[patch] allow crash dumps to Linux swap partitions

[Don Lewis]

On 17 Feb, Andrey V. Elsukov wrote:
> On 17.02.2012 14:16, Doug Barton wrote:
>> So I gave this a try, and I'm getting this:
>> 
>> 
>> GEOM_PART:dumpon:  ioctl(DIOCSKERNELDUMP)P: artition 'ad0s4' not
>> suitable for kernel dumps (wrong type?)
>> Operation not supported by device
>> /etc/rc: WARNING: unable to specify /dev/ad0s7 as a dump device
>> 
>> I'm guessing that this is due to ad0s7 being in an extended partition.
>> So I take it we have no support for dumping to logical partition?
> 
> EBR scheme serves logical partitions. Your extended partition is ad0s4,
> EBR's consumer is attached to MBR's ad0s4 provider. ad0s7 is EBR's provider.
> 
> When you are trying to configure ad0s7 as dump device, GEOM_PART asks EBR scheme:
> is kernel dump allowed or not? After r230064 it answers that dumping is allowed
> to partition with type DOSPTYP_386BSD and DOSPTYP_LINSWP. But, since ad0s7 has
> parent provider it forwards this request to MBR's ad0s4.
> MBR scheme also allows dumping only to the same partition types.
> But ad0s4 partition has type DOSPTYP_EXT. And you got this error message.

Is it possible to detect whether a request has been forwarded?  I think
there is also the possibility of foot shooting in the DOSPTYP_386BSD
case and it would be nice to fix that as well.