P9_OWRITE
if (mode & (P9_OWRITE|P9_ORDWR))
if ((v9ses->cache & CACHE_WRITEBACK) && (omode & P9_OWRITE)) {
int writeback_omode = (omode & ~(P9_OWRITE | o_append)) | P9_ORDWR;
ret = P9_OWRITE;
if ((v9ses->cache & CACHE_WRITEBACK) && (p9_omode & P9_OWRITE)) {
p9_omode = (p9_omode & ~(P9_OWRITE | P9_OAPPEND)) | P9_ORDWR;
if ((v9ses->cache & CACHE_WRITEBACK) && (p9_omode & P9_OWRITE)) {
p9_omode = (p9_omode & ~(P9_OWRITE | P9_DOTL_APPEND)) | P9_ORDWR;