[PATCH] Don't use tapdisk for cd-roms

[PATCH] Don't use tapdisk for cd-roms

[George Dunlap]

blktap does not support the insert / eject commands, and so is not
suitable for cd-roms.

This fixes the bug where libxl uses tapdisk as a cdrom back-end, causing
subsequent eject / insert commands to fail.

Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
CC: Fabio Fantoni <fabio.fantoni@heliman.it>
CC: Ian Jackson <ian.jackson@citrix.com>
CC: Stefano Stabellini <stefano.stabellini@citrix.com>
CC: Ian Campbell <ian.campbell@citrix.com>
---
 tools/libxl/libxl_device.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
index a826ece..a5cf446 100644
--- a/tools/libxl/libxl_device.c
+++ b/tools/libxl/libxl_device.c
@@ -178,6 +178,12 @@ static int disk_try_backend(disk_try_backend_args *a,
     case LIBXL_DISK_BACKEND_TAP:
         if (a->disk->script) goto bad_script;
 
+        if (a->disk->is_cdrom) {
+            LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "Disk vdev=%s, backend tap"
+                       " unsuitable for cdroms",
+                       a->disk->vdev);
+            return 0;
+        }
         if (!libxl__blktap_enabled(a->gc)) {
             LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "Disk vdev=%s, backend tap"
                        " unsuitable because blktap not available",
-- 
1.7.9.5

Re: [PATCH] Don't use tapdisk for cd-roms

[George Dunlap]

On 02/05/13 12:03, George Dunlap wrote:
> blktap does not support the insert / eject commands, and so is not
> suitable for cd-roms.
>
> This fixes the bug where libxl uses tapdisk as a cdrom back-end, causing
> subsequent eject / insert commands to fail.

This is also a candidate for backport to 4.2, as the same issue is 
present there.

  -George

Re: [PATCH] Don't use tapdisk for cd-roms

[Fabio Fantoni]

Il 02/05/2013 13:03, George Dunlap ha scritto:
> blktap does not support the insert / eject commands, and so is not
> suitable for cd-roms.
>
> This fixes the bug where libxl uses tapdisk as a cdrom back-end, causing
> subsequent eject / insert commands to fail.
>
> Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
Tested-by: Fabio Fantoni <fabio.fantoni@m2r.biz>
> CC: Fabio Fantoni <fabio.fantoni@heliman.it>
> CC: Ian Jackson <ian.jackson@citrix.com>
> CC: Stefano Stabellini <stefano.stabellini@citrix.com>
> CC: Ian Campbell <ian.campbell@citrix.com>
> ---
>   tools/libxl/libxl_device.c |    6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
> index a826ece..a5cf446 100644
> --- a/tools/libxl/libxl_device.c
> +++ b/tools/libxl/libxl_device.c
> @@ -178,6 +178,12 @@ static int disk_try_backend(disk_try_backend_args *a,
>       case LIBXL_DISK_BACKEND_TAP:
>           if (a->disk->script) goto bad_script;
>   
> +        if (a->disk->is_cdrom) {
> +            LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "Disk vdev=%s, backend tap"
> +                       " unsuitable for cdroms",
> +                       a->disk->vdev);
> +            return 0;
> +        }
>           if (!libxl__blktap_enabled(a->gc)) {
>               LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "Disk vdev=%s, backend tap"
>                          " unsuitable because blktap not available",
Tested with xen unstable and qemu upstream, domU windows 7 pro 64 bit 
with GPLPV and it is working! :-)
Thanks! I waited cd hotswap working for a long time.

The only thing to fix it seems the help that actually shows:

xl cd-insert --help
Usage: xl [-vfN] cd-insert <Domain> <VirtualDevice> <type:path>

While the command is working removing "type:", for example:

xl cd-insert W7 hdb /mnt/vm/iso/Clonezilla.iso
is working.

Re: [PATCH] Don't use tapdisk for cd-roms

[Ian Jackson]

George Dunlap writes ("[PATCH] Don't use tapdisk for cd-roms"):
> blktap does not support the insert / eject commands, and so is not
> suitable for cd-roms.
> 
> This fixes the bug where libxl uses tapdisk as a cdrom back-end, causing
> subsequent eject / insert commands to fail.
> 
> Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
> CC: Fabio Fantoni <fabio.fantoni@heliman.it>
> CC: Ian Jackson <ian.jackson@citrix.com>
> CC: Stefano Stabellini <stefano.stabellini@citrix.com>
> CC: Ian Campbell <ian.campbell@citrix.com>

Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>