Re: [Qemu-devel] [PATCH trivial] block.c: Correct the return value and the failure object when failure occurs

[Stefan Hajnoczi]

On Sat, Jun 21, 2014 at 10:59:29PM +0800, Chen Gang wrote:
> When failure occurs, 'ret' need be set, or may return 0 to indicate success.
> And error_propagate() also need be called only one time within a function.
> 
> Signed-off-by: Chen Gang <address@hidden>
> ---
>  block.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/block.c b/block.c
> index 74af8d7..12ce4e4 100644
> --- a/block.c
> +++ b/block.c
> @@ -1497,7 +1497,7 @@ int bdrv_open(BlockDriverState **pbs, const char 
> *filename,
>      if (snapshot_flags) {
>          bdrv_append_temp_snapshot(bs, snapshot_flags, &local_err);
>          if (local_err) {
> -            error_propagate(errp, local_err);
> +            ret = -1;
>              goto close_and_fail;
>          }
>      }

The return value of bdrv_open() is a negative errno.  -1 does not make
sense in this case.

Please add an int return value to bdrv_append_temp_snapshot() so the
caller can determine the real errno.  Then the remainder of the patch
can be:

     if (snapshot_flags) {
-        bdrv_append_temp_snapshot(bs, snapshot_flags, &local_err);
+        ret = bdrv_append_temp_snapshot(bs, snapshot_flags, &local_err);
         if (local_err) {
-            error_propagate(errp, local_err);
             goto close_and_fail;
         }
     }

Stefan

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