Commit 83cf6d5e authored by David Sterba's avatar David Sterba
Browse files

btrfs: scrub: simplify superblock checksum calculation 



BTRFS_SUPER_INFO_SIZE is 4096, and fits to a page on all supported
architectures, so we can calculate the checksum in one go.

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent b0485252

fs/btrfs/scrub.c

+4 −27
Original line number Diff line number Diff line
@@ -1907,15 +1907,8 @@ static int scrub_checksum_super(struct scrub_block *sblock) 
	u8 on_disk_csum[BTRFS_CSUM_SIZE];

	struct page *page;

	char *kaddr;

	u64 mapped_size;

	void *p;

	int fail_gen = 0;

	int fail_cor = 0;

	u64 len;

	int index;



	shash->tfm = fs_info->csum_shash;

	crypto_shash_init(shash);



	BUG_ON(sblock->page_count < 1);

	page = sblock->pagev[0]->page;
@@ -1932,27 +1925,11 @@ static int scrub_checksum_super(struct scrub_block *sblock) 
	if (!scrub_check_fsid(s->fsid, sblock->pagev[0]))

		++fail_cor;



	len = BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE;

	mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;

	p = kaddr + BTRFS_CSUM_SIZE;

	index = 0;

	for (;;) {

		u64 l = min_t(u64, len, mapped_size);



		crypto_shash_update(shash, p, l);

		len -= l;

		if (len == 0)

			break;

		index++;

		BUG_ON(index >= sblock->page_count);

		BUG_ON(!sblock->pagev[index]->page);

		page = sblock->pagev[index]->page;

		kaddr = page_address(page);

		mapped_size = PAGE_SIZE;

		p = kaddr;

	}

	shash->tfm = fs_info->csum_shash;

	crypto_shash_init(shash);

	crypto_shash_digest(shash, kaddr + BTRFS_CSUM_SIZE,

			BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE, calculated_csum);



	crypto_shash_final(shash, calculated_csum);

	if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))

		++fail_cor;