HDFS-16326. Simplify the code for DiskBalancer

[tomscut]

JIRA: HDFS-16326.

Simplify the code for DiskBalancer.

[hadoop-yetus]

💔 -1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 56s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 1s		codespell was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
-1 ❌	test4tests	0m 0s		The patch doesn't appear to include any new or modified tests. Please justify why no new tests are needed for this patch. Also please list what manual steps were performed to verify this patch.
			_ trunk Compile Tests _
+1 💚	mvninstall	35m 6s		trunk passed
+1 💚	compile	1m 27s		trunk passed with JDK Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04
+1 💚	compile	1m 19s		trunk passed with JDK Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
+1 💚	checkstyle	1m 0s		trunk passed
+1 💚	mvnsite	1m 27s		trunk passed
+1 💚	javadoc	1m 2s		trunk passed with JDK Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04
+1 💚	javadoc	1m 29s		trunk passed with JDK Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
+1 💚	spotbugs	3m 19s		trunk passed
+1 💚	shadedclient	25m 40s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+1 💚	mvninstall	1m 19s		the patch passed
+1 💚	compile	1m 21s		the patch passed with JDK Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04
+1 💚	javac	1m 21s		the patch passed
+1 💚	compile	1m 13s		the patch passed with JDK Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
+1 💚	javac	1m 13s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	0m 51s		the patch passed
+1 💚	mvnsite	1m 17s		the patch passed
+1 💚	javadoc	0m 51s		the patch passed with JDK Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04
+1 💚	javadoc	1m 25s		the patch passed with JDK Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
+1 💚	spotbugs	3m 26s		the patch passed
+1 💚	shadedclient	25m 8s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
+1 💚	unit	327m 49s		hadoop-hdfs in the patch passed.
+1 💚	asflicense	0m 38s		The patch does not generate ASF License warnings.
		435m 23s

Subsystem	Report/Notes
Docker	ClientAPI=1.41 ServerAPI=1.41 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-3663/1/artifact/out/Dockerfile
GITHUB PR	#3663
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell
uname	Linux 74c361a3195b 4.15.0-147-generic #151-Ubuntu SMP Fri Jun 18 19:21:19 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	trunk / 00cfd07
Default Java	Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
Multi-JDK versions	/usr/lib/jvm/java-11-openjdk-amd64:Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04 /usr/lib/jvm/java-8-openjdk-amd64:Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-3663/1/testReport/
Max. process+thread count	1836 (vs. ulimit of 5500)
modules	C: hadoop-hdfs-project/hadoop-hdfs U: hadoop-hdfs-project/hadoop-hdfs
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-3663/1/console
versions	git=2.25.1 maven=3.6.3 spotbugs=4.2.2
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[virajjasani]

+1 (non-binding)

[tomscut]

Thanks @virajjasani for your review.

[tomscut]

Hi @aajisaka @tasanuma , please take a look at this. Thank you very much.

[tasanuma]

+1.

[tasanuma]

Thanks for your contribution, @tomscut. Thanks for your review, @virajjasani.