Method read_random_ex

src/client/SyntheticClient.cc:2536–2632

}

int SyntheticClient::read_random_ex(string& fn, int size, int rdsize)   // size is in MB, wrsize in bytes
{
  uint64_t chunks = (uint64_t)size * (uint64_t)(1024*1024) / (uint64_t)rdsize;
  UserPerm perms = client->pick_my_perms();
  int fd = client->open(fn.c_str(), O_RDWR, perms);
  dout(5) << "reading from " << fn << " fd " << fd << dendl;
  
  if (fd < 0) return fd;
  int offset = 0;
  char * buf = NULL;
  
  for (unsigned i=0; i<2000; i++) {
    if (time_to_stop()) break;
    
    bool read=false;
    
    time_t seconds;
    time( &seconds);
    srand(seconds);
    
    // use rand instead ??
    double x = drand48();
    
    // cleanup before call 'new'
    if (buf != NULL) {
      delete[] buf;
      buf = NULL;
    }
    if (x < 0.5) {
      buf = new char[rdsize]; 
      memset(buf, 1, rdsize);
      read=true;
    } else {
      buf = new char[rdsize+100];   // 1 MB
      memset(buf, 7, rdsize);
    }
    
    if (read) {
      dout(2) << "reading block " << offset << "/" << chunks << dendl;
	
      int r = client->read(fd, buf, rdsize,
			     offset*rdsize);
      if (r < rdsize) {
	dout(1) << "read_file got r = " << r << ", probably end of file" << dendl;
      }
    } else {
        dout(2) << "writing block " << offset << "/" << chunks << dendl;
	
	// fill buf with a 16 byte fingerprint
	// 64 bits : file offset
	// 64 bits : client id
	// = 128 bits (16 bytes)
	
	int count = rand()%10;
	
	for ( int j=0;j<count; j++ ) {
	  offset=(rand())%(chunks+1);
	  uint64_t *p = (uint64_t*)buf;