Re: [Qemu-devel] [PATCH 2/6] cloop: Fix bdrv_open() error handling

[Markus Armbruster]

Kevin Wolf <address@hidden> writes:

> Return -errno instead of -1 on errors. While touching the
> code, fix a memory leak.
>
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
>  block/cloop.c |   27 +++++++++++++++++----------
>  1 files changed, 17 insertions(+), 10 deletions(-)
>
> diff --git a/block/cloop.c b/block/cloop.c
> index 5a0d0d8..9b36063 100644
> --- a/block/cloop.c
> +++ b/block/cloop.c
> @@ -57,27 +57,32 @@ static int cloop_open(BlockDriverState *bs, int flags)
>  {
>      BDRVCloopState *s = bs->opaque;
>      uint32_t offsets_size, max_compressed_block_size = 1, i;
> +    int ret;
>  
>      bs->read_only = 1;
>  
>      /* read header */
> -    if (bdrv_pread(bs->file, 128, &s->block_size, 4) < 4) {
> -        goto cloop_close;
> +    ret = bdrv_pread(bs->file, 128, &s->block_size, 4);
> +    if (ret < 0) {
> +        return ret;
>      }
>      s->block_size = be32_to_cpu(s->block_size);
>  
> -    if (bdrv_pread(bs->file, 128 + 4, &s->n_blocks, 4) < 4) {
> -        goto cloop_close;
> +    ret = bdrv_pread(bs->file, 128 + 4, &s->n_blocks, 4);
> +    if (ret < 0) {
> +        return ret;
>      }
>      s->n_blocks = be32_to_cpu(s->n_blocks);
>  
>      /* read offsets */
>      offsets_size = s->n_blocks * sizeof(uint64_t);
>      s->offsets = g_malloc(offsets_size);
> -    if (bdrv_pread(bs->file, 128 + 4 + 4, s->offsets, offsets_size) <
> -            offsets_size) {
> -        goto cloop_close;
> +

Empty line visually detaches the /* read offsets */ comment from the
actual read.  Sure you want it?

> +    ret = bdrv_pread(bs->file, 128 + 4 + 4, s->offsets, offsets_size);
> +    if (ret < 0) {
> +        goto fail;
>      }
> +
>      for(i=0;i<s->n_blocks;i++) {
>          s->offsets[i] = be64_to_cpu(s->offsets[i]);
>          if (i > 0) {
> @@ -92,7 +97,8 @@ static int cloop_open(BlockDriverState *bs, int flags)
>      s->compressed_block = g_malloc(max_compressed_block_size + 1);
>      s->uncompressed_block = g_malloc(s->block_size);
>      if (inflateInit(&s->zstream) != Z_OK) {
> -        goto cloop_close;
> +        ret = -EINVAL;

inflateInit() can return a number of different errors.  But your change
doesn't make things worse, and that's good enough.

> +        goto fail;
>      }
>      s->current_block = s->n_blocks;
>  
> @@ -101,8 +107,9 @@ static int cloop_open(BlockDriverState *bs, int flags)
>      qemu_co_mutex_init(&s->lock);
>      return 0;
>  
> -cloop_close:
> -    return -1;
> +fail:
> +    g_free(s->offsets);

What about s->compressed_block and s->uncompressed_block?

> +    return ret;
>  }
>  
>  static inline int cloop_read_block(BlockDriverState *bs, int block_num)