[linux-lvm] bug in CLING allocator on lv extend

[Jens Wilke]

Hi,

I did some extensive tests of the new CLING allocator algorithm which
should allow proper mirror extension.

Testing with CVS HEAD dated 1st december, this is the error I get on 
lvextend in a specific test configuration:
lvextend: metadata/pv_map.c:197: consume_pv_area: Assertion `to_go <= pva->count' failed.

The problem arises in case of an unbalanced amount of free space on the data disks,
mimages twisted (mimage_1 on PV0), and a hole (or at least two areas, I suppose)
that needs to be allocated.

The attached extendtest.sh is the generic code that leads to the error situation 
(set environment varibales disk[0-2] and vg respectively).

The attached extendtest.vg is the meta data backup before the lvextend
with 3 PVs of 128MB each.

Best,

Jens
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# Generated by LVM2: Wed Dec  6 11:41:23 2006

contents = "Text Format Volume Group"
version = 1

description = "vgcfgbackup -f extend.vg dmtestvg"

creation_host = "t6345027"	# Linux t6345027 2.6.9-prep #8 SMP Tue Jun 20 15:36:09 CEST 2006 s390x
creation_time = 1165401683	# Wed Dec  6 11:41:23 2006

dmtestvg {
	id = "y4I28Z-YHvd-ZffY-f7Zw-515t-wB5U-dS5Hv2"
	seqno = 12
	status = ["RESIZEABLE", "READ", "WRITE"]
	extent_size = 8192		# 4 Megabytes
	max_lv = 0
	max_pv = 0

	physical_volumes {

		pv0 {
			id = "pdqOdr-j5sJ-RQeX-wfkd-DiJW-MeHt-Di4Izx"
			device = "/dev/dm-0"	# Hint only

			status = ["ALLOCATABLE"]
			dev_size = 262144	# 128 Megabytes
			pe_start = 384
			pe_count = 31	# 124 Megabytes
		}

		pv1 {
			id = "k7EULd-xRpN-tFtV-gAW9-4zZc-njst-RLwKxk"
			device = "/dev/dm-1"	# Hint only

			status = ["ALLOCATABLE"]
			dev_size = 262144	# 128 Megabytes
			pe_start = 384
			pe_count = 31	# 124 Megabytes
		}

		pv2 {
			id = "jNqEdU-ZWHf-kW7D-XFGG-ti9s-g0VQ-9hbdiL"
			device = "/dev/dm-2"	# Hint only

			status = ["ALLOCATABLE"]
			dev_size = 262144	# 128 Megabytes
			pe_start = 384
			pe_count = 31	# 124 Megabytes
		}
	}

	logical_volumes {

		lx1 {
			id = "ITQ4ue-FCs4-MCmm-RSYX-Vnjh-TbtQ-Myy3uo"
			status = ["READ", "WRITE", "VISIBLE"]
			segment_count = 1

			segment1 {
				start_extent = 0
				extent_count = 1	# 4 Megabytes

				type = "striped"
				stripe_count = 1	# linear

				stripes = [
					"pv0", 0
				]
			}
		}

		lx2 {
			id = "6Ola3N-lOJt-G6Dw-ItpA-T8Cx-wNyn-G8x0IM"
			status = ["READ", "WRITE", "VISIBLE"]
			segment_count = 1

			segment1 {
				start_extent = 0
				extent_count = 1	# 4 Megabytes

				type = "striped"
				stripe_count = 1	# linear

				stripes = [
					"pv1", 0
				]
			}
		}

		m1 {
			id = "FE1p7Y-Criz-mPWF-hJMJ-eY19-wjTM-uPocc0"
			status = ["READ", "WRITE", "VISIBLE"]
			segment_count = 1

			segment1 {
				start_extent = 0
				extent_count = 9	# 36 Megabytes

				type = "mirror"
				mirror_count = 2
				mirror_log = "m1_mlog"
				region_size = 1024

				mirrors = [
					"m1_mimage_0", 0,
					"m1_mimage_1", 0
				]
			}
		}

		lx3 {
			id = "BpzPY5-E87r-VaeG-2FXV-uLId-P94j-5S17iu"
			status = ["READ", "WRITE", "VISIBLE"]
			segment_count = 1

			segment1 {
				start_extent = 0
				extent_count = 3	# 12 Megabytes

				type = "striped"
				stripe_count = 1	# linear

				stripes = [
					"pv2", 9
				]
			}
		}

		l2 {
			id = "1XrfVI-QBn6-CqOF-fxPN-ja8C-rgor-nkrMLI"
			status = ["READ", "WRITE", "VISIBLE"]
			segment_count = 1

			segment1 {
				start_extent = 0
				extent_count = 1	# 4 Megabytes

				type = "striped"
				stripe_count = 1	# linear

				stripes = [
					"pv2", 13
				]
			}
		}

		l4 {
			id = "R8CvQp-EDQx-Ui25-EGZM-i3Tf-zfSL-5Iv6AD"
			status = ["READ", "WRITE", "VISIBLE"]
			segment_count = 1

			segment1 {
				start_extent = 0
				extent_count = 1	# 4 Megabytes

				type = "striped"
				stripe_count = 1	# linear

				stripes = [
					"pv0", 11
				]
			}
		}

		m1_mlog {
			id = "q5XnM3-VtHZ-EoB9-VT52-2Zct-5oCM-UeWwSg"
			status = ["READ", "WRITE"]
			segment_count = 1

			segment1 {
				start_extent = 0
				extent_count = 1	# 4 Megabytes

				type = "striped"
				stripe_count = 1	# linear

				stripes = [
					"pv1", 1
				]
			}
		}

		m1_mimage_0 {
			id = "NZHdXZ-mzK3-eDj8-nLTn-auSY-tou0-xuaicM"
			status = ["READ", "WRITE"]
			segment_count = 1

			segment1 {
				start_extent = 0
				extent_count = 9	# 36 Megabytes

				type = "striped"
				stripe_count = 1	# linear

				stripes = [
					"pv2", 0
				]
			}
		}

		m1_mimage_1 {
			id = "lJphqJ-NebL-V9LD-0SVe-n4ud-sisi-rkE1vO"
			status = ["READ", "WRITE"]
			segment_count = 1

			segment1 {
				start_extent = 0
				extent_count = 9	# 36 Megabytes

				type = "striped"
				stripe_count = 1	# linear

				stripes = [
					"pv0", 1
				]
			}
		}
	}
}