1 files changed, 4 insertions, 2 deletions

diff --git a/qemu-img.c b/qemu-img.c
index 76ac5d3..e757071 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -3505,6 +3505,7 @@ static int img_snapshot(int argc, char **argv)
         break;
 
     case SNAPSHOT_DELETE:
+        bdrv_drain_all_begin();
         bdrv_graph_rdlock_main_loop();
         ret = bdrv_snapshot_find(bs, &sn, snapshot_name);
         if (ret < 0) {
@@ -3520,6 +3521,7 @@ static int img_snapshot(int argc, char **argv)
             }
         }
         bdrv_graph_rdunlock_main_loop();
+        bdrv_drain_all_end();
         break;
     }
 
@@ -4488,10 +4490,10 @@ static void bench_cb(void *opaque, int ret)
          */
         b->in_flight++;
         b->offset += b->step;
-        if (b->image_size == 0) {
+        if (b->image_size <= b->bufsize) {
             b->offset = 0;
         } else {
-            b->offset %= b->image_size;
+            b->offset %= b->image_size - b->bufsize;
         }
         if (b->write) {
             acb = blk_aio_pwritev(b->blk, offset, b->qiov, 0, bench_cb, b);