PTUUID and PARTUUID (was: [PATCH v3] libblkid: print PTUUID, the partition table uuid)

[Karel Zak <kzak@redhat.com>]

On Fri, Jun 07, 2013 at 07:27:00PM +0200, Gabriel de Perthuis wrote:
> ---
> v3: Call it ID_PART_TABLE_UUID in udev rules
> 
>  libblkid/src/partitions/gpt.c        |  8 ++++----
>  libblkid/src/partitions/partitions.c | 14 +++++++++++---
>  misc-utils/blkid.c                   |  3 +++
>  3 files changed, 18 insertions(+), 7 deletions(-)

I have applied a little bit different version. Anyway, you have to
modify udevd to make it usable with in built-in blkid. It also
exports MBR ID (so the change is not GPT specific) as partition
table pseudo UUID. Examples:

 # blkid -p -o udev /dev/sda
 ID_PART_TABLE_UUID=3549290f-417c-4941-8503-f7835109b821
 ID_PART_TABLE_TYPE=gpt

 # blkid -p -o udev /dev/sdb
 ID_PART_TABLE_UUID=54e743a7
 ID_PART_TABLE_TYPE=dos


Note that I have also add support for Dos partitions pseudo-uuids. The
implementation is compatible with Linux kernel root=PARTUUID= command
line option.

The PARTUUID for Dos partitions is based on MBR Id and partition number,
for example:

  # blkid /dev/sdb1
  /dev/sdb1: TYPE="ext2" PARTUUID="54e743a7-01" 

is the first partition on disk with PTUUID=54e743a7. So you can use

  # mount PARTUUID="54e743a7-01" /mnt/test

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com