+ return 1;
+ }
+
+ return 0;
+}
+
+/*
+ * Fill offset and start time into the buffer content, to prevent too
+ * easy compressible data for simple de-dupe attempts. Do this for every
+ * 512b block in the range, since that should be the smallest block size
+ * we can expect from a device.
+ */
+static void small_content_scramble(struct io_u *io_u)
+{
+ unsigned int i, nr_blocks = io_u->buflen / 512;
+ unsigned long long boffset;
+ unsigned int offset;
+ void *p, *end;
+
+ if (!nr_blocks)
+ return;
+
+ p = io_u->xfer_buf;
+ boffset = io_u->offset;
+ io_u->buf_filled_len = 0;
+
+ for (i = 0; i < nr_blocks; i++) {
+ /*
+ * Fill the byte offset into a "random" start offset of
+ * the buffer, given by the product of the usec time
+ * and the actual offset.
+ */
+ offset = (io_u->start_time.tv_usec ^ boffset) & 511;
+ offset &= ~(sizeof(unsigned long long) - 1);
+ if (offset >= 512 - sizeof(unsigned long long))
+ offset -= sizeof(unsigned long long);
+ memcpy(p + offset, &boffset, sizeof(boffset));
+
+ end = p + 512 - sizeof(io_u->start_time);
+ memcpy(end, &io_u->start_time, sizeof(io_u->start_time));
+ p += 512;
+ boffset += 512;
+ }
+}
+
+/*
+ * Return an io_u to be processed. Gets a buflen and offset, sets direction,
+ * etc. The returned io_u is fully ready to be prepped and submitted.
+ */
+struct io_u *get_io_u(struct thread_data *td)
+{
+ struct fio_file *f;
+ struct io_u *io_u;
+ int do_scramble = 0;
+
+ io_u = __get_io_u(td);
+ if (!io_u) {
+ dprint(FD_IO, "__get_io_u failed\n");
+ return NULL;