HDFS-16732. [SBN READ] Avoid get location from observer when the block report is delayed (#4756)

Signed-off-by: Erik Krogen <xkrogen@apache.org>

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

@@ -103,6 +103,7 @@ import java.util.concurrent.atomic.AtomicLong;
 import org.apache.commons.text.CaseUtils;
 import org.apache.hadoop.hdfs.protocol.ECTopologyVerifierResult;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
+import org.apache.hadoop.hdfs.protocol.HdfsLocatedFileStatus;
 import org.apache.hadoop.hdfs.protocol.SnapshotStatus;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_STORAGE_POLICY_ENABLED_KEY;
 import static org.apache.hadoop.hdfs.server.namenode.FSDirStatAndListingOp.*;
@@ -2202,14 +2203,8 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
               }
             }
           }
-        } else if (haEnabled && haContext != null &&
-            haContext.getState().getServiceState() == OBSERVER) {
-          for (LocatedBlock b : res.blocks.getLocatedBlocks()) {
-            if (b.getLocations() == null || b.getLocations().length == 0) {
-              throw new ObserverRetryOnActiveException("Zero blocklocations "
-                  + "for " + srcArg);
-            }
-          }
+        } else if (isObserver()) {
+          checkBlockLocationsWhenObserver(res.blocks, srcArg);
         }
       } finally {
         readUnlock(operationName, getLockReportInfoSupplier(srcArg));
@@ -3470,6 +3465,10 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
       logAuditEvent(false, operationName, src);
       throw e;
     }
+    if (needLocation && isObserver() && stat instanceof HdfsLocatedFileStatus) {
+      LocatedBlocks lbs = ((HdfsLocatedFileStatus) stat).getLocatedBlocks();
+      checkBlockLocationsWhenObserver(lbs, src);
+    }
     logAuditEvent(true, operationName, src);
     return stat;
   }
@@ -4175,6 +4174,14 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
       logAuditEvent(false, operationName, src);
       throw e;
     }
+    if (needLocation && isObserver()) {
+      for (HdfsFileStatus fs : dl.getPartialListing()) {
+        if (fs instanceof HdfsLocatedFileStatus) {
+          LocatedBlocks lbs = ((HdfsLocatedFileStatus) fs).getLocatedBlocks();
+          checkBlockLocationsWhenObserver(lbs, fs.toString());
+        }
+      }
+    }
     logAuditEvent(true, operationName, src);
     return dl;
   }
@@ -9020,4 +9027,17 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
       throw new UnsupportedActionException(operationName + " not supported.");
     }
   }
+
+  private boolean isObserver() {
+    return haEnabled && haContext != null && haContext.getState().getServiceState() == OBSERVER;
+  }
+
+  private void checkBlockLocationsWhenObserver(LocatedBlocks blocks, String src)
+      throws ObserverRetryOnActiveException {
+    for (LocatedBlock b : blocks.getLocatedBlocks()) {
+      if (b.getLocations() == null || b.getLocations().length == 0) {
+        throw new ObserverRetryOnActiveException("Zero blocklocations for " + src);
+      }
+    }
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestObserverNode.java

@@ -369,6 +369,12 @@ public class TestObserverNode {
     dfs.open(testPath);
     assertSentTo(0);
 
+    dfs.getClient().listPaths("/", new byte[0], true);
+    assertSentTo(0);
+
+    dfs.getClient().getLocatedFileInfo(testPath.toString(), false);
+    assertSentTo(0);
+
     Mockito.reset(bmSpy);
   }