Re: [Qemu-devel] [PATCH v2 6/6] qemu-nbd: Use BlockBackend where reasonable

[Paolo Bonzini]

On 18/11/2014 12:21, Max Reitz wrote:
> Because qemu-nbd creates the BlockBackend by itself, it should create
> the according BlockDriverState tree by itself as well; that means, it
> has call bdrv_open() on its own. This is one of the places where
> qemu-nbd still needs to use a BlockDriverState directly (the root BDS
> below the BB); other places are the configuration of zero detection
> (which may be lifted into the BB eventually, but is not yet) and
> temporarily loading a snapshot.
> 
> Everywhere else, though, qemu-nbd can and thus should use BlockBackend.

... which is not much, but is nevertheless a start. :)

Reviewed-by: Paolo Bonzini <address@hidden>

> Suggested-by: Paolo Bonzini <address@hidden>
> Signed-off-by: Max Reitz <address@hidden>
> ---
>  qemu-nbd.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/qemu-nbd.c b/qemu-nbd.c
> index 60ce50f..d222512 100644
> --- a/qemu-nbd.c
> +++ b/qemu-nbd.c
> @@ -146,7 +146,7 @@ static void read_partition(uint8_t *p, struct 
> partition_record *r)
>      r->nb_sectors_abs = p[12] | p[13] << 8 | p[14] << 16 | p[15] << 24;
>  }
>  
> -static int find_partition(BlockDriverState *bs, int partition,
> +static int find_partition(BlockBackend *blk, int partition,
>                            off_t *offset, off_t *size)
>  {
>      struct partition_record mbr[4];
> @@ -155,7 +155,7 @@ static int find_partition(BlockDriverState *bs, int 
> partition,
>      int ext_partnum = 4;
>      int ret;
>  
> -    if ((ret = bdrv_read(bs, 0, data, 1)) < 0) {
> +    if ((ret = blk_read(blk, 0, data, 1)) < 0) {
>          errno = -ret;
>          err(EXIT_FAILURE, "error while reading");
>      }
> @@ -175,7 +175,7 @@ static int find_partition(BlockDriverState *bs, int 
> partition,
>              uint8_t data1[512];
>              int j;
>  
> -            if ((ret = bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) < 
> 0) {
> +            if ((ret = blk_read(blk, mbr[i].start_sector_abs, data1, 1)) < 
> 0) {
>                  errno = -ret;
>                  err(EXIT_FAILURE, "error while reading");
>              }
> @@ -720,10 +720,10 @@ int main(int argc, char **argv)
>      }
>  
>      bs->detect_zeroes = detect_zeroes;
> -    fd_size = bdrv_getlength(bs);
> +    fd_size = blk_getlength(blk);
>  
>      if (partition != -1) {
> -        ret = find_partition(bs, partition, &dev_offset, &fd_size);
> +        ret = find_partition(blk, partition, &dev_offset, &fd_size);
>          if (ret < 0) {
>              errno = -ret;
>              err(EXIT_FAILURE, "Could not find partition %d", partition);
>