cluster: add the RLock back

[rleungx]

Signed-off-by: Ryan Leung rleungx@gmail.com

What problem does this PR solve?

Issue Number: Close #5006.

What is changed and how does it work?

This PR adds the RLock back because we need to ensure the correctness of concurrency.

Related changes

• Need to cherry-pick to the release branch

Release note

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• CabinfeverB
• JmPotato

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[codecov]

Codecov Report

Merging #5022 (61b8b1f) into master (efb4c9f) will decrease coverage by 0.25%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #5022      +/-   ##
==========================================
- Coverage   75.61%   75.35%   -0.26%     
==========================================
  Files         307      307              
  Lines       30231    30233       +2     
==========================================
- Hits        22858    22782      -76     
- Misses       5390     5443      +53     
- Partials     1983     2008      +25     

Flag	Coverage Δ
unittests	75.35% <100.00%> (-0.26%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
server/cluster/cluster.go	82.53% <100.00%> (+0.03%)	⬆️
...erver/config/service_middleware_persist_options.go	88.88% <0.00%> (-11.12%)	⬇️
server/schedulers/shuffle_hot_region.go	55.55% <0.00%> (-10.11%)	⬇️
server/tso/local_allocator.go	71.62% <0.00%> (-6.76%)	⬇️
server/region_syncer/server.go	83.15% <0.00%> (-4.35%)	⬇️
server/tso/allocator_manager.go	61.73% <0.00%> (-3.67%)	⬇️
pkg/etcdutil/etcdutil.go	85.05% <0.00%> (-3.45%)	⬇️
server/tso/tso.go	67.79% <0.00%> (-2.83%)	⬇️
server/schedule/labeler/rules.go	87.50% <0.00%> (-2.28%)	⬇️
server/election/leadership.go	78.35% <0.00%> (-2.07%)	⬇️
... and 17 more

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[rleungx]

/merge

[ti-chi-bot]

@rleungx: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[rleungx]

/merge cancel

[AndreMouche]

LGTM

[rleungx]

/merge

[ti-chi-bot]

@rleungx: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 61b8b1f

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #5023.