Add version of qcow2_reopen_bitmaps_rw, which do the same work but
also return a hint about was header updated or not. This will be
used in the following fix for bitmaps reloading after migration.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/qcow2.h        |  2 ++
 block/qcow2-bitmap.c | 15 ++++++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/block/qcow2.h b/block/qcow2.h
index 6f0ff15dd0..40fa5b7cfe 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -667,6 +667,8 @@ int qcow2_check_bitmaps_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
                                   void **refcount_table,
                                   int64_t *refcount_table_size);
 bool qcow2_load_autoloading_dirty_bitmaps(BlockDriverState *bs, Error **errp);
+int qcow2_reopen_bitmaps_rw_hint(BlockDriverState *bs, bool *header_updated,
+                                 Error **errp);
 int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp);
 void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp);
 int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp);
diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index f45e46cfbd..6c80dcda69 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -1002,7 +1002,8 @@ fail:
     return false;
 }
 
-int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
+int qcow2_reopen_bitmaps_rw_hint(BlockDriverState *bs, bool *header_updated,
+                                 Error **errp)
 {
     BDRVQcow2State *s = bs->opaque;
     Qcow2BitmapList *bm_list;
@@ -1010,6 +1011,10 @@ int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
     GSList *ro_dirty_bitmaps = NULL;
     int ret = 0;
 
+    if (header_updated != NULL) {
+        *header_updated = false;
+    }
+
     if (s->nb_bitmaps == 0) {
         /* No bitmaps - nothing to do */
         return 0;
@@ -1053,6 +1058,9 @@ int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
             error_setg_errno(errp, -ret, "Can't update bitmap directory");
             goto out;
         }
+        if (header_updated != NULL) {
+            *header_updated = true;
+        }
         g_slist_foreach(ro_dirty_bitmaps, set_readonly_helper, false);
     }
 
@@ -1063,6 +1071,11 @@ out:
     return ret;
 }
 
+int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
+{
+    return qcow2_reopen_bitmaps_rw_hint(bs, NULL, errp);
+}
+
 /* store_bitmap_data()
  * Store bitmap to image, filling bitmap table accordingly.
  */
-- 
2.11.1

On 11/28/2017 02:14 AM, Vladimir Sementsov-Ogievskiy wrote:
> Add version of qcow2_reopen_bitmaps_rw, which do the same work but
> also return a hint about was header updated or not. This will be
> used in the following fix for bitmaps reloading after migration.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  block/qcow2.h        |  2 ++
>  block/qcow2-bitmap.c | 15 ++++++++++++++-
>  2 files changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/block/qcow2.h b/block/qcow2.h
> index 6f0ff15dd0..40fa5b7cfe 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -667,6 +667,8 @@ int qcow2_check_bitmaps_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
>                                    void **refcount_table,
>                                    int64_t *refcount_table_size);
>  bool qcow2_load_autoloading_dirty_bitmaps(BlockDriverState *bs, Error **errp);
> +int qcow2_reopen_bitmaps_rw_hint(BlockDriverState *bs, bool *header_updated,
> +                                 Error **errp);
>  int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp);
>  void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp);
>  int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp);
> diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
> index f45e46cfbd..6c80dcda69 100644
> --- a/block/qcow2-bitmap.c
> +++ b/block/qcow2-bitmap.c
> @@ -1002,7 +1002,8 @@ fail:
>      return false;
>  }
>  
> -int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
> +int qcow2_reopen_bitmaps_rw_hint(BlockDriverState *bs, bool *header_updated,
> +                                 Error **errp)
>  {
>      BDRVQcow2State *s = bs->opaque;
>      Qcow2BitmapList *bm_list;
> @@ -1010,6 +1011,10 @@ int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
>      GSList *ro_dirty_bitmaps = NULL;
>      int ret = 0;
>  
> +    if (header_updated != NULL) {
> +        *header_updated = false;
> +    }
> +
>      if (s->nb_bitmaps == 0) {
>          /* No bitmaps - nothing to do */
>          return 0;
> @@ -1053,6 +1058,9 @@ int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
>              error_setg_errno(errp, -ret, "Can't update bitmap directory");
>              goto out;
>          }
> +        if (header_updated != NULL) {
> +            *header_updated = true;
> +        }
>          g_slist_foreach(ro_dirty_bitmaps, set_readonly_helper, false);
>      }
>  
> @@ -1063,6 +1071,11 @@ out:
>      return ret;
>  }
>  
> +int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
> +{
> +    return qcow2_reopen_bitmaps_rw_hint(bs, NULL, errp);
> +}
> +
>  /* store_bitmap_data()
>   * Store bitmap to image, filling bitmap table accordingly.
>   */
> 

Reviewed-by: John Snow <jsnow@redhat.com>