feat(backups): lock VM dir during backup (#5746)

May fix xoa-support#3387

@xen-orchestra/backups/_VmBackup.js

@@ -3,8 +3,9 @@ const findLast = require('lodash/findLast.js')
 const ignoreErrors = require('promise-toolbox/ignoreErrors.js')
 const keyBy = require('lodash/keyBy.js')
 const mapValues = require('lodash/mapValues.js')
-const { asyncMap } = require('@xen-orchestra/async-map')
+const { asyncMap, asyncMapSettled } = require('@xen-orchestra/async-map')
 const { createLogger } = require('@xen-orchestra/log')
+const { defer } = require('golike-defer')
 const { formatDateTime } = require('@xen-orchestra/xapi')
 
 const { DeltaBackupWriter } = require('./writers/DeltaBackupWriter.js')
@@ -321,14 +322,18 @@ exports.VmBackup = class VmBackup {
     this._fullVdisRequired = fullVdisRequired
   }
 
-  async run() {
+  run = defer(this.run)
+  async run($defer) {
     const settings = this._settings
     assert(
       !settings.offlineBackup || settings.snapshotRetention === 0,
       'offlineBackup is not compatible with snapshotRetention'
     )
 
-    await asyncMap(this._writers, writer => writer.beforeBackup())
+    await asyncMapSettled(this._writers, async writer => {
+      await writer.beforeBackup()
+      $defer(() => writer.afterBackup())
+    })
 
     await this._fetchJobSnapshots()
 

@xen-orchestra/backups/writers/_AbstractWriter.js

@@ -5,4 +5,6 @@ exports.AbstractWriter = class AbstractWriter {
   }
 
   beforeBackup() {}
+
+  afterBackup() {}
 }

@xen-orchestra/backups/writers/_MixinBackupWriter.js

@@ -11,15 +11,25 @@ exports.MixinBackupWriter = (BaseClass = Object) =>
 
       this._adapter = rest.backup.remoteAdapters[remoteId]
       this._remoteId = remoteId
+      this._lock = undefined
     }
 
     async beforeBackup() {
+      const adapter = this._adapter
+      const vmBackupDir = getVmBackupDir(this._backup.vm.uuid)
+
       try {
-        await this._adapter.cleanVm(getVmBackupDir(this._backup.vm.uuid), { remove: true, merge: true, onLog: debug })
+        await adapter.cleanVm(vmBackupDir, { remove: true, merge: true, onLog: debug })
       } catch (error) {
         if (error?.code !== 'ENOENT') {
           throw error
         }
       }
+
+      this._lock = await adapter.handler.lock(vmBackupDir)
+    }
+
+    async afterBackup() {
+      await this._lock.dispose()
     }
   }

CHANGELOG.unreleased.md

@@ -11,6 +11,7 @@
 - [NFS remotes] Don't force version 3 by default (PR [#5725](https://github.com/vatesfr/xen-orchestra/pull/5725))
 - [Template] Ability to create a template from a snapshot [#4891](https://github.com/vatesfr/xen-orchestra/issues/4891) (PR [#5736](https://github.com/vatesfr/xen-orchestra/pull/5736))
 - [PIF] Automatically reconfigure management PIF on host case of IP address change to avoid connection loss [#5730](https://github.com/vatesfr/xen-orchestra/issues/5730) (PR [#5745](https://github.com/vatesfr/xen-orchestra/pull/5745))
+- [Backup] Lock VM directory during backup to avoid race conditions (PR [#5746](https://github.com/vatesfr/xen-orchestra/pull/5746))
 
 ### Bug fixes