Problem with DM hardware handler

Problem with DM hardware handler

[Pradipmaya Maharana]

Hi All,

I am writing a DM Hardware handler; so to start with I took, dm-emc.c
code and replaced emc by sample. I also renamed the file to dm-sample
and the module name is dm-sample.ko.

The code compiles fine and even loads okay. I modiefied the
/etc/multipath.conf to point the hardware_handler to my sample
handler.

 hardware_handler        "1 sample"

Now when I run the command,
# multipath -F
# multipath -ll
# multipath -v3

It shows me the following error in the /var/log/messages
Oct 29 16:33:23 localhost kernel: device-mapper: table: 253:0:
multipath: unknown hardware handler type
Oct 29 16:33:23 localhost kernel: device-mapper: ioctl: error adding
target to table

Same works fine, if I add emc as hardware handler.

Any idea, why am I getting this error?

Thanks and Regards,
Pradipmaya.

Re: Problem with DM hardware handler

[Mike Anderson]

Pradipmaya Maharana <pradipmaya@gmail.com> wrote:
> Now when I run the command,
> # multipath -F
> # multipath -ll
> # multipath -v3
> 
> It shows me the following error in the /var/log/messages
> Oct 29 16:33:23 localhost kernel: device-mapper: table: 253:0:
> multipath: unknown hardware handler type
> Oct 29 16:33:23 localhost kernel: device-mapper: ioctl: error adding
> target to table
> 
> Same works fine, if I add emc as hardware handler.
> 
> Any idea, why am I getting this error?
> 

Did you see any indication prior to the dmesg error output that your
handler registered ok or failed to register (i.e., device-mapper:
dm-sample version 0.0.4 loaded)?

-andmike
--
Michael Anderson
andmike@linux.vnet.ibm.com

Re: Problem with DM hardware handler

[Pradipmaya Maharana]

The handler did register okay; I saw the following message in /var/log/messages.

Oct 29 16:32:39 localhost kernel: device-mapper: multipath sample:
version 0.0.0 loaded.

Thanks and Regards,
Pradipmaya.

On 10/29/07, Mike Anderson <andmike@us.ibm.com> wrote:
> Pradipmaya Maharana <pradipmaya@gmail.com> wrote:
> > Now when I run the command,
> > # multipath -F
> > # multipath -ll
> > # multipath -v3
> >
> > It shows me the following error in the /var/log/messages
> > Oct 29 16:33:23 localhost kernel: device-mapper: table: 253:0:
> > multipath: unknown hardware handler type
> > Oct 29 16:33:23 localhost kernel: device-mapper: ioctl: error adding
> > target to table
> >
> > Same works fine, if I add emc as hardware handler.
> >
> > Any idea, why am I getting this error?
> >
>
> Did you see any indication prior to the dmesg error output that your
> handler registered ok or failed to register (i.e., device-mapper:
> dm-sample version 0.0.4 loaded)?
>
> -andmike
> --
> Michael Anderson
> andmike@linux.vnet.ibm.com
>
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel
>

Re: Problem with DM hardware handler

[Mike Anderson]

Pradipmaya Maharana <pradipmaya@gmail.com> wrote:
> The handler did register okay; I saw the following message in /var/log/messages.
> 
> Oct 29 16:32:39 localhost kernel: device-mapper: multipath sample:
> version 0.0.0 loaded.
> 

I did just as you described and it worked for me. I will send you a patch
version of the changes in my version dm-emc.c dm-sample.c off list.

1.) dmesg out
...
[764248.618295] device-mapper: multipath sample: version 0.0.3 loaded
...
[764743.244154] device-mapper: multipath sample: long trespass command
will be send
[764743.288411] device-mapper: multipath sample: honor reservation bit
will not be set (default)
[764743.344077] device-mapper: multipath sample: long trespass command
will be send

2.) multipath -l
...
mpath1 (35333333000001f40) dm-2 Linux,scsi_debug
[size=8.0M][features=0][hwhandler=1 sample]
\_ round-robin 0 [prio=0][active]
 \_ 3:0:0:0 sdb 8:16  [active][undef]

3.) /etc/multipath.conf
/etc/multipath.conf
...
      device {
                vendor                  "Linux.*"
                product                 "scsi.*"
                hardware_handler        "1 sample"
        }

-andmike
--
Michael Anderson
andmike@linux.vnet.ibm.com