/dev/btrfs-control missing on Ubuntu Server install

[Pascal Gaudette]

Binary package hint: btrfs-tools

Trying to use the btrfs-tools package on Ubuntu Server 10.04 (64bit) appears to not function. Package installation (at least) fails to create /dev/btrsf-control, which means that basically all btrfs operations fail.

Diagnostic output from a Ubuntu Server box:

---------------------
pascal@babar:~$ sudo aptitude show btrfs-tools
[sudo] password for pascal:
Package: btrfs-tools
New: yes
State: installed
Automatically installed: no
Version: 0.19-8
Priority: optional
Section: universe/admin
Maintainer: Ubuntu Developers <email address hidden>
Uncompressed Size: 1,122k
Depends: e2fslibs (>= 1.37), libc6 (>= 2.7), libcomerr2 (>= 1.01), libuuid1 (>= 2.16-1), zlib1g (>= 1:1.2.0)
Description: Checksumming Copy on Write Filesystem
 Btrfs is a new copy on write filesystem for Linux aimed at implementing advanced features while focusing on fault
 tolerance, repair and easy administration.

 This package contains utilities (mkfs, fsck, btrfsctl) used to work with btrfs and an utility (btrfs-convert) to make
 a btrfs filesystem from an ext3.

 WARNING: Btrfs is under heavy development, and is not suitable for any uses other than benchmarking and review.
Homepage: http://btrfs.wiki.kernel.org/

pascal@babar:~$ ls -ld /dev/b*
drwxr-xr-x 2 root root 820 2010-06-14 14:15 /dev/block
drwxr-xr-x 2 root root 140 2010-06-14 14:15 /dev/bsg
drwxr-xr-x 3 root root 60 2010-06-14 14:15 /dev/bus

pascal@babar:~$ sudo btrfsctl -A /dev/sdc1
[sudo] password for pascal:
failed to open /dev/btrfs-control: No such file or directory
pascal@babar:~$ lsb_release -rd
Description: Ubuntu 10.04 LTS
Release: 10.04

pascal@babar:~$ uname -a
Linux babar 2.6.32-22-server #36-Ubuntu SMP Thu Jun 3 20:38:33 UTC 2010 x86_64 GNU/Linux
pascal@babar:~$

--------------------------

Same output from a Kubuntu desktop box where I am able to create and use btrfs filesystems:

-----------------------

pascal@djaa:~$ sudo aptitude show btrfs-tools
[sudo] password for pascal:
Package: btrfs-tools
State: installed
Automatically installed: no
Version: 0.19-8
Priority: optional
Section: universe/admin
Maintainer: Ubuntu Developers <email address hidden>
Uncompressed Size: 1,122k
Depends: e2fslibs (>= 1.37), libc6 (>= 2.7), libcomerr2 (>= 1.01), libuuid1 (>= 2.16-1), zlib1g (>= 1:1.2.0)
Description: Checksumming Copy on Write Filesystem
 Btrfs is a new copy on write filesystem for Linux aimed at implementing advanced features while focusing on fault
 tolerance, repair and easy administration.

 This package contains utilities (mkfs, fsck, btrfsctl) used to work with btrfs and an utility (btrfs-convert) to make
 a btrfs filesystem from an ext3.

 WARNING: Btrfs is under heavy development, and is not suitable for any uses other than benchmarking and review.
Homepage: http://btrfs.wiki.kernel.org/

pascal@djaa:~$ ls -ld /dev/b*
drwxr-xr-x 2 root root 740 2010-06-15 17:35 /dev/block
drwxr-xr-x 2 root root 180 2010-06-15 17:35 /dev/bsg
crw-rw---- 1 root root 10, 55 2010-06-14 14:33 /dev/btrfs-control
drwxr-xr-x 3 root root 60 2010-06-10 22:22 /dev/bus

pascal@djaa:~$ sudo btrfsctl -A /dev/sda3
operation complete
Btrfs Btrfs v0.19

pascal@djaa:~$ lsb_release -rd
Description: Ubuntu 10.04 LTS
Release: 10.04

pascal@djaa:~$ uname -a
Linux djaa 2.6.32-22-generic #36-Ubuntu SMP Thu Jun 3 19:31:57 UTC 2010 x86_64 GNU/Linux
pascal@djaa:~$
-------------------------

I think somehow the btrfs-tools package may be tied in some way to the desktop kernel. Unless I am missing something...

[Carey Underwood (cwillu)]

I don't think btrfs-tools is responsible for creating that.

If you run "modprobe btrfs", does the /dev/btrfs-control entry show up?

[Carey Underwood (cwillu)]

Marking as invalid after discussion with reporter in irc.

/dev/btrfs-control shows up when btrfs is modprobe'd, this works fine.
mkfs.btrfs only requires btrfs to be modprobe'd if creating a multi-device filesystem.