/// <summary>
/// Check if the given INode (or one of its descendants) is snapshottable and
/// already has snapshots.
/// </summary>
/// <param name="target">The given INode</param>
/// <param name="snapshottableDirs">
/// The list of directories that are snapshottable
/// but do not have snapshots yet
/// </param>
/// <exception cref="Org.Apache.Hadoop.Hdfs.Protocol.SnapshotException"/>
internal static void CheckSnapshot(INode target, IList <INodeDirectory> snapshottableDirs
)
{
if (target.IsDirectory())
{
INodeDirectory targetDir = target.AsDirectory();
DirectorySnapshottableFeature sf = targetDir.GetDirectorySnapshottableFeature();
if (sf != null)
{
if (sf.GetNumSnapshots() > 0)
{
string fullPath = targetDir.GetFullPathName();
throw new SnapshotException("The directory " + fullPath + " cannot be deleted since "
+ fullPath + " is snapshottable and already has snapshots");
}
else
{
if (snapshottableDirs != null)
{
snapshottableDirs.AddItem(targetDir);
}
}
}
foreach (INode child in targetDir.GetChildrenList(Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot
.CurrentStateId))
{
CheckSnapshot(child, snapshottableDirs);
}
}
}
/// <summary>Get a listing of all the snapshots of a snapshottable directory</summary>
/// <exception cref="System.IO.IOException"/>
private static DirectoryListing GetSnapshotsListing(FSDirectory fsd, string src,
byte[] startAfter)
{
Preconditions.CheckState(fsd.HasReadLock());
Preconditions.CheckArgument(src.EndsWith(HdfsConstants.SeparatorDotSnapshotDir),
"%s does not end with %s", src, HdfsConstants.SeparatorDotSnapshotDir);
string dirPath = FSDirectory.NormalizePath(Sharpen.Runtime.Substring(src, 0, src.
Length - HdfsConstants.DotSnapshotDir.Length));
INode node = fsd.GetINode(dirPath);
INodeDirectory dirNode = INodeDirectory.ValueOf(node, dirPath);
DirectorySnapshottableFeature sf = dirNode.GetDirectorySnapshottableFeature();
if (sf == null)
{
throw new SnapshotException("Directory is not a snapshottable directory: " + dirPath
);
}
ReadOnlyList <Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot> snapshots =
sf.GetSnapshotList();
int skipSize = ReadOnlyList.Util.BinarySearch(snapshots, startAfter);
skipSize = skipSize < 0 ? -skipSize - 1 : skipSize + 1;
int numOfListing = Math.Min(snapshots.Size() - skipSize, fsd.GetLsLimit());
HdfsFileStatus[] listing = new HdfsFileStatus[numOfListing];
for (int i = 0; i < numOfListing; i++)
{
Snapshot.Root sRoot = snapshots.Get(i + skipSize).GetRoot();
listing[i] = CreateFileStatus(fsd, src, sRoot.GetLocalNameBytes(), sRoot, BlockStoragePolicySuite
.IdUnspecified, Org.Apache.Hadoop.Hdfs.Server.Namenode.Snapshot.Snapshot.CurrentStateId
, false, INodesInPath.FromINode(sRoot));
}
return(new DirectoryListing(listing, snapshots.Size() - skipSize - numOfListing));
}