Re: [Qemu-devel] [PATCH v5] mirror: correct buf_size

[Jeff Cody <jcody@redhat.com>]

On Fri, May 15, 2015 at 03:51:36PM +0800, Wen Congyang wrote:
> If bus_size is less than 0, the command fails.
> If buf_size is 0, use DEFAULT_MIRROR_BUF_SIZE.
> If buf_size % granularity is not 0, mirror_free_init() will
> do dangerous things.
> 
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> Reviewed-by: Fam Zheng <famz@redhat.com>
> ---
>  block/mirror.c | 11 ++++++++++-
>  blockdev.c     |  4 +---
>  2 files changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/block/mirror.c b/block/mirror.c
> index 58f391a..25645ef 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -19,6 +19,7 @@
>  
>  #define SLICE_TIME    100000000ULL /* ns */
>  #define MAX_IN_FLIGHT 16
> +#define DEFAULT_MIRROR_BUF_SIZE   (10 << 20)
>  
>  /* The mirroring buffer is a list of granularity-sized chunks.
>   * Free chunks are organized in a list.
> @@ -671,6 +672,14 @@ static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target,
>          return;
>      }
>  
> +    if (buf_size < 0) {
> +        error_setg(errp, "Invalid parameter 'buf-size'");
> +        return;
> +    }
> +
> +    if (buf_size == 0) {
> +        buf_size = DEFAULT_MIRROR_BUF_SIZE;
> +    }
>  
>      s = block_job_create(driver, bs, speed, cb, opaque, errp);
>      if (!s) {
> @@ -684,7 +693,7 @@ static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target,
>      s->is_none_mode = is_none_mode;
>      s->base = base;
>      s->granularity = granularity;
> -    s->buf_size = MAX(buf_size, granularity);
> +    s->buf_size = ROUND_UP(buf_size, granularity);
>  
>      s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp);
>      if (!s->dirty_bitmap) {
> diff --git a/blockdev.c b/blockdev.c
> index 5eaf77e..95a0c6a 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -2619,8 +2619,6 @@ out:
>      aio_context_release(aio_context);
>  }
>  
> -#define DEFAULT_MIRROR_BUF_SIZE   (10 << 20)
> -
>  void qmp_drive_mirror(const char *device, const char *target,
>                        bool has_format, const char *format,
>                        bool has_node_name, const char *node_name,
> @@ -2661,7 +2659,7 @@ void qmp_drive_mirror(const char *device, const char *target,
>          granularity = 0;
>      }
>      if (!has_buf_size) {
> -        buf_size = DEFAULT_MIRROR_BUF_SIZE;
> +        buf_size = 0;
>      }
>  
>      if (granularity != 0 && (granularity < 512 || granularity > 1048576 * 64)) {
> -- 
> 2.1.0


Thanks, applied to my block tree:
https://github.com/codyprime/qemu-kvm-jtc/commits/block

Jeff