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b35fb0b15a
I've changed build_parallel_areas_from_lv to take a new parameter that allows the caller to build parallel areas by LV vs by segment. Previously, the function created a list of parallel areas for each segment in the given LV. When it came time for allocation, the parallel areas were honored on a segment basis. This was problematic for RAID because any new RAID image must avoid being placed on any PVs used by other images in the RAID. For example, if we have a linear LV that has half its space on one PV and half on another, we do not want an up-convert to use either of those PVs. It should especially not wind up with the following, where the first portion of one LV is paired up with the second portion of the other: ------PV1------- ------PV2------- [ 2of2 image_1 ] [ 1of2 image_1 ] [ 1of2 image_0 ] [ 2of2 image_0 ] ---------------- ---------------- Previously, it was possible for this to happen. The change makes it so that the returned parallel areas list contains one "super" segment (seg_pvs) with a list of all the PVs from every actual segment in the given LV and covering the entire logical extent range. This change allows RAID conversions to function properly when there are existing images that contain multiple segments that span more than one PV.