HDFS-13671. Namenode deletes large dir slowly caused by FoldedTreeSet#removeAndGet

[ferhui]

Conflicts:
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockManager.java
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/TestFsDatasetImpl.java

NOTICE

Please create an issue in ASF JIRA before opening a pull request,
and you need to set the title of the pull request which starts with
the corresponding JIRA issue number. (e.g. HADOOP-XXXXX. Fix a typo in YYY.)
For more details, please see https://cwiki.apache.org/confluence/display/HADOOP/How+To+Contribute

[hadoop-yetus]

🎊 +1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 38s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 1s		No case conflicting files found.
+0 🆗	codespell	0m 0s		codespell was not available.
+0 🆗	buf	0m 0s		buf was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
+1 💚	test4tests	0m 0s		The patch appears to include 18 new or modified test files.
			_ branch-3.3 Compile Tests _
+1 💚	mvninstall	30m 4s		branch-3.3 passed
+1 💚	compile	1m 15s		branch-3.3 passed
+1 💚	checkstyle	0m 59s		branch-3.3 passed
+1 💚	mvnsite	1m 22s		branch-3.3 passed
+1 💚	javadoc	1m 28s		branch-3.3 passed
+1 💚	spotbugs	3m 6s		branch-3.3 passed
+1 💚	shadedclient	18m 31s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+1 💚	mvninstall	1m 11s		the patch passed
+1 💚	compile	1m 6s		the patch passed
+1 💚	cc	1m 6s		the patch passed
+1 💚	javac	1m 6s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
-0 ⚠️	checkstyle	0m 49s	/results-checkstyle-hadoop-hdfs-project_hadoop-hdfs.txt	hadoop-hdfs-project/hadoop-hdfs: The patch generated 1 new + 1329 unchanged - 13 fixed = 1330 total (was 1342)
+1 💚	mvnsite	1m 10s		the patch passed
+1 💚	xml	0m 1s		The patch has no ill-formed XML file.
+1 💚	javadoc	1m 20s		the patch passed
+1 💚	spotbugs	3m 3s		the patch passed
+1 💚	shadedclient	18m 8s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
+1 💚	unit	184m 39s		hadoop-hdfs in the patch passed.
+1 💚	asflicense	0m 46s		The patch does not generate ASF License warnings.
		267m 41s

Subsystem	Report/Notes
Docker	ClientAPI=1.41 ServerAPI=1.41 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-3113/1/artifact/out/Dockerfile
GITHUB PR	#3113
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell cc buflint bufcompat xml
uname	Linux 1b5f8eec6845 4.15.0-60-generic #67-Ubuntu SMP Thu Aug 22 16:55:30 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	branch-3.3 / dac7c11
Default Java	Private Build-1.8.0_292-8u292-b10-0ubuntu1~18.04-b10
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-3113/1/testReport/
Max. process+thread count	3455 (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-3113/1/console
versions	git=2.17.1 maven=3.6.0 spotbugs=4.2.2
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[ferhui]

cherry pick to branch-3.3
@AlphaGouGe Could you please double check?

[hust-hhb]

LGTM

[ferhui]

@AlphaGouGe Thanks