[Qemu-block] [PATCH] block: early check for blockers on drive-mirror

[Paolo Bonzini]

Even if an op blocker is present for BLOCK_OP_TYPE_MIRROR_SOURCE,
it is checked a bit late and the result is that the target is
created even if drive-mirror subsequently fails.  Add an early
check to avoid this.

Signed-off-by: Paolo Bonzini <address@hidden>
---
 blockdev.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/blockdev.c b/blockdev.c
index 8e977eef11..c7e2e0a00e 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3565,6 +3565,11 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp)
         return;
     }
 
+    /* Early check to avoid creating target */
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_MIRROR_SOURCE, errp)) {
+        return;
+    }
+
     aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
-- 
2.14.3