/// <summary>
/// Remove the snapshot with the given name from
/// <see cref="snapshotsByNames"/>
/// ,
/// and delete all the corresponding DirectoryDiff.
/// </summary>
/// <param name="snapshotRoot">The directory where we take snapshots</param>
/// <param name="snapshotName">The name of the snapshot to be removed</param>
/// <param name="collectedBlocks">Used to collect information to update blocksMap</param>
/// <returns>
/// The removed snapshot. Null if no snapshot with the given name
/// exists.
/// </returns>
/// <exception cref="Org.Apache.Hadoop.Hdfs.Protocol.SnapshotException"/>
public virtual Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot RemoveSnapshot
(BlockStoragePolicySuite bsps, INodeDirectory snapshotRoot, string snapshotName,
INode.BlocksMapUpdateInfo collectedBlocks, IList <INode> removedINodes)
{
int i = SearchSnapshot(DFSUtil.String2Bytes(snapshotName));
if (i < 0)
{
throw new SnapshotException("Cannot delete snapshot " + snapshotName + " from path "
+ snapshotRoot.GetFullPathName() + ": the snapshot does not exist.");
}
else
{
Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot snapshot = snapshotsByNames
[i];
int prior = Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot.FindLatestSnapshot
(snapshotRoot, snapshot.GetId());
try
{
QuotaCounts counts = snapshotRoot.CleanSubtree(bsps, snapshot.GetId(), prior, collectedBlocks
, removedINodes);
INodeDirectory parent = snapshotRoot.GetParent();
if (parent != null)
{
// there will not be any WithName node corresponding to the deleted
// snapshot, thus only update the quota usage in the current tree
parent.AddSpaceConsumed(counts.Negation(), true);
}
}
catch (QuotaExceededException e)
{
INode.Log.Error("BUG: removeSnapshot increases namespace usage.", e);
}
// remove from snapshotsByNames after successfully cleaning the subtree
snapshotsByNames.Remove(i);
return(snapshot);
}
}