[PATCH blktests] nvme/039: drain udev events before passthru error injection

[Mateusz Nowicki <mateusz.nowicki@posteo.net>]

From: Mateusz Nowicki <Mateusz.Nowicki@posteo.net>

When run repeatedly, nvme/039 fails intermittently with a regular block
read error instead of the expected passthru line, e.g.:

  nvme0n1: Read(0x2) @ LBA 0, 8 blocks, Invalid Command Opcode (sct 0x0 / sc 0x1) DNR

inject_write_fault_on_write() writes LBA 0 of the whole-disk device,
whose release emits a change uevent that makes udev run blkid, reading
LBA 0 asynchronously. The following passthru injection arms a one-shot
fault (times=1); if the stray blkid read races in first it consumes the
fault and is logged via nvme_log_error() (no cdw fields), so the expected
passthru line is never emitted and the test fails.

Drain the pending uevent with udevadm settle before the passthru section.

Signed-off-by: Mateusz Nowicki <Mateusz.Nowicki@posteo.net>
---
 tests/nvme/039 | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tests/nvme/039 b/tests/nvme/039
index 7ca48ec..8c70c5c 100755
--- a/tests/nvme/039
+++ b/tests/nvme/039
@@ -206,6 +206,8 @@ test_device() {
 	inject_invalid_status_on_read "${ns_dev}"
 	inject_write_fault_on_write "${ns_dev}"
 
+	udevadm settle
+
 	if [ -e "$TEST_DEV_SYSFS/passthru_err_log_enabled" ]; then
 		_nvme_passthru_logging_setup "${ns_dev}" "${ctrl_dev}"
 
-- 
2.53.0