+
+int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
+ struct bio *bio, u32 *dst)
+{
+ u32 sum;
+ struct bio_vec *bvec = bio->bi_io_vec;
+ int bio_index = 0;
+ u64 offset;
+ u64 item_start_offset = 0;
+ u64 item_last_offset = 0;
+ u64 disk_bytenr;
+ u32 diff;
+ u16 csum_size =
+ btrfs_super_csum_size(&root->fs_info->super_copy);
+ int ret;
+ struct btrfs_path *path;
+ struct btrfs_csum_item *item = NULL;
+ struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+
+ path = btrfs_alloc_path();
+ if (bio->bi_size > PAGE_CACHE_SIZE * 8)
+ path->reada = 2;
+
+ WARN_ON(bio->bi_vcnt <= 0);
+
+ disk_bytenr = (u64)bio->bi_sector << 9;
+ while (bio_index < bio->bi_vcnt) {
+ offset = page_offset(bvec->bv_page) + bvec->bv_offset;
+ ret = btrfs_find_ordered_sum(inode, offset, disk_bytenr, &sum);
+ if (ret == 0)
+ goto found;
+
+ if (!item || disk_bytenr < item_start_offset ||
+ disk_bytenr >= item_last_offset) {
+ struct btrfs_key found_key;
+ u32 item_size;
+
+ if (item)
+ btrfs_release_path(root, path);
+ item = btrfs_lookup_csum(NULL, root->fs_info->csum_root,
+ path, disk_bytenr, 0);
+ if (IS_ERR(item)) {
+ ret = PTR_ERR(item);
+ if (ret == -ENOENT || ret == -EFBIG)
+ ret = 0;
+ sum = 0;
+ if (BTRFS_I(inode)->root->root_key.objectid ==
+ BTRFS_DATA_RELOC_TREE_OBJECTID) {
+ set_extent_bits(io_tree, offset,
+ offset + bvec->bv_len - 1,
+ EXTENT_NODATASUM, GFP_NOFS);
+ } else {
+ printk(KERN_INFO "btrfs no csum found "
+ "for inode %lu start %llu\n",
+ inode->i_ino,
+ (unsigned long long)offset);
+ }
+ item = NULL;
+ btrfs_release_path(root, path);
+ goto found;
+ }
+ btrfs_item_key_to_cpu(path->nodes[0], &found_key,
+ path->slots[0]);
+
+ item_start_offset = found_key.offset;
+ item_size = btrfs_item_size_nr(path->nodes[0],
+ path->slots[0]);
+ item_last_offset = item_start_offset +
+ (item_size / csum_size) *
+ root->sectorsize;
+ item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_csum_item);
+ }
+ /*
+ * this byte range must be able to fit inside
+ * a single leaf so it will also fit inside a u32
+ */
+ diff = disk_bytenr - item_start_offset;
+ diff = diff / root->sectorsize;
+ diff = diff * csum_size;
+
+ read_extent_buffer(path->nodes[0], &sum,
+ ((unsigned long)item) + diff,
+ csum_size);
+found:
+ if (dst)
+ *dst++ = sum;
+ else
+ set_state_private(io_tree, offset, sum);
+ disk_bytenr += bvec->bv_len;
+ bio_index++;
+ bvec++;
+ }
+ btrfs_free_path(path);
+ return 0;
+}
+
+int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
+ struct list_head *list)
+{
+ struct btrfs_key key;
+ struct btrfs_path *path;
+ struct extent_buffer *leaf;
+ struct btrfs_ordered_sum *sums;
+ struct btrfs_sector_sum *sector_sum;
+ struct btrfs_csum_item *item;
+ unsigned long offset;
+ int ret;
+ size_t size;
+ u64 csum_end;
+ u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy);
+
+ path = btrfs_alloc_path();
+ BUG_ON(!path);
+
+ key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
+ key.offset = start;
+ key.type = BTRFS_EXTENT_CSUM_KEY;
+
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ goto fail;
+ if (ret > 0 && path->slots[0] > 0) {
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
+ if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID &&
+ key.type == BTRFS_EXTENT_CSUM_KEY) {
+ offset = (start - key.offset) >>
+ root->fs_info->sb->s_blocksize_bits;
+ if (offset * csum_size <
+ btrfs_item_size_nr(leaf, path->slots[0] - 1))
+ path->slots[0]--;
+ }
+ }
+
+ while (start <= end) {
+ leaf = path->nodes[0];
+ if (path->slots[0] >= btrfs_header_nritems(leaf)) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0)
+ goto fail;
+ if (ret > 0)
+ break;
+ leaf = path->nodes[0];
+ }
+
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
+ key.type != BTRFS_EXTENT_CSUM_KEY)
+ break;
+
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ if (key.offset > end)
+ break;
+
+ if (key.offset > start)
+ start = key.offset;
+
+ size = btrfs_item_size_nr(leaf, path->slots[0]);
+ csum_end = key.offset + (size / csum_size) * root->sectorsize;
+ if (csum_end <= start) {
+ path->slots[0]++;
+ continue;
+ }
+
+ csum_end = min(csum_end, end + 1);
+ item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_csum_item);
+ while (start < csum_end) {
+ size = min_t(size_t, csum_end - start,
+ MAX_ORDERED_SUM_BYTES(root));
+ sums = kzalloc(btrfs_ordered_sum_size(root, size),
+ GFP_NOFS);
+ BUG_ON(!sums);
+
+ sector_sum = sums->sums;
+ sums->bytenr = start;
+ sums->len = size;
+
+ offset = (start - key.offset) >>
+ root->fs_info->sb->s_blocksize_bits;
+ offset *= csum_size;
+
+ while (size > 0) {
+ read_extent_buffer(path->nodes[0],
+ §or_sum->sum,
+ ((unsigned long)item) +
+ offset, csum_size);
+ sector_sum->bytenr = start;
+
+ size -= root->sectorsize;
+ start += root->sectorsize;
+ offset += csum_size;
+ sector_sum++;
+ }
+ list_add_tail(&sums->list, list);
+ }
+ path->slots[0]++;
+ }
+ ret = 0;
+fail:
+ btrfs_free_path(path);
+ return ret;
+}
+
+int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
+ struct bio *bio, u64 file_start, int contig)