[HDFS-9754] Avoid unnecessary getBlockCollection calls in BlockManager

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.9.0, 3.0.0-alpha1, 2.8.2
• Component/s: namenode
• Hadoop Flags: Reviewed
• Assignee: Jing Zhao
• Reporter: Jing Zhao
• Created: 04/Feb/16 01:02
• Updated: 16/Oct/18 22:56
• Resolved: 30/Nov/17 22:58

Description

Currently BlockManager calls Namesystem#getBlockCollection in order to:
1. check if the block has already been abandoned
2. identify the storage policy of the block
3. meta save

For #1 we can use BlockInfo's internal state instead of checking if the corresponding file still exists.

Issue Links

• breaks: HDFS-12638 Delete copy-on-truncate block along with the original block, when deleting a file being truncated
• is related to: HDFS-13999 Bogus missing block warning if the file is under construction when NN starts
• is related to: HDFS-12880 Disallow abandoned blocks in the BlocksMap