Commit 521e1022 authored by David Sterba's avatar David Sterba
Browse files

btrfs: scrub: simplify tree block checksum calculation 



Use a simpler iteration over tree block pages, same what csum_tree_block
does: first page always exists, loop over the rest.

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent d41ebef2

fs/btrfs/scrub.c

+9 −24
Original line number Diff line number Diff line
@@ -1814,15 +1814,10 @@ static int scrub_checksum_tree_block(struct scrub_block *sblock) 
	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);

	u8 calculated_csum[BTRFS_CSUM_SIZE];

	u8 on_disk_csum[BTRFS_CSUM_SIZE];

	const int num_pages = sctx->fs_info->nodesize >> PAGE_SHIFT;

	int i;

	struct page *page;

	char *kaddr;

	u64 mapped_size;

	void *p;

	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;
@@ -1850,24 +1845,14 @@ static int scrub_checksum_tree_block(struct scrub_block *sblock) 
		   BTRFS_UUID_SIZE))

		sblock->header_error = 1;



	len = sctx->fs_info->nodesize - 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);

	shash->tfm = fs_info->csum_shash;

	crypto_shash_init(shash);

	crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE,

			    PAGE_SIZE - BTRFS_CSUM_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;

	for (i = 1; i < num_pages; i++) {

		kaddr = page_address(sblock->pagev[i]->page);

		crypto_shash_update(shash, kaddr, PAGE_SIZE);

	}



	crypto_shash_final(shash, calculated_csum);