Commit a3ddbaeb authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: scrub: introduce a helper to verify one metadata block 



The new helper, scrub_verify_one_metadata(), is almost the same as
scrub_checksum_tree_block().

The difference is in how we grab the pages from other structures.

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 b9795475

fs/btrfs/scrub.c

+106 −0
Original line number Diff line number Diff line
@@ -2159,6 +2159,112 @@ static int scrub_checksum_data(struct scrub_block *sblock) 
	return sblock->checksum_error;

}



static struct page *scrub_stripe_get_page(struct scrub_stripe *stripe, int sector_nr)

{

	struct btrfs_fs_info *fs_info = stripe->bg->fs_info;

	int page_index = (sector_nr << fs_info->sectorsize_bits) >> PAGE_SHIFT;



	return stripe->pages[page_index];

}



static unsigned int scrub_stripe_get_page_offset(struct scrub_stripe *stripe,

						 int sector_nr)

{

	struct btrfs_fs_info *fs_info = stripe->bg->fs_info;



	return offset_in_page(sector_nr << fs_info->sectorsize_bits);

}



void scrub_verify_one_metadata(struct scrub_stripe *stripe, int sector_nr)

{

	struct btrfs_fs_info *fs_info = stripe->bg->fs_info;

	const u32 sectors_per_tree = fs_info->nodesize >> fs_info->sectorsize_bits;

	const u64 logical = stripe->logical + (sector_nr << fs_info->sectorsize_bits);

	const struct page *first_page = scrub_stripe_get_page(stripe, sector_nr);

	const unsigned int first_off = scrub_stripe_get_page_offset(stripe, sector_nr);

	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);

	u8 on_disk_csum[BTRFS_CSUM_SIZE];

	u8 calculated_csum[BTRFS_CSUM_SIZE];

	struct btrfs_header *header;



	/*

	 * Here we don't have a good way to attach the pages (and subpages)

	 * to a dummy extent buffer, thus we have to directly grab the members

	 * from pages.

	 */

	header = (struct btrfs_header *)(page_address(first_page) + first_off);

	memcpy(on_disk_csum, header->csum, fs_info->csum_size);



	if (logical != btrfs_stack_header_bytenr(header)) {

		bitmap_set(&stripe->csum_error_bitmap, sector_nr, sectors_per_tree);

		bitmap_set(&stripe->error_bitmap, sector_nr, sectors_per_tree);

		btrfs_warn_rl(fs_info,

		"tree block %llu mirror %u has bad bytenr, has %llu want %llu",

			      logical, stripe->mirror_num,

			      btrfs_stack_header_bytenr(header), logical);

		return;

	}

	if (memcmp(header->fsid, fs_info->fs_devices->fsid, BTRFS_FSID_SIZE) != 0) {

		bitmap_set(&stripe->meta_error_bitmap, sector_nr, sectors_per_tree);

		bitmap_set(&stripe->error_bitmap, sector_nr, sectors_per_tree);

		btrfs_warn_rl(fs_info,

		"tree block %llu mirror %u has bad fsid, has %pU want %pU",

			      logical, stripe->mirror_num,

			      header->fsid, fs_info->fs_devices->fsid);

		return;

	}

	if (memcmp(header->chunk_tree_uuid, fs_info->chunk_tree_uuid,

		   BTRFS_UUID_SIZE) != 0) {

		bitmap_set(&stripe->meta_error_bitmap, sector_nr, sectors_per_tree);

		bitmap_set(&stripe->error_bitmap, sector_nr, sectors_per_tree);

		btrfs_warn_rl(fs_info,

		"tree block %llu mirror %u has bad chunk tree uuid, has %pU want %pU",

			      logical, stripe->mirror_num,

			      header->chunk_tree_uuid, fs_info->chunk_tree_uuid);

		return;

	}



	/* Now check tree block csum. */

	shash->tfm = fs_info->csum_shash;

	crypto_shash_init(shash);

	crypto_shash_update(shash, page_address(first_page) + first_off +

			    BTRFS_CSUM_SIZE, fs_info->sectorsize - BTRFS_CSUM_SIZE);



	for (int i = sector_nr + 1; i < sector_nr + sectors_per_tree; i++) {

		struct page *page = scrub_stripe_get_page(stripe, i);

		unsigned int page_off = scrub_stripe_get_page_offset(stripe, i);



		crypto_shash_update(shash, page_address(page) + page_off,

				    fs_info->sectorsize);

	}



	crypto_shash_final(shash, calculated_csum);

	if (memcmp(calculated_csum, on_disk_csum, fs_info->csum_size) != 0) {

		bitmap_set(&stripe->meta_error_bitmap, sector_nr, sectors_per_tree);

		bitmap_set(&stripe->error_bitmap, sector_nr, sectors_per_tree);

		btrfs_warn_rl(fs_info,

		"tree block %llu mirror %u has bad csum, has " CSUM_FMT " want " CSUM_FMT,

			      logical, stripe->mirror_num,

			      CSUM_FMT_VALUE(fs_info->csum_size, on_disk_csum),

			      CSUM_FMT_VALUE(fs_info->csum_size, calculated_csum));

		return;

	}

	if (stripe->sectors[sector_nr].generation !=

	    btrfs_stack_header_generation(header)) {

		bitmap_set(&stripe->meta_error_bitmap, sector_nr, sectors_per_tree);

		bitmap_set(&stripe->error_bitmap, sector_nr, sectors_per_tree);

		btrfs_warn_rl(fs_info,

		"tree block %llu mirror %u has bad generation, has %llu want %llu",

			      logical, stripe->mirror_num,

			      btrfs_stack_header_generation(header),

			      stripe->sectors[sector_nr].generation);

		return;

	}

	bitmap_clear(&stripe->error_bitmap, sector_nr, sectors_per_tree);

	bitmap_clear(&stripe->csum_error_bitmap, sector_nr, sectors_per_tree);

	bitmap_clear(&stripe->meta_error_bitmap, sector_nr, sectors_per_tree);

}



static int scrub_checksum_tree_block(struct scrub_block *sblock)

{

	struct scrub_ctx *sctx = sblock->sctx;

fs/btrfs/scrub.h

+1 −0
Original line number Diff line number Diff line
@@ -24,5 +24,6 @@ int scrub_find_fill_first_stripe(struct btrfs_block_group *bg, 
				 struct btrfs_device *dev, u64 physical,

				 int mirror_num, u64 logical_start,

				 u32 logical_len, struct scrub_stripe *stripe);

void scrub_verify_one_metadata(struct scrub_stripe *stripe, int sector_nr);



#endif