Re: [PATCH v2 4/4] block: Use blk_make_empty() after commits

[Max Reitz <mreitz@redhat.com>]

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On 29.04.20 16:11, Max Reitz wrote:
> bdrv_commit() already has a BlockBackend pointing to the BDS that we
> want to empty, it just has the wrong permissions.
> 
> qemu-img commit has no BlockBackend pointing to the old backing file
> yet, but introducing one is simple.
> 
> After this commit, bdrv_make_empty() is the only remaining caller of
> BlockDriver.bdrv_make_empty().
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>  block/commit.c | 16 +++++++++-------
>  qemu-img.c     | 19 ++++++++++++++-----
>  2 files changed, 23 insertions(+), 12 deletions(-)

[...]

> diff --git a/qemu-img.c b/qemu-img.c
> index 7f52742ef2..77f3575538 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -1065,11 +1065,20 @@ static int img_commit(int argc, char **argv)
>          goto unref_backing;
>      }
>  
> -    if (!drop && bs->drv->bdrv_make_empty) {
> -        ret = bs->drv->bdrv_make_empty(bs);
> -        if (ret) {
> -            error_setg_errno(&local_err, -ret, "Could not empty %s",
> -                             filename);
> +    if (!drop) {
> +        BlockBackend *old_backing_blk;
> +
> +        old_backing_blk = blk_new_with_bs(bs, BLK_PERM_WRITE, BLK_PERM_ALL,
> +                                          &local_err);
> +        if (!old_backing_blk) {
> +            goto unref_backing;
> +        }
> +        ret = blk_make_empty(old_backing_blk, &local_err);
> +        blk_unref(old_backing_blk);
> +        if (ret == -ENOTSUP) {
> +            error_free(local_err);
> +            local_err = NULL;
> +        } else if (ret < 0) {
>              goto unref_backing;
>          }
>      }

This patch should also include a %s/Could not empty/Failed to empty/ on
tests/qemu-iotests/098.out...

Max


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