selftests: ublk: test that teardown after incomplete recovery completes

Before the fix, teardown of a ublk server that was attempting to recover
a device, but died when it had submitted a nonempty proper subset of the
fetch commands to any queue would loop forever. Add a test to verify
that, after the fix, teardown completes. This is done by:

- Adding a new argument to the fault_inject target that causes it die
  after fetching a nonempty proper subset of the IOs to a queue
- Using that argument in a new test while trying to recover an
  already-created device
- Attempting to delete the ublk device at the end of the test; this
  hangs forever if teardown from the fault-injected ublk server never
  completed.

It was manually verified that the test passes with the fix and hangs
without it.

Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://patch.msgid.link/20260405-cancel-v2-2-02d711e643c2@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 7 insertions, 0 deletions

diff --git a/tools/testing/selftests/ublk/kublk.c b/tools/testing/selftests/ublk/kublk.c
index e1c3b3c55e56..e5b787ba2175 100644
--- a/tools/testing/selftests/ublk/kublk.c
+++ b/tools/testing/selftests/ublk/kublk.c
@@ -796,6 +796,8 @@ static void ublk_submit_fetch_commands(struct ublk_thread *t)
 			q = &t->dev->q[q_id];
 			io = &q->ios[tag];
 			io->buf_index = j++;
+			if (q->tgt_ops->pre_fetch_io)
+				q->tgt_ops->pre_fetch_io(t, q, tag, false);
 			ublk_queue_io_cmd(t, io);
 		}
 	} else {
@@ -807,6 +809,8 @@ static void ublk_submit_fetch_commands(struct ublk_thread *t)
 		for (i = 0; i < q->q_depth; i++) {
 			io = &q->ios[i];
 			io->buf_index = i;
+			if (q->tgt_ops->pre_fetch_io)
+				q->tgt_ops->pre_fetch_io(t, q, i, false);
 			ublk_queue_io_cmd(t, io);
 		}
 	}
@@ -983,6 +987,9 @@ static void ublk_batch_setup_queues(struct ublk_thread *t)
 		if (t->q_map[i] == 0)
 			continue;
 
+		if (q->tgt_ops->pre_fetch_io)
+			q->tgt_ops->pre_fetch_io(t, q, 0, true);
+
 		ret = ublk_batch_queue_prep_io_cmds(t, q);
 		ublk_assert(ret >= 0);
 	}