[Parted-maintainers] Bug#671291: parted: Failure to communicate with kernel device-mapper driver.

[Daniel Kahn Gillmor]

Package: parted
Version: 2.3-9.1
Severity: normal

As a non-privileged user, i have r/w access to a specific block device
(created by the device mapper).  But when i try to use parted to
interrogate or change the device, i get an error after the expected
"Watch out for permissions" warning.

This failure seems inappropriate, since i ought to be able to use
parted in this context to inspect modify the contents of the the block
device even if i can't talk to the device mapper directly.

Feel free to forward this further upstream if that would be useful.

Below is a transcript showing the problem:

0 dkg at pip:~/tmp$ ls -l $(readlink -f /dev/mapper/vg_pip0-test)
brw-rw---T 1 dkg disk 253, 7 May  2 22:59 /dev/dm-7
0 dkg at pip:~/tmp$ [ -r /dev/dm-7 ]
0 dkg at pip:~/tmp$ [ -w /dev/dm-7 ]
0 dkg at pip:~/tmp$ /sbin/parted /dev/dm-7 print
WARNING: You are not superuser.  Watch out for permissions.
/dev/mapper/control: open failed: Permission denied
Failure to communicate with kernel device-mapper driver.
                                                                          

You found a bug in GNU Parted! Here's what you have to do:

Don't panic! The bug has most likely not affected any of your data.
Help us to fix this bug by doing the following:

Check whether the bug has already been fixed by checking
the last version of GNU Parted that you can find at:

	http://ftp.gnu.org/gnu/parted/

Please check this version prior to bug reporting.

If this has not been fixed yet or if you don't know how to check,
please visit the GNU Parted website:

	http://www.gnu.org/software/parted

for further information.

Your report should contain the version of this release (2.3)
along with the error message below, the output of

	parted DEVICE unit co print unit s print

and the following history of commands you entered.
Also include any additional information about your setup you
consider important.

Unable to determine the dm type of /dev/dm-7.

1 dkg at pip:~/tmp$ 

Thanks for maintaining parted in debian,

       --dkg

-- System Information:
Debian Release: wheezy/sid
  APT prefers testing
  APT policy: (500, 'testing'), (200, 'unstable'), (1, 'experimental')
Architecture: i386 (i686)

Kernel: Linux 3.2.0-2-686-pae (SMP w/1 CPU core)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages parted depends on:
ii  libblkid1           2.20.1-4
ii  libc6               2.13-30
ii  libdevmapper1.02.1  2:1.02.67-2
ii  libparted0debian1   2.3-9.1
ii  libreadline6        6.2-8
ii  libtinfo5           5.9-6
ii  libuuid1            2.20.1-4

parted recommends no packages.

Versions of packages parted suggests:
pn  parted-doc  <none>

-- no debconf information