[sheepdog] [PATCH v2] sheepdog: selectable object size support

[Hitoshi Mitake]

At Tue, 20 Jan 2015 16:14:28 +0900,
Teruaki Ishizaki wrote:
> 
> Previously, qemu block driver of sheepdog used hard-coded VDI object size.
> This patch enables users to handle "block_size_shift" value for
> calculating VDI object size.
> 
> When you start qemu, you don't need to specify additional command option.
> 
> But when you create the VDI which doesn't have default object size
> with qemu-img command, you specify block_size_shift option.
> 
> If you want to create a VDI of 8MB(1 << 23) object size,
> you need to specify following command option.
> 
>  # qemu-img create -o block_size_shift=23 sheepdog:test1 100M
> 
> In addition, when you don't specify qemu-img command option,
> a default value of sheepdog cluster is used for creating VDI.
> 
>  # qemu-img create sheepdog:test2 100M
> 
> Signed-off-by: Teruaki Ishizaki <ishizaki.teruaki at lab.ntt.co.jp>
> ---
> V2:
>  - Fix coding style problem (white space).
>  - Add members, store_policy and block_size_shift to struct SheepdogVdiReq
>  - Initialize request header to use block_size_shift specified by user.
> ---
>  block/sheepdog.c          |  142 ++++++++++++++++++++++++++++++++++++++-------
>  include/block/block_int.h |    1 +
>  2 files changed, 121 insertions(+), 22 deletions(-)
> 

> @@ -1757,6 +1800,48 @@ static int sd_create(const char *filename, QemuOpts *opts,
>      }
>  
>      s->aio_context = qemu_get_aio_context();
> +
> +    /* if block_size_shift is not specified, get cluster default value */
> +    if (s->inode.block_size_shift == 0) {
> +        SheepdogVdiReq hdr;
> +        SheepdogClusterRsp *rsp = (SheepdogClusterRsp *)&hdr;
> +        Error *local_err = NULL;
> +        int fd;
> +        unsigned int wlen = 0, rlen = 0;
> +
> +        fd = connect_to_sdog(s, &local_err);
> +        if (fd < 0) {
> +            error_report("%s", error_get_pretty(local_err));
> +            error_free(local_err);
> +            ret = -EIO;
> +            goto out;
> +        }
> +
> +        memset(&hdr, 0, sizeof(hdr));

SD_OP_GET_CLUSTER_DEFAULT doesn't require succeeding data, so the below memset() for buf and

> +        memset(&buf, 0, sizeof(buf));
> +        hdr.opcode = SD_OP_GET_CLUSTER_DEFAULT;
> +        hdr.proto_ver = SD_PROTO_VER;

the below two statements aren't required.

> +        hdr.data_length = wlen;
> +        hdr.flags = SD_FLAG_CMD_WRITE;

Thanks,
Hitoshi