Re: [Qemu-devel] [Qemu-block] [PATCH v2 06/16] backup: Request BLK_PERM_AIO_CONTEXT_CHANGE on target

[Stefan Hajnoczi <stefanha@gmail.com>]

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On Wed, Apr 19, 2017 at 05:43:46PM +0800, Fam Zheng wrote:
> What's done in the source's context change notifier is moving the
> target's context to follow the new one, so we request this permission
> here.

It's true that the backup block job must be able to set target's
AioContext, but does this change also allow other users to set target's
AioContext while the backup job is running?  If yes, then we need to
handle that.

> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  block/backup.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/block/backup.c b/block/backup.c
> index a4fb288..546c5c5 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -636,7 +636,7 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
>      }
>  
>      /* The target must match the source in size, so no resize here either */
> -    job->target = blk_new(BLK_PERM_WRITE,
> +    job->target = blk_new(BLK_PERM_WRITE | BLK_PERM_AIO_CONTEXT_CHANGE,
>                            BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE |
>                            BLK_PERM_WRITE_UNCHANGED | BLK_PERM_GRAPH_MOD);
>      ret = blk_insert_bs(job->target, target, errp);
> -- 
> 2.9.3
> 
> 

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