[HDFS-4489] Use InodeID as as an identifier of a file in HDFS protocols and APIs

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.1.0-beta
• Component/s: namenode
• Target Version/s: 2.1.0-beta
• Assignee: Brandon Li
• Reporter: Brandon Li
• Created: 11/Feb/13 18:45
• Updated: 17/Apr/18 21:43
• Resolved: 10/Apr/14 16:45

Description

The benefit of using InodeID to uniquely identify a file can be multiple folds. Here are a few of them:

1. uniquely identify a file cross rename, related JIRAs include HDFS-4258, HDFS-4437.
2. modification checks in tools like distcp. Since a file could have been replaced or renamed to, the file name and size combination is no t reliable, but the combination of file id and size is unique.
3. id based protocol support (e.g., NFS)
4. to make the pluggable block placement policy use fileid instead of filename (HDFS-385).

Issue Links

• duplicates: HADOOP-6149 FileStatus can support a fileid per path
• duplicates: HDFS-487 HDFS should expose a fileid to uniquely identify a file
• is related to: HDFS-4258 Rename of Being Written Files
• relates to: HDFS-13469 RBF: Support InodeID in the Router

Sub-Tasks

• Add a unique id to each INode: Closed
• Persist inode id in fsimage and editlog: Closed
• Refactor INodeId and GenerationStamp: Closed
• Provide a mapping from INodeId to INode: Closed
• The SecondaryNameNode may change the inode id of root while doing checkpoint: Resolved
• NPE in FSDirectory.resolvePath(): Closed
• Concat operation does not remove concatenated files from InodeMap: Closed