Re: [Qemu-devel] [Qemu-block] [PATCH 2/4] qcow2: handle reopening bitmaps on bdrv_invalidate_cache

[John Snow]

On 11/28/2017 02:14 AM, Vladimir Sementsov-Ogievskiy wrote:
> Consider migration with shared storage. Persistent bitmaps are stored
> on bdrv_inactivate. Then, on destination
> process_incoming_migration_bh() calls bdrv_invalidate_cache_all() which
> leads to qcow2_load_autoloading_dirty_bitmaps() which fails if bitmaps
> are already loaded on destination start. In this case we should call
> qcow2_reopen_bitmaps_rw instead.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> ---
>  block/qcow2.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 1914a940e5..f5f205e1b7 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -1450,7 +1450,13 @@ static int qcow2_do_open(BlockDriverState *bs, QDict 
> *options, int flags,
>          s->autoclear_features &= QCOW2_AUTOCLEAR_MASK;
>      }
>  
> -    if (qcow2_load_autoloading_dirty_bitmaps(bs, &local_err)) {
> +    if (bdrv_has_readonly_bitmaps(bs)) {
> +        if (!bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & 
> BDRV_O_INACTIVE)) {
> +            bool header_updated = false;
> +            qcow2_reopen_bitmaps_rw_hint(bs, &header_updated, &local_err);
> +            update_header = update_header && !header_updated;
> +        }
> +    } else if (qcow2_load_autoloading_dirty_bitmaps(bs, &local_err)) {
>          update_header = false;
>      }
>      if (local_err != NULL) {
> 

It sounds right to me, but I'm going to ask for eyes from Kevin or Max.

Acked-by: John Snow <address@hidden>