block: Really pause block jobs on drain

We already requested that block jobs be paused in .bdrv_drained_begin,
but no guarantee was made that the job was actually inactive at the
point where bdrv_drained_begin() returned.

This introduces a new callback BdrvChildRole.bdrv_drained_poll() and
uses it to make bdrv_drain_poll() consider block jobs using the node to
be drained.

For the test case to work as expected, we have to switch from
block_job_sleep_ns() to qemu_co_sleep_ns() so that the test job is even
considered active and must be waited for when draining the node.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/block/mirror.c b/block/mirror.c
index 435268b..c2146c1 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -964,6 +964,12 @@ static void mirror_pause(Job *job)
     mirror_wait_for_all_io(s);
 }
 
+static bool mirror_drained_poll(BlockJob *job)
+{
+    MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
+    return !!s->in_flight;
+}
+
 static void mirror_attached_aio_context(BlockJob *job, AioContext *new_context)
 {
     MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
@@ -997,6 +1003,7 @@ static const BlockJobDriver mirror_job_driver = {
         .pause                  = mirror_pause,
         .complete               = mirror_complete,
     },
+    .drained_poll           = mirror_drained_poll,
     .attached_aio_context   = mirror_attached_aio_context,
     .drain                  = mirror_drain,
 };
@@ -1012,6 +1019,7 @@ static const BlockJobDriver commit_active_job_driver = {
         .pause                  = mirror_pause,
         .complete               = mirror_complete,
     },
+    .drained_poll           = mirror_drained_poll,
     .attached_aio_context   = mirror_attached_aio_context,
     .drain                  = mirror_drain,
 };