Re: minor ID for btrfs-control

[Goffredo Baroncelli <kreijack@libero.it>]

On 04/02/2011 06:45 PM, Helmut Hullen wrote:
> Hallo,
> 
> if I've understood some mails in this list correct, then btrfs needs a  
> character device "btrfs-control"  with the ID 10:55
> 
> When I look for this device in
> 
>         /sys/class/misc/btrfs-control/dev
> 
> I see 10:234
> 
> And when I run the command
> 
>   mkfs.btrfs -d raid0 -m raid1 /dev/sda1 /dev/sdc1
> 
> I get the error messages
> 
>   failed to open /dev/btrfs-control skipping device registration
> 
> ---
> 
>   ls -l /dev/bt*
> 
> shows
> 
>   crw-rw-rw- 1 root root 10,55 2. Apr 17:55 /dev/btrfs-control
> 
> ---
> 
> Kernel 2.6.38.1 (self made), no udev, no initrd, no tempfs. btrfs from  
> nov. 2010
> 
> What goes wrong?

As wrote by Tomasz the minor number of the btrfs-control is allocated
dynamically. A lot of drivers create a device which is registered
dynamically in the "misc" group. In linux this is a well established
behavior from a long time.

If you don't want to use udev you have two choices:
- use devtmpfs
- create manually a device. But nobody guarantee that the minor/major
will not  change.



> 
> 
> Viele Gruesse!
> Helmut
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