tests: raid syncaction activation race

Demonstrace problem of syncaction being called right after activation.

test/shell/lvchange-syncaction-raid.sh

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+#!/bin/sh
+# Copyright (C) 2014 Red Hat, Inc. All rights reserved.
+#
+# This copyrighted material is made available to anyone wishing to use,
+# modify, copy, or redistribute it subject to the terms and conditions
+# of the GNU General Public License v.2.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+# test activation race for raid's --syncaction check
+
+. lib/test
+
+aux have_raid 1 5 0 || skip
+aux prepare_vg 3
+
+lvcreate -n $lv1 $vg -l1 --type raid1
+
+START=$(get pv_field "$dev2" pe_start --units 1k)
+METASIZE=$(get lv_field $vg/${lv1}_rmeta_1 size -a --units 1k)
+SEEK=$((${START%\.00k} + ${METASIZE%\.00k}))
+# Overwrite some portion of  _rimage_1
+dd if=/dev/urandom of="$dev2" bs=1K count=1 seek=$SEEK
+
+lvchange --syncaction check $vg/$lv1
+
+# hmmm it's still in 'dd' buffer and not on real disk ??
+# anyway skip over with 'should'
+should check lv_field $vg/$lv1 raid_mismatch_count "128"
+
+# Ensure it's all on disk now
+sync
+
+lvchange --syncaction check $vg/$lv1
+check lv_field $vg/$lv1 raid_mismatch_count "128"
+
+# Let's deactivate
+lvchange -an $vg/$lv1
+
+# Slow down write by 100ms
+aux delay_dev "$dev2" 0 100
+lvchange -ay $vg/$lv1
+# noone has it open and target is read & running
+dmsetup info -c
+
+#sleep 10 < "$DM_DEV_DIR/$vg/$lv1" &
+# "check" should find discrepancies but not change them
+# 'lvs' should show results
+
+# FIXME
+# this looks like some race with 'write' during activation
+# and syncaction...
+# For now it fails with:
+# device-mapper: message ioctl on  failed: Device or resource busy
+#
+lvchange --syncaction check $vg/$lv1
+
+aux enable_dev "$dev2"
+lvs -o+raid_mismatch_count -a $vg
+
+vgremove -ff $vg