Ceph » CephFS

Error reason:
When do Client::_open, MDS didn't return Fs which causes error on this code
ASSERT_EQ(ceph_ll_delegation(cmount2, fh, CEPH_DELEGATION_RD, dummy_deleg_cb, &recalled), 0);
logs:
2020-03-03 02:59:50.165572 7f74a53e45c0 10 set_deleg: inode 0x1000000048a.head(faked_ino=0 ref=6 ll_ref=1 cap_refs={4=0,2048=0,4096=0,8192=0} open={1=1,2=0} mode=100666 size=32/0 nlink=1 mtime=2020-03-03 02:59:50.163809 caps=pAsLsXsFrw(0=pAsLsXsFrw) flushing_caps=Fw objectset[0x1000000048a ts 0/0 objects 0 dirty_or_tx 0] parents=0x7f7258012fa0 0x7f7258011530)
2020-03-03 02:59:50.165582 7f74a53e45c0 10 set_deleg: cap mismatch, have=pAsLsXsFrw need=pAsLsXsFscr

Check code Client::_open, This function didn't require CEPH_CAP_FILE_SHARED. There is possibility MDS didn't return Fs in time, but the Client::open continues without Fs.
if (deleg_timeout && result == 0) {
int need = 0, have;

if (cmode & CEPH_FILE_MODE_WR)
        need |= CEPH_CAP_FILE_WR;
      if (cmode & CEPH_FILE_MODE_RD)
        need |= CEPH_CAP_FILE_RD;  <<<

result = get_caps(in, need, want, &have, -1);