Re: [Qemu-devel] [PATCH 1/7] block: Convert BlockDriverState.in_use to refcount

[Eric Blake <eblake@redhat.com>]

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On 07/01/2013 11:59 PM, Fam Zheng wrote:
> Use numeric value to replace in_use flag in BDS, this will make
> lifecycle management with ref count possible. This patch only replaces
> existing uses of bdrv_set_in_use, so no logic change here.
> 
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>  block-migration.c               |  4 ++--
>  block.c                         | 23 +++++++++++++++--------
>  blockjob.c                      |  6 +++---
>  hw/block/dataplane/virtio-blk.c |  4 ++--
>  include/block/block.h           |  3 ++-
>  include/block/block_int.h       |  2 +-
>  6 files changed, 25 insertions(+), 17 deletions(-)
> 
> diff --git a/block-migration.c b/block-migration.c
> index 2fd7699..2efb6c0 100644
> --- a/block-migration.c
> +++ b/block-migration.c
> @@ -321,7 +321,7 @@ static void init_blk_migration_it(void *opaque, BlockDriverState *bs)
>          bmds->shared_base = block_mig_state.shared_base;
>          alloc_aio_bitmap(bmds);
>          drive_get_ref(drive_get_by_blockdev(bs));
> -        bdrv_set_in_use(bs, 1);
> +        bdrv_get_ref(bs);

The old code sets the flag, the new code gets a ref.

>  
>          block_mig_state.total_sector_sum += sectors;
>  
> @@ -557,7 +557,7 @@ static void blk_mig_cleanup(void)
>      blk_mig_lock();
>      while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {
>          QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry);
> -        bdrv_set_in_use(bmds->bs, 0);
> +        bdrv_get_ref(bmds->bs);

The old code sets the flag, the new code gets a ref.  Shouldn't this be
clearing a ref, with bdrv_put_ref?

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


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