Re: [PATCH] fstests: generic/158, test dedupe with destination offset past EOF

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

On Fri, Feb 12, 2016 at 04:23:59PM +0000, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> We were testing when the source file offset starts at EOF or beyond,
> but not when the destination offset is beyond EOF or when the
> destination offset is smaller than EOF but destination offset plus
> dedup length is greater than EOF.
> 
> This is motivated by a bug in btrfs' extent_same (dedup) ioctl where
> we allowed the destination offset to start at EOF and beyond (and
> destination offset + length beyond EOF) for the case where the source
> and destination files are the same (was not allowed for different
> files used as source and destination). This also made the file's
> metadata inconsistent when the dedup operation succeeded, which
> happened when the source range corresponded to a file hole, prealloc
> extent or a data extent filled with zeroes.

Good catch!  Unfortunately I seem to have broken it with the gigantic
cleanup/new patch series that I just posted... so I'll fix this up and
post a v2.

--D

> The btrfs issue is fixed by the following patch for the linux kernel:
> 
>   "Btrfs: fix extent_same allowing destination offset beyond i_size"
> 
> Signed-off-by: Filipe Manana <fdmanana@suse.com>
> ---
>  tests/generic/158     | 10 +++++++++-
>  tests/generic/158.out |  6 +++++-
>  2 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/generic/158 b/tests/generic/158
> index 807c247..9c2d17a 100755
> --- a/tests/generic/158
> +++ b/tests/generic/158
> @@ -97,9 +97,17 @@ _dedupe_range "$testdir1/file1" 37 "$testdir1/file1" 59 23
>  echo "Try overlapping dedupe"
>  _dedupe_range "$testdir1/file1" 0 "$testdir1/file1" 1 $((blksz * 2))
>  
> -echo "Try dedupe past EOF"
> +echo "Try dedupe from past EOF"
>  _dedupe_range "$testdir1/file1" $(( (blks + 10) * blksz)) "$testdir1/file1" 0 $blksz
>  
> +echo "Try dedupe to past EOF, destination offset beyond EOF"
> +_dedupe_range "$testdir1/file1" 0 "$testdir1/file1" $(( (blks + 10) * blksz)) \
> +	$blksz
> +
> +echo "Try dedupe to past EOF, destination offset behind EOF"
> +_dedupe_range "$testdir1/file1" 0 "$testdir1/file1" $(( (blks - 1) * blksz)) \
> +	$(( blksz * 2))
> +
>  echo "Try to dedupe a dir"
>  _dedupe_range "$testdir1/dir1" 0 "$testdir1/file2" 0 $blksz
>  
> diff --git a/tests/generic/158.out b/tests/generic/158.out
> index dff3692..9aa337f 100644
> --- a/tests/generic/158.out
> +++ b/tests/generic/158.out
> @@ -7,7 +7,11 @@ Try unaligned dedupe
>  dedupe: Invalid argument
>  Try overlapping dedupe
>  dedupe: Invalid argument
> -Try dedupe past EOF
> +Try dedupe from past EOF
> +dedupe: Invalid argument
> +Try dedupe to past EOF, destination offset beyond EOF
> +dedupe: Invalid argument
> +Try dedupe to past EOF, destination offset behind EOF
>  dedupe: Invalid argument
>  Try to dedupe a dir
>  XFS_IOC_FILE_EXTENT_SAME: Is a directory
> -- 
> 2.7.0.rc3
> 
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