->iomode = disk->iomode;
-        n->cachemode = disk->cachemode;
-        n->discard = disk->discard;
+    /* transfer properties valid for the full chain */
+    src->iomode = disk->iomode;
+    src->cachemode = disk->cachemode;
+    src->discard = disk->discard;
 
-        if (disk->device == VIR_DOMAIN_DISK_DEVICE_FLOPPY)
-            n->floppyimg = true;
-    }
+    if (disk->device == VIR_DOMAIN_DISK_DEVICE_FLOPPY)
+        src->floppyimg = true;
 
     return 0;
 }
@@ -12493,7 +12488,7 @@ qemuDomainPrepareDiskSource(virDomainDiskDefPtr disk,
     if (qemuDomainSecretDiskPrepare(priv, disk) < 0)
         return -1;
 
-    if (qemuDomainPrepareDiskSourceChain(disk, NULL, cfg, priv->qemuCaps) < 0)
+    if (qemuDomainPrepareDiskSourceData(disk, disk->src, cfg, priv->qemuCaps) < 0)
         return -1;
 
     if (qemuDomainPrepareStorageSourcePR(disk->src, priv, disk->info.alias) < 0)

src/qemu/qemu_domain.h

@@ -1003,10 +1003,10 @@ bool qemuDomainCheckCCWS390AddressSupport(const virDomainDef *def,
                                     const char *devicename);
 
 int
-qemuDomainPrepareDiskSourceChain(virDomainDiskDefPtr disk,
-                                 virStorageSourcePtr src,
-                                 virQEMUDriverConfigPtr cfg,
-                                 virQEMUCapsPtr qemuCaps)
+qemuDomainPrepareDiskSourceData(virDomainDiskDefPtr disk,
+                                virStorageSourcePtr src,
+                                virQEMUDriverConfigPtr cfg,
+                                virQEMUCapsPtr qemuCaps)
     ATTRIBUTE_RETURN_CHECK;
 
 int

tests/qemublocktest.c

@@ -215,13 +215,13 @@ testQemuDiskXMLToProps(const void *opaque)
         goto cleanup;
     }
 
-    if (qemuDomainPrepareDiskSourceChain(disk, NULL, NULL, data->qemuCaps) < 0)
-        goto cleanup;
-
     for (n = disk->src; virStorageSourceIsBacking(n); n = n->backingStore) {
         if (testQemuDiskXMLToJSONFakeSecrets(n) < 0)
             goto cleanup;
 
+        if (qemuDomainPrepareDiskSourceData(disk, n, NULL, data->qemuCaps) < 0)
+            goto cleanup;
+
         if (!(formatProps = qemuBlockStorageSourceGetBlockdevProps(n)) ||
             !(storageProps = qemuBlockStorageSourceGetBackendProps(n, false))) {
             if (!data->fail) {