Basically it needs to be repaired, if fsck or Disk Utility don't repair it, save the data to an external.
Generally if you can't fix it, the file system will crash and burn LATER (don't know when) ... and you will get a flashing question mark at some point.
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1. Save the data.
2. Fix the file system
3. If fsck or Disk Utility don't work, there are alternatives.