Method scanObject

src/iocore/cache/CacheVC.cc:666–895

}

int
CacheVC::scanObject(int /* event ATS_UNUSED */, Event * /* e ATS_UNUSED */)
{
  Dbg(dbg_ctl_cache_scan_truss, "inside %p:scanObject", this);

  Doc  *doc    = nullptr;
  void *result = nullptr;
  int   hlen   = 0;
  char  hname[500];
  bool  hostinfo_copied         = false;
  off_t next_object_len         = 0;
  bool  might_need_overlap_read = false;

  cancel_trigger();
  set_io_not_in_progress();
  if (_action.cancelled) {
    return free_CacheVC(this);
  }

  CACHE_TRY_LOCK(lock, stripe->mutex, mutex->thread_holding);
  if (!lock.is_locked()) {
    Dbg(dbg_ctl_cache_scan_truss, "delay %p:scanObject", this);
    mutex->thread_holding->schedule_in_local(this, HRTIME_MSECONDS(cache_config_mutex_retry_delay));
    return EVENT_CONT;
  }

  if (!fragment) { // initialize for first read
    fragment            = 1;
    scan_stripe_map     = make_vol_map(stripe);
    io.aiocb.aio_offset = next_in_map(stripe, scan_stripe_map, stripe->vol_offset_to_offset(0));
    if (io.aiocb.aio_offset >= static_cast<off_t>(stripe->skip + stripe->len)) {
      goto Lnext_vol;
    }
    io.aiocb.aio_nbytes = SCAN_BUF_SIZE;
    io.aiocb.aio_buf    = buf->data();
    io.action           = this;
    io.thread           = AIO_CALLBACK_THREAD_ANY;
    Dbg(dbg_ctl_cache_scan_truss, "read %p:scanObject", this);
    goto Lread;
  }

  if (!io.ok()) {
    result = reinterpret_cast<void *>(-ECACHE_READ_FAIL);
    goto Ldone;
  }

  doc = reinterpret_cast<Doc *>(buf->data() + offset);
  // If there is data in the buffer before the start that is from a partial object read previously
  // Fix things as if we read it this time.
  if (scan_fix_buffer_offset) {
    io.aio_result          += scan_fix_buffer_offset;
    io.aiocb.aio_nbytes    += scan_fix_buffer_offset;
    io.aiocb.aio_offset    -= scan_fix_buffer_offset;
    io.aiocb.aio_buf        = static_cast<char *>(io.aiocb.aio_buf) - scan_fix_buffer_offset;
    scan_fix_buffer_offset  = 0;
  }
  while (static_cast<off_t>(reinterpret_cast<char *>(doc) - buf->data()) + next_object_len <
         static_cast<off_t>(io.aiocb.aio_nbytes)) {