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Need for a unique Linux GPT GUID type code (PATCH included)
From: |
Rod Smith |
Subject: |
Need for a unique Linux GPT GUID type code (PATCH included) |
Date: |
Thu, 23 Jun 2011 00:38:10 -0400 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110514 Lightning/1.0b3pre Thunderbird/3.1.10 |
Hi,
I've recently discovered that when Windows reads a GPT disk with Linux
partitions on it, those partitions are given drive letters and show up
as unformatted. This situation can happen with removable disks or when
Linux and Windows dual-boot on a UEFI-based computer. Because UEFI is
becoming more common, this situation is also becoming more common. This
strikes me as a disaster waiting to happen; sooner or later, somebody is
going to trash a Linux installation by opting to format a Linux
partition in Windows.
This problem occurs because Linux partitioning tools (libparted and my
own GPT fdisk) give Linux partitions the same partition type code GUID
used by Windows for its filesystem partitions
(EBD0A0A2-B9E5-4433-87C0-68B6B72699C7). Linux has its own GUID type
codes for other partition types, such as RAID, LVM, and swap space.
Thus, it seems to me that Linux needs its own partition type code GUID
for filesystem partitions on GPT disks, much as it has its own MBR
partition type code for filesystems (0x83 on MBR). I'd like to implement
such a change in my own program, but I don't want to do this
unilaterally. Assuming there's no unusual protocol for creating
partition type code GUIDs, I suggest the following be used:
0FC63DAF-8483-4772-8E79-3D69D8477DE4
That's just a partition-unique GUID for a partition I created on a test
disk using GNU Parted 3.0.
Alternatively, we could use the existing "Linux reserved" partition type
code (8DA63339-0007-60C0-C436-083AC8230908); however, I don't know who
came up with that code or if it was intended for some specific purpose
or even a general non-filesystem purpose. Lacking that knowledge, my
inclination is to steer clear of that GUID.
Of course, if somebody more needs to be involved in this, I'm happy to
contact whoever it might be. AFAIK, the kernel doesn't use partition
type codes, although some distributions' installers might.
At the risk of jumping the gun, I'm attaching a patch to implement my
suggestion in libparted. (I hope the attachment gets through; but
Thunderbird is rewrapping it if I insert it inline.)
--
Rod Smith
address@hidden
http://www.rodsbooks.com
patch.diff
Description: Text document
- Need for a unique Linux GPT GUID type code (PATCH included),
Rod Smith <=