[HDFS-4771] Remove the assumption that symlink is inside HDFS namespace and resolvable

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: 3.0.0-alpha1
• Component/s: namenode
• Assignee: Unassigned
• Reporter: Brandon Li
• Created: 28/Apr/13 21:21
• Updated: 12/May/16 18:13
• Resolved: 03/Jul/13 19:21

Description

Currently HDFS always resolves symlink when setting certain file attributes, such as setPermission and setTime. And thus the client can't set some file attributes of the symlink itself.

Two major problems with current symlink support:
1. HDFS assumes the link is inside its own namespace. This is a problem when HDFS is integrated into client's file system namespace.
2. Suppose the linked target is inside HFDS, HDFS doesn't really check whether the target saved in the link file is a valid path. Even the target was valid, it could become invalid as the namespace changes.

For example, create a symlink /user/brandon/iamlink.lnk and it has the content(target) as "/invalid/path". The file /user/brandon/iamlink.lnk can't be deleted since HDFS can't resolve it.

Issue Links

• relates to: HDFS-948 Allow setting permissions on links