[Devel] [PATCH vz9] dm-qcow2: enhance merge_backward progress reporting

[Andrey Zhadchenko]

 - Do not reset progress and maximum progress on every stage:
userspace gets confused when it sees 0/0 on a ready stage.
 - Set progress one more time at the end of qcow2_service_iter(),
as we reached the end successfully

https://virtuozzo.atlassian.net/browse/VSTOR-103508
Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>
---
 drivers/md/dm-qcow2-cmd.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/md/dm-qcow2-cmd.c b/drivers/md/dm-qcow2-cmd.c
index 89828f64cfe3..e77052ad61e6 100644
--- a/drivers/md/dm-qcow2-cmd.c
+++ b/drivers/md/dm-qcow2-cmd.c
@@ -111,6 +111,7 @@ static int qcow2_service_iter(struct qcow2_target *tgt, struct qcow2 *qcow2,
 		ret = blk_status_to_errno(READ_ONCE(service_status));
 	}
 
+	backward_merge_update_progress(tgt, (pos > end) ? end : pos);
 	return ret;
 }
 ALLOW_ERROR_INJECTION(qcow2_service_iter, ERRNO);
@@ -178,8 +179,10 @@ static void __backward_merge_update_stage(struct qcow2_target *tgt,
 					   enum qcow2_backward_merge_stage stage)
 {
 	tgt->backward_merge.stage = stage;
-	tgt->backward_merge.progress = 0;
-	tgt->backward_merge.max_progress = 0;
+	if (stage == BACKWARD_MERGE_STAGE_START) {
+		tgt->backward_merge.progress = 0;
+		tgt->backward_merge.max_progress = 0;
+	}
 }
 
 static void backward_merge_update_stage(struct qcow2_target *tgt,
-- 
2.43.0