Re: [PATCH] fstests: Introduce check for explicit SHARED extent flag reporting

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

On Thu, Nov 17, 2016 at 10:06:48AM +0800, Qu Wenruo wrote:
> For fs support reflink, some of them (OK, btrfs again) doesn't split
> SHARED flag for extent fiemap reporting.
> 
> For example:
>   0         4K         8K
>    / File1: Extent 0  \
>   /                    \
>   |<- On disk Extent-->|
>   |        /
>   | File2 /
>     Extent: 0
> 
> Fs supports explicit SHARED extent reporting should report fiemap like:
> File1: 2 extents
> Extent 0-4K: SHARED
> Extent 4-8K:
> File2: 1 extents
> Extent 0-4K: SHARED
> 
> Fs doesn't support explicit reporting will report fiemap like:
> File1: 1 extent
> Extent 0-8K: SHARED
> File2: 1 extent
> Extent 0-4K: SHARED

How difficult /would/ it be to fix btrfs, anyway?

--D

> 
> Test case like generic/372 require explicit reporting will cause false
> alert on btrfs.
> 
> Add such runtime check for that requirememt.
> 
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
> ---
>  common/reflink    | 44 ++++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/372 |  1 +
>  2 files changed, 45 insertions(+)
> 
> diff --git a/common/reflink b/common/reflink
> index 8b34046..9ada2e8 100644
> --- a/common/reflink
> +++ b/common/reflink
> @@ -78,6 +78,50 @@ _require_scratch_reflink()
>  	_scratch_unmount
>  }
>  
> +# this test requires scratch fs to report explicit SHARED flag
> +# e.g.
> +#   0         4K         8K
> +#    / File1: Extent 0  \
> +#   /                    \
> +#   |<- On disk Extent-->|
> +#   |        /
> +#   | File2 /
> +#     Extent: 0
> +# Fs supports explicit SHARED extent reporting should report fiemap like:
> +# File1: 2 extents
> +# Extent 0-4K: SHARED
> +# Extent 4-8K:
> +# File2: 1 extents
> +# Extent 0-4K: SHARED
> +#
> +# Fs doesn't support explicit reporting will report fiemap like:
> +# File1: 1 extent
> +# Extent 0-8K: SHARED
> +# File2: 1 extent
> +# Extent 0-4K: SHARED
> +_require_scratch_explicit_shared_extents()
> +{
> +	_require_scratch
> +	_require_fiemap
> +	_require_scratch_reflink
> +	_require_xfs_io_command "reflink"
> +	local nr_extents
> +
> +	_scratch_mkfs > /dev/null
> +	_scratch_mount
> +
> +	_pwrite_byte 0x61 0 128k $SCRATCH_MNT/file1
> +	_reflink_range $SCRATCH_MNT/file1 0 $SCRATCH_MNT/file2 0 64k
> +
> +	_scratch_cycle_mount
> +
> +	nr_extents=$(_count_extents $SCRATCH_MNT/file1)
> +	if [ $nr_extents -eq 1 ]; then
> +		_notrun "Explicit SHARED flag reporting not support by filesystem type: $FSTYP"
> +	fi
> +	_scratch_unmount
> +}
> +
>  # this test requires the test fs support dedupe...
>  _require_test_dedupe()
>  {
> diff --git a/tests/generic/372 b/tests/generic/372
> index 31dff20..51a3eca 100755
> --- a/tests/generic/372
> +++ b/tests/generic/372
> @@ -47,6 +47,7 @@ _supported_os Linux
>  _supported_fs generic
>  _require_scratch_reflink
>  _require_fiemap
> +_require_scratch_explicit_shared_extents
>  
>  echo "Format and mount"
>  _scratch_mkfs > $seqres.full 2>&1
> -- 
> 2.7.4
> 
> 
> 
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