Re: [dm-devel] dmsetup on uClibc based system

[Kevin Corry <kevcorry us ibm com>]

On Thursday 18 March 2004 6:45 pm, Pete Flugstad wrote:
> Greetings
>
>       (resend now that I'm subscribed and sending from the right
> account...)
>
>       I'm trying to get dmsetup running on an embedded uClibc based
> system - linux kernel 2.6.4 - X86 architecture, GCC 3.3.1.  The first
> problem seems to be that when reading the table file, dmsetup uses the
> 'a' conversion modifier to have sscanf malloc space for the resulting
> string.  uClibc doesn't appear to support this.  No biggy, fairly easy
> fix (I believe - I assume ttype won't be larger than the line read in).
>     Patch attached.
>
>       Next problem is that I'm getting an error when I try and setup a
> "chunk" of a partition:
>
>       [root denis root]# dmsetup create hdc5.000
>       0 204800 linear /dev/hdc5 0<cr>
>       <ctrl-D>
>       device-mapper ioctl cmd 9 failed: Invalid argument
>       Command failed
>       [root denis root]# dmsetup ls
>       hdc5.000        (254, 0)
>       [root denis root]# ls /dev/mapper/
>       control
>
>      The command appears to have worked, but the entry in /dev/mapper is
> not there.
>
>       Does dmsetup not work on partitions?  Or is this probably something
> else going on?  Does it matter if the partition in question is mounted?

Actually, it does matter. You won't be able to activate a DM device on a 
partition that contains a mounted filesystem (2.6 kernels don't allow that).

Try "dmsetup info hdc5.000" and/or "dmsetup table hdc5.000" to see if the 
table was actually loaded into the device. Remember that a DM device can 
exist without any mapping (all I/O to that device will obviously fail).

-- 
Kevin Corry
kevcorry us ibm com
http://evms.sourceforge.net/