On Mon, Aug 26, 2019 at 01:48:32PM +0200, Johannes Thumshirn wrote:
> Create a structure to encode the type and length for the known on-disk
> checksums.
>
> This makes it easier to add new checksums later.
>
> Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
>
> ---
> Changes to v2:
> - Really remove initializer macro *doh*
>
> Changes to v1:
> - Remove initializer macro (David)
> ---
> fs/btrfs/ctree.h | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index b161224b5a0b..139354d02dfa 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -82,9 +82,12 @@ struct btrfs_ref;
> */
> #define BTRFS_LINK_MAX 65535U
>
> -/* four bytes for CRC32 */
> -static const int btrfs_csum_sizes[] = { 4 };
> -static const char *btrfs_csum_names[] = { "crc32c" };
> +static const struct btrfs_csums {
> + u16 size;
> + const char *name;
> +} btrfs_csums[] = {
> + [BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" },
> +};
In one of the previous iterations, I pointed out that the definition is
in a header, thus each file that includes "ctree.h" (many of them)
has a private copy of the table. With just crc32c it's just a few bytes
that gets lost in the noise but now the table is going to be larger the
impact will be noticeable.
