Re: [Qemu-block] [Qemu-devel] [PATCH v20 14/30] qcow2: support .bdrv_reopen_bitmaps_rw

[John Snow]

On 06/02/2017 07:21 AM, Vladimir Sementsov-Ogievskiy wrote:
> Realize bdrv_reopen_bitmaps_rw interface.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>

Reviewed-by: John Snow <address@hidden>

> ---
>  block/qcow2-bitmap.c | 61 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  block/qcow2.c        |  2 ++
>  block/qcow2.h        |  1 +
>  3 files changed, 64 insertions(+)
> 
> diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
> index 2c7b057e21..a21fab8ce8 100644
> --- a/block/qcow2-bitmap.c
> +++ b/block/qcow2-bitmap.c
> @@ -826,3 +826,64 @@ fail:
>  
>      return false;
>  }
> +
> +int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
> +{
> +    BDRVQcow2State *s = bs->opaque;
> +    Qcow2BitmapList *bm_list;
> +    Qcow2Bitmap *bm;
> +    GSList *ro_dirty_bitmaps = NULL;
> +    int ret = 0;
> +
> +    if (s->nb_bitmaps == 0) {
> +        /* No bitmaps - nothing to do */
> +        return 0;
> +    }
> +
> +    if (!can_write(bs)) {
> +        error_setg(errp, "Can't write to the image on reopening bitmaps rw");
> +        return -EINVAL;
> +    }
> +
> +    bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
> +                               s->bitmap_directory_size, errp);
> +    if (bm_list == NULL) {
> +        return -EINVAL;
> +    }
> +
> +    QSIMPLEQ_FOREACH(bm, bm_list, entry) {
> +        if (!(bm->flags & BME_FLAG_IN_USE)) {
> +            BdrvDirtyBitmap *bitmap = bdrv_find_dirty_bitmap(bs, bm->name);
> +            if (bitmap == NULL) {
> +                continue;
> +            }
> +
> +            if (!bdrv_dirty_bitmap_readonly(bitmap)) {
> +                error_setg(errp, "Bitmap %s is not readonly but not marked"
> +                                 "'IN_USE' in the image. Something went 
> wrong,"
> +                                 "all the bitmaps may be corrupted", 
> bm->name);
> +                ret = -EINVAL;
> +                goto out;
> +            }
> +
> +            bm->flags |= BME_FLAG_IN_USE;
> +            ro_dirty_bitmaps = g_slist_append(ro_dirty_bitmaps, bitmap);
> +        }
> +    }
> +
> +    if (ro_dirty_bitmaps != NULL) {
> +        /* in_use flags must be updated */
> +        ret = update_ext_header_and_dir_in_place(bs, bm_list);
> +        if (ret < 0) {
> +            error_setg_errno(errp, -ret, "Can't update bitmap directory");
> +            goto out;
> +        }
> +        g_slist_foreach(ro_dirty_bitmaps, set_readonly_helper, false);
> +    }
> +
> +out:
> +    g_slist_free(ro_dirty_bitmaps);
> +    bitmap_list_free(bm_list);
> +
> +    return ret;
> +}
> diff --git a/block/qcow2.c b/block/qcow2.c
> index a70d284b75..ec00db7e49 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -3596,6 +3596,8 @@ BlockDriver bdrv_qcow2 = {
>  
>      .bdrv_detach_aio_context  = qcow2_detach_aio_context,
>      .bdrv_attach_aio_context  = qcow2_attach_aio_context,
> +
> +    .bdrv_reopen_bitmaps_rw = qcow2_reopen_bitmaps_rw,
>  };
>  
>  static void bdrv_qcow2_init(void)
> diff --git a/block/qcow2.h b/block/qcow2.h
> index 67c61de008..3e23bb7361 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -630,5 +630,6 @@ 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(BlockDriverState *bs, Error **errp);
>  
>  #endif
>