When mirroring or active committing a zero length image, BLOCK_JOB_READY is not reported now, instead the job completes because we short circuit the mirror job loop.
This is inconsistent with non-zero length images, and only confuses management software. Let's do the same thing when seeing a 0-length image: report ready immediately; wait for block-job-cancel or block-job-complete; clear the cancel flag as existing non-zero image synced case (cancelled after ready); then jump to the exit. Reported-by: Eric Blake <ebl...@redhat.com> Signed-off-by: Fam Zheng <f...@redhat.com> Reviewed-by: Eric Blake <ebl...@redhat.com> --- block/mirror.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/block/mirror.c b/block/mirror.c index 94c8661..705260a 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -324,9 +324,18 @@ static void coroutine_fn mirror_run(void *opaque) } s->common.len = bdrv_getlength(bs); - if (s->common.len <= 0) { + if (s->common.len < 0) { ret = s->common.len; goto immediate_exit; + } else if (s->common.len == 0) { + /* Report BLOCK_JOB_READY and wait for complete. */ + block_job_ready(&s->common); + s->synced = true; + while (!block_job_is_cancelled(&s->common) && !s->should_complete) { + block_job_yield(&s->common); + } + s->common.cancelled = false; + goto immediate_exit; } length = DIV_ROUND_UP(s->common.len, s->granularity); -- 2.0.0