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Re: [Qemu-devel] [PATCH v3 2/3] qcow2: rework the cluster compression ro
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
Re: [Qemu-devel] [PATCH v3 2/3] qcow2: rework the cluster compression routine |
Date: |
Tue, 27 Aug 2019 11:59:45 +0000 |
19.08.2019 18:00, Denis Plotnikov wrote:
> 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;
>
> +
> /*
> - * 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
> + */
> 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;
it may be g_assert_not_reached() instead, as we never set state field to
unsupported value.
> + }
> +
> + 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
> + */
> 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;
and here, and may be in previous patch (where call switch on
s->compression_type)
But anyway, with this changed or without:
Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> + }
> +
> + return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
> }
>
>
>
--
Best regards,
Vladimir