[dm-devel] Autoload of DM kernel targets?

[Andrei Borzenkov]

24.04.2017 07:05, NeilBrown пишет:
> On Fri, Apr 21 2017, Andrei Borzenkov wrote:
> 
>> See as example https://bugzilla.opensuse.org/show_bug.cgi?id=983221
>>
>> "non-standard" DM targets do not appear to be autoloaded (the problem
>> was hit with thin-pool, but it seems to apply to other targets as well).
>> "Common" targets (like linear) are provided by dm-mod which seems to be
>> autoloaded by virtue of /dev/mapper/control.
>>
>> Is it expected and intentional? Or are users required to manually load
>> necessary modules on boot?
>>
>> TIA
>>
>> -andrei
>>
>> --
>> dm-devel mailing list
>> dm-devel at redhat.com
>> https://www.redhat.com/mailman/listinfo/dm-devel
> 
> Does this patch fix it for you?
> 

I did not test it, because the problem (at least, this specific problem)
turned out a packaging problem - lvm checks for available targets before
it even tries to call into kernel, so this should not change anything.
But it needs path to modprobe that is detected during build. mkdprobe
was not present in build environment so lvm did not try to autoload
anything and immediately failed. Making sure to BuildRequire (package,
that provides) it fixed the problem.

> diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
> index 8f811dc8b3cc..d2c6a9a12d75 100644
> --- a/drivers/md/dm-thin.c
> +++ b/drivers/md/dm-thin.c
> @@ -4400,3 +4400,4 @@ MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in second
>  MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
>  MODULE_AUTHOR("Joe Thornber <dm-devel at redhat.com>");
>  MODULE_LICENSE("GPL");
> +MODULE_ALIAS("dm-thin-pool");
> 
> NeilBrown
> 


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