server: throw new exception when rootdisksize is required but not set (#7913)

* server: throw new exception when rootdisksize is required but not set

* PR7913: fix an issue with PR6441

api/src/main/java/org/apache/cloudstack/api/command/user/vm/DeployVMCmd.java

diff --git a/api/src/main/java/org/apache/cloudstack/api/command/user/vm/DeployVMCmd.java b/api/src/main/java/org/apache/cloudstack/api/command/user/vm/DeployVMCmd.java
index ef6dba6..107bd81 100644
--- a/api/src/main/java/org/apache/cloudstack/api/command/user/vm/DeployVMCmd.java
+++ b/api/src/main/java/org/apache/cloudstack/api/command/user/vm/DeployVMCmd.java
@@ -315,8 +315,8 @@
             customparameterMap.put(getBootType().toString(), getBootMode().toString());
         }
 
-        if (rootdisksize != null && !customparameterMap.containsKey("rootdisksize")) {
-            customparameterMap.put("rootdisksize", rootdisksize.toString());
+        if (rootdisksize != null && !customparameterMap.containsKey(VmDetailConstants.ROOT_DISK_SIZE)) {
+            customparameterMap.put(VmDetailConstants.ROOT_DISK_SIZE, rootdisksize.toString());
         }
 
         IoDriverPolicy ioPolicy = getIoDriverPolicy();

server/src/main/java/com/cloud/vm/UserVmManagerImpl.java

diff --git a/server/src/main/java/com/cloud/vm/UserVmManagerImpl.java b/server/src/main/java/com/cloud/vm/UserVmManagerImpl.java
index c184006..c9085b3 100644
--- a/server/src/main/java/com/cloud/vm/UserVmManagerImpl.java
+++ b/server/src/main/java/com/cloud/vm/UserVmManagerImpl.java
@@ -3933,7 +3933,7 @@
                 rootDiskOfferingId = diskOfferingId;
                 diskOfferingId = null;
             }
-            if (!customParameters.containsKey(VmDetailConstants.ROOT_DISK_SIZE)) {
+            if (!customParameters.containsKey(VmDetailConstants.ROOT_DISK_SIZE) && diskSize != null) {
                 customParameters.put(VmDetailConstants.ROOT_DISK_SIZE, String.valueOf(diskSize));
             }
         }
@@ -4320,7 +4320,14 @@
      */
     protected long configureCustomRootDiskSize(Map<String, String> customParameters, VMTemplateVO template, HypervisorType hypervisorType, DiskOfferingVO rootDiskOffering) {
         verifyIfHypervisorSupportsRootdiskSizeOverride(hypervisorType);
-        long rootDiskSizeInBytes = verifyAndGetDiskSize(rootDiskOffering, NumbersUtil.parseLong(customParameters.get(VmDetailConstants.ROOT_DISK_SIZE), -1));
+        Long rootDiskSizeCustomParam = null;
+        if (customParameters.containsKey(VmDetailConstants.ROOT_DISK_SIZE)) {
+            rootDiskSizeCustomParam = NumbersUtil.parseLong(customParameters.get(VmDetailConstants.ROOT_DISK_SIZE), -1);
+            if (rootDiskSizeCustomParam <= 0) {
+                throw new InvalidParameterValueException("Root disk size should be a positive number.");
+            }
+        }
+        long rootDiskSizeInBytes = verifyAndGetDiskSize(rootDiskOffering, rootDiskSizeCustomParam);
         if (rootDiskSizeInBytes > 0) { //if the size at DiskOffering is not zero then the Service Offering had it configured, it holds priority over the User custom size
             _volumeService.validateVolumeSizeInBytes(rootDiskSizeInBytes);
             long rootDiskSizeInGiB = rootDiskSizeInBytes / GiB_TO_BYTES;
@@ -4329,11 +4336,7 @@
         }
 
         if (customParameters.containsKey(VmDetailConstants.ROOT_DISK_SIZE)) {
-            Long rootDiskSize = NumbersUtil.parseLong(customParameters.get(VmDetailConstants.ROOT_DISK_SIZE), -1);
-            if (rootDiskSize <= 0) {
-                throw new InvalidParameterValueException("Root disk size should be a positive number.");
-            }
-            rootDiskSize *= GiB_TO_BYTES;
+            Long rootDiskSize = rootDiskSizeCustomParam * GiB_TO_BYTES;
             _volumeService.validateVolumeSizeInBytes(rootDiskSize);
             return rootDiskSize;
         } else {