[HADOOP-18577] ABFS: add probes of readahead fix

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.3.5
• Fix Version/s: 3.4.0, 3.3.5
• Component/s: fs/azure
• Labels: pull-request-available
• Target Version/s: 3.3.5
• Hadoop Flags: Reviewed
• Assignee: Steve Loughran
• Reporter: Steve Loughran
• Created: 15/Dec/22 17:04
• Updated: 27/Jan/24 08:53
• Resolved: 16/Dec/22 16:20

Description

Followup patch as to HADOOP-18456 to
aid in probing for read correctness of
hadoop ABFS client across different releases.

• ReadBufferManager constructor logs the fact it is safe at TRACE
• AbfsInputStream declares it is fixed in toString()
  by including fs.azure.capability.readahead.safe" in the
  result.

The ABFS FileSystem hasPathCapability("fs.azure.capability.readahead.safe")
probe returns true to indicate the client's readahead manager has been fixed
to be safe when prefetching.

All Hadoop releases for which probe this returns false
and for which the probe "fs.capability.etags.available"
returns true at risk of returning invalid data when reading
ADLS Gen2/Azure storage data.

Issue Links

• depends upon: HADOOP-18546 disable purging list of in progress reads in abfs stream closed
• links to: GitHub Pull Request #5205
• links to: GitHub Pull Request #5232