HADOOP-10732. Fix locking in credential update. (Ted Yu via omalley)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1611416 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -28,6 +28,8 @@ Release 2.6.0 - UNRELEASED
     HADOOP-10607. Create an API to separate credentials/password storage
     from applications (Larry McCay via omalley)
 
+    HADOOP-10732. Fix locking in credential update. (Ted Yu via omalley)
+
   OPTIMIZATIONS
 
   BUG FIXES

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/alias/JavaKeyStoreProvider.java

@@ -230,6 +230,7 @@ public class JavaKeyStoreProvider extends CredentialProvider {
 
   CredentialEntry innerSetCredential(String alias, char[] material)
       throws IOException {
+    writeLock.lock();
     try {
       keyStore.setKeyEntry(alias, new SecretKeySpec(
           new String(material).getBytes("UTF-8"), "AES"),
@@ -237,6 +238,8 @@ public class JavaKeyStoreProvider extends CredentialProvider {
     } catch (KeyStoreException e) {
       throw new IOException("Can't store credential " + alias + " in " + this,
           e);
+    } finally {
+      writeLock.unlock();
     }
     changed = true;
     return new CredentialEntry(alias, material);