Function BackupVolume

internal/server/storage/drivers/utils.go:1055–1181

BackupVolume copy a volume into the backup target location.

(d Driver, v Volume, writer instancewriter.InstanceWriter, mountPath string, blockPath string, prefix string)

// BackupVolume copy a volume into the backup target location.
func BackupVolume(d Driver, v Volume, writer instancewriter.InstanceWriter, mountPath string, blockPath string, prefix string) error {
	// Reset hard link cache as we are copying a new volume (instance or snapshot).
	writer.ResetHardLinkMap()

	if v.contentType == ContentTypeBlock || v.contentType == ContentTypeISO {
		// Get size of disk block device for tarball header.
		blockDiskSize, err := BlockDiskSizeBytes(blockPath)
		if err != nil {
			return fmt.Errorf("Error getting block device size %q: %w", blockPath, err)
		}

		var exclude []string // Files to exclude from filesystem volume backup.
		if !linux.IsBlockdevPath(blockPath) {
			// Exclude the volume root disk file from the filesystem volume backup.
			// We will read it as a block device later instead.
			exclude = append(exclude, blockPath)
		}

		if v.IsVMBlock() {
			logMsg := "Copying virtual machine config volume"

			d.Logger().Debug(logMsg, logger.Ctx{"sourcePath": mountPath, "prefix": prefix})
			err = filepath.Walk(mountPath, func(srcPath string, fi os.FileInfo, err error) error {
				if err != nil {
					return err
				}

				// Skip any excluded files.
				if util.StringHasPrefix(srcPath, exclude...) {
					return nil
				}

				name := filepath.Join(prefix, strings.TrimPrefix(srcPath, mountPath))
				err = writer.WriteFile(name, srcPath, fi, false)
				if err != nil {
					return fmt.Errorf("Error adding %q as %q to tarball: %w", srcPath, name, err)
				}

				return nil
			})
			if err != nil {
				return err
			}
		}

		name := fmt.Sprintf("%s.%s", prefix, genericVolumeBlockExtension)

		logMsg := "Copying virtual machine block volume"
		if v.volType == VolumeTypeCustom {
			logMsg = "Copying custom block volume"
		}

		d.Logger().Debug(logMsg, logger.Ctx{"sourcePath": blockPath, "file": name, "size": blockDiskSize})
		from, err := os.Open(blockPath)
		if err != nil {
			return fmt.Errorf("Error opening file for reading %q: %w", blockPath, err)
		}