Re: [PATCH v6] btrfs: Add new test for setting the chunk size.

[Stefan Roesch <shr@fb.com>]

On 11/28/21 7:55 AM, Eryu Guan wrote:
> On Wed, Nov 24, 2021 at 01:12:30PM -0800, Stefan Roesch wrote:
>> Add new testcase for testing the new btrfs sysfs knob to change the
>> chunk size. The new knob uses /sys/fs/btrfs/<UUID>/allocation/<block
>> type>/chunk_size.
>>
>> The test case implements three different cases:
>> - Test allocation with the default chunk size
>> - Test allocation after increasing the chunk size
>> - Test allocation when the free space is smaller than the chunk size.
>>
>> Note: this test needs to force the allocation of space. It uses the
>> /sys/fs/btrfs/<UUID>/allocation/<block type>/force_chunk_alloc knob.
>>
>> Testing:
>> The test has been run with volumes of different sizes.
>>
>> Signed-off-by: Stefan Roesch <shr@fb.com>
>> Reviewed-by: Josef Bacik <josef@toxicpanda.com>
>> ---
>> V6: - renamed test case from 248 to 251
>>     - use _require_fs_sysfs
>>     - use device name in _get_fs_sysfs_attr and _set_fs_sysfs_attr
>> V5: - Modify _get_fs_sysfs_attr and _set_fs_sysfs_attr to support btrfs
>>     - Use _get_fs_sysfs_attr and _set_fs_sysfs_attr
>>     - Remove _get_btrfs_sysfs_attr and _set_btrfs_fsysfs_attr
>>     - Rename local functions to not use "_"
>>     - use $AWK_PROG and $BTRFS_UTIL_PROG
>>     - remove call to _require_scratch_size
>>     - fixes for coding convention
>>     - replace fail calls with echo
>> V4: - fixed indentation in common/btrfs
>>     - Removed UUID code, which is no longer necessary (provided
>>       by helper function)
>>     - Used new helper _get_btrfs_sysfs_attr
>>     - Direct output to /dev/null
>> V3: - removed tests for system block type.
>>     - added failure case for system block type.
>>     - renamed stripe_size to chunk_size
>> V2: - added new functions to common/btrfs and use them in the new test
>>       - _require_btrfs_sysfs_attr - Make sure btrfs supports a sysfs
>>         setting
>>       - _get_btrfs_sysfs_attr - Read sysfs value
>>       - _set_btrfs_sysfs_attr - Write sysfs value
>>     - create file system of required size with _scratch_mkfs_sized
>>     - use shortened error message
>>     - Remove last logging message
>> ---
>>  common/rc           |  29 ++++-
>>  tests/btrfs/251     | 287 ++++++++++++++++++++++++++++++++++++++++++++
>>  tests/btrfs/251.out |  11 ++
>>  3 files changed, 323 insertions(+), 4 deletions(-)
>>  create mode 100755 tests/btrfs/251
>>  create mode 100644 tests/btrfs/251.out
>>
>> diff --git a/common/rc b/common/rc
>> index 0a30a842..9522ba2e 100644
>> --- a/common/rc
>> +++ b/common/rc
>> @@ -4401,7 +4401,14 @@ run_fsx()
>>  _require_fs_sysfs()
>>  {
>>  	local attr=$1
>> -	local dname=$(_short_dev $TEST_DEV)
>> +	local dname
>> +
>> +	case "$FSTYP" in
>> +	btrfs)
>> +		dname=$(findmnt -n -o UUID $TEST_DEV) ;;
>> +	*)
>> +		dname=$(_short_dev $TEST_DEV) ;;
>> +	esac
>>  
>>  	if [ -z "$attr" -o -z "$dname" ];then
>>  		_fail "Usage: _require_fs_sysfs <sysfs_attr_path>"
>> @@ -4436,10 +4443,17 @@ _set_fs_sysfs_attr()
>>  	local content="$*"
>>  
>>  	if [ ! -b "$dev" -o -z "$attr" -o -z "$content" ];then
>> -		_fail "Usage: _set_fs_sysfs_attr <mounted_device> <attr> <content>"
>> +	 	_fail "Usage: _set_fs_sysfs_attr <mounted_device> <attr> <content>"
> 
> What is this change? Seems it adds a space between the first two tabs,
> and causes git am to complain about whitespace damange.
> 

Fixed.

>>  	fi
>>  
>> -	local dname=$(_short_dev $dev)
>> +	local dname
>> +	case "$FSTYP" in
>> +	btrfs)
>> +		dname=$(findmnt -n -o UUID ${dev}) ;;
>> +	*)
>> +		dname=$(_short_dev $dev) ;;
>> +	esac
>> +
>>  	echo "$content" > /sys/fs/${FSTYP}/${dname}/${attr}
>>  }
>>  
>> @@ -4460,7 +4474,14 @@ _get_fs_sysfs_attr()
>>  		_fail "Usage: _get_fs_sysfs_attr <mounted_device> <attr>"
>>  	fi
>>  
>> -	local dname=$(_short_dev $dev)
>> +	local dname
>> +	case "$FSTYP" in
>> +	btrfs)
>> +		dname=$(findmnt -n -o UUID ${dev}) ;;
>> +	*)
>> +		dname=$(_short_dev $dev) ;;
>> +	esac
>> +
>>  	cat /sys/fs/${FSTYP}/${dname}/${attr}
>>  }
>>  
>> diff --git a/tests/btrfs/251 b/tests/btrfs/251
>> new file mode 100755
>> index 00000000..b5c4b623
>> --- /dev/null
>> +++ b/tests/btrfs/251
>> @@ -0,0 +1,287 @@
>> +#!/bin/bash
>> +# SPDX-License-Identifier: GPL-2.0
>> +# Copyright (c) 2021 Facebook.  All Rights Reserved.
>> +#
>> +# FS QA Test 250
>> +#
>> +# Test the new /sys/fs/btrfs/<uuid>/allocation/<block-type>/chunk_size
>> +# setting. This setting allows the admin to change the chunk size
>> +# setting for the next allocation.
>> +#
>> +# Test 1:
>> +#   Allocate storage for all three block types (data, metadata and system)
>> +#   with the default chunk size.
>> +#
>> +# Test 2:
>> +#   Set a new chunk size to double the default size and allocate space
>> +#   for all new block types with the new chunk size.
>> +#
>> +# Test 3:
>> +#   Pick an allocation size that is used in a loop and make sure the last
>> +#   allocation cannot be partially fullfilled.
>> +#
>> +# Note: Variable naming uses the following convention: if a variable name
>> +#       ends in "_B" then its a byte value, if it ends in "_MB" then the
>> +#       value is in megabytes.
>> +#
>> +. ./common/preamble
>> +_begin_fstest auto
>> +
>> +test_file="${TEST_DIR}/${seq}"
> 
> Seems it's not used in the test?
> 

Correct. I removed it.

>> +seq=`basename $0`
>> +seqres="${RESULT_DIR}/${seq}"
>> +
>> +# Override the default cleanup function.
>> +_cleanup()
>> +{
>> +	cd /
>> +	rm -f "$test_file"
> 
> Then there's no need to remove it in cleanup
> 

Removed.

>> +}
>> +
>> +# Parse a size string which is in the format "XX.XXMib".
>> +#
>> +# Parameters:
>> +#   - (IN)    Block group type (Data, Metadata, System)
>> +#   - (INOUT) Variable to store block group size in MB
>> +#
>> +parse_size_string() {
>> +	local SIZE=$(echo "$1" | $AWK_PROG 'match($0, /([0-9.]+)/) { print substr($0, RSTART, RLENGTH) }')
>> +        eval $2="${SIZE%.*}"
> 
> The above "eval" line uses spaces as indentions not tab.
> 

Fixed.

>> +}
>> +
>> +# Determine the size of the device in MB.
>> +#
>> +# Parameters:
>> +#   - (INOUT) Variable to store device size in MB
>> +#
>> +device_size() {
>> +	btrfs fi show ${SCRATCH_MNT} --mbytes | grep devid >> $seqres.full
>> +	local SIZE=$($BTRFS_UTIL_PROG filesystem show ${SCRATCH_MNT} --mbytes | grep devid)
>> +	parse_size_string $(echo "${SIZE}" | awk '{print $4}') SIZE_ALLOC
>> +	eval $1=${SIZE_ALLOC%.*}
>> +}
>> +
>> +# Determine the free space of a block group in MB.
>> +#
>> +# Parameters:
>> +#   - (INOUT) Variable to store free space in MB
>> +#
>> +free_space() {
>> +	local SIZE=$($BTRFS_UTIL_PROG filesystem show ${SCRATCH_MNT} --mbytes | grep devid)
>> +	parse_size_string $(echo "${SIZE}" | awk '{print $4}') SIZE_ALLOC
>> +	parse_size_string $(echo "${SIZE}" | awk '{print $6}') SIZE_USED
>> +	eval $1=$(expr ${SIZE_ALLOC} - ${SIZE_USED})
>> +}
>> +
>> +# Determine how much space in MB has been allocated to a block group.
>> +#
>> +# Parameters:
>> +#   - (IN)    Block group type (Data, Metadata, System)
>> +#   - (INOUT) Variable to store block group size in MB
>> +#
>> +alloc_size() {
>> +	local SIZE_STRING=$($BTRFS_UTIL_PROG filesystem df ${SCRATCH_MNT} -m | grep  "$1" | awk '{print $3}')
>> +	parse_size_string ${SIZE_STRING} BLOCK_GROUP_SIZE
>> +        eval $2="${BLOCK_GROUP_SIZE}"
>> +}
>> +
>> +. ./common/filter
>> +_supported_fs btrfs
>> +_require_test
>> +_require_scratch
>> +_require_btrfs_fs_sysfs
> 
> Looks like we could drop this require, as _require_fs_sysfs below
> ensures this requirement must be met.
> 

Removed.

>> +
>> +# Delete log file if it exists.
>> +rm -f "${seqres}.full"
>> +
>> +# Make filesystem.
>> +_scratch_mkfs_sized $((10 * 1024 * 1024 * 1024)) >> $seqres.full 2>&1
> 
> Any reason we need a 10G filesystem? Some comments would be good.
> 

I added a comment.

>> +_scratch_mount >> $seqres.full 2>&1
>> +
>> +# Check if there is sufficient sysfs support.
>> +_require_fs_sysfs allocation/metadata/chunk_size
>> +_require_fs_sysfs allocation/metadata/force_chunk_alloc
>> +
>> +# Get free space.
>> +free_space  FREE_SPACE_MB
>> +device_size DEVICE_SIZE_MB
>> +
>> +echo "free space = ${FREE_SPACE_MB}MB" >> ${seqres}.full
>> +
>> +# If device is a symbolic link, get block device.
>> +SCRATCH_BDEV=${SCRATCH_DEV}
>> +if [[ -h ${SCRATCH_DEV} ]]; then
>> +	SCRATCH_BDEV=$(readlink -f $SCRATCH_DEV)
>> +fi
>> +
>> +# Get chunk sizes.
>> +echo "Capture default chunk sizes."
>> +FIRST_DATA_CHUNK_SIZE_B=$(_get_fs_sysfs_attr ${SCRATCH_BDEV} allocation/data/chunk_size)
>> +FIRST_METADATA_CHUNK_SIZE_B=$(_get_fs_sysfs_attr ${SCRATCH_BDEV} allocation/metadata/chunk_size)
>> +
>> +echo "Orig Data chunk size    = ${FIRST_DATA_CHUNK_SIZE_B}"     >> ${seqres}.full
>> +echo "Orig Metaata chunk size = ${FIRST_METADATA_CHUNK_SIZE_B}" >> ${seqres}.full
>> +
>> +INIT_ALLOC_SIZE_MB=$(expr \( ${FIRST_DATA_CHUNK_SIZE_B} + ${FIRST_METADATA_CHUNK_SIZE_B} \) / 1024 / 1024)
>> +echo "Allocation size for initial allocation = ${INIT_ALLOC_SIZE_MB}MB" >> $seqres.full
>> +
>> +#
>> +# Do first allocation with the default chunk sizes for the different block
>> +# types.
>> +#
>> +echo "First allocation."
>> +alloc_size "Data"     DATA_SIZE_START_MB
>> +alloc_size "Metadata" METADATA_SIZE_START_MB
>> +
>> +echo "Block group Data alloc size     = ${DATA_SIZE_START_MB}MB"     >> $seqres.full
>> +echo "Block group Metadata alloc size = ${METADATA_SIZE_START_MB}MB" >> $seqres.full
>> +
>> +_set_fs_sysfs_attr ${SCRATCH_BDEV} allocation/data/force_chunk_alloc 1
>> +_set_fs_sysfs_attr ${SCRATCH_BDEV} allocation/metadata/force_chunk_alloc 1
>> +
>> +alloc_size "Data"     FIRST_DATA_SIZE_MB
>> +alloc_size "Metadata" FIRST_METADATA_SIZE_MB
>> +
>> +echo "First block group Data alloc size     = ${FIRST_DATA_SIZE_MB}MB"     >> ${seqres}.full
>> +echo "First block group Metadata alloc size = ${FIRST_METADATA_SIZE_MB}MB" >> ${seqres}.full
>> +
>> +free_space FREE_SPACE_AFTER
>> +echo "Free space after first allocation = ${FREE_SPACE_AFTER}MB" >> ${seqres}.full
>> +
>> +#
>> +# Do allocation with the doubled chunk sizes for the different block types.
>> +#
>> +echo "Second allocation."
>> +SECOND_DATA_CHUNK_SIZE_B=$(expr ${FIRST_DATA_CHUNK_SIZE_B} \* 2)
>> +SECOND_METADATA_CHUNK_SIZE_B=$(expr ${FIRST_METADATA_CHUNK_SIZE_B} \* 2)
>> +
>> +echo "Second block group Data calc alloc size     = ${SECOND_DATA_CHUNK_SIZE_B}"     >> $seqres.full
>> +echo "Second block group Metadata calc alloc size = ${SECOND_METADATA_CHUNK_SIZE_B}" >> $seqres.full
>> +
>> +# Stripe size is limited to 10% of device size.
>> +if [[ ${SECOND_DATA_CHUNK_SIZE_B} -gt $(expr ${DEVICE_SIZE_MB} \* 10 \* 1024 \* 1024 / 100) ]]; then
>> +	SECOND_DATA_CHUNK_SIZE_B=$(expr ${DEVICE_SIZE_MB} \* 10 / 100 \* 1024 \* 1024)
>> +fi
>> +if [[ ${SECOND_METADATA_CHUNK_SIZE_B} -gt $(expr ${DEVICE_SIZE_MB} \* 10 \* 1024 \* 1024 / 100) ]]; then
>> +	SECOND_METADATA_CHUNK_SIZE_B=$(expr ${DEVICE_SIZE_MB} \* 10 / 100 \* 1024 \* 1024)
>> +fi
>> +
>> +echo "Second block group Data alloc size     = ${SECOND_DATA_CHUNK_SIZE_B}"     >> $seqres.full
>> +echo "Second block group Metadata alloc size = ${SECOND_METADATA_CHUNK_SIZE_B}" >> $seqres.full
>> +
>> +_set_fs_sysfs_attr ${SCRATCH_BDEV} allocation/data/chunk_size ${SECOND_DATA_CHUNK_SIZE_B}
>> +_set_fs_sysfs_attr ${SCRATCH_BDEV} allocation/metadata/chunk_size ${SECOND_METADATA_CHUNK_SIZE_B}
>> +
>> +SECOND_DATA_CHUNK_SIZE_READ_B=$(_get_fs_sysfs_attr ${SCRATCH_BDEV} allocation/data/chunk_size)
>> +SECOND_METADATA_CHUNK_SIZE_READ_B=$(_get_fs_sysfs_attr ${SCRATCH_BDEV} allocation/metadata/chunk_size)
>> +
>> +_set_fs_sysfs_attr ${SCRATCH_BDEV} allocation/data/force_chunk_alloc 1
>> +echo "Allocated data chunk" >> $seqres.full
>> +_set_fs_sysfs_attr ${SCRATCH_BDEV} allocation/metadata/force_chunk_alloc 1
>> +echo "Allocated metadata chunk" >> $seqres.full
>> +
>> +alloc_size "Data"     SECOND_DATA_SIZE_MB
>> +alloc_size "Metadata" SECOND_METADATA_SIZE_MB
>> +alloc_size "System"   SECOND_SYSTEM_SIZE_MB
>> +
>> +echo "Calculate request size so last memory allocation cannot be completely fullfilled."
>> +free_space FREE_SPACE_MB
>> +
>> +# Find request size whose space allocation cannot be completely fullfilled.
>> +THIRD_DATA_CHUNK_SIZE_MB=$(expr 256)
>> +until [ ${THIRD_DATA_CHUNK_SIZE_MB} -gt $(expr 7 \* 1024) ]; do
>> +	if [ $((FREE_SPACE_MB%THIRD_DATA_CHUNK_SIZE_MB)) -ne 0 ]; then
>> +		break
>> +        fi
>> +	THIRD_DATA_CHUNK_SIZE_MB=$((THIRD_DATA_CHUNK_SIZE_MB+256))
>> +done
>> +
>> +if [[ ${THIRD_DATA_CHUNK_SIZE_MB} -eq $(expr 7 \* 1024) ]]; then
>> +	_fail "Cannot find allocation size for partial block allocation."
>> +fi
>> +
>> +THIRD_DATA_CHUNK_SIZE_B=$(expr ${THIRD_DATA_CHUNK_SIZE_MB} \* 1024 \* 1024)
>> +echo "Allocation size in mb    = ${THIRD_DATA_CHUNK_SIZE_MB}" >> ${seqres}.full
>> +echo "Allocation size in bytes = ${THIRD_DATA_CHUNK_SIZE_B}"  >> ${seqres}.full
>> +
>> +#
>> +# Do allocation until free space is exhausted.
>> +#
>> +echo "Third allocation."
>> +_set_fs_sysfs_attr ${SCRATCH_BDEV} allocation/data/chunk_size ${THIRD_DATA_CHUNK_SIZE_B}
>> +
>> +free_space FREE_SPACE_MB
>> +while [ $FREE_SPACE_MB -gt $THIRD_DATA_CHUNK_SIZE_MB ]
>> +do
>> +	alloc_size "Data" THIRD_DATA_SIZE_MB
>> +	_set_fs_sysfs_attr ${SCRATCH_BDEV} allocation/data/force_chunk_alloc 1
>> +
>> +	free_space FREE_SPACE_MB
>> +done
>> +
>> +alloc_size "Data" FOURTH_DATA_SIZE_MB
>> +
>> +#
>> +# Force chunk allocation of system block type must fail.
>> +#
>> +echo "Force allocation of system block type must fail."
>> +_set_fs_sysfs_attr ${SCRATCH_BDEV} allocation/system/force_chunk_alloc 1 2>/dev/null
>> +if [ $? -ne 0 ]; then
>> +	_dump_err "_set_fs_sysfs_attr cannot write allocation/system/force_chunk_alloc"
>> +fi
> 
> I don't think we need this check. We could just remove the
> "2 > /dev/null" part from the above _set_fs_sysfs_attr and it will print
> error message and break golden image on error.
> 

If we don't add this, we need to add an error message to the log like:
/common/rc: line 4457: echo: write error: No space left on device

This is pretty fragile.

> Thanks,
> Eryu
> 
>> +
>> +#
>> +# Verification of initial allocation.
>> +#
>> +echo "Verify first allocation."
>> +FIRST_DATA_CHUNK_SIZE_MB=$(expr ${FIRST_DATA_CHUNK_SIZE_B} / 1024 / 1024)
>> +FIRST_METADATA_CHUNK_SIZE_MB=$(expr ${FIRST_METADATA_CHUNK_SIZE_B} / 1024 / 1024)
>> +
>> +# if [[ $(expr ${FIRST_DATA_CHUNK_SIZE_MB} + ${DATA_SIZE_START_MB}) -ne $(expr ${FIRST_DATA_SIZE_MB}) ]]; then
>> +if [[ $(expr ${FIRST_DATA_CHUNK_SIZE_MB} + ${DATA_SIZE_START_MB}) -ne ${FIRST_DATA_SIZE_MB} ]]; then
>> +	echo "tInitial data allocation not correct."
>> +fi
>> +
>> +if [[ $(expr ${FIRST_METADATA_CHUNK_SIZE_MB} + ${METADATA_SIZE_START_MB}) -ne ${FIRST_METADATA_SIZE_MB} ]]; then
>> +	echo "Initial metadata allocation not correct."
>> +fi
>> +
>> +#
>> +# Verification of second allocation.
>> +#
>> +echo "Verify second allocation."
>> +SECOND_DATA_CHUNK_SIZE_MB=$(expr ${SECOND_DATA_CHUNK_SIZE_B} / 1024 / 1024)
>> +SECOND_METADATA_CHUNK_SIZE_MB=$(expr ${SECOND_METADATA_CHUNK_SIZE_B} / 1024 / 1024)
>> +
>> +if [[ ${SECOND_DATA_CHUNK_SIZE_B} -ne ${SECOND_DATA_CHUNK_SIZE_READ_B} ]]; then
>> +	echo "Value written to allocation/data/chunk_size and read value are different."
>> +fi
>> +
>> +if [[ ${SECOND_METADATA_CHUNK_SIZE_B} -ne ${SECOND_METADATA_CHUNK_SIZE_READ_B} ]]; then
>> +	echo "Value written to allocation/metadata/chunk_size and read value are different."
>> +fi
>> +
>> +if [[ $(expr ${SECOND_DATA_CHUNK_SIZE_MB} + ${FIRST_DATA_SIZE_MB}) -ne ${SECOND_DATA_SIZE_MB} ]]; then
>> +	echo "Data allocation after chunk size change not correct."
>> +fi
>> +
>> +if [[ $(expr ${SECOND_METADATA_CHUNK_SIZE_MB} + ${FIRST_METADATA_SIZE_MB}) -ne ${SECOND_METADATA_SIZE_MB} ]]; then
>> +	echo "Metadata allocation after chunk size change not correct."
>> +fi
>> +
>> +#
>> +# Verification of third allocation.
>> +#
>> +echo "Verify third allocation."
>> +if [[ ${FREE_SPACE_MB} -gt ${THIRD_DATA_CHUNK_SIZE_MB} ]]; then
>> +	echo "Free space after allocating over memlimit is too high."
>> +fi
>> +
>> +# The + 1 is required as 1MB is always kept as free space.
>> +if [[ $(expr ${THIRD_DATA_CHUNK_SIZE_MB} + ${THIRD_DATA_SIZE_MB} + 1) -le $(expr ${FOURTH_DATA_SIZE_MB}) ]]; then
>> +	echo "Allocation until out of memory: last memory allocation size is not correct."
>> +fi
>> +
>> +status=0
>> +exit
>> +
>> diff --git a/tests/btrfs/251.out b/tests/btrfs/251.out
>> new file mode 100644
>> index 00000000..bb7b45d8
>> --- /dev/null
>> +++ b/tests/btrfs/251.out
>> @@ -0,0 +1,11 @@
>> +QA output created by 248
>> +Capture default chunk sizes.
>> +First allocation.
>> +Second allocation.
>> +Calculate request size so last memory allocation cannot be completely fullfilled.
>> +Third allocation.
>> +Force allocation of system block type must fail.
>> +_set_fs_sysfs_attr cannot write allocation/system/force_chunk_alloc
>> +Verify first allocation.
>> +Verify second allocation.
>> +Verify third allocation.
>> -- 
>> 2.30.2