/**
   * Remove particular entry from the TRASH directory.
   *
   * @param name Entry name.
   * @param id Entry ID.
   * @return {@code True} in case the entry really was deleted form the file system by this call.
   * @throws IgniteCheckedException If failed.
   */
  private boolean delete(String name, IgniteUuid id) throws IgniteCheckedException {
    assert name != null;
    assert id != null;

    while (true) {
      IgfsFileInfo info = meta.info(id);

      if (info != null) {
        if (info.isDirectory()) {
          deleteDirectory(TRASH_ID, id);

          if (meta.delete(TRASH_ID, name, id)) return true;
        } else {
          assert info.isFile();

          // Delete file content first.
          // In case this node crashes, other node will re-delete the file.
          data.delete(info).get();

          boolean ret = meta.delete(TRASH_ID, name, id);

          if (evts.isRecordable(EVT_IGFS_FILE_PURGED)) {
            if (info.path() != null)
              evts.record(
                  new IgfsEvent(
                      info.path(),
                      igfsCtx.kernalContext().discovery().localNode(),
                      EVT_IGFS_FILE_PURGED));
            else LT.warn(log, null, "Removing file without path info: " + info);
          }

          return ret;
        }
      } else return false; // Entry was deleted concurrently.
    }
  }
  /**
   * Remove particular entry from the trash directory or subdirectory.
   *
   * @param parentId Parent ID.
   * @param id Entry id.
   * @throws IgniteCheckedException If delete failed for some reason.
   */
  private void deleteDirectory(IgniteUuid parentId, IgniteUuid id) throws IgniteCheckedException {
    assert parentId != null;
    assert id != null;

    while (true) {
      IgfsFileInfo info = meta.info(id);

      if (info != null) {
        assert info.isDirectory();

        Map<String, IgfsListingEntry> listing = info.listing();

        if (listing.isEmpty()) return; // Directory is empty.

        Map<String, IgfsListingEntry> delListing;

        if (listing.size() <= MAX_DELETE_BATCH) delListing = listing;
        else {
          delListing = new HashMap<>(MAX_DELETE_BATCH, 1.0f);

          int i = 0;

          for (Map.Entry<String, IgfsListingEntry> entry : listing.entrySet()) {
            delListing.put(entry.getKey(), entry.getValue());

            if (++i == MAX_DELETE_BATCH) break;
          }
        }

        GridCompoundFuture<Object, ?> fut = new GridCompoundFuture<>();

        // Delegate to child folders.
        for (IgfsListingEntry entry : delListing.values()) {
          if (!cancelled) {
            if (entry.isDirectory()) deleteDirectory(id, entry.fileId());
            else {
              IgfsFileInfo fileInfo = meta.info(entry.fileId());

              if (fileInfo != null) {
                assert fileInfo.isFile();

                fut.add(data.delete(fileInfo));
              }
            }
          } else return;
        }

        fut.markInitialized();

        // Wait for data cache to delete values before clearing meta cache.
        try {
          fut.get();
        } catch (IgniteFutureCancelledCheckedException ignore) {
          // This future can be cancelled only due to IGFS shutdown.
          cancelled = true;

          return;
        }

        // Actual delete of folder content.
        Collection<IgniteUuid> delIds = meta.delete(id, delListing);

        if (delListing == listing && delListing.size() == delIds.size())
          break; // All entries were deleted.
      } else break; // Entry was deleted concurrently.
    }
  }