Re: [PATCH v2] common/xfs: Add require_xfs_db_write_array function

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

On Mon, Apr 16, 2018 at 05:07:35PM +0800, yang xu wrote:
> xfsprogs commit 4222d000ed("db: write via array indexing doesn't
> work") fixes a bug that xfs_db write can't support array indexing.
> This function will check whether the bug is fixed on the current
> xfsprogs.
> 
> xfs/444 applies the function, and skips if this bug exists.
> 
> Signed-off-by: yang xu <xuyang.jy@cn.fujitsu.com>
> ---
>  common/xfs    | 18 ++++++++++++++++++
>  tests/xfs/444 |  1 +
>  2 files changed, 19 insertions(+)
> 
> diff --git a/common/xfs b/common/xfs
> index 3169f87..c4611a1 100644
> --- a/common/xfs
> +++ b/common/xfs
> @@ -701,3 +701,21 @@ _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.
> +_require_xfs_db_write_array()
> +{
> +	_scratch_xfs_set_metadata_field "bno[32]" "78" "agfl 0" >/dev/null 2>&1

This is going to fail randomly unless the caller previously called
_require_scratch to make sure that there's some kind of xfs fs image
sitting on the scratch device (and that there even is a scratch device).
Please document that requirement.  Alternately, consider formatting a xfs
image file in $TEST_DIR and poking that with xfs_db so you don't have to
deal with formatting and cleaning up the scratch device.

> +
> +	# Before xfsprogs commit 0ebbf1d58898 ("db: limit AGFL bno
> +	# arrayi printing), When asking for a single agfl entry,
> +	# the result outputs the entire remainder of the array
> +	# starting at the given index.
> +	# It is difficult to extract single entry values.
> +	# So filter useless information.
> +	bno_value=$(_scratch_xfs_get_metadata_field "bno[32]" \
> +		"agfl 0" |sed -e 's/ .*$//g' | sed -e 's/^.*://g')
> +
> +	[ "${bno_value}" != "78" ] && _notrun "xfs_db write can't support array"

It seems like a bad idea to leave a potentially corrupt scratch fs lying
around after this helper exits.

--D

> +}
> diff --git a/tests/xfs/444 b/tests/xfs/444
> index 141be52..9700422 100755
> --- a/tests/xfs/444
> +++ b/tests/xfs/444
> @@ -54,6 +54,7 @@ _supported_os Linux
>  _require_check_dmesg
>  _require_scratch
>  _require_test_program "punch-alternating"
> +_require_xfs_db_write_array
>  
>  # This is only a v5 filesystem problem
>  _require_scratch_xfs_crc
> -- 
> 1.8.3.1
> 
> 
> 
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