qemu: hotplug: Don't try to setup disk image when hotplugging empty cdrom drive

Originally the disk hotplug code didn't know how to attach a CD-ROM
drive, thus didn't have the necessary logic to handle empty cdroms.

Other disks can't be empty which is enforced by the parser validation
logic.

When support for hotplugging cdroms was added the code was not adjusted
to deal with empty drives thus attempted to setup the blockdev backend
for it.

Fixes: 3078799fef82d45ac10624e3bacded7a285d8a4f
Resolves: https://issues.redhat.com/browse/RHEL-16870
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 80a39c159f43554677a6f01c4e8fb684293e2536..f197a9d5ffc83632aa21172c7e02d39e419c31c7 100644 (file)
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -662,53 +662,55 @@ qemuDomainAttachDiskGeneric(virDomainObj *vm,
     g_autoptr(qemuSnapshotDiskContext) transientDiskSnapshotCtxt = NULL;
     bool origReadonly = disk->src->readonly;
 
-    if (disk->transient)
-        disk->src->readonly = true;
+    if (!virStorageSourceIsEmpty(disk->src)) {
+        if (disk->transient)
+            disk->src->readonly = true;
 
-    if (virStorageSourceGetActualType(disk->src) == VIR_STORAGE_TYPE_VHOST_USER) {
-        if (!(data = qemuBuildStorageSourceChainAttachPrepareChardev(disk)))
-            return -1;
-    } else {
-        if (!(data = qemuBuildStorageSourceChainAttachPrepareBlockdev(disk->src)))
-            return -1;
-
-        if (disk->copy_on_read == VIR_TRISTATE_SWITCH_ON) {
-            if (!(data->copyOnReadProps = qemuBlockStorageGetCopyOnReadProps(disk)))
+        if (virStorageSourceGetActualType(disk->src) == VIR_STORAGE_TYPE_VHOST_USER) {
+            if (!(data = qemuBuildStorageSourceChainAttachPrepareChardev(disk)))
                 return -1;
+        } else {
+            if (!(data = qemuBuildStorageSourceChainAttachPrepareBlockdev(disk->src)))
+                return -1;
+
+            if (disk->copy_on_read == VIR_TRISTATE_SWITCH_ON) {
+                if (!(data->copyOnReadProps = qemuBlockStorageGetCopyOnReadProps(disk)))
+                    return -1;
 
-            data->copyOnReadNodename = g_strdup(QEMU_DOMAIN_DISK_PRIVATE(disk)->nodeCopyOnRead);
+                data->copyOnReadNodename = g_strdup(QEMU_DOMAIN_DISK_PRIVATE(disk)->nodeCopyOnRead);
+            }
         }
-    }
 
-    disk->src->readonly = origReadonly;
+        disk->src->readonly = origReadonly;
 
-    if (qemuDomainObjEnterMonitorAsync(vm, asyncJob) < 0)
-        return -1;
+        if (qemuDomainObjEnterMonitorAsync(vm, asyncJob) < 0)
+            return -1;
 
-    rc = qemuBlockStorageSourceChainAttach(priv->mon, data);
+        rc = qemuBlockStorageSourceChainAttach(priv->mon, data);
 
-    qemuDomainObjExitMonitor(vm);
+        qemuDomainObjExitMonitor(vm);
 
-    if (rc < 0)
-        goto rollback;
+        if (rc < 0)
+            goto rollback;
 
-    if (disk->transient) {
-        g_autoptr(qemuBlockStorageSourceAttachData) backend = NULL;
-        g_autoptr(GHashTable) blockNamedNodeData = NULL;
+        if (disk->transient) {
+            g_autoptr(qemuBlockStorageSourceAttachData) backend = NULL;
+            g_autoptr(GHashTable) blockNamedNodeData = NULL;
 
-        if (!(blockNamedNodeData = qemuBlockGetNamedNodeData(vm, asyncJob)))
-            goto rollback;
+            if (!(blockNamedNodeData = qemuBlockGetNamedNodeData(vm, asyncJob)))
+                goto rollback;
 
-        if (!(transientDiskSnapshotCtxt = qemuDomainAttachDiskGenericTransient(vm, disk, blockNamedNodeData, asyncJob)))
-            goto rollback;
+            if (!(transientDiskSnapshotCtxt = qemuDomainAttachDiskGenericTransient(vm, disk, blockNamedNodeData, asyncJob)))
+                goto rollback;
 
 
-        if (qemuSnapshotDiskCreate(transientDiskSnapshotCtxt) < 0)
-            goto rollback;
+            if (qemuSnapshotDiskCreate(transientDiskSnapshotCtxt) < 0)
+                goto rollback;
 
-        QEMU_DOMAIN_DISK_PRIVATE(disk)->transientOverlayCreated = true;
-        backend = qemuBlockStorageSourceDetachPrepare(disk->src);
-        ignore_value(VIR_INSERT_ELEMENT(data->srcdata, 0, data->nsrcdata, backend));
+            QEMU_DOMAIN_DISK_PRIVATE(disk)->transientOverlayCreated = true;
+            backend = qemuBlockStorageSourceDetachPrepare(disk->src);
+            ignore_value(VIR_INSERT_ELEMENT(data->srcdata, 0, data->nsrcdata, backend));
+        }
     }
 
     if (!(devprops = qemuBuildDiskDeviceProps(vm->def, disk, priv->qemuCaps)))
@@ -995,28 +997,30 @@ qemuDomainAttachDeviceDiskLiveInternal(virQEMUDriver *driver,
         goto cleanup;
     }
 
-    if (qemuDomainStorageSourceChainAccessAllow(driver, vm, disk->src) < 0)
+    if (qemuAssignDeviceDiskAlias(vm->def, disk) < 0)
         goto cleanup;
 
-    releaseSeclabel = true;
+    if (!virStorageSourceIsEmpty(disk->src)) {
+        if (qemuDomainStorageSourceChainAccessAllow(driver, vm, disk->src) < 0)
+            goto cleanup;
 
-    if (qemuAssignDeviceDiskAlias(vm->def, disk) < 0)
-        goto cleanup;
+        releaseSeclabel = true;
 
-    if (qemuDomainPrepareDiskSource(disk, priv, cfg) < 0)
-        goto cleanup;
+        if (qemuDomainPrepareDiskSource(disk, priv, cfg) < 0)
+            goto cleanup;
 
-    if (qemuDomainDetermineDiskChain(driver, vm, disk, NULL) < 0)
-        goto cleanup;
+        if (qemuDomainDetermineDiskChain(driver, vm, disk, NULL) < 0)
+            goto cleanup;
 
-    if (qemuProcessPrepareHostStorageDisk(vm, disk) < 0)
-        goto cleanup;
+        if (qemuProcessPrepareHostStorageDisk(vm, disk) < 0)
+            goto cleanup;
 
-    if (qemuHotplugAttachManagedPR(vm, disk->src, VIR_ASYNC_JOB_NONE) < 0)
-        goto cleanup;
+        if (qemuHotplugAttachManagedPR(vm, disk->src, VIR_ASYNC_JOB_NONE) < 0)
+            goto cleanup;
 
-    if (qemuNbdkitStartStorageSource(driver, vm, disk->src) < 0)
-        goto cleanup;
+        if (qemuNbdkitStartStorageSource(driver, vm, disk->src) < 0)
+            goto cleanup;
+    }
 
     ret = qemuDomainAttachDiskGeneric(vm, disk, VIR_ASYNC_JOB_NONE);