fix: Better lock handling on close

[alpe]

Same as #1023 targeting master now

Summary by CodeRabbit

• Bug Fixes

  • Improved error handling for node retrieval methods.
  • Enhanced checks for active readers before deletions to ensure data integrity.

• New Features

  • Added a test case to validate the behavior of the Close method when called multiple times.

• Documentation

  • Updated test cases to cover various scenarios related to storage version management and error handling.

[coderabbitai]

Walkthrough

The changes focus on improving the nodedb.go implementation, particularly in the nodeDB struct and its methods. The modifications enhance error handling, prevent potential deadlocks, and improve the control flow of database operations. Key updates include refining the Close and startPruning methods, adding more robust error checking in node retrieval and storage version management, and ensuring thread-safe operations during pruning and deletion processes.

Changes

File	Changes
nodedb.go	- Updated Close() method to lock mutex after context cancellation - Modified startPruning() to close done channel - Improved error handling in GetNode() and GetFastNode() - Added format validation in SetFastStorageVersionToBatch() - Enhanced concurrency safety in deleteFromPruning() and saveNodeFromPruning() - Strengthened version deletion checks in DeleteVersionsTo()
nodedb_test.go	- Added test case for multiple Close() method calls - Maintained comprehensive test coverage for storage version management - Preserved performance benchmarks

Poem

🐰 In the realm of nodes and database might,
Where bits and bytes dance with delight,
Our pruning logic now stands tall and clean,
No deadlocks lurk, no errors unseen!
A rabbit's code, both swift and bright! 🔍

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📜 Recent review details

Configuration used: CodeRabbit UI
Review profile: CHILL
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📥 Commits

Reviewing files that changed from the base of the PR and between f9c402d and bf2163d.

📒 Files selected for processing (2)

• nodedb.go (2 hunks)
• nodedb_test.go (1 hunks)

🔇 Additional comments (3)

nodedb.go (2)

603-605: Properly signal pruning completion by closing ndb.done

The close(ndb.done) call before returning in the startPruning method ensures that any goroutines waiting on the done channel are notified when pruning is complete. This prevents potential goroutine leaks and ensures clean shutdown of the pruning process.

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1125-1132: Prevent deadlocks by adjusting the mutex lock in Close()

By moving the mutex lock to after the context cancellation and waiting for the pruning to finish, the Close method avoids holding the lock while potentially blocking operations occur. This change prevents possible deadlocks between Close and startPruning, ensuring that Close does not block if startPruning is waiting for the mutex.

nodedb_test.go (1)

447-447: Ensure Close() is idempotent and does not block on subsequent calls

The additional call to ndb.Close() in the TestCloseNodeDB test confirms that calling Close multiple times does not result in blocking or errors. This test enhances the robustness of the nodeDB implementation by verifying that Close is safe to call multiple times.

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