HDFS-16162.Improve DFSUtil#checkProtectedDescendants() related parameter comments.

[jianghuazhu]

…ter comments.

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[hadoop-yetus]

💔 -1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 52s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 0s		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	32m 53s		trunk passed
+1 💚	compile	1m 23s		trunk passed with JDK Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04
+1 💚	compile	1m 15s		trunk passed with JDK Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
+1 💚	checkstyle	0m 59s		trunk passed
+1 💚	mvnsite	1m 21s		trunk passed
+1 💚	javadoc	0m 55s		trunk passed with JDK Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04
+1 💚	javadoc	1m 28s		trunk passed with JDK Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
+1 💚	spotbugs	3m 17s		trunk passed
+1 💚	shadedclient	19m 10s		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 12s		the patch passed with JDK Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
+1 💚	javac	1m 12s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	0m 52s		the patch passed
+1 💚	mvnsite	1m 20s		the patch passed
-1 ❌	javadoc	0m 55s	/results-javadoc-javadoc-hadoop-hdfs-project_hadoop-hdfs-jdkUbuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04.txt	hadoop-hdfs-project_hadoop-hdfs-jdkUbuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04 with JDK Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04 generated 1 new + 98 unchanged - 1 fixed = 99 total (was 99)
+1 💚	javadoc	1m 30s		the patch passed with JDK Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
+1 💚	spotbugs	3m 34s		the patch passed
+1 💚	shadedclient	20m 27s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
-1 ❌	unit	371m 49s	/patch-unit-hadoop-hdfs-project_hadoop-hdfs.txt	hadoop-hdfs in the patch passed.
+1 💚	asflicense	0m 42s		The patch does not generate ASF License warnings.
		466m 2s

Reason	Tests
Failed junit tests	hadoop.hdfs.TestSnapshotCommands
	hadoop.hdfs.server.namenode.TestDecommissioningStatusWithBackoffMonitor
	hadoop.hdfs.TestHDFSFileSystemContract
	hadoop.hdfs.server.namenode.ha.TestSeveralNameNodes
	hadoop.hdfs.server.namenode.ha.TestEditLogTailer

Subsystem	Report/Notes
Docker	ClientAPI=1.41 ServerAPI=1.41 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-3295/1/artifact/out/Dockerfile
GITHUB PR	#3295
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell
uname	Linux ddbc6e9241b3 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 / 186da46
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-3295/1/testReport/
Max. process+thread count	2178 (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-3295/1/console
versions	git=2.25.1 maven=3.6.3 spotbugs=4.2.2
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[jianghuazhu]

Some exceptions occurred in UT.
But it seems that these phenomena are not highly related to the code I submitted;

[jianghuazhu]

@aajisaka , can you help review the code I submitted.
thank you very much.

[jianghuazhu]

@jojochuang, @virajjasani, can you help review the code.
If there are some imperfections, welcome to communicate, and I will work hard to promote improvement.
thank you very much.

[ayushtkn]

+1

[jianghuazhu]

@ayushtkn , thanks for your comment.

[virajjasani]

+1 (non-binding)

[jianghuazhu]

Thanks @virajjasani for the comment.

[jojochuang]

merged. thanks all!