Re: [PATCH v2 07/13] btrfs: add common checksum type validation

[David Sterba <dsterba@suse.cz>]

On Thu, May 16, 2019 at 10:47:57AM +0200, Johannes Thumshirn wrote:
> Currently btrfs is only supporting CRC32C as checksumming algorithm. As
> this is about to change provide a function to validate the checksum type in
> the superblock against all possible algorithms.
> 
> This makes adding new algorithms easier as there are fewer places to adjust
> when adding new algorithms.
> 
> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
> Reviewed-by: Nikolay Borisov <nborisov@suse.com>
> ---
>  fs/btrfs/disk-io.c | 24 +++++++++++++++++-------
>  1 file changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 663efce22d98..ab13282d91d2 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -356,6 +356,16 @@ static int verify_parent_transid(struct extent_io_tree *io_tree,
>  	return ret;
>  }
>  
> +static bool btrfs_supported_super_csum(struct btrfs_super_block *sb)
> +{
> +	switch (btrfs_super_csum_type(sb)) {
> +	case BTRFS_CSUM_TYPE_CRC32:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
>  /*
>   * Return 0 if the superblock checksum type matches the checksum value of that
>   * algorithm. Pass the raw disk superblock data.
> @@ -368,6 +378,12 @@ static int btrfs_check_super_csum(struct btrfs_fs_info *fs_info,
>  	u16 csum_type = btrfs_super_csum_type(disk_sb);
>  	int ret = 0;
>  
> +	if (!btrfs_supported_super_csum(disk_sb)) {
> +		btrfs_err(fs_info, "unsupported checksum algorithm %u",
> +			  csum_type);
> +		ret = 1;

This can be direct 'return 1;', otherwise ok.

Reviewed-by: David Sterba <dsterba@suse.com>