tree fa5d950b9beffa2a10bc698d452ae50b8e195d5e
parent bbf9a31bba8c985780fe94da059cc5813a7920f5
author Boaz Harrosh <bharrosh@panasas.com> 1317200663 +0300
committer Boaz Harrosh <bharrosh@panasas.com> 1318611281 +0200

ore: Support for partial component table

Users like the objlayout-driver would like to only pass
a partial device table that covers the IO in question.
For example exofs divides the file into raid-group-sized
chunks and only serves group_width number of devices at
a time.

The partiality is communicated by setting
ore_componets->first_dev and the array covers all logical
devices from oc->first_dev upto (oc->first_dev + oc->numdevs)

The ore_comp_dev() API receives a logical device index
and returns the actual present device in the table.
An out-of-range dev_index will BUG.

Logical device index is the theoretical device index as if
all the devices of a file are present. .i.e:
	total_devs = group_width * mirror_p1 * group_count
	0 <= dev_index < total_devs

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>