Re: [Qemu-devel] [PATCH v4 2/3] qcow2: rework the cluster compression routine

[Kevin Wolf]

Am 28.08.2019 um 14:56 hat Denis Plotnikov geschrieben:
> The patch allow to process image compression type defined
> in the image header and choose an appropriate method for
> image clusters (de)compression.
> 
> Signed-off-by: Denis Plotnikov <address@hidden>
> ---
>  block/qcow2-threads.c | 78 +++++++++++++++++++++++++++++++++++--------
>  1 file changed, 64 insertions(+), 14 deletions(-)
> 
> diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
> index 3b1e63fe41..14b5bd76fb 100644
> --- a/block/qcow2-threads.c
> +++ b/block/qcow2-threads.c
> @@ -73,8 +73,11 @@ typedef struct Qcow2CompressData {
>      Qcow2CompressFunc func;
>  } Qcow2CompressData;
>  
> +

Accidentally added newline?

>  /*
> - * qcow2_compress()
> + * qcow2_zlib_compress()
> + *
> + * Compress @src_size bytes of data using zlib compression method
>   *
>   * @dest - destination buffer, @dest_size bytes
>   * @src - source buffer, @src_size bytes
> @@ -83,8 +86,8 @@ typedef struct Qcow2CompressData {
>   *          -ENOMEM destination buffer is not enough to store compressed data
>   *          -EIO    on any other error
>   */
> -static ssize_t qcow2_compress(void *dest, size_t dest_size,
> -                              const void *src, size_t src_size)
> +static ssize_t qcow2_zlib_compress(void *dest, size_t dest_size,
> +                                   const void *src, size_t src_size)
>  {
>      ssize_t ret;
>      z_stream strm;
> @@ -119,19 +122,19 @@ static ssize_t qcow2_compress(void *dest, size_t 
> dest_size,
>  }
>  
>  /*
> - * qcow2_decompress()
> + * qcow2_zlib_decompress()
>   *
>   * Decompress some data (not more than @src_size bytes) to produce exactly
> - * @dest_size bytes.
> + * @dest_size bytes using zlib compression method
>   *
>   * @dest - destination buffer, @dest_size bytes
>   * @src - source buffer, @src_size bytes
>   *
>   * Returns: 0 on success
> - *          -1 on fail
> + *          -EIO on fail
>   */
> -static ssize_t qcow2_decompress(void *dest, size_t dest_size,
> -                                const void *src, size_t src_size)
> +static ssize_t qcow2_zlib_decompress(void *dest, size_t dest_size,
> +                                     const void *src, size_t src_size)
>  {
>      int ret = 0;
>      z_stream strm;
> @@ -144,7 +147,7 @@ static ssize_t qcow2_decompress(void *dest, size_t 
> dest_size,
>  
>      ret = inflateInit2(&strm, -12);
>      if (ret != Z_OK) {
> -        return -1;
> +        return -EIO;
>      }
>  
>      ret = inflate(&strm, Z_FINISH);
> @@ -154,7 +157,7 @@ static ssize_t qcow2_decompress(void *dest, size_t 
> dest_size,
>           * @src buffer may be processed partly (because in qcow2 we know 
> size of
>           * compressed data with precision of one sector)
>           */
> -        ret = -1;
> +        ret = -EIO;
>      }
>  
>      inflateEnd(&strm);
> @@ -189,20 +192,67 @@ qcow2_co_do_compress(BlockDriverState *bs, void *dest, 
> size_t dest_size,
>      return arg.ret;
>  }
>  
> +/*
> + * qcow2_co_compress()
> + *
> + * Compress @src_size bytes of data using the compression
> + * method defined by the image compression type
> + *
> + * @dest - destination buffer, @dest_size bytes
> + * @src - source buffer, @src_size bytes
> + *
> + * Returns: 0 on success
> + *          a negative error code on fail

on failure

> + */
>  ssize_t coroutine_fn
>  qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
>                    const void *src, size_t src_size)
>  {
> -    return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
> -                                qcow2_compress);
> +    BDRVQcow2State *s = bs->opaque;
> +    Qcow2CompressFunc fn;
> +
> +    switch (s->compression_type) {
> +    case QCOW2_COMPRESSION_TYPE_ZLIB:
> +        fn = qcow2_zlib_compress;
> +        break;
> +
> +    default:
> +        return -ENOTSUP;
> +    }
> +
> +    return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
>  }
>  
> +/*
> + * qcow2_co_decompress()
> + *
> + * Decompress some data (not more than @src_size bytes) to produce exactly
> + * @dest_size bytes using the compression method defined by the image
> + * compression type
> + *
> + * @dest - destination buffer, @dest_size bytes
> + * @src - source buffer, @src_size bytes
> + *
> + * Returns: 0 on success
> + *          a negative error code on fail

on failure

> + */
>  ssize_t coroutine_fn
>  qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
>                      const void *src, size_t src_size)
>  {
> -    return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
> -                                qcow2_decompress);
> +    BDRVQcow2State *s = bs->opaque;
> +    Qcow2CompressFunc fn;
> +
> +    switch (s->compression_type) {
> +    case QCOW2_COMPRESSION_TYPE_ZLIB:
> +        fn = qcow2_zlib_decompress;
> +        break;
> +
> +    default:
> +        return -ENOTSUP;
> +    }
> +
> +    return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
>  }

Kevin