Re: [Qemu-devel] [PATCH v3 08/21] block: Allow reference for bdrv_file_open()

[Fam Zheng]

On 2013年12月12日 02:11, Max Reitz wrote:
> Allow specifying a reference to an existing block device (by name) for
> bdrv_file_open() instead of a filename and/or options.
>
> Signed-off-by: Max Reitz <address@hidden>
> ---
>   block.c               | 27 ++++++++++++++++++++++++---
>   block/blkdebug.c      |  2 +-
>   block/blkverify.c     |  2 +-
>   block/cow.c           |  3 ++-
>   block/qcow.c          |  3 ++-
>   block/qcow2.c         |  2 +-
>   block/qed.c           |  4 ++--
>   block/sheepdog.c      |  4 ++--
>   block/vhdx.c          |  2 +-
>   block/vmdk.c          |  4 ++--
>   include/block/block.h |  3 ++-
>   qemu-io.c             |  2 +-
>   12 files changed, 41 insertions(+), 17 deletions(-)
>
> diff --git a/block.c b/block.c
> index 13f001a..9e197b3 100644
> --- a/block.c
> +++ b/block.c
> @@ -858,9 +858,10 @@ free_and_fail:
>    * dictionary, it needs to use QINCREF() before calling bdrv_file_open.
>    */
>   int bdrv_file_open(BlockDriverState **pbs, const char *filename,
> -                   QDict *options, int flags, Error **errp)
> +                   const char *reference, QDict *options, int flags,
> +                   Error **errp)
>   {
> -    BlockDriverState *bs;
> +    BlockDriverState *bs = NULL;
>       BlockDriver *drv;
>       const char *drvname;
>       bool allow_protocol_prefix = false;
> @@ -872,6 +873,26 @@ int bdrv_file_open(BlockDriverState **pbs, const char 
> *filename,
>           options = qdict_new();
>       }
>
> +    if (reference) {
> +        if (filename || qdict_size(options)) {
> +            error_setg(errp, "Cannot reference an existing block device with "
> +                       "additional options or a new filename");
> +            ret = -EINVAL;
> +            goto fail;
> +        }
> +        QDECREF(options);

QDECREF called...

> +
> +        bs = bdrv_find(reference);
> +        if (!bs) {
> +            error_setg(errp, "Cannot find block device '%s'", reference);
> +            ret = -ENODEV;
> +            goto fail;

Jump to fail for QDECREF again. Duplicated?

Fam