Btrfs: verify csums on read
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 5230a44..2d2c23c 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -57,3 +57,63 @@
ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
return ret;
}
+
+int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ u64 objectid, u64 offset,
+ char *data, size_t len)
+{
+ int ret;
+ struct btrfs_key file_key;
+ struct btrfs_path path;
+ struct btrfs_csum_item *item;
+
+ btrfs_init_path(&path);
+ file_key.objectid = objectid;
+ file_key.offset = offset;
+ file_key.flags = 0;
+ btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
+ ret = btrfs_insert_empty_item(trans, root, &path, &file_key,
+ BTRFS_CSUM_SIZE);
+ if (ret != 0 && ret != -EEXIST)
+ goto fail;
+ item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
+ struct btrfs_csum_item);
+ ret = 0;
+ ret = btrfs_csum_data(root, data, len, item->csum);
+ mark_buffer_dirty(path.nodes[0]);
+fail:
+ btrfs_release_path(root, &path);
+ return ret;
+}
+
+int btrfs_csum_verify_file_block(struct btrfs_root *root,
+ u64 objectid, u64 offset,
+ char *data, size_t len)
+{
+ int ret;
+ struct btrfs_key file_key;
+ struct btrfs_path path;
+ struct btrfs_csum_item *item;
+ char result[BTRFS_CSUM_SIZE];
+
+ btrfs_init_path(&path);
+ file_key.objectid = objectid;
+ file_key.offset = offset;
+ file_key.flags = 0;
+ btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
+ ret = btrfs_search_slot(NULL, root, &file_key, &path, 0, 0);
+ if (ret)
+ goto fail;
+ item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
+ struct btrfs_csum_item);
+ ret = 0;
+ ret = btrfs_csum_data(root, data, len, result);
+ WARN_ON(ret);
+ if (memcmp(result, item->csum, BTRFS_CSUM_SIZE))
+ ret = 1;
+fail:
+ btrfs_release_path(root, &path);
+ return ret;
+}
+