[Bug 202089] gpart erroneously creates partitions with a '1' label

[bugzilla-noreply at freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=202089

            Bug ID: 202089
           Summary: gpart erroneously creates partitions with a '1' label
           Product: Base System
           Version: 10.2-BETA1
          Hardware: Any
                OS: Any
            Status: New
          Severity: Affects Some People
          Priority: ---
         Component: bin
          Assignee: freebsd-bugs at FreeBSD.org
          Reporter: sub.mesa at gmail.com

*** Problem description

gpart will report partitions to have a label called '1' while no label has been
assigned. The label will not actually propagate to GEOM, so no /dev/gpt/1
device node will exist, but 'gpart show -l' will report the erroneous '1' label
where it should state '-' (dash) instead to indicate the partition has no label
attached.


*** Environment

# uname -a
FreeBSD zfsguru.bsd 10.2-RC1 FreeBSD 10.2-RC1 #0 r286032 *snip* amd64

Kernel is a GENERIC-like kernel with some minor additions (OFED Infiniband,
AltQ traffic shaping and device polling; that is it).

I have seen this issue before, but did not properly diagnose it until today.
This means the actual offending commit can be far into the past. I did not
encounter this bug on 10.1 though.


*** Steps to reproduce

# gpart show ada0
gpart: No such geom: ada0.
# gpart create -s gpt ada0
ada0 created
# gpart add -s 1024 -t freebsd-boot ada0
ada0p1 added
# gpart show -l ada0
=>      34  25165757  ada0  GPT  (12G)
        34      1024     1  1  (512K)
      1058  25164733        - free -  (12G)

### note that gpart says label '1' for the first partition, while no label has
been assigned! Also note that the label is not actually there as device node or
seen by glabel status:

# ls -l /dev/gpt/
ls: /dev/gpt/: No such file or directory
# glabel status
                           Name  Status  Components
         iso9660/ZFSGURU-LIVECD     N/A  cd0
diskid/DISK-VB5bfe914e-38cf2b58     N/A  ada0

### now try some other things by explicitly assigning a label name, which
works:

# gpart add -s 1024 -t freebsd-boot -l 'LabelName' ada0
ada0p2 added
# gpart add -s 1024 -t freebsd-boot -l 1 ada0
ada0p2 added
# gpart add -s 1024 -t freebsd-boot -l 2 ada0
ada0p3 added
# gpart show -l ada0
=>      34  25165757  ada0  GPT  (12G)
        34      1024     1  1  (512K)
      1058      1024     2  LabelName  (512K)
      2082      1024     3  1  (512K)
      3106      1024     4  2  (512K)
      4130  25161661        - free -  (12G)

### note that when explicitly giving '1' or '2' as label name, this does get
seen by glabel and the device node:

# ls -l /dev/gpt
total 0
crw-r-----  1 root  operator  0x77 Aug  4 19:34 1
crw-r-----  1 root  operator  0x75 Aug  4 19:35 2
crw-r-----  1 root  operator  0x73 Aug  4 19:34 LabelName
# glabel status
                           Name  Status  Components
         iso9660/ZFSGURU-LIVECD     N/A  cd0
                  gpt/LabelName     N/A  ada0p2
                          gpt/1     N/A  ada0p3
                          gpt/2     N/A  ada0p4
diskid/DISK-VB5bfe914e-38cf2b58     N/A  ada0



*** Conclusion

It appears gpart always says '1' instead of '-' (dash character) when a
partition has no label. When explicitly giving '1' as label, this works but the
gpart show output shows no distinction between the fake '1' label partitions
and ones that have a genuine '1' label. This is a bug.

This triggers a bug in the ZFSguru storage appliance product, which uses GPT
labels to prevent user error. But now all partitions have a '1' label which
causes all kinds of problems in the ZFSguru web-interface. A workaround/patch
or fix is highly appreciated!

Thanks for all your efforts on improving BSD! It is highly appreciated by
myself and others!

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