+int setup_shared_file(struct thread_data *td)
+{
+ struct fio_file *f;
+ uint64_t file_size;
+ int err = 0;
+
+ if (td->o.nr_files > 1) {
+ log_err("fio: shared file setup called for multiple files\n");
+ return -1;
+ }
+
+ get_file_sizes(td);
+
+ f = td->files[0];
+
+ if (f == NULL) {
+ log_err("fio: NULL shared file\n");
+ return -1;
+ }
+
+ file_size = thread_number * td->o.size;
+ dprint(FD_FILE, "shared setup %s real_file_size=%llu, desired=%llu\n",
+ f->file_name, (unsigned long long)f->real_file_size, (unsigned long long)file_size);
+
+ if (f->real_file_size < file_size) {
+ dprint(FD_FILE, "fio: extending shared file\n");
+ f->real_file_size = file_size;
+ err = extend_file(td, f);
+ if (!err) {
+ err = __file_invalidate_cache(td, f, 0, f->real_file_size);
+ }
+ get_file_sizes(td);
+ dprint(FD_FILE, "shared setup new real_file_size=%llu\n",
+ (unsigned long long)f->real_file_size);
+ }
+
+ return err;
+}
+