/// <returns>the id of the last snapshot.</returns>
public int GetLastSnapshotId()
{
AbstractINodeDiff <N, A, D> last = GetLast();
return(last == null ? Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot.CurrentStateId
: last.GetSnapshotId());
}
/// <summary>Delete a snapshot.</summary>
/// <remarks>
/// Delete a snapshot. The synchronization of the diff list will be done
/// outside. If the diff to remove is not the first one in the diff list, we
/// need to combine the diff with its previous one.
/// </remarks>
/// <param name="snapshot">The id of the snapshot to be deleted</param>
/// <param name="prior">The id of the snapshot taken before the to-be-deleted snapshot
/// </param>
/// <param name="collectedBlocks">Used to collect information for blocksMap update</param>
/// <returns>delta in namespace.</returns>
public QuotaCounts DeleteSnapshotDiff(BlockStoragePolicySuite bsps, int snapshot,
int prior, N currentINode, INode.BlocksMapUpdateInfo collectedBlocks, IList <INode
> removedINodes)
{
int snapshotIndex = Sharpen.Collections.BinarySearch(diffs, snapshot);
QuotaCounts counts = new QuotaCounts.Builder().Build();
D removed = null;
if (snapshotIndex == 0)
{
if (prior != Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot.NoSnapshotId)
{
// there is still snapshot before
// set the snapshot to latestBefore
diffs[snapshotIndex].SetSnapshotId(prior);
}
else
{
// there is no snapshot before
removed = diffs.Remove(0);
counts.Add(removed.DestroyDiffAndCollectBlocks(bsps, currentINode, collectedBlocks
, removedINodes));
}
}
else
{
if (snapshotIndex > 0)
{
AbstractINodeDiff <N, A, D> previous = diffs[snapshotIndex - 1];
if (previous.GetSnapshotId() != prior)
{
diffs[snapshotIndex].SetSnapshotId(prior);
}
else
{
// combine the to-be-removed diff with its previous diff
removed = diffs.Remove(snapshotIndex);
if (previous.snapshotINode == null)
{
previous.snapshotINode = removed.snapshotINode;
}
counts.Add(previous.CombinePosteriorAndCollectBlocks(bsps, currentINode, removed,
collectedBlocks, removedINodes));
previous.SetPosterior(removed.GetPosterior());
removed.SetPosterior(null);
}
}
}
return(counts);
}