Re: [PATCH] generic: add test for zero range over a file range with many small extents

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Tue, Sep 08, 2020 at 11:32:02AM +0100, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> Test a fallocate() zero range operation against a large file range for which
> there are many small extents allocated. Verify the operation does not fail
> and the respective range return zeroes on subsequent reads.

LOL, we didn't already have a stress test for fzero? :/

> This test is motivated by a bug found on btrfs. The patch that fixes the
> bug on btrfs has the following subject:
> 
>  "btrfs: fix metadata reservation for fallocate that leads to transaction aborts"
> 
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Looks good to me!

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  tests/generic/609     | 61 +++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/609.out |  5 ++++
>  tests/generic/group   |  1 +
>  3 files changed, 67 insertions(+)
>  create mode 100755 tests/generic/609
>  create mode 100644 tests/generic/609.out
> 
> diff --git a/tests/generic/609 b/tests/generic/609
> new file mode 100755
> index 00000000..cda2b3dc
> --- /dev/null
> +++ b/tests/generic/609
> @@ -0,0 +1,61 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (C) 2020 SUSE Linux Products GmbH. All Rights Reserved.
> +#
> +# FS QA Test No. 609
> +#
> +# Test a fallocate() zero range operation against a large file range for which
> +# there are many small extents allocated. Verify the operation does not fail
> +# and the respective range return zeroes on subsequent reads.
> +#
> +seq=`basename $0`
> +seqres=$RESULT_DIR/$seq
> +echo "QA output created by $seq"
> +tmp=/tmp/$$
> +status=1	# failure is the default!
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +_cleanup()
> +{
> +	cd /
> +	rm -f $tmp.*
> +}
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +. ./common/filter
> +
> +# real QA test starts here
> +_supported_fs generic
> +_supported_os Linux
> +_require_scratch
> +_require_xfs_io_command "fzero"
> +_require_xfs_io_command "fpunch"
> +_require_test_program "punch-alternating"
> +
> +rm -f $seqres.full
> +
> +_scratch_mkfs >>$seqres.full 2>&1
> +_scratch_mount
> +
> +# Create a file with many small extents. To speed up file creation, do
> +# buffered writes and then punch a hole on every other block.
> +$XFS_IO_PROG -f -c "pwrite -S 0xab -b 10M 0 100M" \
> +	$SCRATCH_MNT/foobar >>$seqres.full
> +$here/src/punch-alternating $SCRATCH_MNT/foobar >>$seqres.full
> +
> +# For btrfs, trigger a transaction commit to force metadata COW for the
> +# following fallocate zero range operation.
> +sync
> +
> +$XFS_IO_PROG -c "fzero 0 100M" $SCRATCH_MNT/foobar
> +
> +# Check the file content after umounting and mounting again the fs, to verify
> +# everything was persisted.
> +_scratch_cycle_mount
> +
> +echo "File content after zero range operation:"
> +od -A d -t x1 $SCRATCH_MNT/foobar
> +
> +status=0
> +exit
> diff --git a/tests/generic/609.out b/tests/generic/609.out
> new file mode 100644
> index 00000000..feb8c211
> --- /dev/null
> +++ b/tests/generic/609.out
> @@ -0,0 +1,5 @@
> +QA output created by 609
> +File content after zero range operation:
> +0000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> +*
> +104857600
> diff --git a/tests/generic/group b/tests/generic/group
> index aa969bcb..f8eabc0a 100644
> --- a/tests/generic/group
> +++ b/tests/generic/group
> @@ -611,3 +611,4 @@
>  606 auto attr quick dax
>  607 auto attr quick dax
>  608 auto attr quick dax
> +609 auto quick prealloc zero
> -- 
> 2.26.2
>