HDFS-17105. mistakenly purge editLogs even after it is empty in NNStorageRetentionManager. (#6036). Contributed by ConfX.

Signed-off-by: He Xiaoqiao <hexiaoqiao@apache.org>

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NNStorageRetentionManager.java

@@ -80,6 +80,9 @@ public class NNStorageRetentionManager {
     Preconditions.checkArgument(numExtraEditsToRetain >= 0,
         DFSConfigKeys.DFS_NAMENODE_NUM_EXTRA_EDITS_RETAINED_KEY +
         " must not be negative");
+    Preconditions.checkArgument(maxExtraEditsSegmentsToRetain >= 0,
+        DFSConfigKeys.DFS_NAMENODE_MAX_EXTRA_EDITS_SEGMENTS_RETAINED_KEY +
+        " must not be negative");
     
     this.storage = storage;
     this.purgeableLogs = purgeableLogs;