/*
 * __rollback_row_add_update --
 *     Add the provided update to the head of the update list.
 */
static inline int
__rollback_row_add_update(WT_SESSION_IMPL *session, WT_PAGE *page, WT_ROW *rip, WT_UPDATE *upd)
{
    WT_DECL_RET;
    WT_PAGE_MODIFY *mod;
    WT_UPDATE *old_upd, **upd_entry;
    size_t upd_size;

    /* If we don't yet have a modify structure, we'll need one. */
    WT_RET(__wt_page_modify_init(session, page));
    mod = page->modify;

    /* Allocate an update array as necessary. */
    WT_PAGE_ALLOC_AND_SWAP(session, page, mod->mod_row_update, upd_entry, page->entries);

    /* Set the WT_UPDATE array reference. */
    upd_entry = &mod->mod_row_update[WT_ROW_SLOT(page, rip)];
    upd_size = __wt_update_list_memsize(upd);

    /*
     * If it's a full update list, we're trying to instantiate the row. Otherwise, it's just a
     * single update that we'd like to append to the update list.
     *
     * Set the "old" entry to the second update in the list so that the serialization function
     * succeeds in swapping the first update into place.
     */
    if (upd->next != NULL)
        *upd_entry = upd->next;
    old_upd = *upd_entry;

    /*
     * Point the new WT_UPDATE item to the next element in the list. The serialization function acts
     * as our memory barrier to flush this write.
     */
    upd->next = old_upd;

    /*
     * Serialize the update. Rollback to stable doesn't need to check the visibility of the on page
     * value to detect conflict.
     */
    WT_ERR(__wt_update_serial(session, NULL, page, upd_entry, &upd, upd_size, true));

err:
    return (ret);
}