Re: [PATCH v7 3/5] generic/574: corrupt btrfs merkle tree data

[Eric Biggers <ebiggers@kernel.org>]

On Tue, Mar 15, 2022 at 03:15:59PM -0700, Boris Burkov wrote:
> generic/574 has tests for corrupting the merkle tree data stored by the
> filesystem. Since btrfs uses a different scheme for storing this data,
> the existing logic for corrupting it doesn't work out of the box. Adapt
> it to properly corrupt btrfs merkle items.
> 
> This test relies on the btrfs implementation of fsverity in the patch:
> btrfs: initial fsverity support
> 
> and on btrfs-corrupt-block for corruption in the patches titled:
> btrfs-progs: corrupt generic item data with btrfs-corrupt-block
> btrfs-progs: expand corrupt_file_extent in btrfs-corrupt-block
> 
> Signed-off-by: Boris Burkov <boris@bur.io>
> ---
>  common/verity     | 15 +++++++++++++++
>  tests/generic/574 |  1 +
>  2 files changed, 16 insertions(+)
> 
> diff --git a/common/verity b/common/verity
> index 77766fca..db03510e 100644
> --- a/common/verity
> +++ b/common/verity
> @@ -328,6 +328,21 @@ _fsv_scratch_corrupt_merkle_tree()
>  		(( offset += ($(_get_filesize $file) + 65535) & ~65535 ))
>  		_fsv_scratch_corrupt_bytes $file $offset
>  		;;
> +	btrfs)
> +		local ino=$(stat -c '%i' $file)
> +		_scratch_unmount
> +		local byte=""
> +		while read -n 1 byte; do
> +			local ascii=$(printf "%d" "'$byte'")
> +			# This command will find a Merkle tree item for the inode (-I $ino,37,0)
> +			# in the default filesystem tree (-r 5) and corrupt one byte (-b 1) at
> +			# $offset (-o $offset) with the ascii representation of the byte we read
> +			# (-v $ascii)
> +			$BTRFS_CORRUPT_BLOCK_PROG -r 5 -I $ino,37,0 -v $ascii -o $offset -b 1 $SCRATCH_DEV
> +			(( offset += 1 ))
> +		done
> +		_scratch_mount
> +		;;
>  	*)
>  		_fail "_fsv_scratch_corrupt_merkle_tree() unimplemented on $FSTYP"
>  		;;
> diff --git a/tests/generic/574 b/tests/generic/574
> index 17fdea52..18810ab2 100755
> --- a/tests/generic/574
> +++ b/tests/generic/574
> @@ -27,6 +27,7 @@ _cleanup()
>  # real QA test starts here
>  _supported_fs generic
>  _require_scratch_verity
> +_require_fsverity_corruption
>  _disable_fsverity_signatures
>  _require_fsverity_corruption
>  

_require_fsverity_corruption is already present above.

That would mean this patch should only change common/verity, and its subject
should have "common/verity", not "generic/574".

- Eric