/// <summary>Finalize the upgrade.</summary>
/// <remarks>
/// Finalize the upgrade. The previous dir, if any, will be renamed and
/// removed. After this is completed, rollback is no longer allowed.
/// </remarks>
/// <param name="sd">the storage directory to finalize</param>
/// <exception cref="System.IO.IOException">in the event of error</exception>
internal static void DoFinalize(Storage.StorageDirectory sd)
{
FilePath prevDir = sd.GetPreviousDir();
if (!prevDir.Exists())
{
// already discarded
Log.Info("Directory " + prevDir + " does not exist.");
Log.Info("Finalize upgrade for " + sd.GetRoot() + " is not required.");
return;
}
Log.Info("Finalizing upgrade of storage directory " + sd.GetRoot());
Preconditions.CheckState(sd.GetCurrentDir().Exists(), "Current directory must exist."
);
FilePath tmpDir = sd.GetFinalizedTmp();
// rename previous to tmp and remove
NNStorage.Rename(prevDir, tmpDir);
NNStorage.DeleteDir(tmpDir);
Log.Info("Finalize upgrade for " + sd.GetRoot() + " is complete.");
}
/// <summary>Perform rollback of the storage dir to the previous state.</summary>
/// <remarks>
/// Perform rollback of the storage dir to the previous state. The existing
/// current dir is removed, and the previous dir is renamed to current.
/// </remarks>
/// <param name="sd">the storage directory to roll back.</param>
/// <exception cref="System.IO.IOException">in the event of error</exception>
internal static void DoRollBack(Storage.StorageDirectory sd)
{
FilePath prevDir = sd.GetPreviousDir();
if (!prevDir.Exists())
{
return;
}
FilePath tmpDir = sd.GetRemovedTmp();
Preconditions.CheckState(!tmpDir.Exists(), "removed.tmp directory must not exist for rollback."
+ "Consider restarting for recovery.");
// rename current to tmp
FilePath curDir = sd.GetCurrentDir();
Preconditions.CheckState(curDir.Exists(), "Current directory must exist for rollback."
);
NNStorage.Rename(curDir, tmpDir);
// rename previous to current
NNStorage.Rename(prevDir, curDir);
// delete tmp dir
NNStorage.DeleteDir(tmpDir);
Log.Info("Rollback of " + sd.GetRoot() + " is complete.");
}
