On Fri, Aug 23, 2013 at 09:14:46AM +0800, Fam Zheng wrote:
> Introduce bdrv_ref/bdrv_unref to manage the lifecycle of
> BlockDriverState. They are unused for now but will used to replace
> bdrv_delete() later.
>
> Signed-off-by: Fam Zheng <f...@redhat.com>
> ---
> block.c | 21 +++++++++++++++++++++
> include/block/block.h | 2 ++
> include/block/block_int.h | 1 +
> 3 files changed, 24 insertions(+)
>
> diff --git a/block.c b/block.c
> index 01b66d8..fea6904 100644
> --- a/block.c
> +++ b/block.c
> @@ -306,6 +306,7 @@ BlockDriverState *bdrv_new(const char *device_name)
> bdrv_iostatus_disable(bs);
> notifier_list_init(&bs->close_notifiers);
> notifier_with_return_list_init(&bs->before_write_notifiers);
> + bs->refcnt = 1;
Just a heads-up: This won't apply cleanly to master because of a conflict,
at the above line, with
'88266f5 block: stop relying on io_flush() in bdrv_drain_all()'.
-Jeff
>
> return bs;
> }
> @@ -1517,6 +1518,9 @@ static void bdrv_move_feature_fields(BlockDriverState
> *bs_dest,
> /* dirty bitmap */
> bs_dest->dirty_bitmap = bs_src->dirty_bitmap;
>
> + /* reference count */
> + bs_dest->refcnt = bs_src->refcnt;
> +
> /* job */
> bs_dest->in_use = bs_src->in_use;
> bs_dest->job = bs_src->job;
> @@ -4391,6 +4395,23 @@ int64_t bdrv_get_dirty_count(BlockDriverState *bs)
> }
> }
>
> +/* Get a reference to bs */
> +void bdrv_ref(BlockDriverState *bs)
> +{
> + bs->refcnt++;
> +}
> +
> +/* Release a previously grabbed reference to bs.
> + * If after releasing, reference count is zero, the BlockDriverState is
> + * deleted. */
> +void bdrv_unref(BlockDriverState *bs)
> +{
> + assert(bs->refcnt > 0);
> + if (--bs->refcnt == 0) {
> + bdrv_delete(bs);
> + }
> +}
> +
> void bdrv_set_in_use(BlockDriverState *bs, int in_use)
> {
> assert(bs->in_use != in_use);
> diff --git a/include/block/block.h b/include/block/block.h
> index 742fce5..b33ef62 100644
> --- a/include/block/block.h
> +++ b/include/block/block.h
> @@ -356,6 +356,8 @@ int64_t bdrv_get_dirty_count(BlockDriverState *bs);
> void bdrv_enable_copy_on_read(BlockDriverState *bs);
> void bdrv_disable_copy_on_read(BlockDriverState *bs);
>
> +void bdrv_ref(BlockDriverState *bs);
> +void bdrv_unref(BlockDriverState *bs);
> void bdrv_set_in_use(BlockDriverState *bs, int in_use);
> int bdrv_in_use(BlockDriverState *bs);
>
> diff --git a/include/block/block_int.h b/include/block/block_int.h
> index e45f2a0..1f85cfb 100644
> --- a/include/block/block_int.h
> +++ b/include/block/block_int.h
> @@ -294,6 +294,7 @@ struct BlockDriverState {
> BlockDeviceIoStatus iostatus;
> char device_name[32];
> HBitmap *dirty_bitmap;
> + int refcnt;
> int in_use; /* users other than guest access, eg. block migration */
> QTAILQ_ENTRY(BlockDriverState) list;
>
> --
> 1.8.3.1
>
