fix(backups/delta writers): compute old entries before run

@xen-orchestra/backups/_ContinuousReplicationWriter.js

@@ -25,8 +25,6 @@ exports.ContinuousReplicationWriter = class ContinuousReplicationWriter {
       },
       this.transfer
     )
-
-    this[settings.deleteFirst ? 'prepare' : 'cleanup'] = this._deleteOld
   }
 
   async checkBaseVdis(baseUuidToSrcVdi, baseVm) {
@@ -53,13 +51,22 @@ exports.ContinuousReplicationWriter = class ContinuousReplicationWriter {
     }
   }
 
-  async _deleteOld() {
+  async prepare() {
+    const settings = this._settings
     const { uuid: srUuid, $xapi: xapi } = this._sr
     const { scheduleId, vm } = this._backup
 
-    const oldVms = getOldEntries(this._settings.copyRetention - 1, listReplicatedVms(xapi, scheduleId, srUuid, vm.uuid))
+    this._oldEntries = getOldEntries(settings.copyRetention - 1, listReplicatedVms(xapi, scheduleId, srUuid, vm.uuid))
 
-    return asyncMapSettled(oldVms, vm => xapi.VM_destroy(vm.$ref))
+    if (settings.deleteFirst) {
+      await this._deleteOldEntries()
+    } else {
+      this.cleanup = this._deleteOldEntries
+    }
+  }
+
+  async _deleteOldEntries() {
+    return asyncMapSettled(this._oldEntries, vm => vm.$destroy())
   }
 
   async transfer({ timestamp, deltaExport, sizeContainers }) {

@xen-orchestra/backups/_DeltaBackupWriter.js

@@ -34,7 +34,7 @@ exports.DeltaBackupWriter = class DeltaBackupWriter {
       this.transfer
     )
 
-    this[settings.deleteFirst ? 'prepare' : 'cleanup'] = this._deleteOld
+    this[settings.deleteFirst ? 'prepare' : 'cleanup'] = this._deleteOldEntries
   }
 
   async checkBaseVdis(baseUuidToSrcVdi) {
@@ -72,14 +72,16 @@ exports.DeltaBackupWriter = class DeltaBackupWriter {
     })
   }
 
-  async _deleteOld() {
+  async prepare() {
     const adapter = this._adapter
+    const settings = this._settings
     const { scheduleId, vm } = this._backup
 
-    const oldBackups = getOldEntries(
-      this._settings.exportRetention - 1,
+    const oldEntries = getOldEntries(
+      settings.exportRetention - 1,
       await adapter.listVmBackups(vm.uuid, _ => _.mode === 'delta' && _.scheduleId === scheduleId)
     )
+    this._oldEntries = oldEntries
 
     // FIXME: implement optimized multiple VHDs merging with synthetic
     // delta
@@ -91,15 +93,26 @@ exports.DeltaBackupWriter = class DeltaBackupWriter {
     // The old backups will be eventually merged in future runs of the
     // job.
     const { maxMergedDeltasPerRun } = this._settings
-    if (oldBackups.length > maxMergedDeltasPerRun) {
-      oldBackups.length = maxMergedDeltasPerRun
+    if (oldEntries.length > maxMergedDeltasPerRun) {
+      oldEntries.length = maxMergedDeltasPerRun
     }
 
+    if (settings.deleteFirst) {
+      await this._deleteOldEntries()
+    } else {
+      this.cleanup = this._deleteOldEntries
+    }
+  }
+
+  async _deleteOldEntries() {
     return Task.run({ name: 'merge' }, async () => {
+      const adapter = this._adapter
+      const oldEntries = this._oldEntries
+
       let size = 0
       // delete sequentially from newest to oldest to avoid unnecessary merges
-      for (let i = oldBackups.length; i-- > 0; ) {
-        size += await adapter.deleteDeltaVmBackups([oldBackups[i]])
+      for (let i = oldEntries.length; i-- > 0; ) {
+        size += await adapter.deleteDeltaVmBackups([oldEntries[i]])
       }
       return {
         size,

CHANGELOG.unreleased.md

@@ -28,4 +28,5 @@
 >
 > In case of conflict, the highest (lowest in previous list) `$version` wins.
 
+- @xen-orchestra/backups patch
 - xo-server patch