Re: [Qemu-devel] [PATCH 3/7] qcow: Fix bdrv_write_compressed error handling

[Paolo Bonzini <pbonzini@redhat.com>]

On 10/26/2011 02:31 PM, Kevin Wolf wrote:
> Signed-off-by: Kevin Wolf<kwolf@redhat.com>
> ---
>   block/qcow.c |   30 +++++++++++++++++++-----------
>   1 files changed, 19 insertions(+), 11 deletions(-)
>
> diff --git a/block/qcow.c b/block/qcow.c
> index ab36b29..35e21eb 100644
> --- a/block/qcow.c
> +++ b/block/qcow.c
> @@ -736,8 +736,6 @@ static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
>           return -EINVAL;
>
>       out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
> -    if (!out_buf)
> -        return -1;
>
>       /* best compression, small window, no zlib header */
>       memset(&strm, 0, sizeof(strm));
> @@ -745,8 +743,8 @@ static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
>                          Z_DEFLATED, -12,
>                          9, Z_DEFAULT_STRATEGY);
>       if (ret != 0) {
> -        g_free(out_buf);
> -        return -1;
> +        ret = -EINVAL;
> +        goto fail;
>       }
>
>       strm.avail_in = s->cluster_size;
> @@ -756,9 +754,9 @@ static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
>
>       ret = deflate(&strm, Z_FINISH);
>       if (ret != Z_STREAM_END&&  ret != Z_OK) {
> -        g_free(out_buf);
>           deflateEnd(&strm);
> -        return -1;
> +        ret = -EINVAL;
> +        goto fail;
>       }
>       out_len = strm.next_out - out_buf;
>
> @@ -766,19 +764,29 @@ static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
>
>       if (ret != Z_STREAM_END || out_len>= s->cluster_size) {
>           /* could not compress: write normal cluster */
> -        bdrv_write(bs, sector_num, buf, s->cluster_sectors);
> +        ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors);
> +        if (ret<  0) {
> +            goto fail;
> +        }
>       } else {
>           cluster_offset = get_cluster_offset(bs, sector_num<<  9, 2,
>                                               out_len, 0, 0);
> +        if (cluster_offset == 0) {
> +            ret = -EIO;
> +            goto fail;
> +        }
> +
>           cluster_offset&= s->cluster_offset_mask;
> -        if (bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len) != out_len) {
> -            g_free(out_buf);
> -            return -1;
> +        ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len);
> +        if (ret<  0) {
> +            goto fail;
>           }
>       }
>
> +    ret = 0;
> +fail:
>       g_free(out_buf);
> -    return 0;
> +    return ret;
>   }
>
>   static coroutine_fn int qcow_co_flush(BlockDriverState *bs)

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>