[Qemu-devel] [PATCH 14/18] block/mirror: Distinguish active from passive ops

[Max Reitz <mreitz@redhat.com>]

Currently, the mirror block job only knows passive operations.  But once
we introduce active writes, we need to distinguish between the two; for
example, mirror_wait_for_free_in_flight_slot() should wait for a passive
operation because active writes will not use the same in-flight slots.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/mirror.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/block/mirror.c b/block/mirror.c
index 612fab660e..8fea619a68 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -96,6 +96,7 @@ struct MirrorOp {
     /* Set by mirror_co_read() before yielding for the first time */
     uint64_t bytes_copied;
 
+    bool is_active_write;
     CoQueue waiting_requests;
 
     QTAILQ_ENTRY(MirrorOp) next;
@@ -286,9 +287,14 @@ static inline void mirror_wait_for_free_in_flight_slot(MirrorBlockJob *s)
 {
     MirrorOp *op;
 
-    op = QTAILQ_FIRST(&s->ops_in_flight);
-    assert(op);
-    qemu_co_queue_wait(&op->waiting_requests, NULL);
+    QTAILQ_FOREACH(op, &s->ops_in_flight, next) {
+        if (!op->is_active_write) {
+            /* Only non-active operations use up in-flight slots */
+            qemu_co_queue_wait(&op->waiting_requests, NULL);
+            return;
+        }
+    }
+    abort();
 }
 
 /* Submit async read while handling COW.
-- 
2.13.5