HDFS-15706. HttpFS: Log more information on request failures. (#2515)

(cherry picked from commit 07655a7040806c4c9687288de89e42cfacf0365e)
(cherry picked from commit a7dbd3b6f978d28ef7e046add2e3270ae3d9d9f6)

hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/fs/http/server/HttpFSExceptionProvider.java

@@ -70,12 +70,16 @@ public class HttpFSExceptionProvider extends ExceptionProvider {
       status = Response.Status.NOT_FOUND;
     } else if (throwable instanceof IOException) {
       status = Response.Status.INTERNAL_SERVER_ERROR;
+      logErrorFully(status, throwable);
     } else if (throwable instanceof UnsupportedOperationException) {
       status = Response.Status.BAD_REQUEST;
+      logErrorFully(status, throwable);
     } else if (throwable instanceof IllegalArgumentException) {
       status = Response.Status.BAD_REQUEST;
+      logErrorFully(status, throwable);
     } else {
       status = Response.Status.INTERNAL_SERVER_ERROR;
+      logErrorFully(status, throwable);
     }
     return createResponse(status, throwable);
   }
@@ -95,4 +99,7 @@ public class HttpFSExceptionProvider extends ExceptionProvider {
     LOG.warn("[{}:{}] response [{}] {}", new Object[]{method, path, status, message}, throwable);
   }
 
+  private void logErrorFully(Response.Status status, Throwable throwable) {
+    LOG.debug("Failed with {}", status, throwable);
+  }
 }