sd卡大概存了几百g之后，能生成文件，但是存不进数据，程序卡在f_write()中的create_chain()中的for循环里

for (;;) { ncl++; / Next cluster / if (ncl >= fs->n_fatent) { / Check wrap-around / ncl = 2; if (ncl > scl) return 0; / No free cluster found? / } cs = get_fat(obj, ncl); / Get the cluster status / if (cs == 0) break; / Found a free cluster? / if (cs == 1 || cs == 0xFFFFFFFF) return cs; / Test for error / if (ncl == scl) return 0; / No free cluster found? / }