actions/image-partition: add optional fslabel property

Added optional fslabel property to partition to allow truncation of
filesystem label and allow user to modify filesystem label without
modifying the name. Filesystem label defaults to the name property
of the partition.

The filesystem label can be up to 11 characters long for vfat,
16 characters long for ext2/3/4, 255 characters long for btrfs,
512 characters long for hfs/hfsplus and 12 characters long for xfs.
Any longer labels will be automatically truncated.

Fixes: #251

Suggested-by: Christopher Obbard <chris.obbard@collabora.com>
Signed-off-by: Vignesh Raman <vignesh.raman@collabora.com>

actions/image_partition_action.go

@@ -43,6 +43,7 @@ Yaml syntax for partitions:
  - name: partition name
  partlabel: partition label
  fs: filesystem
+ fslabel: filesystem label
  start: offset
  end: offset
  features: list of filesystem features
@@ -72,6 +73,12 @@ Optional properties:
 - partlabel -- label for the partition in the GPT partition table. Defaults
 to the `name` property of the partition. May only be used for GPT partitions.
 
+- fslabel -- Sets the volume name (label) of the filesystem. Defaults to the
+`name` property of the partition. The filesystem label can be up to 11 characters
+long for vfat, 16 characters long for ext2/3/4, 255 characters long for btrfs,
+512 characters long for hfs/hfsplus and 12 characters long for xfs. Any longer
+labels will be automatically truncated.
+
 - parttype -- set the partition type in the partition table. The string should
 be in a hexadecimal format (2-characters) for msdos partition tables and GUID format
 (36-characters) for GPT partition tables. For instance, "82" for msdos sets the
@@ -168,6 +175,7 @@ type Partition struct {
  number int
  Name string
  PartLabel string
+ FSLabel string
  PartType string
  Start string
  End string
@@ -305,37 +313,37 @@ func (i ImagePartitionAction) formatPartition(p *Partition, context debos.DebosC
  cmdline := []string{}
  switch p.FS {
  case "vfat":
- cmdline = append(cmdline, "mkfs.vfat", "-F32", "-n", p.Name)
+ cmdline = append(cmdline, "mkfs.vfat", "-F32", "-n", p.FSLabel)
  case "btrfs":
  // Force formatting to prevent failure in case if partition was formatted already
- cmdline = append(cmdline, "mkfs.btrfs", "-L", p.Name, "-f")
+ cmdline = append(cmdline, "mkfs.btrfs", "-L", p.FSLabel, "-f")
  if len(p.Features) > 0 {
  cmdline = append(cmdline, "-O", strings.Join(p.Features, ","))
  }
  if len(p.FSUUID) > 0 {
  cmdline = append(cmdline, "-U", p.FSUUID)
  }
  case "f2fs":
- cmdline = append(cmdline, "mkfs.f2fs", "-l", p.Name)
+ cmdline = append(cmdline, "mkfs.f2fs", "-l", p.FSLabel)
  if len(p.Features) > 0 {
  cmdline = append(cmdline, "-O", strings.Join(p.Features, ","))
  }
  case "hfs":
- cmdline = append(cmdline, "mkfs.hfs", "-h", "-v", p.Name)
+ cmdline = append(cmdline, "mkfs.hfs", "-h", "-v", p.FSLabel)
  case "hfsplus":
- cmdline = append(cmdline, "mkfs.hfsplus", "-v", p.Name)
+ cmdline = append(cmdline, "mkfs.hfsplus", "-v", p.FSLabel)
  case "hfsx":
- cmdline = append(cmdline, "mkfs.hfsplus", "-s", "-v", p.Name)
+ cmdline = append(cmdline, "mkfs.hfsplus", "-s", "-v", p.FSLabel)
  // hfsx is case-insensitive hfs+, should be treated as "normal" hfs+ from now on
  p.FS = "hfsplus"
  case "xfs":
- cmdline = append(cmdline, "mkfs.xfs", "-L", p.Name)
+ cmdline = append(cmdline, "mkfs.xfs", "-L", p.FSLabel)
  if len(p.FSUUID) > 0 {
  cmdline = append(cmdline, "-m", "uuid="+p.FSUUID)
  }
  case "none":
  default:
- cmdline = append(cmdline, fmt.Sprintf("mkfs.%s", p.FS), "-L", p.Name)
+ cmdline = append(cmdline, fmt.Sprintf("mkfs.%s", p.FS), "-L", p.FSLabel)
  if len(p.Features) > 0 {
  cmdline = append(cmdline, "-O", strings.Join(p.Features, ","))
  }
@@ -599,6 +607,7 @@ func (i *ImagePartitionAction) Verify(context *debos.DebosContext) error {
 
  num := 1
  for idx, _ := range i.Partitions {
+ var maxLength int = 0
  p := &i.Partitions[idx]
  p.number = num
  num++
@@ -654,6 +663,31 @@ func (i *ImagePartitionAction) Verify(context *debos.DebosContext) error {
  case "":
  return fmt.Errorf("Partition %s missing fs type", p.Name)
  }
+
+ if p.FSLabel == "" {
+ p.FSLabel = p.Name
+ }
+
+ switch p.FS {
+ case "vfat":
+ maxLength = 11
+ case "ext2", "ext3", "ext4":
+ maxLength = 16
+ case "btrfs":
+ maxLength = 255
+ case "f2fs":
+ maxLength = 512
+ case "hfs", "hfsplus":
+ maxLength = 255
+ case "xfs":
+ maxLength = 12
+ }
+
+ if maxLength > 0 && len(p.FSLabel) > maxLength {
+ truncated := p.FSLabel[0:maxLength]
+ log.Printf("Warning: fs label for %s '%s' is too long; truncated to '%s'", p.Name, p.FSLabel, truncated)
+ p.FSLabel = truncated
+ }
  }
 
  for idx, _ := range i.Mountpoints {