public static void AddDiskToRaid5Volume(List <DynamicDisk> disks, Raid5Volume volume, DiskExtent newExtent, ref long bytesCopied)
{
DiskGroupDatabase database = DiskGroupDatabase.ReadFromDisks(disks, volume.DiskGroupGuid);
if (database == null)
{
throw new DatabaseNotFoundException();
}
// If there will be a power failure during the conversion, our RAID volume will resync during boot,
// To prevent destruction of the data, we temporarily convert the array to striped volume
VolumeManagerDatabaseHelper.ConvertRaidToStripedVolume(database, volume.VolumeGuid);
ulong newExtentID = VolumeManagerDatabaseHelper.AddNewExtentToVolume(database, volume, newExtent);
// Backup the first sector of the first extent to the last sector of the new extent
// (We replace the filesystem boot record with our own sector for recovery purposes)
byte[] filesystemBootRecord = volume.Extents[0].ReadSector(0);
newExtent.WriteSectors(newExtent.TotalSectors - 1, filesystemBootRecord);
AddDiskOperationBootRecord resumeRecord = new AddDiskOperationBootRecord();
resumeRecord.VolumeGuid = volume.VolumeGuid;
PrivateHeader privateHeader = PrivateHeader.ReadFromDisk(newExtent.Disk);
// privateHeader cannot be null at this point
resumeRecord.NumberOfCommittedSectors = 0;
// we use volume.WriteSectors so that the parity information will be update
// this way, we could recover the first sector of each extent if a disk will fail
volume.WriteSectors(0, resumeRecord.GetBytes());
ResumeAddDiskToRaid5Volume(disks, volume, new DynamicDiskExtent(newExtent, newExtentID), resumeRecord, ref bytesCopied);
}
public const int BackupBufferSizeLBA = 128; // there are about 180 contiguous free sectors in a private region
/// <summary>
/// Move extent to another disk
/// </summary>
public static void MoveExtentToAnotherDisk(List<DynamicDisk> disks, DynamicVolume volume, DynamicDiskExtent sourceExtent, DiskExtent relocatedExtent, ref long bytesCopied)
{
DiskGroupDatabase database = DiskGroupDatabase.ReadFromDisks(disks, volume.DiskGroupGuid);
if (database == null)
{
throw new DatabaseNotFoundException();
}
// copy the data
long transferSizeLBA = Settings.MaximumTransferSizeLBA;
for (long sectorIndex = 0; sectorIndex < relocatedExtent.TotalSectors; sectorIndex += transferSizeLBA)
{
long sectorsLeft = relocatedExtent.TotalSectors - sectorIndex;
int sectorsToRead = (int)Math.Min(transferSizeLBA, sectorsLeft);
byte[] data = sourceExtent.ReadSectors(sectorIndex, sectorsToRead);
relocatedExtent.WriteSectors(sectorIndex, data);
bytesCopied += sectorsToRead * sourceExtent.BytesPerSector;
}
// Update the database to point to the relocated extent
DynamicDisk targetDisk = DynamicDisk.ReadFromDisk(relocatedExtent.Disk);
DynamicDiskExtent dynamicRelocatedExtent = new DynamicDiskExtent(relocatedExtent, sourceExtent.ExtentID);
dynamicRelocatedExtent.Name = sourceExtent.Name;
dynamicRelocatedExtent.DiskGuid = targetDisk.DiskGuid;
VolumeManagerDatabaseHelper.UpdateExtentLocation(database, volume, dynamicRelocatedExtent);
}
private static void MoveExtentLeft(List<DynamicDisk> disks, DynamicVolume volume, MoveExtentOperationBootRecord resumeRecord, ref long bytesCopied)
{
DiskGroupDatabase database = DiskGroupDatabase.ReadFromDisks(disks, volume.DiskGroupGuid);
if (database == null)
{
throw new DatabaseNotFoundException();
}
DynamicDiskExtent relocatedExtent = DynamicDiskExtentHelper.GetByExtentID(volume.DynamicExtents, resumeRecord.ExtentID);
if (resumeRecord.OldStartSector == (ulong)relocatedExtent.FirstSector)
{
// the database update was not completed (this must be a resume operation)
relocatedExtent = new DynamicDiskExtent(relocatedExtent.Disk, (long)resumeRecord.NewStartSector, relocatedExtent.Size, resumeRecord.ExtentID);
VolumeManagerDatabaseHelper.UpdateExtentLocation(database, volume, relocatedExtent);
}
DiskExtent sourceExtent = new DiskExtent(relocatedExtent.Disk, (long)resumeRecord.OldStartSector, relocatedExtent.Size);
MoveHelper.MoveExtentDataLeft(volume, sourceExtent, relocatedExtent, resumeRecord, ref bytesCopied);
// if this is a resume, then volume is StripedVolume, otherwise it is a Raid5Volume
if (resumeRecord.RestoreRAID5)
{
VolumeManagerDatabaseHelper.ConvertStripedVolumeToRaid(database, volume.VolumeGuid);
// get the updated volume (we just reconverted to RAID-5)
volume = DynamicVolumeHelper.GetVolumeByGuid(disks, volume.VolumeGuid);
}
// restore the filesystem boot sector
byte[] filesystemBootRecord = relocatedExtent.Disk.ReadSector((long)resumeRecord.BootRecordBackupSector);
volume.WriteSectors(0, filesystemBootRecord);
ClearBackupData(relocatedExtent.Disk, resumeRecord);
}
private static void MoveExtentRight(List <DynamicDisk> disks, DynamicVolume volume, MoveExtentOperationBootRecord resumeRecord, ref long bytesCopied)
{
DiskGroupDatabase database = DiskGroupDatabase.ReadFromDisks(disks, volume.DiskGroupGuid);
if (database == null)
{
throw new DatabaseNotFoundException();
}
int extentIndex = DynamicDiskExtentHelper.GetIndexOfExtentID(volume.DynamicExtents, resumeRecord.ExtentID);
DynamicDiskExtent sourceExtent = volume.DynamicExtents[extentIndex];
DiskExtent relocatedExtent = new DiskExtent(sourceExtent.Disk, (long)resumeRecord.NewStartSector, sourceExtent.Size);
MoveHelper.MoveExtentDataRight(volume, sourceExtent, relocatedExtent, resumeRecord, ref bytesCopied);
// even if the database update won't complete, the resume record was copied
// update the database
DynamicDiskExtent dynamicRelocatedExtent = new DynamicDiskExtent(relocatedExtent, sourceExtent.ExtentID);
dynamicRelocatedExtent.Name = sourceExtent.Name;
dynamicRelocatedExtent.DiskGuid = sourceExtent.DiskGuid;
VolumeManagerDatabaseHelper.UpdateExtentLocation(database, volume, dynamicRelocatedExtent);
// if this is a resume, then volume is StripedVolume, otherwise it is a Raid5Volume
if (resumeRecord.RestoreRAID5)
{
VolumeManagerDatabaseHelper.ConvertStripedVolumeToRaid(database, volume.VolumeGuid);
}
// get the updated volume (we moved an extent and possibly reconverted to RAID-5)
volume = DynamicVolumeHelper.GetVolumeByGuid(disks, volume.VolumeGuid);
// restore the filesystem boot sector
byte[] filesystemBootRecord = relocatedExtent.Disk.ReadSector((long)resumeRecord.BootRecordBackupSector);
volume.WriteSectors(0, filesystemBootRecord);
ClearBackupData(relocatedExtent.Disk, resumeRecord);
}
private static void ResumeAddDiskToRaid5Volume(List <DynamicDisk> disks, Raid5Volume volume, DynamicDiskExtent newExtent, AddDiskOperationBootRecord resumeRecord, ref long bytesCopied)
{
// When reading from the volume, we must use the old volume (without the new disk)
// However, when writing the boot sector to the volume, we must use the new volume or otherwise parity information will be invalid
List <DynamicColumn> newVolumeColumns = new List <DynamicColumn>();
newVolumeColumns.AddRange(volume.Columns);
newVolumeColumns.Add(new DynamicColumn(newExtent));
Raid5Volume newVolume = new Raid5Volume(newVolumeColumns, volume.SectorsPerStripe, volume.VolumeGuid, volume.DiskGroupGuid);
int oldColumnCount = volume.Columns.Count;
int newColumnCount = oldColumnCount + 1;
long resumeFromStripe = (long)resumeRecord.NumberOfCommittedSectors / volume.SectorsPerStripe;
// it would be prudent to write the new extent before committing to the operation, however, it would take much longer.
// The number of sectors in extent / column is always a multiple of SectorsPerStripe.
// We read enough stripes to write a vertical stripe segment in the new array,
// We will read MaximumTransferSizeLBA and make sure maximumStripesToTransfer is multiple of (NumberOfColumns - 1).
int maximumStripesToTransfer = (Settings.MaximumTransferSizeLBA / volume.SectorsPerStripe) / (newColumnCount - 1) * (newColumnCount - 1);
long totalStripesInVolume = volume.TotalStripes;
long stripeIndexInVolume = resumeFromStripe;
while (stripeIndexInVolume < totalStripesInVolume)
{
// When we add a column, the distance between the stripes we read (later in the column) to thes one we write (earlier),
// Is growing constantly (because we can stack more stripes in each vertical stripe), so we increment the number of stripes we
// can safely transfer as we go.
// (We assume that the segment we write will be corrupted if there will be a power failure)
long stripeToReadIndexInColumn = stripeIndexInVolume / (oldColumnCount - 1);
long stripeToWriteIndexInColumn = stripeIndexInVolume / (newColumnCount - 1);
long numberOfStripesSafeToTransfer = (stripeToReadIndexInColumn - stripeToWriteIndexInColumn) * (newColumnCount - 1);
bool verticalStripeAtRisk = (numberOfStripesSafeToTransfer == 0);
if (numberOfStripesSafeToTransfer == 0)
{
// The first few stripes in each column are 'at rist', meaning that we may overwrite crucial data (that is only stored in memory)
// when writing the segment that will be lost forever if a power failure will occur during the write operation.
// Note: The number of 'at risk' vertical stripes is equal to the number of columns in the old array - 1
numberOfStripesSafeToTransfer = (newColumnCount - 1);
}
int numberOfStripesToTransfer = (int)Math.Min(numberOfStripesSafeToTransfer, maximumStripesToTransfer);
long stripesLeft = totalStripesInVolume - stripeIndexInVolume;
numberOfStripesToTransfer = (int)Math.Min(numberOfStripesToTransfer, stripesLeft);
byte[] segmentData = volume.ReadStripes(stripeIndexInVolume, numberOfStripesToTransfer);
if (numberOfStripesToTransfer % (newColumnCount - 1) > 0)
{
// this is the last segment and we need to zero-fill it for the write:
int numberOfStripesToWrite = (int)Math.Ceiling((decimal)numberOfStripesToTransfer / (newColumnCount - 1)) * (newColumnCount - 1);
byte[] temp = new byte[numberOfStripesToWrite * volume.BytesPerStripe];
Array.Copy(segmentData, temp, segmentData.Length);
segmentData = temp;
}
long firstStripeIndexInColumn = stripeIndexInVolume / (newColumnCount - 1);
if (verticalStripeAtRisk)
{
// we write 'at risk' stripes one at a time to the new volume, this will make sure they will not overwrite crucial data
// (because they will be written in an orderly fashion, and not in bulk from the first column to the last)
newVolume.WriteStripes(stripeIndexInVolume, segmentData);
}
else
{
WriteSegment(volume, newExtent, firstStripeIndexInColumn, segmentData);
}
// update resume record
resumeRecord.NumberOfCommittedSectors += (ulong)(numberOfStripesToTransfer * volume.SectorsPerStripe);
bytesCopied = (long)resumeRecord.NumberOfCommittedSectors * volume.BytesPerSector;
newVolume.WriteSectors(0, resumeRecord.GetBytes());
stripeIndexInVolume += numberOfStripesToTransfer;
}
// we're done, let's restore the filesystem boot record
byte[] filesystemBootRecord = newExtent.ReadSector(newExtent.TotalSectors - 1);
newVolume.WriteSectors(0, filesystemBootRecord);
DiskGroupDatabase database = DiskGroupDatabase.ReadFromDisks(disks, volume.DiskGroupGuid);
VolumeManagerDatabaseHelper.ConvertStripedVolumeToRaid(database, volume.VolumeGuid);
}
/// <summary>
/// Move extent to a new location on the same disk
/// </summary>
public static void MoveExtentWithinSameDisk(List<DynamicDisk> disks, DynamicVolume volume, DynamicDiskExtent sourceExtent, DiskExtent relocatedExtent, ref long bytesCopied)
{
DiskGroupDatabase database = DiskGroupDatabase.ReadFromDisks(disks, volume.DiskGroupGuid);
if (database == null)
{
throw new DatabaseNotFoundException();
}
MoveExtentOperationBootRecord resumeRecord = new MoveExtentOperationBootRecord();
// If there will be a power failure during the move, a RAID volume will resync during boot,
// To prevent destruction of the data, we temporarily convert the array to striped volume
if (volume is Raid5Volume)
{
VolumeManagerDatabaseHelper.ConvertRaidToStripedVolume(database, volume.VolumeGuid);
resumeRecord.RestoreRAID5 = true;
}
// We want to write our own volume boot sector for recovery purposes, so we must find where to backup the old boot sector.
// We don't want to store the backup in the range of the existing or relocated extent, because then we would have to move
// the backup around during the move operation, other options include:
// 1. Store it between sectors 1-62 (cons: Could be in use, Windows occasionally start a volume from sector 1)
// 2. Find an easily compressible sector (e.g. zero-filled) within the existing extent, overwrite it with the backup, and restore it when the operation is done.
// 3. use the LDM private region to store the sector.
DynamicDisk dynamicDisk = DynamicDisk.ReadFromDisk(relocatedExtent.Disk);
// Note: backupSectorIndex will be from the beginning of the private region while backupBufferStartSector will be from the end
// so there is no need to allocate them
long backupSectorIndex = DynamicDiskHelper.FindUnusedSectorInPrivateRegion(dynamicDisk);
resumeRecord.VolumeGuid = volume.VolumeGuid;
resumeRecord.NumberOfCommittedSectors = 0;
resumeRecord.ExtentID = sourceExtent.ExtentID;
resumeRecord.OldStartSector = (ulong)sourceExtent.FirstSector;
resumeRecord.NewStartSector = (ulong)relocatedExtent.FirstSector;
resumeRecord.BootRecordBackupSector = (ulong)backupSectorIndex;
long distanceLBA = Math.Abs((long)resumeRecord.NewStartSector - (long)resumeRecord.OldStartSector);
if (distanceLBA < MoveHelper.BufferedModeThresholdLBA)
{
long backupBufferStartSector = DynamicDiskHelper.FindUnusedRegionInPrivateRegion(dynamicDisk, BackupBufferSizeLBA);
if (backupBufferStartSector == -1)
{
throw new Exception("Private region is full");
}
if (backupBufferStartSector <= backupSectorIndex)
{
throw new Exception("Private region structure is unknown");
}
resumeRecord.BackupBufferStartSector = (ulong)backupBufferStartSector;
resumeRecord.BackupBufferSizeLBA = BackupBufferSizeLBA;
}
// Backup the first sector of the first extent
// (We replace the filesystem boot record with our own sector for recovery purposes)
byte[] filesystemBootRecord = volume.ReadSector(0);
relocatedExtent.Disk.WriteSectors(backupSectorIndex, filesystemBootRecord);
// we write the resume record instead of the boot record
volume.WriteSectors(0, resumeRecord.GetBytes());
if (sourceExtent.FirstSector < relocatedExtent.FirstSector)
{
// move right
MoveExtentRight(disks, volume, resumeRecord, ref bytesCopied);
}
else
{
// move left
// we write the resume record at the new location as well (to be able to resume if a power failure will occur immediately after updating the database)
relocatedExtent.WriteSectors(0, resumeRecord.GetBytes());
DynamicDiskExtent dynamicRelocatedExtent = new DynamicDiskExtent(relocatedExtent, sourceExtent.ExtentID);
dynamicRelocatedExtent.Name = sourceExtent.Name;
dynamicRelocatedExtent.DiskGuid = sourceExtent.DiskGuid;
VolumeManagerDatabaseHelper.UpdateExtentLocation(database, volume, dynamicRelocatedExtent);
int extentIndex = DynamicDiskExtentHelper.GetIndexOfExtentID(volume.DynamicExtents, sourceExtent.ExtentID);
// get the updated volume (we just moved an extent)
volume = DynamicVolumeHelper.GetVolumeByGuid(disks, volume.VolumeGuid);
MoveExtentLeft(disks, volume, resumeRecord, ref bytesCopied);
}
}
