[PULL 13/14] block/backup: implement .cancel job handler

[Eric Blake]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Cancel in-flight io on target to not waste the time.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210205163720.887197-10-vsementsov@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 block/backup.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/block/backup.c b/block/backup.c
index cc525d55445e..94e6dcd72e33 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -35,6 +35,7 @@ typedef struct BackupBlockJob {
     BlockJob common;
     BlockDriverState *backup_top;
     BlockDriverState *source_bs;
+    BlockDriverState *target_bs;

     BdrvDirtyBitmap *sync_bitmap;

@@ -329,6 +330,13 @@ static void coroutine_fn backup_set_speed(BlockJob *job, 
int64_t speed)
     }
 }

+static void backup_cancel(Job *job)
+{
+    BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
+
+    bdrv_cancel_in_flight(s->target_bs);
+}
+
 static const BlockJobDriver backup_job_driver = {
     .job_driver = {
         .instance_size          = sizeof(BackupBlockJob),
@@ -340,6 +348,7 @@ static const BlockJobDriver backup_job_driver = {
         .abort                  = backup_abort,
         .clean                  = backup_clean,
         .pause                  = backup_pause,
+        .cancel                 = backup_cancel,
     },
     .set_speed = backup_set_speed,
 };
@@ -528,6 +537,7 @@ BlockJob *backup_job_create(const char *job_id, 
BlockDriverState *bs,

     job->backup_top = backup_top;
     job->source_bs = bs;
+    job->target_bs = target;
     job->on_source_error = on_source_error;
     job->on_target_error = on_target_error;
     job->sync_mode = sync_mode;
-- 
2.30.1