refactor: don't handke immutability in fs

@xen-orchestra/backups/RemoteAdapter.mjs

@@ -30,11 +30,15 @@ import { isValidXva } from './_isValidXva.mjs'
 import { listPartitions, LVM_PARTITION_TYPE } from './_listPartitions.mjs'
 import { lvs, pvs } from './_lvm.mjs'
 import { watchStreamSize } from './_watchStreamSize.mjs'
+import { fstat } from 'node:fs'
 
 export const DIR_XO_CONFIG_BACKUPS = 'xo-config-backups'
 
 export const DIR_XO_POOL_METADATA_BACKUPS = 'xo-pool-metadata-backups'
 
+
+const IMMUTABILTY_METADATA_FILENAME = 'immutability.json'
+
 const { debug, warn } = createLogger('xo:backups:RemoteAdapter')
 
 const compareTimestamp = (a, b) => a.timestamp - b.timestamp
@@ -749,29 +753,31 @@ export class RemoteAdapter {
   }
 
   async readVmBackupMetadata(path) {
-    const handler = this._handler
     let json
     let isImmutable = false
+    let remoteIsImmutable = false
     // if the remote is immutable, check if this metadatas are also immutables
-    if (handler.immutability !== undefined) {
+    try{
+      await fstat.stat( IMMUTABILTY_METADATA_FILENAME)
+      remoteIsImmutable = true
+    }catch(error){
+      if(error.code !== 'ENOENT'){
+        throw error
+      }
+    }
+    if (remoteIsImmutable) {
       let fd
       try {
-        // this will trigger e EPERM error if the file is immutable
-        fd = (await handler.openFile(path, 'r+')).fd
-        json = await this.handler.readFile(fd)
+        // this will trigger an EPERM error if the file is immutable 
+        json = await this.handler.readFile(fd, {flags: 'r+'})
       } catch (err) {
-        if (err.code === 'EPERM') {
-          isImmutable = true
+        // retry without triggerring a potential change
+        if (err.code === 'EPERM' && remoteIsImmutable ) {
+          json = await this._handler.readFile(path)
         }
-      } finally {
-        if (fd !== undefined) {
-          await handler.closeFile(fd)
-        }
-      }
-    }
-    if (json === undefined) {
-      json = await this._handler.readFile(path)
+      }  
     }
+
     // _filename is a private field used to compute the backup id
     //
     // it's enumerable to make it cacheable

@xen-orchestra/fs/src/abstract.js

@@ -27,7 +27,6 @@ const DEFAULT_MAX_PARALLEL_OPERATIONS = 10
 
 const ENCRYPTION_DESC_FILENAME = 'encryption.json'
 const ENCRYPTION_METADATA_FILENAME = 'metadata.json'
-const IMMUTABILTY_METADATA_FILENAME = 'immutability.json'
 
 const ignoreEnoent = error => {
   if (error == null || error.code !== 'ENOENT') {
@@ -77,7 +76,6 @@ class PrefixWrapper {
 
 export default class RemoteHandlerAbstract {
   #rawEncryptor
-  #immutability
 
   get #encryptor() {
     if (this.#rawEncryptor === undefined) {
@@ -86,10 +84,6 @@ export default class RemoteHandlerAbstract {
     return this.#rawEncryptor
   }
 
-  get immutability(){
-    return this.#immutability
-  }
-
   constructor(remote, options = {}) {
     if (remote.url === 'test://') {
       this._remote = remote
@@ -287,7 +281,7 @@ export default class RemoteHandlerAbstract {
   }
 
   async __readFile(file, { flags = 'r' } = {}) {
-    const data = await this._readFile(typeof file === 'string' ? normalizePath(file) : file, { flags })
+    const data = await this._readFile(normalizePath(file), { flags })
     return this.#encryptor.decryptData(data)
   }
 
@@ -403,14 +397,6 @@ export default class RemoteHandlerAbstract {
         }
       }
     }
-
-    try{
-      this.#immutability = JSON.parse( await this._readFile(normalizePath(IMMUTABILTY_METADATA_FILENAME), 'utf-8'))
-    }catch(error){
-      if (error.code !== 'ENOENT') {
-        throw error
-      }
-    }
   }
 
   async test() {

@xen-orchestra/fs/src/local.js

@@ -172,16 +172,8 @@ export default class LocalHandler extends RemoteHandlerAbstract {
   }
 
   async _readFile(file, options) {
-    const isPath = typeof file === 'string' 
-    return await this.#addSyncStackTrace(retry, () => {
-        if(isPath){
-          const filePath = this.getFilePath(file)
-          return fs.readFile(filePath, options)
-        } else {
-          return fs.readFile(file, options)
-        }
-      }, this.#retriesOnEagain)
-
+    const filePath = this.getFilePath(file)
+    return await this.#addSyncStackTrace(retry, () => fs.readFile(filePath, options), this.#retriesOnEagain)
   }
 
   async _rename(oldPath, newPath) {