[lvm-devel] [PATCH v1 12/17] tests: idm: Add testing for the fabric's half brain failure

[Leo Yan]

If the fabric is broken instantly and the partial drives connected on
the fabric disappear from the system.  For this case, according to the
locking algorithm in idm, the lease will not lose since the half drives
are still alive so can renew the lease for the half drives.  On the
other hand, since the VG lock requires to acquire the majority of drive
number, but half drives failure cannot achieve the majority, so it
cannot acquire the lock for VG and thus cannot change metadata for VG.

This patch is to add half brain failure for idm; the test command is as
below:

  # make check_lvmlockd_idm \
	LVM_TEST_BACKING_DEVICE=/dev/sdp3,/dev/sdo3 LVM_TEST_FAILURE=1 \
	T=idm_fabric_failure_half_brain.sh

Signed-off-by: Leo Yan <leo.yan at linaro.org>
---
 test/shell/idm_fabric_failure_half_brain.sh | 78 +++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 test/shell/idm_fabric_failure_half_brain.sh

diff --git a/test/shell/idm_fabric_failure_half_brain.sh b/test/shell/idm_fabric_failure_half_brain.sh
new file mode 100644
index 000000000..c692a12ad
--- /dev/null
+++ b/test/shell/idm_fabric_failure_half_brain.sh
@@ -0,0 +1,78 @@
+#!/usr/bin/env bash
+
+# Copyright (C) 2020 Seagate, 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 v2.
+#
+# 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+
+SKIP_WITH_LVMPOLLD=1
+
+. lib/inittest
+
+[ -z "$LVM_TEST_LOCK_TYPE_IDM" ] && skip;
+[ -z "$LVM_TEST_FAILURE" ] && skip;
+
+aux prepare_devs 2
+aux extend_filter_LVMTEST
+
+DRIVE1=`dmsetup deps -o devname $dev1 | awk '{gsub(/[()]/,""); print $4;}' | sed 's/[0-9]*$//'`
+DRIVE2=`dmsetup deps -o devname $dev2 | awk '{gsub(/[()]/,""); print $4;}' | sed 's/[0-9]*$//'`
+
+[ "$(basename -- $DRIVE1)" = "$(basename -- $DRIVE2)" ] && die "Need to pass two different drives!?"
+
+# The previous device-mapper are removed, but LVM still can directly
+# access VGs from the specified physical drives.  So enable drives
+# for these drives.
+aux extend_filter_LVMTEST "a|/dev/$DRIVE1*|" "a|/dev/$DRIVE2*|"
+aux lvmconf "devices/allow_changes_with_duplicate_pvs = 1"
+
+vgcreate $SHARED $vg "$dev1" "$dev2"
+
+# Create new logic volume
+lvcreate -a ey --zero n -l 100%FREE -n $lv1 $vg
+
+drive_list=($DRIVE1)
+
+# Find all drives with the same WWN and delete them from system,
+# so that we can emulate the same drive with multiple paths are
+# disconnected with system.
+drive_wwn=`udevadm info /dev/${DRIVE1} | awk -F= '/E: ID_WWN=/ {print $2}'`
+for dev in /dev/*; do
+	if [ -b "$dev" ] && [[ ! "$dev" =~ [0-9] ]]; then
+		wwn=`udevadm info "${dev}" | awk -F= '/E: ID_WWN=/ {print $2}'`
+		if [ "$wwn" = "$drive_wwn" ]; then
+			base_name="$(basename -- ${dev})"
+			drive_list+=("$base_name")
+			host_list+=(`readlink /sys/block/$base_name | awk -F'/' '{print $6}'`)
+		fi
+	fi
+done
+
+for d in "${drive_list[@]}"; do
+	[ -f /sys/block/$d/device/delete ] && echo 1 > /sys/block/$d/device/delete
+done
+
+# Fail to create new logic volume
+not lvcreate -a n --zero n -l 1 -n $lv2 $vg
+
+# Wait for lock time out caused by drive failure
+sleep 70
+
+not check grep_lvmlockd_dump "S lvm_$vg kill_vg"
+
+# Rescan drives so can probe the deleted drives and join back them
+for h in "${host_list[@]}"; do
+	[ -f /sys/class/scsi_host/${h}/scan ] && echo "- - -" > /sys/class/scsi_host/${h}/scan
+done
+
+# After the drive is reconnected, $vg should be visible again.
+vgchange --lock-start
+lvremove -f $vg/$lv1
+lvcreate -a ey --zero n -l 1 -n $lv2 $vg
+vgremove -ff $vg
-- 
2.25.1