*** 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!