zfs/tests/zfs-tests/include/blkdev.shlib - backupdr - Git at Google

 #
 # This file and its contents are supplied under the terms of the
 # Common Development and Distribution License ("CDDL"), version 1.0.
 # You may only use this file in accordance with the terms of version
 # 1.0 of the CDDL.
 #
 # A full copy of the text of the CDDL should have accompanied this
 # source.  A copy of the CDDL is also available via the Internet at
 # http://www.illumos.org/license/CDDL.
 #

 #
 # Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 # Use is subject to license terms.
 # Copyright (c) 2012, 2019 by Delphix. All rights reserved.
 # Copyright 2016 Nexenta Systems, Inc.
 # Copyright (c) 2016, 2017 by Intel Corporation. All rights reserved.
 # Copyright (c) 2017 Lawrence Livermore National Security, LLC.
 # Copyright (c) 2017 Datto Inc.
 # Copyright (c) 2017 Open-E, Inc. All Rights Reserved.
 # Copyright 2019 Richard Elling
 #

 #
 # Returns SCSI host number for the given disk
 #
 function get_scsi_host #disk
 {
 	typeset disk=$1
 	ls /sys/block/${disk}/device/scsi_device | cut -d : -f 1
 }

 #
 # Cause a scan of all scsi host adapters by default
 #
 # $1 optional host number
 #
 function scan_scsi_hosts
 {
 	typeset hostnum=${1}

 	if is_linux; then
 		if [[ -z $hostnum ]]; then
 			for host in /sys/class/scsi_host/host*; do
 				log_must eval "echo '- - -' > $host/scan"
 			done
 		else
 			log_must eval \
 			    "echo /sys/class/scsi_host/host$hostnum/scan" \
 			    > /dev/null
 			log_must eval \
 			    "echo '- - -' > /sys/class/scsi_host/host$hostnum/scan"
 		fi
 	fi
 }

 #
 # Wait for newly created block devices to have their minors created.
 # Additional arguments can be passed to udevadm trigger, with the expected
 # arguments to typically be a block device pathname. This is useful when
 # checking waiting on a specific device to settle rather than triggering
 # all devices and waiting for them all to settle.
 #
 # The udevadm settle timeout can be 120 or 180 seconds by default for
 # some distros. If a long delay is experienced, it could be due to some
 # strangeness in a malfunctioning device that isn't related to the devices
 # under test. To help debug this condition, a notice is given if settle takes
 # too long.
 #
 # Note: there is no meaningful return code if udevadm fails. Consumers
 # should not expect a return code (do not call as argument to log_must)
 #
 function block_device_wait
 {
 	if is_linux; then
 		udevadm trigger $*
 		typeset local start=$SECONDS
 		udevadm settle
 		typeset local elapsed=$((SECONDS - start))
 		[[ $elapsed > 60 ]] && \
 		    log_note udevadm settle time too long: $elapsed
 	fi
 }

 #
 # Check if the given device is physical device
 #
 function is_physical_device #device
 {
 	typeset device=${1#$DEV_DSKDIR}
 	device=${device#$DEV_RDSKDIR}

 	if is_linux; then
 		[[ -b "$DEV_DSKDIR/$device" ]] && \
 		[[ -f /sys/module/loop/parameters/max_part ]]
 		return $?
 	else
 		echo $device | egrep "^c[0-F]+([td][0-F]+)+$" > /dev/null 2>&1
 		return $?
 	fi
 }

 #
 # Check if the given device is a real device (ie SCSI device)
 #
 function is_real_device #disk
 {
 	typeset disk=$1
 	[[ -z $disk ]] && log_fail "No argument for disk given."

 	if is_linux; then
 		lsblk $DEV_RDSKDIR/$disk -o TYPE 2>/dev/null | \
 		    egrep disk >/dev/null
 		return $?
 	fi
 }

 #
 # Check if the given device is a loop device
 #
 function is_loop_device #disk
 {
 	typeset disk=$1
 	[[ -z $disk ]] && log_fail "No argument for disk given."

 	if is_linux; then
 		lsblk $DEV_RDSKDIR/$disk -o TYPE 2>/dev/null | \
 		    egrep loop >/dev/null
 		return $?
 	fi
 }

 #
 # Check if the given device is a multipath device and if there is a symbolic
 # link to a device mapper and to a disk
 # Currently no support for dm devices alone without multipath
 #
 function is_mpath_device #disk
 {
 	typeset disk=$1
 	[[ -z $disk ]] && log_fail "No argument for disk given."

 	if is_linux; then
 		lsblk $DEV_MPATHDIR/$disk -o TYPE 2>/dev/null | \
 		   egrep mpath >/dev/null
 		if (($? == 0)); then
 			readlink $DEV_MPATHDIR/$disk > /dev/null 2>&1
 			return $?
 		else
 			return $?
 		fi
 	fi
 }

 # Set the slice prefix for disk partitioning depending
 # on whether the device is a real, multipath, or loop device.
 # Currently all disks have to be of the same type, so only
 # checks first disk to determine slice prefix.
 #
 function set_slice_prefix
 {
 	typeset disk
 	typeset -i i=0

 	if is_linux; then
 		while (( i < $DISK_ARRAY_NUM )); do
 			disk="$(echo $DISKS | nawk '{print $(i + 1)}')"
 			if ( is_mpath_device $disk ) && [[ -z $(echo $disk | awk 'substr($1,18,1)\
 			     ~ /^[[:digit:]]+$/') ]] || ( is_real_device $disk ); then
 				export SLICE_PREFIX=""
 				return 0
 			elif ( is_mpath_device $disk || is_loop_device \
 			    $disk ); then
 				export SLICE_PREFIX="p"
 				return 0
 			else
 				log_fail "$disk not supported for partitioning."
 			fi
 			(( i = i + 1))
 		done
 	fi
 }

 #
 # Set the directory path of the listed devices in $DISK_ARRAY_NUM
 # Currently all disks have to be of the same type, so only
 # checks first disk to determine device directory
 # default = /dev (linux)
 # real disk = /dev (linux)
 # multipath device = /dev/mapper (linux)
 #
 function set_device_dir
 {
 	typeset disk
 	typeset -i i=0

 	if is_linux; then
 		while (( i < $DISK_ARRAY_NUM )); do
 			disk="$(echo $DISKS | nawk '{print $(i + 1)}')"
 			if is_mpath_device $disk; then
 				export DEV_DSKDIR=$DEV_MPATHDIR
 				return 0
 			else
 				export DEV_DSKDIR=$DEV_RDSKDIR
 				return 0
 			fi
 			(( i = i + 1))
 		done
 	else
 		export DEV_DSKDIR=$DEV_RDSKDIR
 	fi
 }

 #
 # Get the directory path of given device
 #
 function get_device_dir #device
 {
 	typeset device=$1

 	if ! $(is_physical_device $device) ; then
 		if [[ $device != "/" ]]; then
 			device=${device%/*}
 		fi
 		if [[ -b "$DEV_DSKDIR/$device" ]]; then
 			device="$DEV_DSKDIR"
 		fi
 		echo $device
 	else
 		echo "$DEV_DSKDIR"
 	fi
 }

 #
 # Get persistent name for given disk
 #
 function get_persistent_disk_name #device
 {
 	typeset device=$1
 	typeset dev_id

 	if is_linux; then
 		if is_real_device $device; then
 			dev_id="$(udevadm info -q all -n $DEV_DSKDIR/$device \
 			    | egrep disk/by-id | nawk '{print $2; exit}' \
 			    | nawk -F / '{print $3}')"
 			echo $dev_id
 		elif is_mpath_device $device; then
 			dev_id="$(udevadm info -q all -n $DEV_DSKDIR/$device \
 			    | egrep disk/by-id/dm-uuid \
 			    | nawk '{print $2; exit}' \
 			    | nawk -F / '{print $3}')"
 			echo $dev_id
 		else
 			echo $device
 		fi
 	else
 		echo $device
 	fi
 }

 #
 # Online or offline a disk on the system
 #
 # First checks state of disk. Test will fail if disk is not properly onlined
 # or offlined. Online is a full rescan of SCSI disks by echoing to every
 # host entry.
 #
 function on_off_disk # disk state{online,offline} host
 {
 	typeset disk=$1
 	typeset state=$2
 	typeset host=$3

 	[[ -z $disk ]] || [[ -z $state ]] &&  \
 	    log_fail "Arguments invalid or missing"

 	if is_linux; then
 		if [[ $state == "offline" ]] && ( is_mpath_device $disk ); then
 			dm_name="$(readlink $DEV_DSKDIR/$disk \
 			    | nawk -F / '{print $2}')"
 			slave="$(ls /sys/block/${dm_name}/slaves \
 			    | nawk '{print $1}')"
 			while [[ -n $slave ]]; do
 				#check if disk is online
 				lsscsi | egrep $slave > /dev/null
 				if (($? == 0)); then
 					slave_dir="/sys/block/${dm_name}"
 					slave_dir+="/slaves/${slave}/device"
 					ss="${slave_dir}/state"
 					sd="${slave_dir}/delete"
 					log_must eval "echo 'offline' > ${ss}"
 					log_must eval "echo '1' > ${sd}"
 					lsscsi | egrep $slave > /dev/null
 						if (($? == 0)); then
 							log_fail "Offlining" \
 							    "$disk failed"
 						fi
 				fi
 				slave="$(ls /sys/block/$dm_name/slaves \
 				    2>/dev/null | nawk '{print $1}')"
 			done
 		elif [[ $state == "offline" ]] && ( is_real_device $disk ); then
 			#check if disk is online
 			lsscsi | egrep $disk > /dev/null
 			if (($? == 0)); then
 				dev_state="/sys/block/$disk/device/state"
 				dev_delete="/sys/block/$disk/device/delete"
 				log_must eval "echo 'offline' > ${dev_state}"
 				log_must eval "echo '1' > ${dev_delete}"
 				lsscsi | egrep $disk > /dev/null
 					if (($? == 0)); then
 						log_fail "Offlining $disk" \
 						    "failed"
 					fi
 			else
 				log_note "$disk is already offline"
 			fi
 		elif [[ $state == "online" ]]; then
 			#force a full rescan
 			scan_scsi_hosts $host
 			block_device_wait
 			if is_mpath_device $disk; then
 				dm_name="$(readlink $DEV_DSKDIR/$disk \
 				    | nawk -F / '{print $2}')"
 				slave="$(ls /sys/block/$dm_name/slaves \
 				    | nawk '{print $1}')"
 				lsscsi | egrep $slave > /dev/null
 				if (($? != 0)); then
 					log_fail "Onlining $disk failed"
 				fi
 			elif is_real_device $disk; then
 				block_device_wait
 				typeset -i retries=0
 				while ! lsscsi | egrep -q $disk; do
 					if (( $retries > 2 )); then
 						log_fail "Onlining $disk failed"
 						break
 					fi
 					(( ++retries ))
 					sleep 1
 				done
 			else
 				log_fail "$disk is not a real dev"
 			fi
 		else
 			log_fail "$disk failed to $state"
 		fi
 	fi
 }

 #
 # Simulate disk removal
 #
 function remove_disk #disk
 {
 	typeset disk=$1
 	on_off_disk $disk "offline"
 	block_device_wait
 }

 #
 # Simulate disk insertion for the given SCSI host
 #
 function insert_disk #disk scsi_host
 {
 	typeset disk=$1
 	typeset scsi_host=$2
 	on_off_disk $disk "online" $scsi_host
 	block_device_wait
 }

 #
 # Load scsi_debug module with specified parameters
 # $blksz can be either one of: < 512b | 512e | 4Kn >
 #
 function load_scsi_debug # dev_size_mb add_host num_tgts max_luns blksz
 {
 	typeset devsize=$1
 	typeset hosts=$2
 	typeset tgts=$3
 	typeset luns=$4
 	typeset blksz=$5

 	[[ -z $devsize ]] || [[ -z $hosts ]] || [[ -z $tgts ]] || \
 	    [[ -z $luns ]] || [[ -z $blksz ]] && \
 	    log_fail "Arguments invalid or missing"

 	case "$5" in
 		'512b')
 			typeset sector=512
 			typeset blkexp=0
 		;;
 		'512e')
 			typeset sector=512
 			typeset blkexp=3
 		;;
 		'4Kn')
 			typeset sector=4096
 			typeset blkexp=0
 		;;
 		*) log_fail "Unsupported blksz value: $5" ;;
 	esac

 	if is_linux; then
 		modprobe -n scsi_debug
 		if (($? != 0)); then
 			log_unsupported "Platform does not have scsi_debug"
 			    "module"
 		fi
 		lsmod | egrep scsi_debug > /dev/null
 		if (($? == 0)); then
 			log_fail "scsi_debug module already installed"
 		else
 			log_must modprobe scsi_debug dev_size_mb=$devsize \
 			    add_host=$hosts num_tgts=$tgts max_luns=$luns \
 			    sector_size=$sector physblk_exp=$blkexp
 			block_device_wait
 			lsscsi | egrep scsi_debug > /dev/null
 			if (($? == 1)); then
 				log_fail "scsi_debug module install failed"
 			fi
 		fi
 	fi
 }

 #
 # Unload scsi_debug module, if needed.
 #
 function unload_scsi_debug
 {
 	log_must_retry "in use" 5 modprobe -r scsi_debug
 }

 #
 # Get scsi_debug device name.
 # Returns basename of scsi_debug device (for example "sdb").
 #
 function get_debug_device
 {
 	for i in {1..10} ; do
 		val=$(lsscsi | nawk '/scsi_debug/ {print $6; exit}' | cut -d / -f3)

 		# lsscsi can take time to settle
 		if [ "$val" != "-" ] ; then
 			break
 		fi
 		sleep 1
 	done
 	echo "$val"
 }

 #
 # Get actual devices used by the pool (i.e. linux sdb1 not sdb).
 #
 function get_pool_devices #testpool #devdir
 {
 	typeset testpool=$1
 	typeset devdir=$2
 	typeset out=""

 	if is_linux; then
 		out=$(zpool status -P $testpool |grep ${devdir} | awk '{print $1}')
 		out=$(echo $out | sed -e "s|${devdir}/||g" | tr '\n' ' ')
 	fi
 	echo $out
 }

 #
 # Write to standard out giving the level, device name, offset and length
 # of all blocks in an input file. The offset and length are in units of
 # 512 byte blocks. In the case of mirrored vdevs, only the first
 # device is listed, as the levels, blocks and offsets will be the same
 # on other devices. Note that this function only works with mirrored
 # or non-redundant pools, not raidz.
 #
 # The output of this function can be used to introduce corruption at
 # varying levels of indirection.
 #
 function list_file_blocks # input_file
 {
 	typeset input_file=$1

 	[[ -f $input_file ]] || log_fail "Couldn't find $input_file"

 	typeset ds="$(zfs list -H -o name $input_file)"
 	typeset pool="${ds%%/*}"
 	typeset inum="$(stat -c '%i' $input_file)"

 	#
 	# Establish a mapping between vdev ids as shown in a DVA and the
 	# pathnames they correspond to in ${VDEV_MAP[]}.
 	#
 	eval $(zdb -C $pool | awk '
 		BEGIN {
 			printf("typeset VDEV_MAP\n");
 			looking = 0;
 		}
 		/^            children/ {
 			id = $1;
 			looking = 1;
 		}
 		/path: / && looking == 1 {
 			print id" "$2;
 			looking = 0;
 		}
 	' | sed -n 's/^children\[\([0-9]\)\]: \(.*\)$/VDEV_MAP[\1]=\2/p')

 	#
 	# The awk below parses the output of zdb, printing out the level
 	# of each block along with vdev id, offset and length. The last
 	# two are converted to decimal in the while loop. 4M is added to
 	# the offset to compensate for the first two labels and boot
 	# block. Lastly, the offset and length are printed in units of
 	# 512b blocks for ease of use with dd.
 	#
 	log_must zpool sync -f
 	typeset level path offset length
 	zdb -ddddd $ds $inum | awk -F: '
 		BEGIN { looking = 0 }
 		/^Indirect blocks:/ { looking = 1}
 		/^\t\tsegment / { looking = 0}
 		/L[0-8]/ && looking == 1 { print $0}
 	' | sed -n 's/^.*\(L[0-9]\) \([0-9]*\):\([0-9a-f]*\):\([0-9a-f]*\) .*$/\1 \2 \3 \4/p' | \
 	while read level path offset length; do
 		offset=$((16#$offset))  # Conversion from hex
 		length=$((16#$length))
 		offset="$(((offset + 4 * 1024 * 1024) / 512))"
 		length="$((length / 512))"
 		echo "$level ${VDEV_MAP[$path]} $offset $length"
 	done 2>/dev/null
 }

 function corrupt_blocks_at_level # input_file corrupt_level
 {
 	typeset input_file=$1
 	typeset corrupt_level="L${2:-0}"
 	typeset level path offset length

 	[[ -f $input_file ]] || log_fail "Couldn't find $input_file"


 	log_must list_file_blocks $input_file | \
 	    while read level path offset length; do
 		if [[ $level = $corrupt_level ]]; then
 			log_must dd if=/dev/urandom of=$path bs=512 \
 			    count=$length seek=$offset conv=notrunc
 		fi
 	    done

 	# This is necessary for pools made of loop devices.
 	sync
 }
	#
	# This file and its contents are supplied under the terms of the
	# Common Development and Distribution License ("CDDL"), version 1.0.
	# You may only use this file in accordance with the terms of version
	# 1.0 of the CDDL.
	#
	# A full copy of the text of the CDDL should have accompanied this
	# source. A copy of the CDDL is also available via the Internet at
	# http://www.illumos.org/license/CDDL.
	#

	#
	# Copyright 2009 Sun Microsystems, Inc. All rights reserved.
	# Use is subject to license terms.
	# Copyright (c) 2012, 2019 by Delphix. All rights reserved.
	# Copyright 2016 Nexenta Systems, Inc.
	# Copyright (c) 2016, 2017 by Intel Corporation. All rights reserved.
	# Copyright (c) 2017 Lawrence Livermore National Security, LLC.
	# Copyright (c) 2017 Datto Inc.
	# Copyright (c) 2017 Open-E, Inc. All Rights Reserved.
	# Copyright 2019 Richard Elling
	#

	#
	# Returns SCSI host number for the given disk
	#
	function get_scsi_host #disk
	{
	typeset disk=$1
	ls /sys/block/${disk}/device/scsi_device \| cut -d : -f 1
	}

	#
	# Cause a scan of all scsi host adapters by default
	#
	# $1 optional host number
	#
	function scan_scsi_hosts
	{
	typeset hostnum=${1}

	if is_linux; then
	if [[ -z $hostnum ]]; then
	for host in /sys/class/scsi_host/host*; do
	log_must eval "echo '- - -' > $host/scan"
	done
	else
	log_must eval \
	"echo /sys/class/scsi_host/host$hostnum/scan" \
	> /dev/null
	log_must eval \
	"echo '- - -' > /sys/class/scsi_host/host$hostnum/scan"
	fi
	fi
	}

	#
	# Wait for newly created block devices to have their minors created.
	# Additional arguments can be passed to udevadm trigger, with the expected
	# arguments to typically be a block device pathname. This is useful when
	# checking waiting on a specific device to settle rather than triggering
	# all devices and waiting for them all to settle.
	#
	# The udevadm settle timeout can be 120 or 180 seconds by default for
	# some distros. If a long delay is experienced, it could be due to some
	# strangeness in a malfunctioning device that isn't related to the devices
	# under test. To help debug this condition, a notice is given if settle takes
	# too long.
	#
	# Note: there is no meaningful return code if udevadm fails. Consumers
	# should not expect a return code (do not call as argument to log_must)
	#
	function block_device_wait
	{
	if is_linux; then
	udevadm trigger $*
	typeset local start=$SECONDS
	udevadm settle
	typeset local elapsed=$((SECONDS - start))
	[[ $elapsed > 60 ]] && \
	log_note udevadm settle time too long: $elapsed
	fi
	}

	#
	# Check if the given device is physical device
	#
	function is_physical_device #device
	{
	typeset device=${1#$DEV_DSKDIR}
	device=${device#$DEV_RDSKDIR}

	if is_linux; then
	[[ -b "$DEV_DSKDIR/$device" ]] && \
	[[ -f /sys/module/loop/parameters/max_part ]]
	return $?
	else
	echo $device \| egrep "^c[0-F]+([td][0-F]+)+$" > /dev/null 2>&1
	return $?
	fi
	}

	#
	# Check if the given device is a real device (ie SCSI device)
	#
	function is_real_device #disk
	{
	typeset disk=$1
	[[ -z $disk ]] && log_fail "No argument for disk given."

	if is_linux; then
	lsblk $DEV_RDSKDIR/$disk -o TYPE 2>/dev/null \| \
	egrep disk >/dev/null
	return $?
	fi
	}

	#
	# Check if the given device is a loop device
	#
	function is_loop_device #disk
	{
	typeset disk=$1
	[[ -z $disk ]] && log_fail "No argument for disk given."

	if is_linux; then
	lsblk $DEV_RDSKDIR/$disk -o TYPE 2>/dev/null \| \
	egrep loop >/dev/null
	return $?
	fi
	}

	#
	# Check if the given device is a multipath device and if there is a symbolic
	# link to a device mapper and to a disk
	# Currently no support for dm devices alone without multipath
	#
	function is_mpath_device #disk
	{
	typeset disk=$1
	[[ -z $disk ]] && log_fail "No argument for disk given."

	if is_linux; then
	lsblk $DEV_MPATHDIR/$disk -o TYPE 2>/dev/null \| \
	egrep mpath >/dev/null
	if (($? == 0)); then
	readlink $DEV_MPATHDIR/$disk > /dev/null 2>&1
	return $?
	else
	return $?
	fi
	fi
	}

	# Set the slice prefix for disk partitioning depending
	# on whether the device is a real, multipath, or loop device.
	# Currently all disks have to be of the same type, so only
	# checks first disk to determine slice prefix.
	#
	function set_slice_prefix
	{
	typeset disk
	typeset -i i=0

	if is_linux; then
	while (( i < $DISK_ARRAY_NUM )); do
	disk="$(echo $DISKS \| nawk '{print $(i + 1)}')"
	if ( is_mpath_device $disk ) && [[ -z $(echo $disk \| awk 'substr($1,18,1)\
	~ /^[[:digit:]]+$/') ]] \|\| ( is_real_device $disk ); then
	export SLICE_PREFIX=""
	return 0
	elif ( is_mpath_device $disk \|\| is_loop_device \
	$disk ); then
	export SLICE_PREFIX="p"
	return 0
	else
	log_fail "$disk not supported for partitioning."
	fi
	(( i = i + 1))
	done
	fi
	}

	#
	# Set the directory path of the listed devices in $DISK_ARRAY_NUM
	# Currently all disks have to be of the same type, so only
	# checks first disk to determine device directory
	# default = /dev (linux)
	# real disk = /dev (linux)
	# multipath device = /dev/mapper (linux)
	#
	function set_device_dir
	{
	typeset disk
	typeset -i i=0

	if is_linux; then
	while (( i < $DISK_ARRAY_NUM )); do
	disk="$(echo $DISKS \| nawk '{print $(i + 1)}')"
	if is_mpath_device $disk; then
	export DEV_DSKDIR=$DEV_MPATHDIR
	return 0
	else
	export DEV_DSKDIR=$DEV_RDSKDIR
	return 0
	fi
	(( i = i + 1))
	done
	else
	export DEV_DSKDIR=$DEV_RDSKDIR
	fi
	}

	#
	# Get the directory path of given device
	#
	function get_device_dir #device
	{
	typeset device=$1

	if ! $(is_physical_device $device) ; then
	if [[ $device != "/" ]]; then
	device=${device%/*}
	fi
	if [[ -b "$DEV_DSKDIR/$device" ]]; then
	device="$DEV_DSKDIR"
	fi
	echo $device
	else
	echo "$DEV_DSKDIR"
	fi
	}

	#
	# Get persistent name for given disk
	#
	function get_persistent_disk_name #device
	{
	typeset device=$1
	typeset dev_id

	if is_linux; then
	if is_real_device $device; then
	dev_id="$(udevadm info -q all -n $DEV_DSKDIR/$device \
	\| egrep disk/by-id \| nawk '{print $2; exit}' \
	\| nawk -F / '{print $3}')"
	echo $dev_id
	elif is_mpath_device $device; then
	dev_id="$(udevadm info -q all -n $DEV_DSKDIR/$device \
	\| egrep disk/by-id/dm-uuid \
	\| nawk '{print $2; exit}' \
	\| nawk -F / '{print $3}')"
	echo $dev_id
	else
	echo $device
	fi
	else
	echo $device
	fi
	}

	#
	# Online or offline a disk on the system
	#
	# First checks state of disk. Test will fail if disk is not properly onlined
	# or offlined. Online is a full rescan of SCSI disks by echoing to every
	# host entry.
	#
	function on_off_disk # disk state{online,offline} host
	{
	typeset disk=$1
	typeset state=$2
	typeset host=$3

	[[ -z $disk ]] \|\| [[ -z $state ]] && \
	log_fail "Arguments invalid or missing"

	if is_linux; then
	if [[ $state == "offline" ]] && ( is_mpath_device $disk ); then
	dm_name="$(readlink $DEV_DSKDIR/$disk \
	\| nawk -F / '{print $2}')"
	slave="$(ls /sys/block/${dm_name}/slaves \
	\| nawk '{print $1}')"
	while [[ -n $slave ]]; do
	#check if disk is online
	lsscsi \| egrep $slave > /dev/null
	if (($? == 0)); then
	slave_dir="/sys/block/${dm_name}"
	slave_dir+="/slaves/${slave}/device"
	ss="${slave_dir}/state"
	sd="${slave_dir}/delete"
	log_must eval "echo 'offline' > ${ss}"
	log_must eval "echo '1' > ${sd}"
	lsscsi \| egrep $slave > /dev/null
	if (($? == 0)); then
	log_fail "Offlining" \
	"$disk failed"
	fi
	fi
	slave="$(ls /sys/block/$dm_name/slaves \
	2>/dev/null \| nawk '{print $1}')"
	done
	elif [[ $state == "offline" ]] && ( is_real_device $disk ); then
	#check if disk is online
	lsscsi \| egrep $disk > /dev/null
	if (($? == 0)); then
	dev_state="/sys/block/$disk/device/state"
	dev_delete="/sys/block/$disk/device/delete"
	log_must eval "echo 'offline' > ${dev_state}"
	log_must eval "echo '1' > ${dev_delete}"
	lsscsi \| egrep $disk > /dev/null
	if (($? == 0)); then
	log_fail "Offlining $disk" \
	"failed"
	fi
	else
	log_note "$disk is already offline"
	fi
	elif [[ $state == "online" ]]; then
	#force a full rescan
	scan_scsi_hosts $host
	block_device_wait
	if is_mpath_device $disk; then
	dm_name="$(readlink $DEV_DSKDIR/$disk \
	\| nawk -F / '{print $2}')"
	slave="$(ls /sys/block/$dm_name/slaves \
	\| nawk '{print $1}')"
	lsscsi \| egrep $slave > /dev/null
	if (($? != 0)); then
	log_fail "Onlining $disk failed"
	fi
	elif is_real_device $disk; then
	block_device_wait
	typeset -i retries=0
	while ! lsscsi \| egrep -q $disk; do
	if (( $retries > 2 )); then
	log_fail "Onlining $disk failed"
	break
	fi
	(( ++retries ))
	sleep 1
	done
	else
	log_fail "$disk is not a real dev"
	fi
	else
	log_fail "$disk failed to $state"
	fi
	fi
	}

	#
	# Simulate disk removal
	#
	function remove_disk #disk
	{
	typeset disk=$1
	on_off_disk $disk "offline"
	block_device_wait
	}

	#
	# Simulate disk insertion for the given SCSI host
	#
	function insert_disk #disk scsi_host
	{
	typeset disk=$1
	typeset scsi_host=$2
	on_off_disk $disk "online" $scsi_host
	block_device_wait
	}

	#
	# Load scsi_debug module with specified parameters
	# $blksz can be either one of: < 512b \| 512e \| 4Kn >
	#
	function load_scsi_debug # dev_size_mb add_host num_tgts max_luns blksz
	{
	typeset devsize=$1
	typeset hosts=$2
	typeset tgts=$3
	typeset luns=$4
	typeset blksz=$5

	[[ -z $devsize ]] \|\| [[ -z $hosts ]] \|\| [[ -z $tgts ]] \|\| \
	[[ -z $luns ]] \|\| [[ -z $blksz ]] && \
	log_fail "Arguments invalid or missing"

	case "$5" in
	'512b')
	typeset sector=512
	typeset blkexp=0
	;;
	'512e')
	typeset sector=512
	typeset blkexp=3
	;;
	'4Kn')
	typeset sector=4096
	typeset blkexp=0
	;;
	*) log_fail "Unsupported blksz value: $5" ;;
	esac

	if is_linux; then
	modprobe -n scsi_debug
	if (($? != 0)); then
	log_unsupported "Platform does not have scsi_debug"
	"module"
	fi
	lsmod \| egrep scsi_debug > /dev/null
	if (($? == 0)); then
	log_fail "scsi_debug module already installed"
	else
	log_must modprobe scsi_debug dev_size_mb=$devsize \
	add_host=$hosts num_tgts=$tgts max_luns=$luns \
	sector_size=$sector physblk_exp=$blkexp
	block_device_wait
	lsscsi \| egrep scsi_debug > /dev/null
	if (($? == 1)); then
	log_fail "scsi_debug module install failed"
	fi
	fi
	fi
	}

	#
	# Unload scsi_debug module, if needed.
	#
	function unload_scsi_debug
	{
	log_must_retry "in use" 5 modprobe -r scsi_debug
	}

	#
	# Get scsi_debug device name.
	# Returns basename of scsi_debug device (for example "sdb").
	#
	function get_debug_device
	{
	for i in {1..10} ; do
	val=$(lsscsi \| nawk '/scsi_debug/ {print $6; exit}' \| cut -d / -f3)

	# lsscsi can take time to settle
	if [ "$val" != "-" ] ; then
	break
	fi
	sleep 1
	done
	echo "$val"
	}

	#
	# Get actual devices used by the pool (i.e. linux sdb1 not sdb).
	#
	function get_pool_devices #testpool #devdir
	{
	typeset testpool=$1
	typeset devdir=$2
	typeset out=""

	if is_linux; then
	out=$(zpool status -P $testpool \|grep ${devdir} \| awk '{print $1}')
	out=$(echo $out \| sed -e "s\|${devdir}/\|\|g" \| tr '\n' ' ')
	fi
	echo $out
	}

	#
	# Write to standard out giving the level, device name, offset and length
	# of all blocks in an input file. The offset and length are in units of
	# 512 byte blocks. In the case of mirrored vdevs, only the first
	# device is listed, as the levels, blocks and offsets will be the same
	# on other devices. Note that this function only works with mirrored
	# or non-redundant pools, not raidz.
	#
	# The output of this function can be used to introduce corruption at
	# varying levels of indirection.
	#
	function list_file_blocks # input_file
	{
	typeset input_file=$1

	[[ -f $input_file ]] \|\| log_fail "Couldn't find $input_file"

	typeset ds="$(zfs list -H -o name $input_file)"
	typeset pool="${ds%%/*}"
	typeset inum="$(stat -c '%i' $input_file)"

	#
	# Establish a mapping between vdev ids as shown in a DVA and the
	# pathnames they correspond to in ${VDEV_MAP[]}.
	#
	eval $(zdb -C $pool \| awk '
	BEGIN {
	printf("typeset VDEV_MAP\n");
	looking = 0;
	}
	/^ children/ {
	id = $1;
	looking = 1;
	}
	/path: / && looking == 1 {
	print id" "$2;
	looking = 0;
	}
	' \| sed -n 's/^children\[\([0-9]\)\]: \(.*\)$/VDEV_MAP[\1]=\2/p')

	#
	# The awk below parses the output of zdb, printing out the level
	# of each block along with vdev id, offset and length. The last
	# two are converted to decimal in the while loop. 4M is added to
	# the offset to compensate for the first two labels and boot
	# block. Lastly, the offset and length are printed in units of
	# 512b blocks for ease of use with dd.
	#
	log_must zpool sync -f
	typeset level path offset length
	zdb -ddddd $ds $inum \| awk -F: '
	BEGIN { looking = 0 }
	/^Indirect blocks:/ { looking = 1}
	/^\t\tsegment / { looking = 0}
	/L[0-8]/ && looking == 1 { print $0}
	' \| sed -n 's/^.\(L[0-9]\) \([0-9]\):\([0-9a-f]\):\([0-9a-f]\) .*$/\1 \2 \3 \4/p' \| \
	while read level path offset length; do
	offset=$((16#$offset)) # Conversion from hex
	length=$((16#$length))
	offset="$(((offset + 4 * 1024 * 1024) / 512))"
	length="$((length / 512))"
	echo "$level ${VDEV_MAP[$path]} $offset $length"
	done 2>/dev/null
	}

	function corrupt_blocks_at_level # input_file corrupt_level
	{
	typeset input_file=$1
	typeset corrupt_level="L${2:-0}"
	typeset level path offset length

	[[ -f $input_file ]] \|\| log_fail "Couldn't find $input_file"


	log_must list_file_blocks $input_file \| \
	while read level path offset length; do
	if [[ $level = $corrupt_level ]]; then
	log_must dd if=/dev/urandom of=$path bs=512 \
	count=$length seek=$offset conv=notrunc
	fi
	done

	# This is necessary for pools made of loop devices.
	sync
	}