C++ DEVICE::dunblock方法代码示例

/*********************************************************************
 * Acquire device for reading.
 *  The drive should have previously been reserved by calling
 *  reserve_device_for_read(). We read the Volume label from the block and
 *  leave the block pointers just after the label.
 *
 *  Returns: NULL if failed for any reason
 *           dcr  if successful
 */
bool acquire_device_for_read(DCR *dcr)
{
   DEVICE *dev;
   JCR *jcr = dcr->jcr;
   bool ok = false;
   bool tape_previously_mounted;
   VOL_LIST *vol;
   bool try_autochanger = true;
   int i;
   int vol_label_status;
   int retry = 0;

   Enter(rdbglvl);
   dev = dcr->dev;
   dev->Lock_read_acquire();
   Dmsg2(rdbglvl, "dcr=%p dev=%p\n", dcr, dcr->dev);
   Dmsg2(rdbglvl, "MediaType dcr=%s dev=%s\n", dcr->media_type, dev->device->media_type);
   dev->dblock(BST_DOING_ACQUIRE);

   if (dev->num_writers > 0) {
      Jmsg2(jcr, M_FATAL, 0, _("Acquire read: num_writers=%d not zero. Job %d canceled.\n"),
         dev->num_writers, jcr->JobId);
      goto get_out;
   }

   /* Find next Volume, if any */
   vol = jcr->VolList;
   if (!vol) {
      char ed1[50];
      Jmsg(jcr, M_FATAL, 0, _("No volumes specified for reading. Job %s canceled.\n"),
         edit_int64(jcr->JobId, ed1));
      goto get_out;
   }
   jcr->CurReadVolume++;
   for (i=1; i<jcr->CurReadVolume; i++) {
      vol = vol->next;
   }
   if (!vol) {
      Jmsg(jcr, M_FATAL, 0, _("Logic error: no next volume to read. Numvol=%d Curvol=%d\n"),
         jcr->NumReadVolumes, jcr->CurReadVolume);
      goto get_out;                   /* should not happen */
   }
   set_dcr_from_vol(dcr, vol);

   Dmsg2(rdbglvl, "Want Vol=%s Slot=%d\n", vol->VolumeName, vol->Slot);

   /*
    * If the MediaType requested for this volume is not the
    *  same as the current drive, we attempt to find the same
    *  device that was used to write the orginal volume.  If
    *  found, we switch to using that device.
    *
    *  N.B. A lot of routines rely on the dcr pointer not changing
    *    read_records.c even has multiple dcrs cached, so we take care
    *    here to release all important parts of the dcr and re-acquire
    *    them such as the block pointer (size may change), but we do
    *    not release the dcr.
    */
   Dmsg2(rdbglvl, "MediaType dcr=%s dev=%s\n", dcr->media_type, dev->device->media_type);
   if (dcr->media_type[0] && !bstrcmp(dcr->media_type, dev->device->media_type)) {
      RCTX rctx;
      DIRSTORE *store;
      int status;

      Jmsg3(jcr, M_INFO, 0, _("Changing read device. Want Media Type=\"%s\" have=\"%s\"\n"
                              "  device=%s\n"),
            dcr->media_type, dev->device->media_type, dev->print_name());
      Dmsg3(rdbglvl, "Changing read device. Want Media Type=\"%s\" have=\"%s\"\n"
                     "  device=%s\n",
            dcr->media_type, dev->device->media_type, dev->print_name());

      dev->dunblock(DEV_UNLOCKED);

      lock_reservations();
      memset(&rctx, 0, sizeof(RCTX));
      rctx.jcr = jcr;
      jcr->read_dcr = dcr;
      jcr->reserve_msgs = New(alist(10, not_owned_by_alist));
      rctx.any_drive = true;
      rctx.device_name = vol->device;
      store = new DIRSTORE;
      memset(store, 0, sizeof(DIRSTORE));
      store->name[0] = 0; /* No dir name */
      bstrncpy(store->media_type, vol->MediaType, sizeof(store->media_type));
      bstrncpy(store->pool_name, dcr->pool_name, sizeof(store->pool_name));
      bstrncpy(store->pool_type, dcr->pool_type, sizeof(store->pool_type));
      store->append = false;
      rctx.store = store;
      clean_device(dcr);                     /* clean up the dcr */

      /*
//.........这里部分代码省略.........

//.........这里部分代码省略.........
                  dev->getVolCatName(), dev->print_name());
         }
         if (dev->num_writers == 0) {         /* if not being used */
            volume_unused(dcr);               /*  we obviously are not using the volume */
         }
      }

   } else {
      /*
       * If we reach here, it is most likely because the job has failed,
       * since the device is not in read mode and there are no writers.
       * It was probably reserved.
       */
      volume_unused(dcr);
   }

   Dmsg3(100, "%d writers, %d reserve, dev=%s\n", dev->num_writers, dev->num_reserved(), dev->print_name());

   /*
    * If no writers, close if file or !CAP_ALWAYS_OPEN
    */
   if (dev->num_writers == 0 && (!dev->is_tape() || !dev->has_cap(CAP_ALWAYSOPEN))) {
      dev->close(dcr);
      free_volume(dev);
   }

   unlock_volumes();

   /*
    * Fire off Alert command and include any output
    */
   if (!job_canceled(jcr)) {
      if (!dcr->device->drive_tapealert_enabled && dcr->device->alert_command) {
         int status = 1;
         POOLMEM *alert, *line;
         BPIPE *bpipe;

         alert = get_pool_memory(PM_FNAME);
         line = get_pool_memory(PM_FNAME);

         alert = edit_device_codes(dcr, alert, dcr->device->alert_command, "");

         /*
          * Wait maximum 5 minutes
          */
         bpipe = open_bpipe(alert, 60 * 5, "r");
         if (bpipe) {
            while (bfgets(line, bpipe->rfd)) {
               Jmsg(jcr, M_ALERT, 0, _("Alert: %s"), line);
            }
            status = close_bpipe(bpipe);
         } else {
            status = errno;
         }
         if (status != 0) {
            berrno be;
            Jmsg(jcr, M_ALERT, 0, _("3997 Bad alert command: %s: ERR=%s.\n"), alert, be.bstrerror(status));
         }

         Dmsg1(400, "alert status=%d\n", status);
         free_pool_memory(alert);
         free_pool_memory(line);
      } else {
         /*
          * If all reservations are cleared for this device raise an event that SD plugins can register to.
          */
         if (dev->num_reserved() == 0) {
            generate_plugin_event(jcr, bsdEventDeviceReleased, dcr);
         }
      }
   }

   pthread_cond_broadcast(&dev->wait_next_vol);
   Dmsg2(100, "JobId=%u broadcast wait_device_release at %s\n",
         (uint32_t)jcr->JobId, bstrftimes(tbuf, sizeof(tbuf), (utime_t)time(NULL)));
   release_device_cond();

   /*
    * If we are the thread that blocked the device, then unblock it
    */
   if (pthread_equal(dev->no_wait_id, pthread_self())) {
      dev->dunblock(true);
   } else {
      /*
       * Otherwise, reset the prior block status and unlock
       */
      dev->set_blocked(was_blocked);
      dev->Unlock();
   }

   if (dcr->keep_dcr) {
      detach_dcr_from_dev(dcr);
   } else {
      free_dcr(dcr);
   }

   Dmsg2(100, "Device %s released by JobId=%u\n", dev->print_name(), (uint32_t)jcr->JobId);

   return ok;
}