From 501a2c04a4cb009a4c6497cd601801b2fe32fb4e Mon Sep 17 00:00:00 2001
From: Peter Rajnoha <prajnoha@redhat.com>
Date: Wed, 9 May 2012 12:30:56 +0000
Subject: [PATCH] Fix division by zero if PV with zero PE count is used during
 vgcfgrestore.

---
 WHATS_NEW                        | 1 +
 lib/format_text/format-text.c    | 2 +-
 test/shell/pvcreate-operation.sh | 8 ++++++++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/WHATS_NEW b/WHATS_NEW
index 07e87541f..3a9e41592 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
 Version 2.02.96 - 
 ================================
+  Fix division by zero if PV with zero PE count is used during vgcfgrestore.
   Add initial support for thin pool lvconvert.
   Fix lvrename for thin volumes (regression in for_each_sub_lv() 2.02.89).
   Fix up-convert when mirror activation is controled by volume_list and tags.
diff --git a/lib/format_text/format-text.c b/lib/format_text/format-text.c
index abd02c8e6..3c89dfabd 100644
--- a/lib/format_text/format-text.c
+++ b/lib/format_text/format-text.c
@@ -1713,7 +1713,7 @@ static int _text_pv_setup(const struct format_type *fmt,
 			   pv->pe_start + size_reduction;
 
 	/* Recalculate number of extents that will fit */
-	if (!pv->pe_count) {
+	if (!pv->pe_count && vg->extent_size) {
 		pe_count = (pv->size - pv->pe_start - size_reduction) /
 			   vg->extent_size;
 		if (pe_count > UINT32_MAX) {
diff --git a/test/shell/pvcreate-operation.sh b/test/shell/pvcreate-operation.sh
index e5d7239bb..19d9e8e9f 100644
--- a/test/shell/pvcreate-operation.sh
+++ b/test/shell/pvcreate-operation.sh
@@ -111,6 +111,14 @@ pvcreate --norestorefile --uuid $uuid1 "$dev1"
 vgcfgbackup -f $backupfile
 not pvcreate --uuid $uuid2 --restorefile $backupfile "$dev2"
 
+# vgcfgrestore of a VG containing a PV with zero PEs (bz #820116)
+# (use case: one PV in a VG used solely to keep metadata)
+size_mb=$(($(blockdev --getsz $dev1) / 2048))
+pvcreate --metadatasize $size_mb $dev1
+vgcreate $vg1 $dev1
+vgcfgbackup -f $backupfile
+vgcfgrestore -f $backupfile $vg1
+
 # pvcreate wipes swap signature when forced
 dd if=/dev/zero of="$dev1" bs=1024 count=64
 mkswap "$dev1"