HDFS-16939. Fix the thread safety bug in LowRedundancyBlocks. (#5450)…

[zhangshuyan0]

…. Contributed by Shuyan Zhang.

Description of PR

Cherry-pick from trunk.
The remove method in LowRedundancyBlocks is not protected by synchronized. This method is private and is called by BlockManager. As a result, priorityQueues has the risk of being accessed concurrently by multiple threads.

[hadoop-yetus]

💔 -1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	7m 19s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 0s		codespell was not available.
+0 🆗	detsecrets	0m 0s		detect-secrets 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.
			_ branch-3.3 Compile Tests _
+1 💚	mvninstall	40m 41s		branch-3.3 passed
+1 💚	compile	1m 18s		branch-3.3 passed
+1 💚	checkstyle	0m 56s		branch-3.3 passed
+1 💚	mvnsite	1m 25s		branch-3.3 passed
+1 💚	javadoc	1m 39s		branch-3.3 passed
+1 💚	spotbugs	3m 24s		branch-3.3 passed
+1 💚	shadedclient	26m 28s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+1 💚	mvninstall	1m 16s		the patch passed
+1 💚	compile	1m 6s		the patch passed
+1 💚	javac	1m 6s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	0m 41s		the patch passed
+1 💚	mvnsite	1m 14s		the patch passed
+1 💚	javadoc	1m 24s		the patch passed
+1 💚	spotbugs	3m 10s		the patch passed
+1 💚	shadedclient	25m 39s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
-1 ❌	unit	204m 2s	/patch-unit-hadoop-hdfs-project_hadoop-hdfs.txt	hadoop-hdfs in the patch passed.
+1 💚	asflicense	0m 51s		The patch does not generate ASF License warnings.
		320m 24s

Reason	Tests
Failed junit tests	hadoop.hdfs.server.datanode.TestDataNodeRollingUpgrade

Subsystem	Report/Notes
Docker	ClientAPI=1.42 ServerAPI=1.42 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-5471/1/artifact/out/Dockerfile
GITHUB PR	#5471
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell detsecrets
uname	Linux acefb07392f6 4.15.0-200-generic #211-Ubuntu SMP Thu Nov 24 18:16:04 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	branch-3.3 / d12c16d
Default Java	Private Build-1.8.0_362-8u362-ga-0ubuntu1~18.04.1-b09
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-5471/1/testReport/
Max. process+thread count	3387 (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-5471/1/console
versions	git=2.17.1 maven=3.6.0 spotbugs=4.2.2
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[Hexiaoqiao]

LGTM. +1 from my side. The failed unit test looks not relate with this PR.

[Hexiaoqiao]

Committed to branch-3.3 and branch-3.3.5