Re: [Qemu-devel] [PATCH 2/2] qcow2: Fix bdrv_write_compressed error handling

[Dong Xu Wang <wdongxu@linux.vnet.ibm.com>]

On Tue, Oct 18, 2011 at 11:47 PM, Kevin Wolf <kwolf@redhat.com> wrote:
> If during allocation of compressed clusters the cluster was already
allocated
> uncompressed, fail and properly release the l2_table (the latter avoids a
> failed assertion).
>
> While at it, make it return some real error numbers instead of -1.
>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block/qcow2-cluster.c |    6 ++++--
>  block/qcow2.c         |   11 ++++++-----
>  2 files changed, 10 insertions(+), 7 deletions(-)
>
> diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
> index 2f76311..f4e049f 100644
> --- a/block/qcow2-cluster.c
> +++ b/block/qcow2-cluster.c
> @@ -568,8 +568,10 @@ uint64_t
qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
>     }
>
>     cluster_offset = be64_to_cpu(l2_table[l2_index]);
> -    if (cluster_offset & QCOW_OFLAG_COPIED)
> -        return cluster_offset & ~QCOW_OFLAG_COPIED;
> +    if (cluster_offset & QCOW_OFLAG_COPIED) {
> +        qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
> +        return 0;
> +    }
>
>     if (cluster_offset)
>         qcow2_free_any_clusters(bs, cluster_offset, 1);
> diff --git a/block/qcow2.c b/block/qcow2.c
> index 4dc980c..bf399f3 100644
> --- a/block/qcow2.c
> +++ b/block/qcow2.c
> @@ -1054,7 +1054,7 @@ static int
qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
>                        9, Z_DEFAULT_STRATEGY);
>     if (ret != 0) {
>         g_free(out_buf);
> -        return -1;
> +        return -EINVAL;
>     }
>
>     strm.avail_in = s->cluster_size;
> @@ -1066,7 +1066,7 @@ static int
qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
>     if (ret != Z_STREAM_END && ret != Z_OK) {
>         g_free(out_buf);
>         deflateEnd(&strm);
> -        return -1;
> +        return -EINVAL;
>     }
>     out_len = strm.next_out - out_buf;
>
> @@ -1079,12 +1079,13 @@ static int
qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
>         cluster_offset = qcow2_alloc_compressed_cluster_offset(bs,
>             sector_num << 9, out_len);
>         if (!cluster_offset)
> -            return -1;
> +            return -EIO;

Should free out_buf here?

>         cluster_offset &= s->cluster_offset_mask;
>         BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
> -        if (bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len)
!= out_len) {
> +        ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len);
> +        if (ret < 0) {
>             g_free(out_buf);
> -            return -1;
> +            return ret;
>         }
>     }
>
> --
> 1.7.6.4
>
>
>