fix(@xen-orchestra/fs): fix deadlock between "outputFile" and "mkdir" (#4831)

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

@@ -283,17 +283,7 @@ export default class RemoteHandlerAbstract {
   }
 
   async mkdir(dir: string): Promise<void> {
-    dir = normalizePath(dir)
-    try {
-      await this._mkdir(dir)
-    } catch (error) {
-      if (error == null || error.code !== 'EEXIST') {
-        throw error
-      }
-
-      // this operation will throw if it's not already a directory
-      await this._list(dir)
-    }
+    await this.__mkdir(normalizePath(dir))
   }
 
   async mktree(dir: string): Promise<void> {
@@ -456,6 +446,19 @@ export default class RemoteHandlerAbstract {
     await timeout.call(this._closeFile(fd.fd), this._timeout)
   }
 
+  async __mkdir(dir: string): Promise<void> {
+    try {
+      await this._mkdir(dir)
+    } catch (error) {
+      if (error == null || error.code !== 'EEXIST') {
+        throw error
+      }
+
+      // this operation will throw if it's not already a directory
+      await this._list(dir)
+    }
+  }
+
   async __openFile(path: string, flags: string): Promise<FileDescriptor> {
     path = normalizePath(path)
 
@@ -513,7 +516,7 @@ export default class RemoteHandlerAbstract {
 
   async _mktree(dir: string): Promise<void> {
     try {
-      return await this.mkdir(dir)
+      return await this.__mkdir(dir)
     } catch (error) {
       if (error.code !== 'ENOENT') {
         throw error

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

@@ -219,6 +219,12 @@ handlers.forEach(url => {
         const error = await rejectionOf(handler.outputFile('file', ''))
         expect(error.code).toBe('EEXIST')
       })
+
+      it("shouldn't timeout in case of the respect of the parallel execution restriction", async () => {
+        const handler = getHandler({ url }, { maxParallelOperations: 1 })
+        await handler.sync()
+        await handler.outputFile(`xo-fs-tests-${Date.now()}/test`, '')
+      }, 40)
     })
 
     describe('#read()', () => {

CHANGELOG.unreleased.md

@@ -15,6 +15,7 @@
 
 - [Backup reports] Fix backup report not sent in case of interrupted backup job (PR [#4772](https://github.com/vatesfr/xen-orchestra/pull/4772))
 - Fix TLS error (`unsupported protocol`) with XenServer <= 6.5 and Node >= 12 (PR [#8437](https://github.com/vatesfr/xen-orchestra/pull/8437))
+- [Metadata backup] Fix timeout when lots of pools are backed up [#4819](https://github.com/vatesfr/xen-orchestra/issues/4819) (PR [#4831](https://github.com/vatesfr/xen-orchestra/pull/4831))
 
 ### Released packages
 
@@ -23,6 +24,7 @@
 >
 > Rule of thumb: add packages on top.
 
+- @xen-orchestra/fs v0.10.3
 - xen-api v0.28.1
 - xo-server-backup-reports v0.16.5
 - xo-server v5.58.0