public static void MoveExtentDataRight(Volume volume, DiskExtent sourceExtent, DiskExtent relocatedExtent, MoveExtentOperationResumeRecord resumeRecord, ref long bytesCopied) { // we make sure no data will be overwritten too soon: long distanceLBA = (long)(resumeRecord.NewStartSector - resumeRecord.OldStartSector); bool bufferedMode = false; if (distanceLBA < BufferedModeThresholdLBA) { bufferedMode = true; } int transferSizeLBA; if (bufferedMode) { transferSizeLBA = (int)resumeRecord.BackupBufferSizeLBA; } else { transferSizeLBA = (int)Math.Min(Settings.MaximumTransferSizeLBA, distanceLBA); } // move the data for (long readCount = (long)resumeRecord.NumberOfCommittedSectors; readCount < relocatedExtent.TotalSectors; readCount += transferSizeLBA) { // we read (and write) from the end of the extent and progress to the left long sectorsLeft = relocatedExtent.TotalSectors - readCount; int sectorsToRead = (int)Math.Min(transferSizeLBA, sectorsLeft); long sectorIndex = relocatedExtent.TotalSectors - readCount - sectorsToRead; byte[] data = sourceExtent.ReadSectors(sectorIndex, sectorsToRead); if (bufferedMode) { // we write the data to the buffer for recovery purposes relocatedExtent.Disk.WriteSectors((long)resumeRecord.BackupBufferStartSector, data); resumeRecord.RestoreFromBuffer = true; // Note: if the extent we move is the first in the volume, we will write the resume record to // the source extent, which is the one that the database is still referring to volume.WriteSectors(0, resumeRecord.GetBytes(volume.BytesPerSector)); } relocatedExtent.WriteSectors(sectorIndex, data); // update the resume record resumeRecord.RestoreFromBuffer = false; resumeRecord.NumberOfCommittedSectors += (ulong)sectorsToRead; volume.WriteSectors(0, resumeRecord.GetBytes(volume.BytesPerSector)); bytesCopied = (long)resumeRecord.NumberOfCommittedSectors * sourceExtent.BytesPerSector; } }
public static void MoveExtentDataLeft(Volume volume, DiskExtent sourceExtent, DiskExtent relocatedExtent, MoveExtentOperationResumeRecord resumeRecord, ref long bytesCopied) { // we make sure no data will be overwritten too soon: long distanceLBA = (long)(resumeRecord.OldStartSector - resumeRecord.NewStartSector); bool bufferedMode = false; if (distanceLBA < BufferedModeThresholdLBA) { bufferedMode = true; } int transferSizeLBA; if (bufferedMode) { transferSizeLBA = (int)resumeRecord.BackupBufferSizeLBA;; } else { transferSizeLBA = (int)Math.Min(Settings.MaximumTransferSizeLBA, distanceLBA); } // move the data for (long sectorIndex = (long)resumeRecord.NumberOfCommittedSectors; sectorIndex < relocatedExtent.TotalSectors; sectorIndex += transferSizeLBA) { long sectorsLeft = relocatedExtent.TotalSectors - sectorIndex; int sectorsToRead = (int)Math.Min(transferSizeLBA, sectorsLeft); byte[] data = sourceExtent.ReadSectors(sectorIndex, sectorsToRead); if (bufferedMode) { // we write the data to the buffer for recovery purposes relocatedExtent.Disk.WriteSectors((long)resumeRecord.BackupBufferStartSector, data); resumeRecord.RestoreFromBuffer = true; relocatedExtent.WriteSectors(0, resumeRecord.GetBytes(relocatedExtent.BytesPerSector)); } relocatedExtent.WriteSectors(sectorIndex, data); // update the resume record resumeRecord.RestoreFromBuffer = false; resumeRecord.NumberOfCommittedSectors += (ulong)sectorsToRead; volume.WriteSectors(0, resumeRecord.GetBytes(volume.BytesPerSector)); bytesCopied = (long)resumeRecord.NumberOfCommittedSectors * sourceExtent.BytesPerSector; } }
/// <summary> /// Move extent to a new location on the same disk /// </summary> public static void MoveExtentWithinSameDisk(DiskGroupDatabase database, DynamicVolume volume, DynamicDiskExtent sourceExtent, DiskExtent relocatedExtent, ref long bytesCopied) { MoveExtentOperationResumeRecord resumeRecord = new MoveExtentOperationResumeRecord(); // 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 = PrivateRegionHelper.FindUnusedSector(dynamicDisk.PrivateHeader, dynamicDisk.TOCBlock); 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 = (long)Math.Abs((double)resumeRecord.NewStartSector - resumeRecord.OldStartSector); if (distanceLBA < MoveHelper.BufferedModeThresholdLBA) { long backupBufferStartSector = PrivateRegionHelper.FindUnusedRegion(dynamicDisk.PrivateHeader, dynamicDisk.TOCBlock, 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(volume.BytesPerSector)); if (sourceExtent.FirstSector < relocatedExtent.FirstSector) { // move right MoveExtentRight(database, 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(relocatedExtent.BytesPerSector)); 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(database.Disks, volume.VolumeGuid); MoveExtentLeft(database, volume, resumeRecord, ref bytesCopied); } }