[SPARK-18764][CORE] Add a warning log when skipping a corrupted file

## What changes were proposed in this pull request?

It's better to add a warning log when skipping a corrupted file. It will be helpful when we want to finish the job first, then find them in the log and fix these files.

## How was this patch tested?

Jenkins

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #16192 from zsxwing/SPARK-18764.

core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala

@@ -259,7 +259,9 @@ class HadoopRDD[K, V](
         try {
           finished = !reader.next(key, value)
         } catch {
-          case e: IOException if ignoreCorruptFiles => finished = true
+          case e: IOException if ignoreCorruptFiles =>
+            logWarning(s"Skipped the rest content in the corrupted file: ${split.inputSplit}", e)
+            finished = true
         }
         if (!finished) {
           inputMetrics.incRecordsRead(1)

core/src/main/scala/org/apache/spark/rdd/NewHadoopRDD.scala

@@ -189,7 +189,11 @@ class NewHadoopRDD[K, V](
           try {
             finished = !reader.nextKeyValue
           } catch {
-            case e: IOException if ignoreCorruptFiles => finished = true
+            case e: IOException if ignoreCorruptFiles =>
+              logWarning(
+                s"Skipped the rest content in the corrupted file: ${split.serializableHadoopSplit}",
+                e)
+              finished = true
           }
           if (finished) {
             // Close and release the reader here; close() will also be called when the task

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/FileScanRDD.scala

@@ -139,6 +139,7 @@ class FileScanRDD(
                     }
                   } catch {
                     case e: IOException =>
+                      logWarning(s"Skipped the rest content in the corrupted file: $currentFile", e)
                       finished = true
                       null
                   }