Re: [Qemu-devel] [PATCH V3] virtio-blk: add default serial id

[Dave Young <dyoung@redhat.com>]

Hi, Eric

This is in fact same with v1 except the spelling fixes.

I switched back to v1 because of your concern about the same id reusing
issue. For v1, unplugging 100000 times is not likely and insane, so I
think we can safely ignore it.

Unless qemu-img create some uuid for disk imgs I think there's no way
to create some really ideal *uniq* ids.

On 09/26/2012 04:18 PM, Dave Young wrote:

> For virtio block device, if user does not specify the serial attribute,
> There will be no serial availabe, this is not convenient for identifying
> the disk.
> 
> Doing something similar to ide disks, add a "VD0000?" default serial
> number if user does not specify it.
> 
> Signed-off-by: Dave Young <dyoung@redhat.com>
> ---
>  hw/virtio-blk.c |    9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> --- qemu-kvm.orig/hw/virtio-blk.c	2012-09-02 09:45:03.115696878 +0800
> +++ qemu-kvm/hw/virtio-blk.c	2012-09-20 20:57:56.177206991 +0800
> @@ -22,6 +22,7 @@
>  # include <scsi/sg.h>
>  #endif
>  
> +#define DEFAULT_VIRTIO_BLK_SERIAL_LEN 8
>  typedef struct VirtIOBlock
>  {
>      VirtIODevice vdev;
> @@ -33,6 +34,7 @@ typedef struct VirtIOBlock
>      VirtIOBlkConf *blk;
>      unsigned short sector_mask;
>      DeviceState *qdev;
> +    int drive_serial;
>  } VirtIOBlock;
>  
>  static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
> @@ -364,6 +366,7 @@ static void virtio_blk_handle_request(Vi
>      MultiReqBuffer *mrb)
>  {
>      uint32_t type;
> +    char serial[DEFAULT_VIRTIO_BLK_SERIAL_LEN];
>  
>      if (req->elem.out_num < 1 || req->elem.in_num < 1) {
>          error_report("virtio-blk missing headers");
> @@ -388,12 +391,14 @@ static void virtio_blk_handle_request(Vi
>      } else if (type & VIRTIO_BLK_T_GET_ID) {
>          VirtIOBlock *s = req->dev;
>  
> +        snprintf(serial, DEFAULT_VIRTIO_BLK_SERIAL_LEN,
> +                 "VD%05d", s->drive_serial);
>          /*
>           * NB: per existing s/n string convention the string is
>           * terminated by '\0' only when shorter than buffer.
>           */
>          strncpy(req->elem.in_sg[0].iov_base,
> -                s->blk->serial ? s->blk->serial : "",
> +                s->blk->serial ? s->blk->serial : serial,
>                  MIN(req->elem.in_sg[0].iov_len, VIRTIO_BLK_ID_BYTES));
>          virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
>          g_free(req);
> @@ -611,6 +616,7 @@ static const BlockDevOps virtio_block_op
>  
>  VirtIODevice *virtio_blk_init(DeviceState *dev, VirtIOBlkConf *blk)
>  {
> +    static int drive_serial = 1;
>      VirtIOBlock *s;
>      static int virtio_blk_id;
>  
> @@ -632,6 +638,7 @@ VirtIODevice *virtio_blk_init(DeviceStat
>                                            sizeof(struct virtio_blk_config),
>                                            sizeof(VirtIOBlock));
>  
> +    s->drive_serial = drive_serial++;
>      s->vdev.get_config = virtio_blk_update_config;
>      s->vdev.set_config = virtio_blk_set_config;
>      s->vdev.get_features = virtio_blk_get_features;
> 
> 



-- 
Thanks
Dave