On Wed, May 22, 2019 at 10:19:04AM +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@xxxxxxx>
> Reviewed-by: Nikolay Borisov <nborisov@xxxxxxxx>
> Reviewed-by: David Sterba <dsterba@xxxxxxxx>
>
> ---
> Changes to v2:
> - Only pass csum_type into btrfs_supported_csum() (David)
> - Directly return in btrfs_check_super_csum() (David)
> ---
> fs/btrfs/disk-io.c | 29 +++++++++++++++++++----------
> 1 file changed, 19 insertions(+), 10 deletions(-)
>
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 663efce22d98..594583273782 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(u16 csum_type)
> +{
> + switch (csum_type) {
> + 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.
> @@ -366,7 +376,12 @@ static int btrfs_check_super_csum(struct btrfs_fs_info *fs_info,
> struct btrfs_super_block *disk_sb =
> (struct btrfs_super_block *)raw_disk_sb;
> u16 csum_type = btrfs_super_csum_type(disk_sb);
> - int ret = 0;
> +
> + if (!btrfs_supported_super_csum(csum_type)) {
> + btrfs_err(fs_info, "unsupported checksum algorithm %u",
> + csum_type);
> + return 1;
> + }
>
> if (csum_type == BTRFS_CSUM_TYPE_CRC32) {
> u32 crc = ~(u32)0;
> @@ -382,16 +397,10 @@ static int btrfs_check_super_csum(struct btrfs_fs_info *fs_info,
> btrfs_csum_final(crc, result);
>
> if (memcmp(raw_disk_sb, result, sizeof(result)))
> - ret = 1;
> + return 1;
> }
>
> - if (csum_type >= ARRAY_SIZE(btrfs_csum_sizes)) {
> - btrfs_err(fs_info, "unsupported checksum algorithm %u",
> - csum_type);
> - ret = 1;
> - }
> -
> - return ret;
> + return 0;
> }
>
> int btrfs_verify_level_key(struct extent_buffer *eb, int level,
> @@ -2577,7 +2586,7 @@ static int btrfs_validate_write_super(struct btrfs_fs_info *fs_info,
> ret = validate_super(fs_info, sb, -1);
> if (ret < 0)
> goto out;
> - if (btrfs_super_csum_type(sb) != BTRFS_CSUM_TYPE_CRC32) {
> + if (!btrfs_supported_super_csum(sb)) {
Type mismatch, this needs the type now, not the superblock. And
open_ctree also needs an update.
> ret = -EUCLEAN;
> btrfs_err(fs_info, "invalid csum type, has %u want %u",
> btrfs_super_csum_type(sb), BTRFS_CSUM_TYPE_CRC32);
> --
> 2.16.4
