forwarded 401393 [EMAIL PROTECTED]
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Hi,
This is a followup for Debian bug <http://bugs.debian.org/401393>.
On Thu, Dec 07, 2006, Loïc Minier wrote:
> - check why running ioctls on dm-* devices fails (is it bad style?
> should we create /dev/mapper/dm-* devices? why does it fail when we
> pass a full device path?); perhaps we can fix the problem at the
> libdevmapper level and make dmsetup table /dev/dm-1 work
I've explained the problem in the hope of getting some answers on
[EMAIL PROTECTED] in the attached message.
Bye,
--
Loïc Minier <[EMAIL PROTECTED]>
--- Begin Message ---
Hi,
When issuing the same dmsetup commands on two device nodes with the
same major/minor, the results are puzzling:
bee:~# file /dev/dm-1
/dev/dm-1: block special (254/1)
bee:~# file /dev/mapper/bee--sata-refuge
/dev/mapper/bee--sata-refuge: block special (254/1)
bee:~# dmsetup table /dev/mapper/bee--sata-refuge
0 131072 linear 8:2 117440896
bee:~# dmsetup table /dev/dm-1
dm_task_set_name: Device /dev/dm-1 not found
Command failed
(Same problem with short names:)
bee:~# dmsetup table bee--sata-refuge
0 131072 linear 8:2 117440896
bee:~# dmsetup table dm-1
device-mapper: table ioctl failed: No such device or address
Command failed
This is a problem hitting lilo relatively hard as it has logic to
ignore devices with the same major/minor; that is, if lilo sees "dm-1"
first and then the corresponding /dev/mapper device, it will drop any
reference to the mapper device. As having /boot on RAID 1 for lilo
requires calling "dmsetup table" on the root device, this breaks lilo
for a lot of people.
Of course, it would be possible to patch lilo to explicitely skip
/dev/dm-* devices, but it seems this would be a workaround instead of
the real fix.
This is under 2.6.18 and libdevmapper 1.02.12-1.
You can find more details in Debian bug
<http://bugs.debian.org/401393>, the bug was triggered by the addition
of the /dev/dm-* device in udev (see <http://bugs.debian.org/392623>),
and affects other distributions as well,
<https://launchpad.net/distros/ubuntu/+source/lilo-installer/+bug/23835>.
(RAID 1 support in lilo comes from a third-party patch added in the
Debian packaging.)
Bye,
--
Loïc Minier <[EMAIL PROTECTED]>
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