initial raid1 kiobuf support

[Marcelo Tosatti <marcelo@xxxxxxxxxxxxxxxx>]

Hi, 

I'm attaching a patch which adds kiobuf IO support to the raid1 code. 

Its not complete yet --- it does not reschedule read requests to other
mirrors of the raid1 array in case of a IO error. I hope to do that soon.

Also, I've modified generic_make_request() function and touched some other
kernel bits.

The patch is against SGI XFS tree from 1 hour ago. 

Comments are welcome.

raid1-kio.patch
Description: Text document