Commit 53f3251d authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: scrub: support subpage tree block scrub 



To support subpage tree block scrub, scrub_checksum_tree_block() only
needs to learn 2 new tricks:

- Follow sector size
  Now scrub_page only represents one sector, we need to follow it
  properly.

- Run checksum on all sectors
  Since scrub_page only represents one sector, we need to run checksum
  on all sectors, not only (nodesize >> PAGE_SIZE).

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent d0a7a9c0

fs/btrfs/scrub.c

+14 −4
Original line number Diff line number Diff line
@@ -1811,12 +1811,22 @@ 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;

	/*

	 * This is done in sectorsize steps even for metadata as there's a

	 * constraint for nodesize to be aligned to sectorsize. This will need

	 * to change so we don't misuse data and metadata units like that.

	 */

	const u32 sectorsize = sctx->fs_info->sectorsize;

	const int num_sectors = fs_info->nodesize >> fs_info->sectorsize_bits;

	int i;

	struct scrub_page *spage;

	char *kaddr;



	BUG_ON(sblock->page_count < 1);



	/* Each member in pagev is just one block, not a full page */

	ASSERT(sblock->page_count == num_sectors);



	spage = sblock->pagev[0];

	kaddr = page_address(spage->page);

	h = (struct btrfs_header *)kaddr;
@@ -1845,11 +1855,11 @@ static int scrub_checksum_tree_block(struct scrub_block *sblock) 
	shash->tfm = fs_info->csum_shash;

	crypto_shash_init(shash);

	crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE,

			    PAGE_SIZE - BTRFS_CSUM_SIZE);

			    sectorsize - BTRFS_CSUM_SIZE);



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

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

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

		crypto_shash_update(shash, kaddr, PAGE_SIZE);

		crypto_shash_update(shash, kaddr, sectorsize);

	}



	crypto_shash_final(shash, calculated_csum);