/*
* Roll back to old snapshot at the block pool level
* If previous directory exists:
* <ol>
* <li>Rename <SD>/current/<bpid>/current to removed.tmp</li>
* <li>Rename * <SD>/current/<bpid>/previous to current</li>
* <li>Remove removed.tmp</li>
* </ol>
*
* Do nothing if previous directory does not exist.
* @param bpSd Block pool storage directory at <SD>/current/<bpid>
*/
/// <exception cref="System.IO.IOException"/>
internal virtual void DoRollback(Storage.StorageDirectory bpSd, NamespaceInfo nsInfo
)
{
FilePath prevDir = bpSd.GetPreviousDir();
// regular startup if previous dir does not exist
if (!prevDir.Exists())
{
return;
}
// read attributes out of the VERSION file of previous directory
Org.Apache.Hadoop.Hdfs.Server.Datanode.BlockPoolSliceStorage prevInfo = new Org.Apache.Hadoop.Hdfs.Server.Datanode.BlockPoolSliceStorage
();
prevInfo.ReadPreviousVersionProperties(bpSd);
// We allow rollback to a state, which is either consistent with
// the namespace state or can be further upgraded to it.
// In another word, we can only roll back when ( storedLV >= software LV)
// && ( DN.previousCTime <= NN.ctime)
if (!(prevInfo.GetLayoutVersion() >= HdfsConstants.DatanodeLayoutVersion && prevInfo
.GetCTime() <= nsInfo.GetCTime()))
{
// cannot rollback
throw new InconsistentFSStateException(bpSd.GetRoot(), "Cannot rollback to a newer state.\nDatanode previous state: LV = "
+ prevInfo.GetLayoutVersion() + " CTime = " + prevInfo.GetCTime() + " is newer than the namespace state: LV = "
+ HdfsConstants.DatanodeLayoutVersion + " CTime = " + nsInfo.GetCTime());
}
Log.Info("Rolling back storage directory " + bpSd.GetRoot() + ".\n target LV = "
+ nsInfo.GetLayoutVersion() + "; target CTime = " + nsInfo.GetCTime());
FilePath tmpDir = bpSd.GetRemovedTmp();
System.Diagnostics.Debug.Assert(!tmpDir.Exists(), "removed.tmp directory must not exist."
);
// 1. rename current to tmp
FilePath curDir = bpSd.GetCurrentDir();
System.Diagnostics.Debug.Assert(curDir.Exists(), "Current directory must exist.");
Rename(curDir, tmpDir);
// 2. rename previous to current
Rename(prevDir, curDir);
// 3. delete removed.tmp dir
DeleteDir(tmpDir);
Log.Info("Rollback of " + bpSd.GetRoot() + " is complete");
}
/// <exception cref="System.IO.IOException"/>
private bool CheckLayoutVersion(NamespaceInfo nsInfo)
{
return(nsInfo.GetLayoutVersion() == HdfsConstants.NamenodeLayoutVersion);
}
/// <summary>
/// Analyze whether a transition of the BP state is required and
/// perform it if necessary.
/// </summary>
/// <remarks>
/// Analyze whether a transition of the BP state is required and
/// perform it if necessary.
/// <br />
/// Rollback if previousLV >= LAYOUT_VERSION && prevCTime <= namenode.cTime.
/// Upgrade if this.LV > LAYOUT_VERSION || this.cTime < namenode.cTime Regular
/// startup if this.LV = LAYOUT_VERSION && this.cTime = namenode.cTime
/// </remarks>
/// <param name="sd">storage directory <SD>/current/<bpid></param>
/// <param name="nsInfo">namespace info</param>
/// <param name="startOpt">startup option</param>
/// <exception cref="System.IO.IOException"/>
private void DoTransition(DataNode datanode, Storage.StorageDirectory sd, NamespaceInfo
nsInfo, HdfsServerConstants.StartupOption startOpt)
{
if (startOpt == HdfsServerConstants.StartupOption.Rollback && sd.GetPreviousDir()
.Exists())
{
Preconditions.CheckState(!GetTrashRootDir(sd).Exists(), sd.GetPreviousDir() + " and "
+ GetTrashRootDir(sd) + " should not " + " both be present.");
DoRollback(sd, nsInfo);
}
else
{
// rollback if applicable
if (startOpt == HdfsServerConstants.StartupOption.Rollback && !sd.GetPreviousDir(
).Exists())
{
// Restore all the files in the trash. The restored files are retained
// during rolling upgrade rollback. They are deleted during rolling
// upgrade downgrade.
int restored = RestoreBlockFilesFromTrash(GetTrashRootDir(sd));
Log.Info("Restored " + restored + " block files from trash.");
}
}
ReadProperties(sd);
CheckVersionUpgradable(this.layoutVersion);
System.Diagnostics.Debug.Assert(this.layoutVersion >= HdfsConstants.DatanodeLayoutVersion
, "Future version is not allowed");
if (GetNamespaceID() != nsInfo.GetNamespaceID())
{
throw new IOException("Incompatible namespaceIDs in " + sd.GetRoot().GetCanonicalPath
() + ": namenode namespaceID = " + nsInfo.GetNamespaceID() + "; datanode namespaceID = "
+ GetNamespaceID());
}
if (!blockpoolID.Equals(nsInfo.GetBlockPoolID()))
{
throw new IOException("Incompatible blockpoolIDs in " + sd.GetRoot().GetCanonicalPath
() + ": namenode blockpoolID = " + nsInfo.GetBlockPoolID() + "; datanode blockpoolID = "
+ blockpoolID);
}
if (this.layoutVersion == HdfsConstants.DatanodeLayoutVersion && this.cTime == nsInfo
.GetCTime())
{
return;
}
// regular startup
if (this.layoutVersion > HdfsConstants.DatanodeLayoutVersion)
{
int restored = RestoreBlockFilesFromTrash(GetTrashRootDir(sd));
Log.Info("Restored " + restored + " block files from trash " + "before the layout upgrade. These blocks will be moved to "
+ "the previous directory during the upgrade");
}
if (this.layoutVersion > HdfsConstants.DatanodeLayoutVersion || this.cTime < nsInfo
.GetCTime())
{
DoUpgrade(datanode, sd, nsInfo);
// upgrade
return;
}
// layoutVersion == LAYOUT_VERSION && this.cTime > nsInfo.cTime
// must shutdown
throw new IOException("Datanode state: LV = " + this.GetLayoutVersion() + " CTime = "
+ this.GetCTime() + " is newer than the namespace state: LV = " + nsInfo.GetLayoutVersion
() + " CTime = " + nsInfo.GetCTime());
}
