diff options
authorShin'ichiro Kawasaki <>2019-09-25 17:29:24 +0900
committerJens Axboe <>2019-09-25 03:12:05 -0600
commit3c029ac46c3478243932f76cadf04ca10b64ab3e (patch)
parent0d0601479d593ca9e96e35f43e2c0586f8358f34 (diff)
filesetup: Extend file size for 'null' and 'filecreate' ioengines
It was reported the fio command with following options fails because of file access beyond the file size specified with size option. ./fio --name=test --rw=randread --runtime=10s --offset=90% --time_based --ioengine=null --size=1T --norandommap --randrepeat=0 One of the options specifies null ioengine which has FIO_DISKLESSIO and FIO_FAKEIO flags. When FIO_DISKLESSIO flag is set, current fio code does not extend the file size even when io_size + file_offset is larger than real_file_size. With this, random offsets are generated within io_size + file_offset range and fail comparison with real_file_size. This failure does not happen with other engines such as libaio since the target file is extended to ensure real_file_size is larger than io_size + file_offset. To avoid the failure, extend file size for ioengines with FIO_DISKLESSIO and FIO_FAKEIO. This changes behavior of two ioengines only: null ioengine and filecreate engine. It does not change behavior of all other ioengines including 12 ioengines with FIO_DISKLESSIO flag, such as nbd, glusterfs, pmemblk, etc. Signed-off-by: Masato Suzuki <> Signed-off-by: Shin'ichiro Kawasaki <> Signed-off-by: Jens Axboe <>
1 files changed, 6 insertions, 4 deletions
diff --git a/filesetup.c b/filesetup.c
index 7904d187..a439b6d6 100644
--- a/filesetup.c
+++ b/filesetup.c
@@ -1104,13 +1104,15 @@ int setup_files(struct thread_data *td)
if (f->filetype == FIO_TYPE_FILE &&
- (f->io_size + f->file_offset) > f->real_file_size &&
- !td_ioengine_flagged(td, FIO_DISKLESSIO)) {
- if (!o->create_on_open) {
+ (f->io_size + f->file_offset) > f->real_file_size) {
+ if (!td_ioengine_flagged(td, FIO_DISKLESSIO) &&
+ !o->create_on_open) {
extend_size += (f->io_size + f->file_offset);
- } else
+ } else if (!td_ioengine_flagged(td, FIO_DISKLESSIO) ||
+ (td_ioengine_flagged(td, FIO_DISKLESSIO) &&
+ td_ioengine_flagged(td, FIO_FAKEIO)))
f->real_file_size = f->io_size + f->file_offset;