common/xfs - pub/scm/linux/kernel/git/dgc/xfstests-dev - Git at Google

 #
 # XFS specific common functions.
 #

 _setup_large_xfs_fs()
 {
 	fs_size=$1
 	local tmp_dir=/tmp/

 	[ "$LARGE_SCRATCH_DEV" != yes ] && return 0
 	[ -z "$SCRATCH_DEV_EMPTY_SPACE" ] && SCRATCH_DEV_EMPTY_SPACE=0
 	[ $SCRATCH_DEV_EMPTY_SPACE -ge $fs_size ] && return 0

 	# calculate the size of the file we need to allocate.
 	# Default free space in the FS is 50GB, but you can specify more via
 	# SCRATCH_DEV_EMPTY_SPACE
 	file_size=$(($fs_size - 50*1024*1024*1024))
 	file_size=$(($file_size - $SCRATCH_DEV_EMPTY_SPACE))

 	# mount the filesystem, create the file, unmount it
 	_try_scratch_mount 2>&1 >$tmp_dir/mnt.err
 	local status=$?
 	if [ $status -ne 0 ]; then
 		echo "mount failed"
 		cat $tmp_dir/mnt.err >&2
 		rm -f $tmp_dir/mnt.err
 		return $status
 	fi
 	rm -f $tmp_dir/mnt.err

 	xfs_io -F -f \
 		-c "truncate $file_size" \
 		-c "falloc -k 0 $file_size" \
 		-c "chattr +d" \
 		$SCRATCH_MNT/.use_space 2>&1 > /dev/null
 	export NUM_SPACE_FILES=1
 	status=$?
 	_scratch_unmount
 	if [ $status -ne 0 ]; then
 		echo "large file prealloc failed"
 		cat $tmp_dir/mnt.err >&2
 		return $status
 	fi
 	return 0
 }

 _scratch_mkfs_xfs_opts()
 {
 	mkfs_opts=$*

 	# remove metadata related mkfs options if mkfs.xfs doesn't them
 	if [ -n "$XFS_MKFS_HAS_NO_META_SUPPORT" ]; then
 		mkfs_opts=`echo $mkfs_opts | sed "s/-m\s\+\S\+//g"`
 	fi

 	_scratch_options mkfs

 	echo "$MKFS_XFS_PROG $SCRATCH_OPTIONS $mkfs_opts"
 }


 _scratch_mkfs_xfs_supported()
 {
 	local mkfs_opts=$*

 	_scratch_options mkfs

 	$MKFS_XFS_PROG -N $MKFS_OPTIONS $SCRATCH_OPTIONS $mkfs_opts $SCRATCH_DEV
 	local mkfs_status=$?

 	# a mkfs failure may be caused by conflicts between $MKFS_OPTIONS and
 	# $mkfs_opts, try again without $MKFS_OPTIONS
 	if [ $mkfs_status -ne 0 -a -n "$mkfs_opts" ]; then
 		$MKFS_XFS_PROG -N $SCRATCH_OPTIONS $mkfs_opts $SCRATCH_DEV
 		mkfs_status=$?
 	fi
 	return $mkfs_status
 }

 _scratch_mkfs_xfs()
 {
 	local mkfs_cmd="`_scratch_mkfs_xfs_opts`"
 	local mkfs_filter="sed -e '/less than device physical sector/d' \
 			       -e '/switching to logical sector/d' \
 			       -e '/Default configuration/d'"
 	local tmp=`mktemp -u`
 	local mkfs_status

 	_scratch_do_mkfs "$mkfs_cmd" "$mkfs_filter" $* 2>$tmp.mkfserr 1>$tmp.mkfsstd
 	mkfs_status=$?


 	if [ $mkfs_status -eq 0 -a "$LARGE_SCRATCH_DEV" = yes ]; then
 		# manually parse the mkfs output to get the fs size in bytes
 		local fs_size
 		fs_size=`cat $tmp.mkfsstd | perl -ne '
 			if (/^data\s+=\s+bsize=(\d+)\s+blocks=(\d+)/) {
 				my $size = $1 * $2;
 				print STDOUT "$size\n";
 			}'`
 		_setup_large_xfs_fs $fs_size
 		mkfs_status=$?
 	fi

 	# output mkfs stdout and stderr
 	cat $tmp.mkfsstd
 	cat $tmp.mkfserr >&2
 	rm -f $tmp.mkfserr $tmp.mkfsstd

 	return $mkfs_status
 }

 # xfs_check script is planned to be deprecated. But, we want to
 # be able to invoke "xfs_check" behavior in xfstests in order to
 # maintain the current verification levels.
 _xfs_check()
 {
 	OPTS=" "
 	DBOPTS=" "
 	USAGE="Usage: xfs_check [-fsvV] [-l logdev] [-i ino]... [-b bno]... special"

 	OPTIND=1
 	while getopts "b:fi:l:stvV" c; do
 		case $c in
 			s) OPTS=$OPTS"-s ";;
 			t) OPTS=$OPTS"-t ";;
 			v) OPTS=$OPTS"-v ";;
 			i) OPTS=$OPTS"-i "$OPTARG" ";;
 			b) OPTS=$OPTS"-b "$OPTARG" ";;
 			f) DBOPTS=$DBOPTS" -f";;
 			l) DBOPTS=$DBOPTS" -l "$OPTARG" ";;
 			V) $XFS_DB_PROG -p xfs_check -V
 			   return $?
 			   ;;
 		esac
 	done
 	set -- extra $@
 	shift $OPTIND
 	case $# in
 		1) ${XFS_DB_PROG}${DBOPTS} -F -i -p xfs_check -c "check$OPTS" $1
 		   status=$?
 		   ;;
 		2) echo $USAGE 1>&1
 		   status=2
 		   ;;
 	esac
 	return $status
 }

 _scratch_xfs_db_options()
 {
 	SCRATCH_OPTIONS=""
 	[ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_LOGDEV" ] && \
 		SCRATCH_OPTIONS="-l$SCRATCH_LOGDEV"
 	echo $SCRATCH_OPTIONS $* $SCRATCH_DEV
 }

 _scratch_xfs_db()
 {
 	$XFS_DB_PROG "$@" $(_scratch_xfs_db_options)
 }

 _scratch_xfs_logprint()
 {
 	SCRATCH_OPTIONS=""
 	[ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_LOGDEV" ] && \
 		SCRATCH_OPTIONS="-l$SCRATCH_LOGDEV"
 	$XFS_LOGPRINT_PROG $SCRATCH_OPTIONS $* $SCRATCH_DEV
 }

 _test_xfs_logprint()
 {
 	TEST_OPTIONS=""
 	[ "$USE_EXTERNAL" = yes -a ! -z "$TEST_LOGDEV" ] && \
 		TEST_OPTIONS="-l$TEST_LOGDEV"
 	$XFS_LOGPRINT_PROG $TEST_OPTIONS $* $TEST_DEV
 }

 _scratch_xfs_check()
 {
 	SCRATCH_OPTIONS=""
 	[ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_LOGDEV" ] && \
 		SCRATCH_OPTIONS="-l $SCRATCH_LOGDEV"
 	[ "$LARGE_SCRATCH_DEV" = yes ] && \
 		SCRATCH_OPTIONS=$SCRATCH_OPTIONS" -t"
 	_xfs_check $SCRATCH_OPTIONS $* $SCRATCH_DEV
 }

 _scratch_xfs_repair()
 {
 	SCRATCH_OPTIONS=""
 	[ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_LOGDEV" ] && \
 		SCRATCH_OPTIONS="-l$SCRATCH_LOGDEV"
 	[ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_RTDEV" ] && \
 		SCRATCH_OPTIONS=$SCRATCH_OPTIONS" -r$SCRATCH_RTDEV"
 	[ "$LARGE_SCRATCH_DEV" = yes ] && SCRATCH_OPTIONS=$SCRATCH_OPTIONS" -t"
 	$XFS_REPAIR_PROG $SCRATCH_OPTIONS $* $SCRATCH_DEV
 }

 # this test requires the projid32bit feature to be available in mkfs.xfs.
 #
 _require_projid32bit()
 {
        _scratch_mkfs_xfs_supported -i projid32bit=1 >/dev/null 2>&1 \
 	   || _notrun "mkfs.xfs doesn't have projid32bit feature"
 }

 _require_projid16bit()
 {
 	_scratch_mkfs_xfs_supported -i projid32bit=0 >/dev/null 2>&1 \
 	   || _notrun "16 bit project IDs not supported on $SCRATCH_DEV"
 }

 # this test requires the crc feature to be available in mkfs.xfs
 #
 _require_xfs_mkfs_crc()
 {
 	_scratch_mkfs_xfs_supported -m crc=1 >/dev/null 2>&1 \
 	   || _notrun "mkfs.xfs doesn't have crc feature"
 }

 # this test requires the xfs kernel support crc feature
 #
 _require_xfs_crc()
 {
 	_scratch_mkfs_xfs -m crc=1 >/dev/null 2>&1
 	_try_scratch_mount >/dev/null 2>&1 \
 	   || _notrun "Kernel doesn't support crc feature"
 	_scratch_unmount
 }

 # this test requires the xfs kernel support crc feature on scratch device
 #
 _require_scratch_xfs_crc()
 {
 	_scratch_mkfs_xfs >/dev/null 2>&1
 	_try_scratch_mount >/dev/null 2>&1 \
 	   || _notrun "Kernel doesn't support crc feature"
 	xfs_info $SCRATCH_MNT | grep -q 'crc=1' || _notrun "crc feature not supported by this filesystem"
 	_scratch_unmount
 }

 # this test requires the finobt feature to be available in mkfs.xfs
 #
 _require_xfs_mkfs_finobt()
 {
 	_scratch_mkfs_xfs_supported -m crc=1,finobt=1 >/dev/null 2>&1 \
 	   || _notrun "mkfs.xfs doesn't have finobt feature"
 }

 # this test requires the xfs kernel support finobt feature
 #
 _require_xfs_finobt()
 {
 	_scratch_mkfs_xfs -m crc=1,finobt=1 >/dev/null 2>&1
 	_try_scratch_mount >/dev/null 2>&1 \
 	   || _notrun "Kernel doesn't support finobt feature"
 	_scratch_unmount
 }

 # this test requires xfs sysfs attribute support
 #
 _require_xfs_sysfs()
 {
 	attr=$1
 	sysfsdir=/sys/fs/xfs

 	if [ ! -e $sysfsdir ]; then
 		_notrun "no kernel support for XFS sysfs attributes"
 	fi

 	if [ ! -z $1 ] && [ ! -e $sysfsdir/$attr ]; then
 		_notrun "sysfs attribute '$attr' is not supported"
 	fi
 }

 # this test requires the xfs sparse inode feature
 #
 _require_xfs_sparse_inodes()
 {
 	_scratch_mkfs_xfs_supported -m crc=1 -i sparse > /dev/null 2>&1 \
 		|| _notrun "mkfs.xfs does not support sparse inodes"
 	_scratch_mkfs_xfs -m crc=1 -i sparse > /dev/null 2>&1
 	_try_scratch_mount >/dev/null 2>&1 \
 		|| _notrun "kernel does not support sparse inodes"
 	_scratch_unmount
 }

 # check that xfs_db supports a specific command
 _require_xfs_db_command()
 {
 	if [ $# -ne 1 ]; then
 		echo "Usage: _require_xfs_db_command command" 1>&2
 		exit 1
 	fi
 	command=$1

 	_scratch_xfs_db -x -c "help" | grep $command > /dev/null || \
 		_notrun "xfs_db $command support is missing"
 }

 # Does the filesystem mounted from a particular device support scrub?
 _supports_xfs_scrub()
 {
 	local mountpoint="$1"
 	local device="$2"

 	if [ -z "$device" ] || [ -z "$mountpoint" ]; then
 		echo "Usage: _supports_xfs_scrub mountpoint device"
 		return 1
 	fi

 	if [ ! -b "$device" ] || [ ! -e "$mountpoint" ]; then
 		return 1
 	fi

 	test "$FSTYP" = "xfs" || return 1
 	test -x "$XFS_SCRUB_PROG" || return 1

 	# Probe for kernel support...
 	$XFS_IO_PROG -c 'help scrub' 2>&1 | grep -q 'types are:.*probe' || return 1
 	$XFS_IO_PROG -c "scrub probe" "$mountpoint" 2>&1 | grep -q "Inappropriate ioctl" && return 1

 	# Scrub can't run on norecovery mounts
 	_fs_options "$device" | grep -q "norecovery" && return 1

 	return 0
 }

 # run xfs_check and friends on a FS.
 _check_xfs_filesystem()
 {
 	if [ $# -ne 3 ]; then
 		echo "Usage: _check_xfs_filesystem device <logdev>|none <rtdev>|none" 1>&2
 		exit 1
 	fi

 	extra_mount_options=""
 	extra_log_options=""
 	extra_options=""
 	device=$1
 	if [ -f $device ]; then
 		extra_options="-f"
 	fi

 	if [ "$2" != "none" ]; then
 		extra_log_options="-l$2"
 		extra_mount_options="-ologdev=$2"
 	fi

 	if [ "$3" != "none" ]; then
 		extra_rt_options="-r$3"
 		extra_mount_options=$extra_mount_options" -ortdev=$3"
 	fi
 	extra_mount_options=$extra_mount_options" $MOUNT_OPTIONS"

 	[ "$FSTYP" != xfs ] && return 0

 	type=`_fs_type $device`
 	ok=1

 	# Run online scrub if we can.
 	mntpt="$(_is_dev_mounted $device)"
 	if [ -n "$mntpt" ] && _supports_xfs_scrub "$mntpt" "$device"; then
 		"$XFS_SCRUB_PROG" $scrubflag -v -d -n $mntpt > $tmp.scrub 2>&1
 		if [ $? -ne 0 ]; then
 			_log_err "_check_xfs_filesystem: filesystem on $device failed scrub"
 			echo "*** xfs_scrub $scrubflag -v -d -n output ***" >> $seqres.full
 			cat $tmp.scrub >> $seqres.full
 			echo "*** end xfs_scrub output" >> $serqres.full
 			ok=0
 		fi
 		rm -f $tmp.scrub
 	fi

 	if [ "$type" = "xfs" ]; then
 		# mounted ...
 		mountpoint=`_umount_or_remount_ro $device`
 	fi

 	$XFS_LOGPRINT_PROG -t $extra_log_options $device 2>&1 \
 		| tee $tmp.logprint | grep -q "<CLEAN>"
 	if [ $? -ne 0 -a "$HOSTOS" = "Linux" ]; then
 		_log_err "_check_xfs_filesystem: filesystem on $device has dirty log"
 		echo "*** xfs_logprint -t output ***"	>>$seqres.full
 		cat $tmp.logprint			>>$seqres.full
 		echo "*** end xfs_logprint output"	>>$seqres.full

 		ok=0
 	fi

 	# xfs_check runs out of memory on large files, so even providing the test
 	# option (-t) to avoid indexing the free space trees doesn't make it pass on
 	# large filesystems. Avoid it.
 	if [ "$LARGE_SCRATCH_DEV" != yes ]; then
 		_xfs_check $extra_log_options $device 2>&1 > $tmp.fs_check
 	fi
 	if [ -s $tmp.fs_check ]; then
 		_log_err "_check_xfs_filesystem: filesystem on $device is inconsistent (c)"
 		echo "*** xfs_check output ***"		>>$seqres.full
 		cat $tmp.fs_check			>>$seqres.full
 		echo "*** end xfs_check output"		>>$seqres.full

 		ok=0
 	fi

 	$XFS_REPAIR_PROG -n $extra_options $extra_log_options $extra_rt_options $device >$tmp.repair 2>&1
 	if [ $? -ne 0 ]; then
 		_log_err "_check_xfs_filesystem: filesystem on $device is inconsistent (r)"
 		echo "*** xfs_repair -n output ***"	>>$seqres.full
 		cat $tmp.repair				>>$seqres.full
 		echo "*** end xfs_repair output"	>>$seqres.full

 		ok=0
 	fi
 	rm -f $tmp.fs_check $tmp.logprint $tmp.repair

 	# Optionally test the index rebuilding behavior.
 	if [ -n "$TEST_XFS_REPAIR_REBUILD" ]; then
 		$XFS_REPAIR_PROG $extra_options $extra_log_options $extra_rt_options $device >$tmp.repair 2>&1
 		if [ $? -ne 0 ]; then
 			_log_err "_check_xfs_filesystem: filesystem on $device is inconsistent (rebuild)"
 			echo "*** xfs_repair output ***"	>>$seqres.full
 			cat $tmp.repair				>>$seqres.full
 			echo "*** end xfs_repair output"	>>$seqres.full

 			ok=0
 		fi
 		rm -f $tmp.repair

 		$XFS_REPAIR_PROG -n $extra_options $extra_log_options $extra_rt_options $device >$tmp.repair 2>&1
 		if [ $? -ne 0 ]; then
 			_log_err "_check_xfs_filesystem: filesystem on $device is inconsistent (rebuild-reverify)"
 			echo "*** xfs_repair -n output ***"	>>$seqres.full
 			cat $tmp.repair				>>$seqres.full
 			echo "*** end xfs_repair output"	>>$seqres.full

 			ok=0
 		fi
 		rm -f $tmp.repair
 	fi

 	if [ $ok -eq 0 ]; then
 		echo "*** mount output ***"		>>$seqres.full
 		_mount					>>$seqres.full
 		echo "*** end mount output"		>>$seqres.full
 	elif [ "$type" = "xfs" ]; then
 		_mount_or_remount_rw "$extra_mount_options" $device $mountpoint
 	fi

 	if [ $ok -eq 0 ]; then
 		status=1
 		if [ "$iam" != "check" ]; then
 			exit 1
 		fi
 		return 1
 	fi

 	return 0
 }

 _check_xfs_test_fs()
 {
 	TEST_LOG="none"
 	TEST_RT="none"
 	[ "$USE_EXTERNAL" = yes -a ! -z "$TEST_LOGDEV" ] && \
 		TEST_LOG="$TEST_LOGDEV"

 	[ "$USE_EXTERNAL" = yes -a ! -z "$TEST_RTDEV" ] && \
 		TEST_RT="$TEST_RTDEV"

 	_check_xfs_filesystem $TEST_DEV $TEST_LOG $TEST_RT
 	return $?
 }

 _require_xfs_test_rmapbt()
 {
 	_require_test

 	if [ "$(xfs_info "$TEST_DIR" | grep -c "rmapbt=1")" -ne 1 ]; then
 		_notrun "rmapbt not supported by test filesystem type: $FSTYP"
 	fi
 }

 _require_xfs_scratch_rmapbt()
 {
 	_require_scratch

 	_scratch_mkfs > /dev/null
 	_scratch_mount
 	if [ "$(xfs_info "$SCRATCH_MNT" | grep -c "rmapbt=1")" -ne 1 ]; then
 		_scratch_unmount
 		_notrun "rmapbt not supported by scratch filesystem type: $FSTYP"
 	fi
 	_scratch_unmount
 }

 _xfs_bmapx_find()
 {
 	case "$1" in
 	"attr")
 		param="a"
 		;;
 	"cow")
 		param="c"
 		;;
 	*)
 		param="e"
 		;;
 	esac
 	shift
 	file="$1"
 	shift

 	$XFS_IO_PROG -c "bmap -${param}lpv" "$file" | grep -c "$@"
 }

 # Reset all xfs error handling attributes, set them to original
 # status.
 #
 # Only one argument, and it's mandatory:
 #  - dev: device name, e.g. $SCRATCH_DEV
 #
 # Note: this function only works for XFS
 _reset_xfs_sysfs_error_handling()
 {
 	local dev=$1

 	if [ ! -b "$dev" -o "$FSTYP" != "xfs" ]; then
 		_fail "Usage: reset_xfs_sysfs_error_handling <device>"
 	fi

 	_set_fs_sysfs_attr $dev error/fail_at_unmount 1
 	echo -n "error/fail_at_unmount="
 	_get_fs_sysfs_attr $dev error/fail_at_unmount

 	# Make sure all will be configured to retry forever by default, except
 	# for ENODEV, which is an unrecoverable error, so it will be configured
 	# to not retry on error by default.
 	for e in default EIO ENOSPC; do
 		_set_fs_sysfs_attr $dev \
 				   error/metadata/${e}/max_retries -1
 		echo -n "error/metadata/${e}/max_retries="
 		_get_fs_sysfs_attr $dev error/metadata/${e}/max_retries

 		_set_fs_sysfs_attr $dev \
 				   error/metadata/${e}/retry_timeout_seconds 0
 		echo -n "error/metadata/${e}/retry_timeout_seconds="
 		_get_fs_sysfs_attr $dev \
 				   error/metadata/${e}/retry_timeout_seconds
 	done
 }

 # Skip if we are running an older binary without the stricter input checks.
 # Make multiple checks to be sure that there is no regression on the one
 # selected feature check, which would skew the result.
 #
 # At first, make a common function that runs the tests and returns
 # number of failed cases.
 _xfs_mkfs_validation_check()
 {
 	local tmpfile=`mktemp`
 	local cmd="$MKFS_XFS_PROG -f -N -d file,name=$tmpfile,size=1g"

 	$cmd -s size=8s >/dev/null 2>&1
 	local sum=$?

 	$cmd -l version=2,su=260k >/dev/null 2>&1
 	sum=`expr $sum + $?`

 	rm -f $tmpfile
 	return $sum
 }

 # Skip the test if all calls passed - mkfs accepts invalid input
 _require_xfs_mkfs_validation()
 {
 	_xfs_mkfs_validation_check
 	if [ "$?" -eq 0 ]; then
 		_notrun "Requires newer mkfs with stricter input checks: the oldest supported version of xfsprogs is 4.7."
 	fi
 }

 # The opposite of _require_xfs_mkfs_validation.
 _require_xfs_mkfs_without_validation()
 {
 	_xfs_mkfs_validation_check
 	if [ "$?" -ne 0 ]; then
 		_notrun "Requires older mkfs without strict input checks: the last supported version of xfsprogs is 4.5."
 	fi
 }

 # XFS ability to change UUIDs on V5/CRC filesystems
 #
 _require_meta_uuid()
 {
 	# This will create a crc fs on $SCRATCH_DEV
 	_require_xfs_crc

 	_scratch_xfs_db -x -c "uuid restore" 2>&1 \
 	   | grep -q "invalid UUID\|supported on V5 fs" \
 	   && _notrun "Userspace doesn't support meta_uuid feature"

 	_scratch_xfs_db -x -c "uuid generate" >/dev/null 2>&1

 	_try_scratch_mount >/dev/null 2>&1 \
 	   || _notrun "Kernel doesn't support meta_uuid feature"
 	_scratch_unmount
 }

 # this test requires mkfs.xfs have case-insensitive naming support
 _require_xfs_mkfs_ciname()
 {
 	_scratch_mkfs_xfs_supported -n version=ci >/dev/null 2>&1 \
 		|| _notrun "need case-insensitive naming support in mkfs.xfs"
 }

 # XFS_DEBUG requirements
 _require_xfs_debug()
 {
 	if grep -q "debug 0" /proc/fs/xfs/stat; then
 		_notrun "Require XFS built with CONFIG_XFS_DEBUG"
 	fi
 }
 _require_no_xfs_debug()
 {
 	if grep -q "debug 1" /proc/fs/xfs/stat; then
 		_notrun "Require XFS built without CONFIG_XFS_DEBUG"
 	fi
 }

 # Require that assertions will not crash the system.
 #
 # Assertions would always crash the system if XFS assert fatal was enabled
 # (CONFIG_XFS_ASSERT_FATAL=y).  If a test is designed to trigger an assertion,
 # skip the test on a CONFIG_XFS_ASSERT_FATAL built XFS by default.  Note:
 # CONFIG_XFS_ASSERT_FATAL can be disabled by setting bug_on_assert to zero if
 # we want test to run.
 _require_no_xfs_bug_on_assert()
 {
 	if [ -f /sys/fs/xfs/debug/bug_on_assert ]; then
 		grep -q "1" /sys/fs/xfs/debug/bug_on_assert && \
 		   _notrun "test requires XFS bug_on_assert to be off, turn it off to run the test"
 	else
 		# Note: Prior to the creation of CONFIG_XFS_ASSERT_FATAL (and
 		# the sysfs knob bug_on_assert), assertions would always crash
 		# the system if XFS debug was enabled (CONFIG_XFS_DEBUG=y).  If
 		# a test is designed to trigger an assertion and the test
 		# designer does not want to hang fstests, skip the test.
 		_require_no_xfs_debug
 	fi
 }

 # Get a metadata field
 # The first arg is the field name
 # The rest of the arguments are xfs_db commands to find the metadata.
 _scratch_xfs_get_metadata_field()
 {
 	local key="$1"
 	shift

 	local grep_key="$(echo "${key}" | tr '[]()' '....')"
 	local cmds=()
 	local arg
 	for arg in "$@"; do
 		cmds+=("-c" "${arg}")
 	done
 	_scratch_xfs_db "${cmds[@]}" -c "print ${key}" | grep "^${grep_key}" | \
 		sed -e 's/^.* = //g'
 }

 # Set a metadata field
 # The first arg is the field name
 # The second arg is the new value
 # The rest of the arguments are xfs_db commands to find the metadata.
 _scratch_xfs_set_metadata_field()
 {
 	local key="$1"
 	local value="$2"
 	shift; shift

 	local cmds=()
 	local arg
 	for arg in "$@"; do
 		cmds+=("-c" "${arg}")
 	done

 	local wr_cmd="write"
 	_scratch_xfs_db -x -c "help write" | egrep -q "(-c|-d)" && value="-- ${value}"
 	_scratch_xfs_db -x -c "help write" | egrep -q "(-d)" && wr_cmd="${wr_cmd} -d"
 	_scratch_xfs_db -x "${cmds[@]}" -c "${wr_cmd} ${key} ${value}"
 }

 _scratch_xfs_get_sb_field()
 {
 	_scratch_xfs_get_metadata_field "$1" "sb 0"
 }

 _scratch_xfs_set_sb_field()
 {
 	_scratch_xfs_set_metadata_field "$1" "$2" "sb 0"
 }

 # Before xfsprogs commit 4222d000ed("db: write via array indexing doesn't
 # work"), xfs_db command to write a specific AGFL index doesn't work. It's a
 # bug in a diagnostic tool that is only used by XFS developers as a test
 # infrastructure, so it's fine to treat it as a infrastructure dependency as
 # all other _require rules.
 _require_xfs_db_write_array()
 {
 	local supported=0

 	_require_test
 	touch $TEST_DIR/$seq.img
 	$MKFS_XFS_PROG -d file,name=$TEST_DIR/$seq.img,size=512m >/dev/null 2>&1
 	$XFS_DB_PROG -x -c "agfl 0" -c "write bno[32] 78" $TEST_DIR/$seq.img \
 		>/dev/null 2>&1
 	$XFS_DB_PROG -x -c "agfl 0" -c "print bno[32]" $TEST_DIR/$seq.img \
 		| grep -q "bno\[32\] = 78" && supported=1
 	rm -f $TEST_DIR/$seq.img
 	[ $supported -eq 0 ] && _notrun "xfs_db write can't support array"
 }
	#
	# XFS specific common functions.
	#

	_setup_large_xfs_fs()
	{
	fs_size=$1
	local tmp_dir=/tmp/

	[ "$LARGE_SCRATCH_DEV" != yes ] && return 0
	[ -z "$SCRATCH_DEV_EMPTY_SPACE" ] && SCRATCH_DEV_EMPTY_SPACE=0
	[ $SCRATCH_DEV_EMPTY_SPACE -ge $fs_size ] && return 0

	# calculate the size of the file we need to allocate.
	# Default free space in the FS is 50GB, but you can specify more via
	# SCRATCH_DEV_EMPTY_SPACE
	file_size=$(($fs_size - 5010241024*1024))
	file_size=$(($file_size - $SCRATCH_DEV_EMPTY_SPACE))

	# mount the filesystem, create the file, unmount it
	_try_scratch_mount 2>&1 >$tmp_dir/mnt.err
	local status=$?
	if [ $status -ne 0 ]; then
	echo "mount failed"
	cat $tmp_dir/mnt.err >&2
	rm -f $tmp_dir/mnt.err
	return $status
	fi
	rm -f $tmp_dir/mnt.err

	xfs_io -F -f \
	-c "truncate $file_size" \
	-c "falloc -k 0 $file_size" \
	-c "chattr +d" \
	$SCRATCH_MNT/.use_space 2>&1 > /dev/null
	export NUM_SPACE_FILES=1
	status=$?
	_scratch_unmount
	if [ $status -ne 0 ]; then
	echo "large file prealloc failed"
	cat $tmp_dir/mnt.err >&2
	return $status
	fi
	return 0
	}

	_scratch_mkfs_xfs_opts()
	{
	mkfs_opts=$*

	# remove metadata related mkfs options if mkfs.xfs doesn't them
	if [ -n "$XFS_MKFS_HAS_NO_META_SUPPORT" ]; then
	mkfs_opts=`echo $mkfs_opts \| sed "s/-m\s\+\S\+//g"`
	fi

	_scratch_options mkfs

	echo "$MKFS_XFS_PROG $SCRATCH_OPTIONS $mkfs_opts"
	}


	_scratch_mkfs_xfs_supported()
	{
	local mkfs_opts=$*

	_scratch_options mkfs

	$MKFS_XFS_PROG -N $MKFS_OPTIONS $SCRATCH_OPTIONS $mkfs_opts $SCRATCH_DEV
	local mkfs_status=$?

	# a mkfs failure may be caused by conflicts between $MKFS_OPTIONS and
	# $mkfs_opts, try again without $MKFS_OPTIONS
	if [ $mkfs_status -ne 0 -a -n "$mkfs_opts" ]; then
	$MKFS_XFS_PROG -N $SCRATCH_OPTIONS $mkfs_opts $SCRATCH_DEV
	mkfs_status=$?
	fi
	return $mkfs_status
	}

	_scratch_mkfs_xfs()
	{
	local mkfs_cmd="`_scratch_mkfs_xfs_opts`"
	local mkfs_filter="sed -e '/less than device physical sector/d' \
	-e '/switching to logical sector/d' \
	-e '/Default configuration/d'"
	local tmp=`mktemp -u`
	local mkfs_status

	_scratch_do_mkfs "$mkfs_cmd" "$mkfs_filter" $* 2>$tmp.mkfserr 1>$tmp.mkfsstd
	mkfs_status=$?


	if [ $mkfs_status -eq 0 -a "$LARGE_SCRATCH_DEV" = yes ]; then
	# manually parse the mkfs output to get the fs size in bytes
	local fs_size
	fs_size=`cat $tmp.mkfsstd \| perl -ne '
	if (/^data\s+=\s+bsize=(\d+)\s+blocks=(\d+)/) {
	my $size = $1 * $2;
	print STDOUT "$size\n";
	}'`
	_setup_large_xfs_fs $fs_size
	mkfs_status=$?
	fi

	# output mkfs stdout and stderr
	cat $tmp.mkfsstd
	cat $tmp.mkfserr >&2
	rm -f $tmp.mkfserr $tmp.mkfsstd

	return $mkfs_status
	}

	# xfs_check script is planned to be deprecated. But, we want to
	# be able to invoke "xfs_check" behavior in xfstests in order to
	# maintain the current verification levels.
	_xfs_check()
	{
	OPTS=" "
	DBOPTS=" "
	USAGE="Usage: xfs_check [-fsvV] [-l logdev] [-i ino]... [-b bno]... special"

	OPTIND=1
	while getopts "b:fi:l:stvV" c; do
	case $c in
	s) OPTS=$OPTS"-s ";;
	t) OPTS=$OPTS"-t ";;
	v) OPTS=$OPTS"-v ";;
	i) OPTS=$OPTS"-i "$OPTARG" ";;
	b) OPTS=$OPTS"-b "$OPTARG" ";;
	f) DBOPTS=$DBOPTS" -f";;
	l) DBOPTS=$DBOPTS" -l "$OPTARG" ";;
	V) $XFS_DB_PROG -p xfs_check -V
	return $?
	;;
	esac
	done
	set -- extra $@
	shift $OPTIND
	case $# in
	1) ${XFS_DB_PROG}${DBOPTS} -F -i -p xfs_check -c "check$OPTS" $1
	status=$?
	;;
	2) echo $USAGE 1>&1
	status=2
	;;
	esac
	return $status
	}

	_scratch_xfs_db_options()
	{
	SCRATCH_OPTIONS=""
	[ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_LOGDEV" ] && \
	SCRATCH_OPTIONS="-l$SCRATCH_LOGDEV"
	echo $SCRATCH_OPTIONS $* $SCRATCH_DEV
	}

	_scratch_xfs_db()
	{
	$XFS_DB_PROG "$@" $(_scratch_xfs_db_options)
	}

	_scratch_xfs_logprint()
	{
	SCRATCH_OPTIONS=""
	[ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_LOGDEV" ] && \
	SCRATCH_OPTIONS="-l$SCRATCH_LOGDEV"
	$XFS_LOGPRINT_PROG $SCRATCH_OPTIONS $* $SCRATCH_DEV
	}

	_test_xfs_logprint()
	{
	TEST_OPTIONS=""
	[ "$USE_EXTERNAL" = yes -a ! -z "$TEST_LOGDEV" ] && \
	TEST_OPTIONS="-l$TEST_LOGDEV"
	$XFS_LOGPRINT_PROG $TEST_OPTIONS $* $TEST_DEV
	}

	_scratch_xfs_check()
	{
	SCRATCH_OPTIONS=""
	[ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_LOGDEV" ] && \
	SCRATCH_OPTIONS="-l $SCRATCH_LOGDEV"
	[ "$LARGE_SCRATCH_DEV" = yes ] && \
	SCRATCH_OPTIONS=$SCRATCH_OPTIONS" -t"
	_xfs_check $SCRATCH_OPTIONS $* $SCRATCH_DEV
	}

	_scratch_xfs_repair()
	{
	SCRATCH_OPTIONS=""
	[ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_LOGDEV" ] && \
	SCRATCH_OPTIONS="-l$SCRATCH_LOGDEV"
	[ "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_RTDEV" ] && \
	SCRATCH_OPTIONS=$SCRATCH_OPTIONS" -r$SCRATCH_RTDEV"
	[ "$LARGE_SCRATCH_DEV" = yes ] && SCRATCH_OPTIONS=$SCRATCH_OPTIONS" -t"
	$XFS_REPAIR_PROG $SCRATCH_OPTIONS $* $SCRATCH_DEV
	}

	# this test requires the projid32bit feature to be available in mkfs.xfs.
	#
	_require_projid32bit()
	{
	_scratch_mkfs_xfs_supported -i projid32bit=1 >/dev/null 2>&1 \
	\|\| _notrun "mkfs.xfs doesn't have projid32bit feature"
	}

	_require_projid16bit()
	{
	_scratch_mkfs_xfs_supported -i projid32bit=0 >/dev/null 2>&1 \
	\|\| _notrun "16 bit project IDs not supported on $SCRATCH_DEV"
	}

	# this test requires the crc feature to be available in mkfs.xfs
	#
	_require_xfs_mkfs_crc()
	{
	_scratch_mkfs_xfs_supported -m crc=1 >/dev/null 2>&1 \
	\|\| _notrun "mkfs.xfs doesn't have crc feature"
	}

	# this test requires the xfs kernel support crc feature
	#
	_require_xfs_crc()
	{
	_scratch_mkfs_xfs -m crc=1 >/dev/null 2>&1
	_try_scratch_mount >/dev/null 2>&1 \
	\|\| _notrun "Kernel doesn't support crc feature"
	_scratch_unmount
	}

	# this test requires the xfs kernel support crc feature on scratch device
	#
	_require_scratch_xfs_crc()
	{
	_scratch_mkfs_xfs >/dev/null 2>&1
	_try_scratch_mount >/dev/null 2>&1 \
	\|\| _notrun "Kernel doesn't support crc feature"
	xfs_info $SCRATCH_MNT \| grep -q 'crc=1' \|\| _notrun "crc feature not supported by this filesystem"
	_scratch_unmount
	}

	# this test requires the finobt feature to be available in mkfs.xfs
	#
	_require_xfs_mkfs_finobt()
	{
	_scratch_mkfs_xfs_supported -m crc=1,finobt=1 >/dev/null 2>&1 \
	\|\| _notrun "mkfs.xfs doesn't have finobt feature"
	}

	# this test requires the xfs kernel support finobt feature
	#
	_require_xfs_finobt()
	{
	_scratch_mkfs_xfs -m crc=1,finobt=1 >/dev/null 2>&1
	_try_scratch_mount >/dev/null 2>&1 \
	\|\| _notrun "Kernel doesn't support finobt feature"
	_scratch_unmount
	}

	# this test requires xfs sysfs attribute support
	#
	_require_xfs_sysfs()
	{
	attr=$1
	sysfsdir=/sys/fs/xfs

	if [ ! -e $sysfsdir ]; then
	_notrun "no kernel support for XFS sysfs attributes"
	fi

	if [ ! -z $1 ] && [ ! -e $sysfsdir/$attr ]; then
	_notrun "sysfs attribute '$attr' is not supported"
	fi
	}

	# this test requires the xfs sparse inode feature
	#
	_require_xfs_sparse_inodes()
	{
	_scratch_mkfs_xfs_supported -m crc=1 -i sparse > /dev/null 2>&1 \
	\|\| _notrun "mkfs.xfs does not support sparse inodes"
	_scratch_mkfs_xfs -m crc=1 -i sparse > /dev/null 2>&1
	_try_scratch_mount >/dev/null 2>&1 \
	\|\| _notrun "kernel does not support sparse inodes"
	_scratch_unmount
	}

	# check that xfs_db supports a specific command
	_require_xfs_db_command()
	{
	if [ $# -ne 1 ]; then
	echo "Usage: _require_xfs_db_command command" 1>&2
	exit 1
	fi
	command=$1

	_scratch_xfs_db -x -c "help" \| grep $command > /dev/null \|\| \
	_notrun "xfs_db $command support is missing"
	}

	# Does the filesystem mounted from a particular device support scrub?
	_supports_xfs_scrub()
	{
	local mountpoint="$1"
	local device="$2"

	if [ -z "$device" ] \|\| [ -z "$mountpoint" ]; then
	echo "Usage: _supports_xfs_scrub mountpoint device"
	return 1
	fi

	if [ ! -b "$device" ] \|\| [ ! -e "$mountpoint" ]; then
	return 1
	fi

	test "$FSTYP" = "xfs" \|\| return 1
	test -x "$XFS_SCRUB_PROG" \|\| return 1

	# Probe for kernel support...
	$XFS_IO_PROG -c 'help scrub' 2>&1 \| grep -q 'types are:.*probe' \|\| return 1
	$XFS_IO_PROG -c "scrub probe" "$mountpoint" 2>&1 \| grep -q "Inappropriate ioctl" && return 1

	# Scrub can't run on norecovery mounts
	_fs_options "$device" \| grep -q "norecovery" && return 1

	return 0
	}

	# run xfs_check and friends on a FS.
	_check_xfs_filesystem()
	{
	if [ $# -ne 3 ]; then
	echo "Usage: _check_xfs_filesystem device <logdev>\|none <rtdev>\|none" 1>&2
	exit 1
	fi

	extra_mount_options=""
	extra_log_options=""
	extra_options=""
	device=$1
	if [ -f $device ]; then
	extra_options="-f"
	fi

	if [ "$2" != "none" ]; then
	extra_log_options="-l$2"
	extra_mount_options="-ologdev=$2"
	fi

	if [ "$3" != "none" ]; then
	extra_rt_options="-r$3"
	extra_mount_options=$extra_mount_options" -ortdev=$3"
	fi
	extra_mount_options=$extra_mount_options" $MOUNT_OPTIONS"

	[ "$FSTYP" != xfs ] && return 0

	type=`_fs_type $device`
	ok=1

	# Run online scrub if we can.
	mntpt="$(_is_dev_mounted $device)"
	if [ -n "$mntpt" ] && _supports_xfs_scrub "$mntpt" "$device"; then
	"$XFS_SCRUB_PROG" $scrubflag -v -d -n $mntpt > $tmp.scrub 2>&1
	if [ $? -ne 0 ]; then
	_log_err "_check_xfs_filesystem: filesystem on $device failed scrub"
	echo "* xfs_scrub $scrubflag -v -d -n output *" >> $seqres.full
	cat $tmp.scrub >> $seqres.full
	echo "*** end xfs_scrub output" >> $serqres.full
	ok=0
	fi
	rm -f $tmp.scrub
	fi

	if [ "$type" = "xfs" ]; then
	# mounted ...
	mountpoint=`_umount_or_remount_ro $device`
	fi

	$XFS_LOGPRINT_PROG -t $extra_log_options $device 2>&1 \
	\| tee $tmp.logprint \| grep -q "<CLEAN>"
	if [ $? -ne 0 -a "$HOSTOS" = "Linux" ]; then
	_log_err "_check_xfs_filesystem: filesystem on $device has dirty log"
	echo "* xfs_logprint -t output *" >>$seqres.full
	cat $tmp.logprint >>$seqres.full
	echo "*** end xfs_logprint output" >>$seqres.full

	ok=0
	fi

	# xfs_check runs out of memory on large files, so even providing the test
	# option (-t) to avoid indexing the free space trees doesn't make it pass on
	# large filesystems. Avoid it.
	if [ "$LARGE_SCRATCH_DEV" != yes ]; then
	_xfs_check $extra_log_options $device 2>&1 > $tmp.fs_check
	fi
	if [ -s $tmp.fs_check ]; then
	_log_err "_check_xfs_filesystem: filesystem on $device is inconsistent (c)"
	echo "* xfs_check output *" >>$seqres.full
	cat $tmp.fs_check >>$seqres.full
	echo "*** end xfs_check output" >>$seqres.full

	ok=0
	fi

	$XFS_REPAIR_PROG -n $extra_options $extra_log_options $extra_rt_options $device >$tmp.repair 2>&1
	if [ $? -ne 0 ]; then
	_log_err "_check_xfs_filesystem: filesystem on $device is inconsistent (r)"
	echo "* xfs_repair -n output *" >>$seqres.full
	cat $tmp.repair >>$seqres.full
	echo "*** end xfs_repair output" >>$seqres.full

	ok=0
	fi
	rm -f $tmp.fs_check $tmp.logprint $tmp.repair

	# Optionally test the index rebuilding behavior.
	if [ -n "$TEST_XFS_REPAIR_REBUILD" ]; then
	$XFS_REPAIR_PROG $extra_options $extra_log_options $extra_rt_options $device >$tmp.repair 2>&1
	if [ $? -ne 0 ]; then
	_log_err "_check_xfs_filesystem: filesystem on $device is inconsistent (rebuild)"
	echo "* xfs_repair output *" >>$seqres.full
	cat $tmp.repair >>$seqres.full
	echo "*** end xfs_repair output" >>$seqres.full

	ok=0
	fi
	rm -f $tmp.repair

	$XFS_REPAIR_PROG -n $extra_options $extra_log_options $extra_rt_options $device >$tmp.repair 2>&1
	if [ $? -ne 0 ]; then
	_log_err "_check_xfs_filesystem: filesystem on $device is inconsistent (rebuild-reverify)"
	echo "* xfs_repair -n output *" >>$seqres.full
	cat $tmp.repair >>$seqres.full
	echo "*** end xfs_repair output" >>$seqres.full

	ok=0
	fi
	rm -f $tmp.repair
	fi

	if [ $ok -eq 0 ]; then
	echo "* mount output *" >>$seqres.full
	_mount >>$seqres.full
	echo "*** end mount output" >>$seqres.full
	elif [ "$type" = "xfs" ]; then
	_mount_or_remount_rw "$extra_mount_options" $device $mountpoint
	fi

	if [ $ok -eq 0 ]; then
	status=1
	if [ "$iam" != "check" ]; then
	exit 1
	fi
	return 1
	fi

	return 0
	}

	_check_xfs_test_fs()
	{
	TEST_LOG="none"
	TEST_RT="none"
	[ "$USE_EXTERNAL" = yes -a ! -z "$TEST_LOGDEV" ] && \
	TEST_LOG="$TEST_LOGDEV"

	[ "$USE_EXTERNAL" = yes -a ! -z "$TEST_RTDEV" ] && \
	TEST_RT="$TEST_RTDEV"

	_check_xfs_filesystem $TEST_DEV $TEST_LOG $TEST_RT
	return $?
	}

	_require_xfs_test_rmapbt()
	{
	_require_test

	if [ "$(xfs_info "$TEST_DIR" \| grep -c "rmapbt=1")" -ne 1 ]; then
	_notrun "rmapbt not supported by test filesystem type: $FSTYP"
	fi
	}

	_require_xfs_scratch_rmapbt()
	{
	_require_scratch

	_scratch_mkfs > /dev/null
	_scratch_mount
	if [ "$(xfs_info "$SCRATCH_MNT" \| grep -c "rmapbt=1")" -ne 1 ]; then
	_scratch_unmount
	_notrun "rmapbt not supported by scratch filesystem type: $FSTYP"
	fi
	_scratch_unmount
	}

	_xfs_bmapx_find()
	{
	case "$1" in
	"attr")
	param="a"
	;;
	"cow")
	param="c"
	;;
	*)
	param="e"
	;;
	esac
	shift
	file="$1"
	shift

	$XFS_IO_PROG -c "bmap -${param}lpv" "$file" \| grep -c "$@"
	}

	# Reset all xfs error handling attributes, set them to original
	# status.
	#
	# Only one argument, and it's mandatory:
	# - dev: device name, e.g. $SCRATCH_DEV
	#
	# Note: this function only works for XFS
	_reset_xfs_sysfs_error_handling()
	{
	local dev=$1

	if [ ! -b "$dev" -o "$FSTYP" != "xfs" ]; then
	_fail "Usage: reset_xfs_sysfs_error_handling <device>"
	fi

	_set_fs_sysfs_attr $dev error/fail_at_unmount 1
	echo -n "error/fail_at_unmount="
	_get_fs_sysfs_attr $dev error/fail_at_unmount

	# Make sure all will be configured to retry forever by default, except
	# for ENODEV, which is an unrecoverable error, so it will be configured
	# to not retry on error by default.
	for e in default EIO ENOSPC; do
	_set_fs_sysfs_attr $dev \
	error/metadata/${e}/max_retries -1
	echo -n "error/metadata/${e}/max_retries="
	_get_fs_sysfs_attr $dev error/metadata/${e}/max_retries

	_set_fs_sysfs_attr $dev \
	error/metadata/${e}/retry_timeout_seconds 0
	echo -n "error/metadata/${e}/retry_timeout_seconds="
	_get_fs_sysfs_attr $dev \
	error/metadata/${e}/retry_timeout_seconds
	done
	}

	# Skip if we are running an older binary without the stricter input checks.
	# Make multiple checks to be sure that there is no regression on the one
	# selected feature check, which would skew the result.
	#
	# At first, make a common function that runs the tests and returns
	# number of failed cases.
	_xfs_mkfs_validation_check()
	{
	local tmpfile=`mktemp`
	local cmd="$MKFS_XFS_PROG -f -N -d file,name=$tmpfile,size=1g"

	$cmd -s size=8s >/dev/null 2>&1
	local sum=$?

	$cmd -l version=2,su=260k >/dev/null 2>&1
	sum=`expr $sum + $?`

	rm -f $tmpfile
	return $sum
	}

	# Skip the test if all calls passed - mkfs accepts invalid input
	_require_xfs_mkfs_validation()
	{
	_xfs_mkfs_validation_check
	if [ "$?" -eq 0 ]; then
	_notrun "Requires newer mkfs with stricter input checks: the oldest supported version of xfsprogs is 4.7."
	fi
	}

	# The opposite of _require_xfs_mkfs_validation.
	_require_xfs_mkfs_without_validation()
	{
	_xfs_mkfs_validation_check
	if [ "$?" -ne 0 ]; then
	_notrun "Requires older mkfs without strict input checks: the last supported version of xfsprogs is 4.5."
	fi
	}

	# XFS ability to change UUIDs on V5/CRC filesystems
	#
	_require_meta_uuid()
	{
	# This will create a crc fs on $SCRATCH_DEV
	_require_xfs_crc

	_scratch_xfs_db -x -c "uuid restore" 2>&1 \
	\| grep -q "invalid UUID\\|supported on V5 fs" \
	&& _notrun "Userspace doesn't support meta_uuid feature"

	_scratch_xfs_db -x -c "uuid generate" >/dev/null 2>&1

	_try_scratch_mount >/dev/null 2>&1 \
	\|\| _notrun "Kernel doesn't support meta_uuid feature"
	_scratch_unmount
	}

	# this test requires mkfs.xfs have case-insensitive naming support
	_require_xfs_mkfs_ciname()
	{
	_scratch_mkfs_xfs_supported -n version=ci >/dev/null 2>&1 \
	\|\| _notrun "need case-insensitive naming support in mkfs.xfs"
	}

	# XFS_DEBUG requirements
	_require_xfs_debug()
	{
	if grep -q "debug 0" /proc/fs/xfs/stat; then
	_notrun "Require XFS built with CONFIG_XFS_DEBUG"
	fi
	}
	_require_no_xfs_debug()
	{
	if grep -q "debug 1" /proc/fs/xfs/stat; then
	_notrun "Require XFS built without CONFIG_XFS_DEBUG"
	fi
	}

	# Require that assertions will not crash the system.
	#
	# Assertions would always crash the system if XFS assert fatal was enabled
	# (CONFIG_XFS_ASSERT_FATAL=y). If a test is designed to trigger an assertion,
	# skip the test on a CONFIG_XFS_ASSERT_FATAL built XFS by default. Note:
	# CONFIG_XFS_ASSERT_FATAL can be disabled by setting bug_on_assert to zero if
	# we want test to run.
	_require_no_xfs_bug_on_assert()
	{
	if [ -f /sys/fs/xfs/debug/bug_on_assert ]; then
	grep -q "1" /sys/fs/xfs/debug/bug_on_assert && \
	_notrun "test requires XFS bug_on_assert to be off, turn it off to run the test"
	else
	# Note: Prior to the creation of CONFIG_XFS_ASSERT_FATAL (and
	# the sysfs knob bug_on_assert), assertions would always crash
	# the system if XFS debug was enabled (CONFIG_XFS_DEBUG=y). If
	# a test is designed to trigger an assertion and the test
	# designer does not want to hang fstests, skip the test.
	_require_no_xfs_debug
	fi
	}

	# Get a metadata field
	# The first arg is the field name
	# The rest of the arguments are xfs_db commands to find the metadata.
	_scratch_xfs_get_metadata_field()
	{
	local key="$1"
	shift

	local grep_key="$(echo "${key}" \| tr '[]()' '....')"
	local cmds=()
	local arg
	for arg in "$@"; do
	cmds+=("-c" "${arg}")
	done
	_scratch_xfs_db "${cmds[@]}" -c "print ${key}" \| grep "^${grep_key}" \| \
	sed -e 's/^.* = //g'
	}

	# Set a metadata field
	# The first arg is the field name
	# The second arg is the new value
	# The rest of the arguments are xfs_db commands to find the metadata.
	_scratch_xfs_set_metadata_field()
	{
	local key="$1"
	local value="$2"
	shift; shift

	local cmds=()
	local arg
	for arg in "$@"; do
	cmds+=("-c" "${arg}")
	done

	local wr_cmd="write"
	_scratch_xfs_db -x -c "help write" \| egrep -q "(-c\|-d)" && value="-- ${value}"
	_scratch_xfs_db -x -c "help write" \| egrep -q "(-d)" && wr_cmd="${wr_cmd} -d"
	_scratch_xfs_db -x "${cmds[@]}" -c "${wr_cmd} ${key} ${value}"
	}

	_scratch_xfs_get_sb_field()
	{
	_scratch_xfs_get_metadata_field "$1" "sb 0"
	}

	_scratch_xfs_set_sb_field()
	{
	_scratch_xfs_set_metadata_field "$1" "$2" "sb 0"
	}

	# Before xfsprogs commit 4222d000ed("db: write via array indexing doesn't
	# work"), xfs_db command to write a specific AGFL index doesn't work. It's a
	# bug in a diagnostic tool that is only used by XFS developers as a test
	# infrastructure, so it's fine to treat it as a infrastructure dependency as
	# all other _require rules.
	_require_xfs_db_write_array()
	{
	local supported=0

	_require_test
	touch $TEST_DIR/$seq.img
	$MKFS_XFS_PROG -d file,name=$TEST_DIR/$seq.img,size=512m >/dev/null 2>&1
	$XFS_DB_PROG -x -c "agfl 0" -c "write bno[32] 78" $TEST_DIR/$seq.img \
	>/dev/null 2>&1
	$XFS_DB_PROG -x -c "agfl 0" -c "print bno[32]" $TEST_DIR/$seq.img \
	\| grep -q "bno\[32\] = 78" && supported=1
	rm -f $TEST_DIR/$seq.img
	[ $supported -eq 0 ] && _notrun "xfs_db write can't support array"
	}