256 lines
6.9 KiB
C
256 lines
6.9 KiB
C
#include <linux/module.h>
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#include "ctree.h"
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#include "disk-io.h"
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#include "transaction.h"
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#define MAX_CSUM_ITEMS(r) ((((BTRFS_LEAF_DATA_SIZE(r) - \
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sizeof(struct btrfs_item) * 2) / \
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sizeof(struct btrfs_csum_item)) - 1))
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int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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u64 objectid, u64 pos,
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u64 offset, u64 num_blocks)
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{
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int ret = 0;
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struct btrfs_file_extent_item *item;
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struct btrfs_key file_key;
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struct btrfs_path *path;
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path = btrfs_alloc_path();
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BUG_ON(!path);
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btrfs_init_path(path);
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file_key.objectid = objectid;
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file_key.offset = pos;
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file_key.flags = 0;
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btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
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ret = btrfs_insert_empty_item(trans, root, path, &file_key,
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sizeof(*item));
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BUG_ON(ret);
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item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
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struct btrfs_file_extent_item);
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btrfs_set_file_extent_disk_blocknr(item, offset);
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btrfs_set_file_extent_disk_num_blocks(item, num_blocks);
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btrfs_set_file_extent_offset(item, 0);
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btrfs_set_file_extent_num_blocks(item, num_blocks);
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btrfs_set_file_extent_generation(item, trans->transid);
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btrfs_set_file_extent_type(item, BTRFS_FILE_EXTENT_REG);
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btrfs_mark_buffer_dirty(path->nodes[0]);
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btrfs_release_path(root, path);
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btrfs_free_path(path);
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return 0;
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}
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struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct btrfs_path *path,
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u64 objectid, u64 offset,
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int cow)
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{
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int ret;
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struct btrfs_key file_key;
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struct btrfs_key found_key;
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struct btrfs_csum_item *item;
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struct btrfs_leaf *leaf;
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u64 csum_offset = 0;
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int csums_in_item;
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file_key.objectid = objectid;
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file_key.offset = offset;
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file_key.flags = 0;
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btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
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ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
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if (ret < 0)
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goto fail;
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leaf = btrfs_buffer_leaf(path->nodes[0]);
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if (ret > 0) {
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ret = 1;
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if (path->slots[0] == 0)
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goto fail;
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path->slots[0]--;
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btrfs_disk_key_to_cpu(&found_key,
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&leaf->items[path->slots[0]].key);
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if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
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found_key.objectid != objectid) {
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goto fail;
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}
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csum_offset = (offset - found_key.offset) >>
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root->fs_info->sb->s_blocksize_bits;
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csums_in_item = btrfs_item_size(leaf->items + path->slots[0]);
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csums_in_item /= sizeof(struct btrfs_csum_item);
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if (csum_offset >= csums_in_item) {
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ret = -EFBIG;
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goto fail;
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}
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}
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item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
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item += csum_offset;
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return item;
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fail:
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if (ret > 0)
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ret = -ENOENT;
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return ERR_PTR(ret);
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}
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int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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struct btrfs_path *path, u64 objectid,
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u64 offset, int mod)
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{
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int ret;
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struct btrfs_key file_key;
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int ins_len = mod < 0 ? -1 : 0;
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int cow = mod != 0;
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file_key.objectid = objectid;
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file_key.offset = offset;
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file_key.flags = 0;
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btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
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ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
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return ret;
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}
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int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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u64 objectid, u64 offset,
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char *data, size_t len)
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{
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int ret;
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struct btrfs_key file_key;
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struct btrfs_key found_key;
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struct btrfs_path *path;
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struct btrfs_csum_item *item;
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struct btrfs_leaf *leaf;
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u64 csum_offset;
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path = btrfs_alloc_path();
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BUG_ON(!path);
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file_key.objectid = objectid;
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file_key.offset = offset;
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file_key.flags = 0;
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btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
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item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
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if (!IS_ERR(item))
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goto found;
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ret = PTR_ERR(item);
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if (ret == -EFBIG) {
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u32 item_size;
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/* we found one, but it isn't big enough yet */
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leaf = btrfs_buffer_leaf(path->nodes[0]);
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item_size = btrfs_item_size(leaf->items + path->slots[0]);
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if ((item_size / sizeof(struct btrfs_csum_item)) >=
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MAX_CSUM_ITEMS(root)) {
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/* already at max size, make a new one */
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goto insert;
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}
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} else {
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/* we didn't find a csum item, insert one */
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goto insert;
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}
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/*
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* at this point, we know the tree has an item, but it isn't big
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* enough yet to put our csum in. Grow it
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*/
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btrfs_release_path(root, path);
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ret = btrfs_search_slot(trans, root, &file_key, path,
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sizeof(struct btrfs_csum_item), 1);
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if (ret < 0)
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goto fail;
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if (ret == 0) {
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BUG();
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}
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if (path->slots[0] == 0) {
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goto insert;
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}
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path->slots[0]--;
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leaf = btrfs_buffer_leaf(path->nodes[0]);
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btrfs_disk_key_to_cpu(&found_key, &leaf->items[path->slots[0]].key);
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csum_offset = (offset - found_key.offset) >>
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root->fs_info->sb->s_blocksize_bits;
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if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
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found_key.objectid != objectid ||
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csum_offset >= MAX_CSUM_ITEMS(root)) {
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WARN_ON(1);
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goto insert;
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}
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if (csum_offset >= btrfs_item_size(leaf->items + path->slots[0]) /
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sizeof(struct btrfs_csum_item)) {
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u32 diff = (csum_offset + 1) * sizeof(struct btrfs_csum_item);
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diff = diff - btrfs_item_size(leaf->items + path->slots[0]);
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WARN_ON(diff != sizeof(struct btrfs_csum_item));
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ret = btrfs_extend_item(trans, root, path, diff);
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BUG_ON(ret);
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goto csum;
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}
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insert:
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btrfs_release_path(root, path);
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csum_offset = 0;
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ret = btrfs_insert_empty_item(trans, root, path, &file_key,
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sizeof(struct btrfs_csum_item));
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if (ret != 0) {
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printk("at insert for %Lu %u %Lu ret is %d\n", file_key.objectid, file_key.flags, file_key.offset, ret);
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WARN_ON(1);
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goto fail;
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}
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csum:
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item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
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struct btrfs_csum_item);
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ret = 0;
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item += csum_offset;
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found:
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btrfs_check_bounds(item->csum, BTRFS_CSUM_SIZE, path->nodes[0]->b_data, root->fs_info->sb->s_blocksize);
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ret = btrfs_csum_data(root, data, len, item->csum);
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btrfs_mark_buffer_dirty(path->nodes[0]);
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fail:
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btrfs_release_path(root, path);
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btrfs_free_path(path);
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return ret;
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}
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int btrfs_csum_verify_file_block(struct btrfs_root *root,
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u64 objectid, u64 offset,
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char *data, size_t len)
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{
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int ret;
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struct btrfs_key file_key;
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struct btrfs_path *path;
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struct btrfs_csum_item *item;
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char result[BTRFS_CSUM_SIZE];
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path = btrfs_alloc_path();
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BUG_ON(!path);
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btrfs_init_path(path);
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file_key.objectid = objectid;
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file_key.offset = offset;
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file_key.flags = 0;
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btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
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mutex_lock(&root->fs_info->fs_mutex);
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item = btrfs_lookup_csum(NULL, root, path, objectid, offset, 0);
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if (IS_ERR(item)) {
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ret = PTR_ERR(item);
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/* a csum that isn't present is a preallocated region. */
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if (ret == -ENOENT || ret == -EFBIG)
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ret = 1;
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goto fail;
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}
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ret = btrfs_csum_data(root, data, len, result);
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WARN_ON(ret);
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if (memcmp(result, item->csum, BTRFS_CSUM_SIZE))
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ret = 1;
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fail:
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btrfs_release_path(root, path);
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btrfs_free_path(path);
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mutex_unlock(&root->fs_info->fs_mutex);
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return ret;
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}
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