On Thu, Apr 08, 2021 at 11:57:50AM -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.
>
> Note that there is a bit of a kludge here: since btrfs_corrupt_block
> doesn't handle streaming corruption bytes from stdin (I could change
> that, but it feels like overkill for this purpose), I just read the
> first corruption byte and duplicate it for the desired length. That is
> how the test is using the interface in practice, anyway.
>
> This relies on the following kernel patch for btrfs verity support:
> <btrfs-verity-patch>
> And the following btrfs-progs patch for btrfs_corrupt_block support:
> <btrfs-corrupt-block-patch>
>
> Signed-off-by: Boris Burkov <[email protected]>
> ---
> common/verity | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/common/verity b/common/verity
> index d2c1ea24..fdd05783 100644
> --- a/common/verity
> +++ b/common/verity
> @@ -3,8 +3,7 @@
> #
> # Functions for setting up and testing fs-verity
>
> -_require_scratch_verity()
> -{
> +_require_scratch_verity() {
No need to change this.
> _require_scratch
> _require_command "$FSVERITY_PROG" fsverity
>
> @@ -315,6 +314,18 @@ _fsv_scratch_corrupt_merkle_tree()
> (( offset += ($(_get_filesize $file) + 65535) & ~65535 ))
> _fsv_scratch_corrupt_bytes $file $offset
> ;;
> + btrfs)
> + ino=$(ls -i $file | awk '{print $1}')
stat -c %i $1
And declare local variables with local.
> + sync
Why a system wide sync is needed here?
> + cat > $tmp.bytes
I think this cat would just hang there.
> + sz=$(_get_filesize $tmp.bytes)
> + read -n 1 byte < $tmp.bytes
> + ascii=$(printf "%d" "'$byte'")
> + _scratch_unmount
> + $BTRFS_CORRUPT_BLOCK_PROG -r 5 -I $ino,37,0 -v $ascii -o
> $offset -b $sz $SCRATCH_DEV
It'd be better to explain this command in comments.
> + sync
Again, is this sync really needed?
Thanks,
Eryu
> + _scratch_mount
> + ;;
> *)
> _fail "_fsv_scratch_corrupt_merkle_tree() unimplemented on
> $FSTYP"
> ;;
> --
> 2.30.2
