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Commit c40a3d38 authored by Chandan Rajendra's avatar Chandan Rajendra Committed by David Sterba
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Btrfs: Compute and look up csums based on sectorsized blocks 



Checksums are applicable to sectorsize units. The current code uses
bio->bv_len units to compute and look up checksums. This works on machines
where sectorsize == PAGE_SIZE. This patch makes the checksum computation and
look up code to work with sectorsize units.

Reviewed-by: default avatarLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: default avatarChandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 2e78c927

fs/btrfs/file-item.c

+59 −33
Original line number Diff line number Diff line
@@ -172,6 +172,7 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, 
	u64 item_start_offset = 0;

	u64 item_last_offset = 0;

	u64 disk_bytenr;

	u64 page_bytes_left;

	u32 diff;

	int nblocks;

	int bio_index = 0;
@@ -220,6 +221,8 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, 
	disk_bytenr = (u64)bio->bi_iter.bi_sector << 9;

	if (dio)

		offset = logical_offset;



	page_bytes_left = bvec->bv_len;

	while (bio_index < bio->bi_vcnt) {

		if (!dio)

			offset = page_offset(bvec->bv_page) + bvec->bv_offset;
@@ -243,7 +246,7 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, 
				if (BTRFS_I(inode)->root->root_key.objectid ==

				    BTRFS_DATA_RELOC_TREE_OBJECTID) {

					set_extent_bits(io_tree, offset,

						offset + bvec->bv_len - 1,

						offset + root->sectorsize - 1,

						EXTENT_NODATASUM, GFP_NOFS);

				} else {

					btrfs_info(BTRFS_I(inode)->root->fs_info,
@@ -281,11 +284,17 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root, 
found:

		csum += count * csum_size;

		nblocks -= count;

		bio_index += count;



		while (count--) {

			disk_bytenr += bvec->bv_len;

			offset += bvec->bv_len;

			disk_bytenr += root->sectorsize;

			offset += root->sectorsize;

			page_bytes_left -= root->sectorsize;

			if (!page_bytes_left) {

				bio_index++;

				bvec++;

				page_bytes_left = bvec->bv_len;

			}



		}

	}

	btrfs_free_path(path);
@@ -432,6 +441,8 @@ int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode, 
	struct bio_vec *bvec = bio->bi_io_vec;

	int bio_index = 0;

	int index;

	int nr_sectors;

	int i;

	unsigned long total_bytes = 0;

	unsigned long this_sum_bytes = 0;

	u64 offset;
@@ -459,9 +470,18 @@ int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode, 
		if (!contig)

			offset = page_offset(bvec->bv_page) + bvec->bv_offset;



		data = kmap_atomic(bvec->bv_page);



		nr_sectors = BTRFS_BYTES_TO_BLKS(root->fs_info,

						bvec->bv_len + root->sectorsize

						- 1);



		for (i = 0; i < nr_sectors; i++) {

			if (offset >= ordered->file_offset + ordered->len ||

				offset < ordered->file_offset) {

				unsigned long bytes_left;



				kunmap_atomic(data);

				sums->len = this_sum_bytes;

				this_sum_bytes = 0;

				btrfs_add_ordered_sum(inode, ordered, sums);
@@ -473,27 +493,33 @@ int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode, 
					GFP_NOFS);

				BUG_ON(!sums); /* -ENOMEM */

				sums->len = bytes_left;

			ordered = btrfs_lookup_ordered_extent(inode, offset);

			BUG_ON(!ordered); /* Logic error */

			sums->bytenr = ((u64)bio->bi_iter.bi_sector << 9) +

				       total_bytes;

				ordered = btrfs_lookup_ordered_extent(inode,

								offset);

				ASSERT(ordered); /* Logic error */

				sums->bytenr = ((u64)bio->bi_iter.bi_sector << 9)

					+ total_bytes;

				index = 0;

		}



				data = kmap_atomic(bvec->bv_page);

			}



			sums->sums[index] = ~(u32)0;

		sums->sums[index] = btrfs_csum_data(data + bvec->bv_offset,

			sums->sums[index]

				= btrfs_csum_data(data + bvec->bv_offset

						+ (i * root->sectorsize),

						sums->sums[index],

						    bvec->bv_len);

		kunmap_atomic(data);

						root->sectorsize);

			btrfs_csum_final(sums->sums[index],

					(char *)(sums->sums + index));

			index++;

			offset += root->sectorsize;

			this_sum_bytes += root->sectorsize;

			total_bytes += root->sectorsize;

		}



		kunmap_atomic(data);



		bio_index++;

		index++;

		total_bytes += bvec->bv_len;

		this_sum_bytes += bvec->bv_len;

		offset += bvec->bv_len;

		bvec++;

	}

	this_sum_bytes = 0;