[HDFS-13829] Remove redundant condition judgement in DirectoryScanner#scan

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.1.0
• Fix Version/s: 3.2.0
• Component/s: datanode
• Target Version/s: 3.2.0
• Hadoop Flags: Reviewed
• Assignee: liaoyuxiangqin
• Reporter: liaoyuxiangqin
• Created: 16/Aug/18 03:36
• Updated: 16/Aug/18 11:08
• Resolved: 16/Aug/18 10:47

Description

When i read the scan() of DirectoryScanner class in datanode, i found the following condition code could be more simplify and easy to understand.

DirectoryScanner.java

if (d < blockpoolReport.length) {
            // There may be multiple on-disk records for the same block, don't increment
            // the memory record pointer if so.
            ScanInfo nextInfo = blockpoolReport[Math.min(d, blockpoolReport.length - 1)];
            if (nextInfo.getBlockId() != info.getBlockId()) {
              ++m;
            }
} else {
            ++m;
 }

as described above code segmet, i find the code of d < blockpoolReport.length and the max of d is blockpoolReport.length-1, so that result of Math.min(d, blockpoolReport.length - 1) always is d, so i think needn't to get min value of scan index and length for blockpoolReport.

thanks!