NIFI-11472 Check working directory after making directory in PutFTP

- Multiple threads can attempt to create a remote directory when PutFTP has multiple concurrent tasks.

This closes #7184

Signed-off-by: David Handermann <exceptionfactory@apache.org>

nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/util/FTPTransfer.java

@@ -395,7 +395,7 @@ public class FTPTransfer implements FileTransfer {
         if (!cdSuccessful) {
             if (client.makeDirectory(remoteDirectory)) {
                 logger.debug("Remote Directory not found: created directory [{}]", remoteDirectory);
-            } else {
+            } else if (!setWorkingDirectory(remoteDirectory)) { // Double check that the dir exists as it might have been created in another thread
                 throw new IOException("Failed to create remote directory " + remoteDirectory);
             }
         }