[HDFS-15760] Validate the target indices in ErasureCoding worker in reconstruction process

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.4.0
• Component/s: ec
• Assignee: Uma Maheswara Rao G
• Reporter: Uma Maheswara Rao G
• Created: 04/Jan/21 17:41
• Updated: 05/Apr/21 10:00

Description

As we have seen issues like 

1. HDFS-15186
2. HDFS-14768

It is a good idea to validate the indices at the ECWorker side and skip the unintended in indices from target list.

Both of the issues triggered because, NN accidentally scheduled for reconstruction in decom process due to busy node. We have fixed to make sure NN considers busy nodes as live replicas. However, it may be good idea to safe gaud the condition at ECWorker also in case if any other condition triggers and that leads ECWroker to calculate the indices similar the above issues, then EC function returns wrong o/p.  I think it's ok to recover only the missing indices from the given src indices.