函数fsp_seg_inode_page_find_free

/**********************************************************************//**
Looks for an unused segment inode on a segment inode page.
@return    segment inode index, or ULINT_UNDEFINED if not found */
static
ulint
fsp_seg_inode_page_find_free(
/*=========================*/
    page_t*    page,    /*!< in: segment inode page */
    ulint    i,    /*!< in: search forward starting from this index */
    ulint    zip_size,/*!< in: compressed page size, or 0 */
    mtr_t*    mtr)    /*!< in: mini-transaction handle */
{
    fseg_inode_t*    inode;

    for (; i < FSP_SEG_INODES_PER_PAGE(zip_size); i++) { //宏详见

        inode = fsp_seg_inode_page_get_nth_inode( //详见
            page, i, zip_size, mtr);

            /* This is unused */

            return(i);
        }

        ut_ad(mach_read_from_4(inode + FSEG_MAGIC_N)
              == FSEG_MAGIC_N_VALUE);
    }

    return(ULINT_UNDEFINED);
}