Re: [Qemu-devel] [PATCH 4/4] qcow2: Check failure of bdrv_getlength()

[Philippe Mathieu-Daudé]

On 08/07/2017 05:30 PM, Eric Blake wrote:
> qcow2_co_pwritev_compressed() should not call bdrv_truncate()
> if determining the size failed.
>
> Reported-by: Markus Armbruster <address@hidden>
> Signed-off-by: Eric Blake <address@hidden>

Reviewed-by: Philippe Mathieu-Daudé <address@hidden>

> ---
>   block/qcow2.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 99407403ea..40ba26c111 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -3282,12 +3282,15 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, 
> uint64_t offset,
>       z_stream strm;
>       int ret, out_len;
>       uint8_t *buf, *out_buf;
> -    uint64_t cluster_offset;
> +    int64_t cluster_offset;
>
>       if (bytes == 0) {
>           /* align end of file to a sector boundary to ease reading with
>              sector based I/Os */
>           cluster_offset = bdrv_getlength(bs->file->bs);
> +        if (cluster_offset < 0) {
> +            return cluster_offset;
> +        }
>           return bdrv_truncate(bs->file, cluster_offset, PREALLOC_MODE_OFF, 
> NULL);
>       }