Re: [Qemu-block] [Qemu-devel] [PATCH 06/20] xen_disk: Call blk_set_enable_write_cache() explicitly

[Stefano Stabellini]

On Fri, 18 Mar 2016, Kevin Wolf wrote:
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
>  hw/block/xen_disk.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
> index 635328f..c358709 100644
> --- a/hw/block/xen_disk.c
> +++ b/hw/block/xen_disk.c
> @@ -888,12 +888,14 @@ static int blk_connect(struct XenDevice *xendev)
>      struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, 
> xendev);
>      int pers, index, qflags;
>      bool readonly = true;
> +    bool writethrough = true;
>  
>      /* read-only ? */
>      if (blkdev->directiosafe) {
>          qflags = BDRV_O_NOCACHE | BDRV_O_NATIVE_AIO;
>      } else {
> -        qflags = BDRV_O_CACHE_WB;
> +        qflags = 0;

You might as well initialize qflags to 0 above and leave it unchanged
here. In any case:

Acked-by: Stefano Stabellini <address@hidden>


> +        writethrough = false;
>      }
>      if (strcmp(blkdev->mode, "w") == 0) {
>          qflags |= BDRV_O_RDWR;
> @@ -925,6 +927,7 @@ static int blk_connect(struct XenDevice *xendev)
>              error_free(local_err);
>              return -1;
>          }
> +        blk_set_enable_write_cache(blkdev->blk, !writethrough);
>      } else {
>          /* setup via qemu cmdline -> already setup for us */
>          xen_be_printf(&blkdev->xendev, 2, "get configured bdrv (cmdline 
> setup)\n");
> -- 
> 1.8.3.1
> 
>