Re: device-mapper: remove ioctl failed: device or resource busy

[Milan Broz <mbroz@redhat.com>]

On 02/06/2010 04:32 AM, Bai Shuwei wrote:
>    I port the xts-aes algorithm to FPGA board and use it to
> encrypt/decrypt the disc.  i will get the bellow information
> 
>    But when excute the bellow commands
>    cryptsetup luksFormat -c aes-xts-plain -s 256 /dev/loop0
>   or
>    cryptsetup luksOpen /dev/loop0 test0
> 
>    I get the bellow information
>    ....
>    device-mapper: remove ioctl failed: device or resource busy


Probably some udev rule triggers scan on temporary keyslot device.
This is known problem with some badly written udev rules and old versions
of DevKit-disks (recent version should not touch these internal devices at all).

Use cryptsetup 1.1.0 and run it with --debug to get more info, also see syslog (there
will be exact information which device was busy, I expect temp-cryptsetup*...)
(It will retry after 1 sec anyway, so it usually works - see that debug log.)

This is not kernel problem at all, just userspace race between some asynchronous
device scan triggered from udev (usually blkid check) and cryptsetup.

Milan