Re: [Qemu-devel] [PATCH] block: Print its file name if backing file opening failed

[Eric Blake]

On 11/07/2013 12:34 AM, Fam Zheng wrote:
> If backing file doesn't exist, the error message is confusing and
> misleading:
> 

> 
> This is not intuitive. It's better to have the missing file's name in
> the error message. With this patch:
> 
>     $ qemu-io -c 'read 0 512' /tmp/a.qcow2
>     qemu-io: can't open device /tmp/a.qcow2: Could not open backing
>     file: Could not open '/stor/vm/arch.raw': No such file or directory
>     no file open, try 'help open'
> 
> Which is a little bit better.

Indeed.  Are you trying to get this into 1.7?

> 
> Signed-off-by: Fam Zheng <address@hidden>
> ---
>  block.c                    | 3 ++-
>  block/raw-posix.c          | 1 -
>  block/raw-win32.c          | 1 -
>  tests/qemu-iotests/051.out | 2 +-
>  tests/qemu-iotests/069.out | 2 +-
>  5 files changed, 4 insertions(+), 5 deletions(-)

> 
> diff --git a/block.c b/block.c
> index f706634..a8dbcfc 100644
> --- a/block.c
> +++ b/block.c
> @@ -1009,7 +1009,8 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict 
> *options, Error **errp)
>          bdrv_unref(bs->backing_hd);
>          bs->backing_hd = NULL;
>          bs->open_flags |= BDRV_O_NO_BACKING;
> -        error_propagate(errp, local_err);
> +        error_setg(errp, "Could not open backing file: %s",
> +                   error_get_pretty(local_err));
>          return ret;

Needs a v2, that doesn't leak local_err.

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

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