[PATCH 1/2] io_u: fix offset generation for mix of random and sequential workload

[Ankit Kumar <ankit.kumar@samsung.com>]

Sometimes while running a mix of sequential and random I/O's the
generated sequential offset is outside the I/O region. This usually
happens if the previous I/O is the last block in the region and
thus results in this sequential I/O's offset to be just outside the
region.
With this fix, fio generates a random offset within the I/O region.

This fixes #1486

Signed-off-by: Ankit Kumar <ankit.kumar@samsung.com>
---
 io_u.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/io_u.c b/io_u.c
index 8035f4b7..e49b1b29 100644
--- a/io_u.c
+++ b/io_u.c
@@ -432,8 +432,11 @@ static int get_next_block(struct thread_data *td, struct io_u *io_u,
 				*is_random = false;
 				io_u_set(td, io_u, IO_U_F_BUSY_OK);
 				ret = get_next_seq_offset(td, f, ddir, &offset);
-				if (ret)
+				if (ret || offset >= f->io_size) {
 					ret = get_next_rand_block(td, f, ddir, &b);
+					offset = -1ULL;
+					*is_random = true;
+				}
 			}
 		} else {
 			*is_random = false;
-- 
2.17.1