Re: [Qemu-devel] [PATCH 2/2] block: assert no image modification under BDRV_O_INACTIVE

[Eric Blake]

On 04/05/2017 10:18 AM, Denis V. Lunev wrote:
> As long as BDRV_O_INACTIVE is set, the image file is only opened so we
> have a file descriptor for it. We're definitely not supposed to modify
> the image, it's still owned by the migration source.
> 
> This commit is an addition to 09e0c771 but the assert() is added to
> bdrv_truncate().
> 
> Signed-off-by: Denis V. Lunev <address@hidden>
> CC: Kevin Wolf <address@hidden>
> CC: Max Reitz <address@hidden>
> ---
>  block.c | 2 ++
>  1 file changed, 2 insertions(+)

I don't feel comfortable adding an assert this late in the 2.9 phase,
but think it makes perfect sense as a 2.10 addition.

Reviewed-by: Eric Blake <address@hidden>

> 
> diff --git a/block.c b/block.c
> index 927ba89..9273741 100644
> --- a/block.c
> +++ b/block.c
> @@ -3279,6 +3279,8 @@ int bdrv_truncate(BdrvChild *child, int64_t offset)
>      if (bs->read_only)
>          return -EACCES;
>  
> +    assert(!(bs->open_flags & BDRV_O_INACTIVE));
> +
>      ret = drv->bdrv_truncate(bs, offset);
>      if (ret == 0) {
>          ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
> 

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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