Re: [xfstests PATCH] generic/567: add partial pages zeroing out case

[Nirjhar Roy <nirjhar@linux.ibm.com>]

On Mon, 2024-12-23 at 10:39 +0800, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@huawei.com>
> 
> This addresses a data corruption issue encountered during partial
> page
> zeroing in ext4 which the block size is smaller than the page size
> [1].
> Expand this test to include a zeroing range test that spans two
> partial
> pages to cover this case.
> 
> Link: 
> https://lore.kernel.org/linux-ext4/20241220011637.1157197-2-yi.zhang@huaweicloud.com/
>  [1]
> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
> ---
>  tests/generic/567     | 50 +++++++++++++++++++++++++--------------
> ----
>  tests/generic/567.out | 18 ++++++++++++++++
>  2 files changed, 47 insertions(+), 21 deletions(-)
> 
> diff --git a/tests/generic/567 b/tests/generic/567
> index fc109d0d..756280e8 100755
> --- a/tests/generic/567
> +++ b/tests/generic/567
> @@ -4,43 +4,51 @@
>  #
>  # FS QA Test No. generic/567
>  #
> -# Test mapped writes against punch-hole to ensure we get the data
> -# correctly written. This can expose data corruption bugs on
> filesystems
> -# where the block size is smaller than the page size.
> +# Test mapped writes against punch-hole and zero-range to ensure we
> get
> +# the data correctly written. This can expose data corruption bugs
> on
> +# filesystems where the block size is smaller than the page size.
>  #
>  # (generic/029 is a similar test but for truncate.)
>  #
>  . ./common/preamble
> -_begin_fstest auto quick rw punch
> +_begin_fstest auto quick rw punch zero
>  
>  # Import common functions.
>  . ./common/filter
>  
>  _require_scratch
>  _require_xfs_io_command "fpunch"
> +_require_xfs_io_command "fzero"
>  
>  testfile=$SCRATCH_MNT/testfile
>  
>  _scratch_mkfs > /dev/null 2>&1
Since this test requires block size < page size, do you think it is a
good idea to hard code the _scratch_mkfs parameters to explicitly pass
the block size to < less than zero? This will require less manipulation
with the local.config file. Or maybe have a _notrun to _notrun the test
if the block size is not less than the page size?
>  _scratch_mount
>  
> -# Punch a hole straddling two pages to check that the mapped write
> after the
> -# hole-punching is correctly handled.
> -
> -$XFS_IO_PROG -t -f \
> --c "pwrite -S 0x58 0 12288" \
> --c "mmap -rw 0 12288" \
> --c "mwrite -S 0x5a 2048 8192" \
> --c "fpunch 2048 8192" \
> --c "mwrite -S 0x59 2048 8192" \
> --c "close" 
Minor: isn't the close command redundant? xfs_io will in any case close
the file right?
>      \
> -$testfile | _filter_xfs_io
> -
> -echo "==== Pre-Remount ==="
> -_hexdump $testfile
> -_scratch_cycle_mount
> -echo "==== Post-Remount =="
> -_hexdump $testfile
> +# Punch a hole and zero out straddling two pages to check that the
> mapped
> +# write after the hole-punching and range-zeroing are correctly
> handled.
> +_straddling_test()
> +{
> +	local test_cmd=$1
> +
> +	$XFS_IO_PROG -t -f \
> +		-c "pwrite -S 0x58 0 12288" \
> +		-c "mmap -rw 0 12288" \
> +		-c "mwrite -S 0x5a 2048 8192" \
> +		-c "$test_cmd 2048 8192" \
> +		-c "mwrite -S 0x59 2048 8192" \
> +		-c "close"      \
> +	$testfile | _filter_xfs_io
> +
> +	echo "==== Pre-Remount ==="
> +	_hexdump $testfile
> +	_scratch_cycle_mount
> +	echo "==== Post-Remount =="
> +	_hexdump $testfile
Just guessing here: Do you think it is makes sense to test with both
delayed and non-delayed allocation? I mean with and without "msync"?
> +}
> +
> +_straddling_test "fpunch"
> +_straddling_test "fzero"
Minor: Since we are running 2 independant sub-tests, isn't it better to
use 2 different files?

--NR
>  
>  status=0
>  exit
> diff --git a/tests/generic/567.out b/tests/generic/567.out
> index 0e826ed3..df89b8f3 100644
> --- a/tests/generic/567.out
> +++ b/tests/generic/567.out
> @@ -17,3 +17,21 @@ XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX
> ops/sec)
>  002800 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58
> 58  >XXXXXXXXXXXXXXXX<
>  *
>  003000
> +wrote 12288/12288 bytes at offset 0
> +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> +==== Pre-Remount ===
> +000000 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58
> 58  >XXXXXXXXXXXXXXXX<
> +*
> +000800 59 59 59 59 59 59 59 59 59 59 59 59 59 59 59
> 59  >YYYYYYYYYYYYYYYY<
> +*
> +002800 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58
> 58  >XXXXXXXXXXXXXXXX<
> +*
> +003000
> +==== Post-Remount ==
> +000000 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58
> 58  >XXXXXXXXXXXXXXXX<
> +*
> +000800 59 59 59 59 59 59 59 59 59 59 59 59 59 59 59
> 59  >YYYYYYYYYYYYYYYY<
> +*
> +002800 58 58 58 58 58 58 58 58 58 58 58 58 58 58 58
> 58  >XXXXXXXXXXXXXXXX<
> +*
> +003000