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  1. Hadoop HDFS
  2. HDFS-6908

incorrect snapshot directory diff generated by snapshot deletion

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Details

    • Bug
    • Status: Closed
    • Critical
    • Resolution: Fixed
    • None
    • 2.6.0
    • snapshots
    • None
    • Reviewed

    Description

      In the following scenario, delete snapshot could generate incorrect snapshot directory diff and corrupted fsimage, if you restart NN after that, you will get NullPointerException.
      1. create a directory and create a file under it
      2. take a snapshot
      3. create another file under that directory
      4. take second snapshot
      5. delete both files and the directory
      6. delete second snapshot
      incorrect directory diff will be generated.

      Restart NN will throw NPE

      java.lang.NullPointerException
      	at org.apache.hadoop.hdfs.server.namenode.snapshot.FSImageFormatPBSnapshot$Loader.addToDeletedList(FSImageFormatPBSnapshot.java:246)
      	at org.apache.hadoop.hdfs.server.namenode.snapshot.FSImageFormatPBSnapshot$Loader.loadDeletedList(FSImageFormatPBSnapshot.java:265)
      	at org.apache.hadoop.hdfs.server.namenode.snapshot.FSImageFormatPBSnapshot$Loader.loadDirectoryDiffList(FSImageFormatPBSnapshot.java:328)
      	at org.apache.hadoop.hdfs.server.namenode.snapshot.FSImageFormatPBSnapshot$Loader.loadSnapshotDiffSection(FSImageFormatPBSnapshot.java:192)
      	at org.apache.hadoop.hdfs.server.namenode.FSImageFormatProtobuf$Loader.loadInternal(FSImageFormatProtobuf.java:254)
      	at org.apache.hadoop.hdfs.server.namenode.FSImageFormatProtobuf$Loader.load(FSImageFormatProtobuf.java:168)
      	at org.apache.hadoop.hdfs.server.namenode.FSImageFormat$LoaderDelegator.load(FSImageFormat.java:208)
      	at org.apache.hadoop.hdfs.server.namenode.FSImage.loadFSImage(FSImage.java:906)
      	at org.apache.hadoop.hdfs.server.namenode.FSImage.loadFSImage(FSImage.java:892)
      	at org.apache.hadoop.hdfs.server.namenode.FSImage.loadFSImageFile(FSImage.java:715)
      	at org.apache.hadoop.hdfs.server.namenode.FSImage.loadFSImage(FSImage.java:653)
      	at org.apache.hadoop.hdfs.server.namenode.FSImage.recoverTransitionRead(FSImage.java:276)
      	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFSImage(FSNamesystem.java:882)
      	at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.loadFromDisk(FSNamesystem.java:629)
      	at org.apache.hadoop.hdfs.server.namenode.NameNode.loadNamesystem(NameNode.java:498)
      	at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:554)
      

      Attachments

        1. HDFS-6908.001.patch
          3 kB
          Juan Yu
        2. HDFS-6908.002.patch
          5 kB
          Juan Yu
        3. HDFS-6908.003.patch
          5 kB
          Juan Yu

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              jyu@cloudera.com Juan Yu
              jyu@cloudera.com Juan Yu
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              Dates

                Created:
                Updated:
                Resolved: