Re: [Qemu-devel] [PATCH 06/10] block: Remove bdrv_new() from bdrv_file_open()

[Kevin Wolf <kwolf@redhat.com>]

Am 26.01.2014 um 20:02 hat Max Reitz geschrieben:
> Change bdrv_file_open() to take a simple pointer to an already existing
> BDS instead of an indirect one. The BDS will be created in bdrv_open()
> if necessary.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>  block.c | 29 ++++++++++++++++++-----------
>  1 file changed, 18 insertions(+), 11 deletions(-)
> 
> diff --git a/block.c b/block.c
> index 6c29115..72eddd5 100644
> --- a/block.c
> +++ b/block.c
> @@ -947,17 +947,15 @@ free_and_fail:
>   * after the call (even on failure), so if the caller intends to reuse the
>   * dictionary, it needs to use QINCREF() before calling bdrv_file_open.
>   */
> -static int bdrv_file_open(BlockDriverState **pbs, const char *filename,
> +static int bdrv_file_open(BlockDriverState *bs, const char *filename,
>                            QDict *options, int flags, Error **errp)
>  {
> -    BlockDriverState *bs = NULL;
>      BlockDriver *drv;
>      const char *drvname;
>      bool allow_protocol_prefix = false;
>      Error *local_err = NULL;
>      int ret;
>  
> -    bs = bdrv_new("");
>      bs->options = options;
>      options = qdict_clone_shallow(options);
>  
> @@ -1036,7 +1034,6 @@ static int bdrv_file_open(BlockDriverState **pbs, const char *filename,
>      QDECREF(options);
>  
>      bs->growable = 1;
> -    *pbs = bs;
>      return 0;
>  
>  fail:
> @@ -1044,7 +1041,6 @@ fail:
>      if (!bs->drv) {
>          QDECREF(bs->options);
>      }
> -    bdrv_unref(bs);
>      return ret;
>  }
>  
> @@ -1235,17 +1231,28 @@ int bdrv_open(BlockDriverState **pbs, const char *filename,
>          return 0;
>      }
>  
> -    if (flags & BDRV_O_PROTOCOL) {
> -        assert(!drv);
> -        return bdrv_file_open(pbs, filename, options, flags & ~BDRV_O_PROTOCOL,
> -                              errp);
> -    }
> -
>      if (*pbs) {
>          bs = *pbs;
>      } else {
>          bs = bdrv_new("");
>      }
> +
> +    if (flags & BDRV_O_PROTOCOL) {
> +        assert(!drv);
> +        ret = bdrv_file_open(bs, filename, options, flags & ~BDRV_O_PROTOCOL,
> +                             errp);
> +        if (ret) {
> +            if (*pbs) {
> +                bdrv_close(bs);

Why would bs be open when bdrv_file_open() just failed?

> +            } else {
> +                bdrv_unref(bs);
> +            }
> +        } else {
> +            *pbs = bs;
> +        }
> +        return ret;
> +    }
> +
>      bs->options = options;
>      options = qdict_clone_shallow(options);

Kevin