Fix another potential race in the file settings watcher (#90388)

Fix another potential race in the file settings watcher for issue #89500 This backports #90302
elastic · Sep 27, 2022 · 5f55955 · 5f55955
1 parent e913f6c
commit 5f55955
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diff --git a/docs/changelog/90302.yaml b/docs/changelog/90302.yaml
@@ -0,0 +1,5 @@
+pr: 90302
+summary: Fix another potential race in the file settings watcher
+area: Infra/Core
+type: bug
+issues: [89500]
diff --git a/server/src/main/java/org/elasticsearch/reservedstate/service/FileSettingsService.java b/server/src/main/java/org/elasticsearch/reservedstate/service/FileSettingsService.java
@@ -345,6 +345,7 @@ synchronized void stopWatcher() {
         logger.debug("stopping watcher ...");
         if (watching()) {
             try {
+                // make sure the watcher thread hits the processing latch correctly
                 cleanupWatchKeys();
                 fileUpdateState = null;
                 watchService.close();
@@ -354,6 +355,8 @@ synchronized void stopWatcher() {
                 if (watcherThreadLatch != null) {
                     watcherThreadLatch.await();
                 }
+                // the watcher thread might have snuck in behind us and re-created the settings watch again
+                cleanupWatchKeys();
             } catch (IOException e) {
                 logger.warn("encountered exception while closing watch service", e);
             } catch (InterruptedException interruptedException) {