Re: [PATCH v3 10/13] ext4/061: Atomic writes stress test for bigalloc using fio crc verifier

Darrick J. Wong
2025-07-29T19:47:09Z

On Sat, Jul 12, 2025 at 07:42:52PM +0530, Ojaswin Mujoo wrote:
> From: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
>
> We brute force all possible blocksize & clustersize combinations on
> a bigalloc filesystem for stressing atomic write using fio data crc
> verifier. We run nproc * $LOAD_FACTOR threads in parallel writing to
> a single $SCRATCH_MNT/test-file. With atomic writes this test ensures
> that we never see the mix of data contents from different threads on
> a given bsrange.

Err, how does this differ from the next patch? It looks like this one
creates one IO thread, whereas the next one creates 8? If so, what does
this test add over ext4/062?

(and now that I look at it, ext4/062 says "FS QA Test 061"...)

--D

> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
> Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
> ---
> tests/ext4/061 | 130 +++++++++++++++++++++++++++++++++++++++++++++
> tests/ext4/061.out | 2 +
> 2 files changed, 132 insertions(+)
> create mode 100755 tests/ext4/061
> create mode 100644 tests/ext4/061.out
>
> diff --git a/tests/ext4/061 b/tests/ext4/061
> new file mode 100755
> index 00000000..a0e49249
> --- /dev/null
> +++ b/tests/ext4/061
> @@ -0,0 +1,130 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2025 IBM Corporation. All Rights Reserved.
> +#
> +# FS QA Test 061
> +#
> +# Brute force all possible blocksize clustersize combination on a bigalloc
> +# filesystem for stressing atomic write using fio data crc verifier. We run
> +# nproc * 2 * $LOAD_FACTOR threads in parallel writing to a single
> +# $SCRATCH_MNT/test-file. With fio aio-dio atomic write this test ensures that
> +# we should never see the mix of data contents from different threads for any
> +# given fio blocksize.
> +#
> +
> +. ./common/preamble
> +. ./common/atomicwrites
> +
> +_begin_fstest auto rw stress atomicwrites
> +
> +_require_scratch_write_atomic
> +_require_aiodio
> +
> +FIO_LOAD=$(($(nproc) * 2 * LOAD_FACTOR))
> +SIZE=$((100*1024*1024))
> +fiobsize=4096
> +
> +# Calculate fsblocksize as per bdev atomic write units.
> +bdev_awu_min=$(_get_atomic_write_unit_min $SCRATCH_DEV)
> +bdev_awu_max=$(_get_atomic_write_unit_max $SCRATCH_DEV)
> +fsblocksize=$(_max 4096 "$bdev_awu_min")
> +
> +function create_fio_configs()
> +{
> + create_fio_aw_config
> + create_fio_verify_config
> +}
> +
> +function create_fio_verify_config()
> +{
> +cat >$fio_verify_config <<EOF
> + [aio-dio-aw-verify]
> + direct=1
> + ioengine=libaio
> + rw=randwrite
> + bs=$fiobsize
> + fallocate=native
> + filename=$SCRATCH_MNT/test-file
> + size=$SIZE
> + iodepth=$FIO_LOAD
> + numjobs=$FIO_LOAD
> + atomic=1
> + group_reporting=1
> +
> + verify_only=1
> + verify_state_save=0
> + verify=crc32c
> + verify_fatal=1
> + verify_write_sequence=0
> +EOF
> +}
> +
> +function create_fio_aw_config()
> +{
> +cat >$fio_aw_config <<EOF
> + [aio-dio-aw]
> + direct=1
> + ioengine=libaio
> + rw=randwrite
> + bs=$fiobsize
> + fallocate=native
> + filename=$SCRATCH_MNT/test-file
> + size=$SIZE
> + iodepth=$FIO_LOAD
> + numjobs=$FIO_LOAD
> + group_reporting=1
> + atomic=1
> +
> + verify_state_save=0
> + verify=crc32c
> + do_verify=0
> +
> +EOF
> +}
> +
> +# Let's create a sample fio config to check whether fio supports all options.
> +fio_aw_config=$tmp.aw.fio
> +fio_verify_config=$tmp.verify.fio
> +fio_out=$tmp.fio.out
> +
> +create_fio_configs
> +_require_fio $fio_aw_config
> +
> +for ((fsblocksize=$fsblocksize; fsblocksize <= $(_get_page_size); fsblocksize = $fsblocksize << 1)); do
> + # cluster sizes above 16 x blocksize are experimental so avoid them
> + # Also, cap cluster size at 128kb to keep it reasonable for large
> + # blocks size
> + fs_max_clustersize=$(_min $((16 * fsblocksize)) "$bdev_awu_max" $((128 * 1024)))
> +
> + for ((fsclustersize=$fsblocksize; fsclustersize <= $fs_max_clustersize; fsclustersize = $fsclustersize << 1)); do
> + for ((fiobsize = $fsblocksize; fiobsize <= $fsclustersize; fiobsize = $fiobsize << 1)); do
> + MKFS_OPTIONS="-O bigalloc -b $fsblocksize -C $fsclustersize"
> + _scratch_mkfs_ext4 >> $seqres.full 2>&1 || continue
> + if _try_scratch_mount >> $seqres.full 2>&1; then
> + echo "== FIO test for fsblocksize=$fsblocksize fsclustersize=$fsclustersize fiobsize=$fiobsize ==" >> $seqres.full
> +
> + touch $SCRATCH_MNT/f1
> + create_fio_configs
> +
> + cat $fio_aw_config >> $seqres.full
> + echo >> $seqres.full
> + cat $fio_verify_config >> $seqres.full
> +
> + $FIO_PROG $fio_aw_config >> $seqres.full
> + ret1=$?
> +
> + $FIO_PROG $fio_verify_config >> $seqres.full
> + ret2=$?
> +
> + _scratch_unmount
> +
> + [[ $ret1 -eq 0 && $ret2 -eq 0 ]] || _fail "fio with atomic write failed"
> + fi
> + done
> + done
> +done
> +
> +# success, all done
> +echo Silence is golden
> +status=0
> +exit
> diff --git a/tests/ext4/061.out b/tests/ext4/061.out
> new file mode 100644
> index 00000000..273be9e0
> --- /dev/null
> +++ b/tests/ext4/061.out
> @@ -0,0 +1,2 @@
> +QA output created by 061
> +Silence is golden
> --
> 2.49.0
>
>