From 51bce6c9b97729835bb55ceb37febd5c8fa962dd Mon Sep 17 00:00:00 2001 From: Johannes Thumshirn Date: Mon, 3 Jun 2019 16:58:55 +0200 Subject: [PATCH] btrfs: Simplify btrfs_check_super_csum() and get rid of size assumptions Now that we have already checked for a valid checksum type before calling btrfs_check_super_csum(), it can be simplified even further. While at it get rid of the implicit size assumption of the resulting checksum as well. This is a preparation for changing all checksum functionality to use the crypto layer later. Reviewed-by: Nikolay Borisov Signed-off-by: Johannes Thumshirn Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/disk-io.c | 42 ++++++++++++++++-------------------------- 1 file changed, 16 insertions(+), 26 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index ce6dc95effae..c9ce0b002008 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -371,30 +371,20 @@ 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); + u32 crc = ~(u32)0; + char result[BTRFS_CSUM_SIZE]; - if (!btrfs_supported_super_csum(csum_type)) { - btrfs_err(fs_info, "unsupported checksum algorithm %u", - csum_type); + /* + * The super_block structure does not span the whole + * BTRFS_SUPER_INFO_SIZE range, we expect that the unused space is + * filled with zeros and is included in the checksum. + */ + crc = btrfs_csum_data(raw_disk_sb + BTRFS_CSUM_SIZE, + crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE); + btrfs_csum_final(crc, result); + + if (memcmp(disk_sb->csum, result, btrfs_super_csum_size(disk_sb))) return 1; - } - - if (csum_type == BTRFS_CSUM_TYPE_CRC32) { - u32 crc = ~(u32)0; - char result[sizeof(crc)]; - - /* - * The super_block structure does not span the whole - * BTRFS_SUPER_INFO_SIZE range, we expect that the unused space - * is filled with zeros and is included in the checksum. - */ - crc = btrfs_csum_data(raw_disk_sb + BTRFS_CSUM_SIZE, - crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE); - btrfs_csum_final(crc, result); - - if (memcmp(raw_disk_sb, result, sizeof(result))) - return 1; - } return 0; } @@ -2611,6 +2601,7 @@ int open_ctree(struct super_block *sb, u32 stripesize; u64 generation; u64 features; + u16 csum_type; struct btrfs_key location; struct buffer_head *bh; struct btrfs_super_block *disk_super; @@ -2820,11 +2811,10 @@ int open_ctree(struct super_block *sb, * Verify the type first, if that or the the checksum value are * corrupted, we'll find out */ - if (!btrfs_supported_super_csum(btrfs_super_csum_type( - (struct btrfs_super_block *) bh->b_data))) { + csum_type = btrfs_super_csum_type((struct btrfs_super_block *)bh->b_data); + if (!btrfs_supported_super_csum(csum_type)) { btrfs_err(fs_info, "unsupported checksum algorithm: %u", - btrfs_super_csum_type((struct btrfs_super_block *) - bh->b_data)); + csum_type); err = -EINVAL; brelse(bh); goto fail_alloc;