Package org.apache.hadoop.hdfs.server.namenode

Class INodeSymlink

java.lang.Object
org.apache.hadoop.hdfs.server.namenode.INode
org.apache.hadoop.hdfs.server.namenode.INodeWithAdditionalFields
org.apache.hadoop.hdfs.server.namenode.INodeSymlink
All Implemented Interfaces:
Comparable<byte[]>, INodeAttributes, Diff.Element<byte[]>, org.apache.hadoop.util.LightWeightGSet.LinkedElement
@Private public class INodeSymlink extends INodeWithAdditionalFields
An INode representing a symbolic link.

  • Method Details

    • isSymlink

      public boolean isSymlink()
      Description copied from class: INode
      Check whether it's a symlink
      Overrides:
      isSymlink in class INode
      Returns:
      true unconditionally.

    • asSymlink

      public INodeSymlink asSymlink()
      Description copied from class: INode
      Cast this inode to an INodeSymlink.
      Overrides:
      asSymlink in class INode
      Returns:
      this object.

    • getSymlinkString

      public String getSymlinkString()

    • getSymlink

      public byte[] getSymlink()

    • cleanSubtree

      public void cleanSubtree(INode.ReclaimContext reclaimContext, int snapshotId, int priorSnapshotId)
      Description copied from class: INode
      Clean the subtree under this inode and collect the blocks from the descents for further block deletion/update. The current inode can either resides in the current tree or be stored as a snapshot copy. 
       In general, we have the following rules. 
 1. When deleting a file/directory in the current tree, we have different 
 actions according to the type of the node to delete. 
 
 1.1 The current inode (this) is an INodeFile. 
 1.1.1 If prior is null, there is no snapshot taken on ancestors 
 before. Thus we simply destroy (i.e., to delete completely, no need to save 
 snapshot copy) the current INode and collect its blocks for further 
 cleansing.
 1.1.2 Else do nothing since the current INode will be stored as a snapshot
 copy.
 
 1.2 The current inode is an INodeDirectory.
 1.2.1 If prior is null, there is no snapshot taken on ancestors 
 before. Similarly, we destroy the whole subtree and collect blocks.
 1.2.2 Else do nothing with the current INode. Recursively clean its 
 children.
 
 1.3 The current inode is a file with snapshot.
 Call recordModification(..) to capture the current states.
 Mark the INode as deleted.
 
 1.4 The current inode is an INodeDirectory with snapshot feature.
 Call recordModification(..) to capture the current states. 
 Destroy files/directories created after the latest snapshot 
 (i.e., the inodes stored in the created list of the latest snapshot).
 Recursively clean remaining children. 

 2. When deleting a snapshot.
 2.1 To clean INodeFile: do nothing.
 2.2 To clean INodeDirectory: recursively clean its children.
 2.3 To clean INodeFile with snapshot: delete the corresponding snapshot in
 its diff list.
 2.4 To clean INodeDirectory with snapshot: delete the corresponding 
 snapshot in its diff list. Recursively clean its children.
      Specified by:
      cleanSubtree in class INode
      Parameters:
      reclaimContext - Record blocks and inodes that need to be reclaimed.
      snapshotId - The id of the snapshot to delete. Snapshot.CURRENT_STATE_ID means to delete the current file/directory.
      priorSnapshotId - The id of the latest snapshot before the to-be-deleted snapshot. When deleting a current inode, this parameter captures the latest snapshot.

    • destroyAndCollectBlocks

      public void destroyAndCollectBlocks(INode.ReclaimContext reclaimContext)
      Description copied from class: INode
      Destroy self and clear everything! If the INode is a file, this method collects its blocks for further block deletion. If the INode is a directory, the method goes down the subtree and collects blocks from the descents, and clears its parent/children references as well. The method also clears the diff list if the INode contains snapshot diff list.
      Specified by:
      destroyAndCollectBlocks in class INode
      Parameters:
      reclaimContext - Record blocks and inodes that need to be reclaimed.

    • computeQuotaUsage

      public QuotaCounts computeQuotaUsage(BlockStoragePolicySuite bsps, byte blockStoragePolicyId, boolean useCache, int lastSnapshotId)
      Description copied from class: INode
      Count subtree Quota.NAMESPACE and Quota.STORAGESPACE usages. With the existence of INodeReference, the same inode and its subtree may be referred by multiple INodeReference.WithName nodes and a INodeReference.DstReference node. To avoid circles while quota usage computation, we have the following rules: 
       1. For a INodeReference.DstReference node, since the node must be in the current
 tree (or has been deleted as the end point of a series of rename 
 operations), we compute the quota usage of the referred node (and its 
 subtree) in the regular manner, i.e., including every inode in the current
 tree and in snapshot copies, as well as the size of diff list.
 
 2. For a INodeReference.WithName node, since the node must be in a snapshot, we 
 only count the quota usage for those nodes that still existed at the 
 creation time of the snapshot associated with the INodeReference.WithName node.
 We do not count in the size of the diff list.
      Specified by:
      computeQuotaUsage in class INode
      Parameters:
      bsps - Block storage policy suite to calculate intended storage type usage
      blockStoragePolicyId - block storage policy id of the current INode
      useCache - Whether to use cached quota usage. Note that INodeReference.WithName node never uses cache for its subtree.
      lastSnapshotId - Snapshot.CURRENT_STATE_ID indicates the computation is in the current tree. Otherwise the id indicates the computation range for a INodeReference.WithName node.
      Returns:
      The subtree quota counts.

    • computeContentSummary

      public ContentSummaryComputationContext computeContentSummary(int snapshotId, ContentSummaryComputationContext summary)
      Description copied from class: INode
      Count subtree content summary with a ContentCounts.
      Specified by:
      computeContentSummary in class INode
      Parameters:
      snapshotId - Specify the time range for the calculation. If this parameter equals to Snapshot.CURRENT_STATE_ID, the result covers both the current states and all the snapshots. Otherwise the result only covers all the files/directories contained in the specific snapshot.
      summary - the context object holding counts for the subtree.
      Returns:
      The same objects as summary.

    • dumpTreeRecursively

      public void dumpTreeRecursively(PrintWriter out, StringBuilder prefix, int snapshot)
      Description copied from class: INode
      Dump tree recursively.
      Overrides:
      dumpTreeRecursively in class INode
      prefix - The prefix string that each line should print.

    • accept

      public void accept(NamespaceVisitor visitor, int snapshot)
      Description copied from class: INode
      Accept a visitor to visit this INode.
      Overrides:
      accept in class INode

    • removeAclFeature

      public void removeAclFeature()
      Overrides:
      removeAclFeature in class INodeWithAdditionalFields

    • addAclFeature

      public void addAclFeature(AclFeature f)
      Overrides:
      addAclFeature in class INodeWithAdditionalFields

    • removeXAttrFeature

      public void removeXAttrFeature()
      Overrides:
      removeXAttrFeature in class INodeWithAdditionalFields

    • addXAttrFeature

      public void addXAttrFeature(XAttrFeature f)
      Overrides:
      addXAttrFeature in class INodeWithAdditionalFields

    • getStoragePolicyID

      public byte getStoragePolicyID()
      Specified by:
      getStoragePolicyID in class INode
      Returns:
      the latest block storage policy id of the INode. Specifically, if a storage policy is directly specified on the INode then return the ID of that policy. Otherwise follow the latest parental path and return the ID of the first specified storage policy.

    • getLocalStoragePolicyID

      public byte getLocalStoragePolicyID()
      Specified by:
      getLocalStoragePolicyID in class INode
      Returns:
      the storage policy directly specified on the INode. Return HdfsConstants.BLOCK_STORAGE_POLICY_ID_UNSPECIFIED if no policy has been specified.