fix(xo-server): migration of vm with cbt enabled disk (#8017)

CHANGELOG.unreleased.md

@@ -15,6 +15,8 @@
 
 > Users must be able to say: “I had this issue, happy to know it's fixed”
 
+- [Migration/CBT] Fix an infinite loop when migrating a VM with CBT enabled (PR [#8017](https://github.com/vatesfr/xen-orchestra/pull/8017))
+
 ### Packages to release
 
 > When modifying a package, add it here with its release type.

packages/xo-server/src/xapi/index.mjs

@@ -614,16 +614,16 @@ export default class Xapi extends XapiBase {
         }
       }
     }
-    const loop = async () => {
+    const loop = async (_failOnCbtError = false) => {
       try {
         await this.callAsync('VM.migrate_send', ...params)
       } catch (err) {
-        if (err.code === 'VDI_CBT_ENABLED') {
+        if (err.code === 'VDI_CBT_ENABLED' && !_failOnCbtError) {
           // as of 20240619, CBT must be disabled on all disks to allow migration to go through
           // it will be re enabled if needed by backups
           // the next backup after a storage migration will be a full backup
           await this.VM_disableChangedBlockTracking(vm.$ref)
-          return loop()
+          return loop(true)
         }
         if (err.code === 'TOO_MANY_STORAGE_MIGRATES') {
           await pDelay(1e4)