Re: [PATCH] qcow2: set bdi->is_dirty

[Kirill Tkhai]

On 04.05.2021 19:06, Vladimir Sementsov-Ogievskiy wrote:
> Set bdi->is_dirty, so that qemu-img info could show dirty flag.
> 
> After this commit the following check will show '"dirty-flag": true':
> 
> ./build/qemu-img create -f qcow2 -o lazy_refcounts=on x 1M
> ./build/qemu-io x
> qemu-io> write 0 1M
> 
>  After "write" command success, kill the qemu-io process:
> 
> kill -9 <qemu-io pid>
> 
> ./build/qemu-img info --output=json x
> 
> This will show '"dirty-flag": true' among other things. (before this
> commit it shows '"dirty-flag": false')
> 
> Note, that qcow2's dirty-bit is not a "dirty bit for the image". It
> only protects qcow2 lazy refcounts feature. So, there are a lot of
> conditions when qcow2 session may be not closed correctly, but bit is
> 0. Still, when bit is set, the last session is definitely not finished
> correctly and it's better to report it.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Works for me. Thanks,

Tested-by: Kirill Tkhai <ktkhai@virtuozzo.com>

> ---
>  block/qcow2.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 9727ae8fe3..39b91ef940 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -5089,6 +5089,7 @@ static int qcow2_get_info(BlockDriverState *bs, 
> BlockDriverInfo *bdi)
>      BDRVQcow2State *s = bs->opaque;
>      bdi->cluster_size = s->cluster_size;
>      bdi->vm_state_offset = qcow2_vm_state_offset(s);
> +    bdi->is_dirty = s->incompatible_features & QCOW2_INCOMPAT_DIRTY;
>      return 0;
>  }
>  
>