Block volume shrink on Xen

Author: João Jandre

plugins/hypervisors/xenserver/src/main/java/com/cloud/hypervisor/xenserver/resource/wrapper/xenbase/CitrixResizeVolumeCommandWrapper.java

@@ -49,9 +49,12 @@ public Answer execute(final ResizeVolumeCommand command, final CitrixResourceBas
 
         try {
 
-            if (command.getCurrentSize() >= newSize) {
-                logger.info("No need to resize volume: " + volId +", current size " + toHumanReadableSize(command.getCurrentSize()) + " is same as  new size " + toHumanReadableSize(newSize));
+            if (command.getCurrentSize() == newSize) {
+                logger.info("No need to resize volume [{}], current size [{}] is same as new size [{}].", volId, toHumanReadableSize(command.getCurrentSize()), toHumanReadableSize(newSize));
                 return new ResizeVolumeAnswer(command, true, "success", newSize);
+            } else if (command.getCurrentSize() > newSize) {
+                logger.error("XenServer does not support volume shrink. Volume [{}] current size [{}] is smaller than new size [{}]", volId, toHumanReadableSize(command.getCurrentSize()), toHumanReadableSize(newSize));
+                return new ResizeVolumeAnswer(command, false, "operation not supported");
             }
             if (command.isManaged()) {
                 resizeSr(conn, command);

server/src/main/java/com/cloud/storage/VolumeApiServiceImpl.java

@@ -2429,6 +2429,9 @@ private void validateVolumeResizeWithSize(VolumeVO volume, long currentSize, Lon
                     throw new InvalidParameterValueException("Going from existing size of " + currentSize + " to size of " + newSize + " would shrink the volume."
                             + "Need to sign off by supplying the shrinkok parameter with value of true.");
                 }
+                if (ApiDBUtils.getHypervisorTypeFromFormat(volume.getDataCenterId(), volume.getFormat()) == HypervisorType.XenServer) {
+                    throw new InvalidParameterValueException("Shrink volume is not supported for the XenServer hypervisor.");
+                }
             }
         }
         /* Check resource limit for this account */

ui/src/views/storage/ChangeOfferingForVolume.vue

@@ -90,7 +90,7 @@
         :checked="autoMigrate"
         @change="val => { autoMigrate = val }"/>
     </a-form-item>
-    <a-form-item name="shrinkOk" ref="shrinkOk" :label="$t('label.shrinkok')">
+    <a-form-item name="shrinkOk" ref="shrinkOk" :label="$t('label.shrinkok')" v-if="!['XenServer'].includes(resource.hypervisor)">
       <a-switch
         v-model:checked="form.shrinkOk"
         :checked="shrinkOk"