Details
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Bug
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Status: Resolved
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Minor
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Resolution: Fixed
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1.3.0
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None
Description
There are two race conditions of subDirs in DiskBlockManager:
1. `getAllFiles` does not use correct locks to read the contents in `subDirs`. Although it's designed for testing, it's still worth to add correct locks to eliminate the race condition.
2. The double-check has a race condition in `getFile(filename: String)`. If a thread finds `subDirs(dirId)(subDirId)` is not null out of the `synchronized` block, it may not be able to see the correct content of the File instance pointed by `subDirs(dirId)(subDirId)` according to the Java memory model (there is no volatile variable here).