Ceph

LIBRADOS modify Pipe::connect() to return the error code

Steps to Reproduce:

1. create a qemu instance
2. reduce the fd limits with prlimit command
3. try to attach rbd image to this qemu instance
4. ceph client side log file will have logs as given below :

7f0b769e7700 1 - 192.168.128.30:0/2021513 >> 192.168.128.35:6800/24374 pipe(0x7f0bcabc0000 sd=-1 :0 s=1 pgs=0 cs=0 l=1 c=0x7f0bc55e1ce0).connect couldn't created socket (24) Too many open files

5. But qemu logs will not log anything regarding this error as rados_connect call from qemu wont have proper return code from librados Pipe::connect().

Ceph source file : src/msg/simple/Pipe.cc

 870 int Pipe::connect()
 871 {
 872   bool got_bad_auth = false;
 873 
 874   ldout(msgr->cct,10) << "connect " << connect_seq << dendl;
 875   assert(pipe_lock.is_locked());

....................
.....................

 901   // create socket?
 902   sd = ::socket(peer_addr.get_family(), SOCK_STREAM, 0);
 903   if (sd < 0) {
 904     lderr(msgr->cct) << "connect couldn't created socket " << cpp_strerror(errno) << dendl;
 905     goto fail;
 906   }

........................
.........................

1215  fail:
1216   if (conf->ms_inject_internal_delays) {
1217     ldout(msgr->cct, 10) << " sleep for " << msgr->cct->_conf->ms_inject_internal_delays << dendl;
1218     utime_t t;
1219     t.set_from_double(msgr->cct->_conf->ms_inject_internal_delays);
1220     t.sleep();
1221   }
1222 
1223   pipe_lock.Lock();
1224  fail_locked:
1225   if (state == STATE_CONNECTING)
1226     fault();
1227   else
1228     ldout(msgr->cct,3) << "connect fault, but state = " << get_state_name()
1229                        << " != connecting, stopping" << dendl;
1230 
1231  stop_locked:
1232   delete authorizer;
1233   return -1;
1234 }

- "connect couldn't created socket (24) Too many open files"
- This error is coming from this function socket() from Pipe::connect() function.
- Here we are going to fail label but if we check fail we returning "-1" but we need proper error handling in this function.