memzero_extent_buffer
memzero_extent_buffer(eb, 0, eb->len);
memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));
memzero_extent_buffer(eb, end, eb->len - end);
memzero_extent_buffer(eb, start, end - start);
void memzero_extent_buffer(const struct extent_buffer *eb, unsigned long start,
memzero_extent_buffer(leaf, item_offset + offset,
memzero_extent_buffer(leaf, (unsigned long)inode_item,
memzero_extent_buffer(leaf, (unsigned long)header, sizeof(*header));
memzero_extent_buffer(path->nodes[0], (unsigned long)inode_item,
memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));