Re: [Xen-devel] [PATCH RFC 2/5] blkif: document new blkback path xenstore node

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Fri, May 22, 2015 at 11:18:55AM +0200, Roger Pau Monne wrote:
> FreeBSD blkback uses the path xenstore node in order to fetch the path to
> the underlying backing storage (either a block device or raw image). This
> node is set by the hotplug scripts.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
> Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Tim Deegan <tim@xxxxxxx>
> ---
>  xen/include/public/io/blkif.h | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/include/public/io/blkif.h b/xen/include/public/io/blkif.h
> index 6baf7fb..b1e2245 100644
> --- a/xen/include/public/io/blkif.h
> +++ b/xen/include/public/io/blkif.h
> @@ -89,8 +89,15 @@
>   *      Values:         string
>   *
>   *      A free formatted string providing sufficient information for the
> - *      backend driver to open the backing device.  (e.g. the path to the
> - *      file or block device representing the backing store.)
> + *      hotplug script to attach the device and provide a suitable
> + *      handler (ie: a block device) for blkback to use.
> + *
> + * path
> + *      Values:         string
> + *      Notes: 11
> + *
> + *      A free formatted string that contains the path to the backing device
> + *      for this blkback instance.

Why can't FreeBSD use the same "physical-device" node as Linux and
NetBSD do? AIUI from reading this doc "physical-device" node already
covers both "file" and "block device", i.e. it's a superset of the
proposed "path" node here.

Wei.

>   *
>   * type
>   *      Values:         "file", "phy", "tap"
> @@ -385,6 +392,7 @@
>   *     than RING_SIZE * BLKIF_MAX_SEGMENTS_PER_REQUEST.
>   *(10) The discard-secure property may be present and will be set to 1 if the
>   *     backing device supports secure discard.
> + *(11) This node is only present on FreeBSD.
>   */
>  
>  /*
> -- 
> 1.9.5 (Apple Git-50.3)
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel