Do not acquire lock for file.Sync() fsync call

[1978629634]

What this PR does / why we need it:

For file.Sync() (the fsync system call that flushes the kernel buffer to disk), there is no need to acquire a lock; let the kernel handle it.

Which issue(s) this PR fixes:

Fixes #403

Release note:

Do not acquire lock for file.Sync() fsync call

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: 1978629634 / name: Chen Pu (ccda4e7)

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[1978629634]

Hi @pohly @harshanarayana @mengjiao-liu , Could you please take a look at this pull request when you have a chance? I'd appreciate your review and feedback.

[dims]

xref: golang#68

[1978629634]

xref: golang#68

Could you please review it again?

[yuzhiquan]

/lgtm

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[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: 1978629634, yuzhiquan
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[k8s-ci-robot]

New changes are detected. LGTM label has been removed.

[1978629634]

xref: golang#68

Could you please review it again?

The changes to the glog have a potential issue. Besides the FlushDaemon, there is also an exit() call that invokes flushAll. If we release the lock and call file.Sync() in the exit code, the program may continue to write logs, which could lead to the program running longer than expected.
In the exit(), we should acquire the lock and call file.Sync() to ensure a clean shutdown.
cc @dims

[dims]

/assign @pohly

[1978629634]

@pohly I'd appreciate it if you could take a look at this pull request and offer any suggestions you may have. Your feedback would be invaluable. Thank you so much!

[pohly]

I have it on my TODO list, but it may take a while before I get to it.

[logicalhan]

/triage accepted
/assign @pohly

[logicalhan]

/assign @shiva1333

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