+static int get_next_rand_offset(struct thread_data *td, struct fio_file *f,
+ int ddir, unsigned long long *b)
+{
+ unsigned long long max_blocks = f->io_size / td->o.min_bs[ddir];
+ unsigned long long r, rb;
+ int loops = 5;
+
+ do {
+ r = os_random_long(&td->random_state);
+ if (!max_blocks)
+ *b = 0;
+ else
+ *b = ((max_blocks - 1) * r / (unsigned long long) (RAND_MAX+1.0));
+ if (td->o.norandommap)
+ break;
+ rb = *b + (f->file_offset / td->o.min_bs[ddir]);
+ loops--;
+ } while (!random_map_free(td, f, rb) && loops);
+
+ /*
+ * if we failed to retrieve a truly random offset within
+ * the loops assigned, see if there are free ones left at all
+ */
+ if (!loops && get_next_free_block(td, f, b))
+ return 1;
+
+ return 0;
+}
+