[libvirt] [PATCHv2] Ignore thin pool LVM devices.

[Cole Robinson]

On 10/08/2013 11:51 PM, Dusty Mabe wrote:
> This should resolve:
> 
>   https://bugzilla.redhat.com/show_bug.cgi?id=924672
> 
> For BZ 924672 the problem stems from the fact that thin pool logical
> volume devices show up in /sbin/lvs output just like normal logical
> volumes do. Libvirt incorrectly assumes they are just normal logical
> volumes and that they will have a corresponding /dev/vgname/lvname
> device that has been created by udev and tries to use this device.
> 
> To illustrate here is an example of the /dev/vgname/ directory and
> the lvs output for a normal lv, thin lv, and thin pool:
> 
>     LV     VG       Attr      LSize  Pool Origin Data%  Move Log Copy%  Convert
>     lv     vgguests -wi-a----  1.00g
>     pool   vgguests twi-a-tz- 11.00g               0.00
>     thinlv vgguests Vwi-a-tz-  1.00g pool          0.00
> total 0
> lrwxrwxrwx. 1 root root 7 Oct  8 19:35 lv -> ../dm-7
> lrwxrwxrwx. 1 root root 7 Oct  8 19:37 thinlv -> ../dm-6
> 
> This patch modifies virStorageBackendLogicalMakeVol() to ignore thin pool
> devices.
> 
> ---
>  src/storage/storage_backend_logical.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/src/storage/storage_backend_logical.c b/src/storage/storage_backend_logical.c
> index a1a37a1..81ee4a4 100644
> --- a/src/storage/storage_backend_logical.c
> +++ b/src/storage/storage_backend_logical.c
> @@ -85,6 +85,14 @@ virStorageBackendLogicalMakeVol(virStoragePoolObjPtr pool,
>      if (attrs[4] != 'a')
>          return 0;
>  
> +    /*
> +     * Skip thin pools(t). These show up in normal lvs output
> +     * but do not have a corresponding /dev/$vg/$lv device that
> +     * is created by udev. This breaks assumptions in later code.
> +     */
> +    if (attrs[0] == 't')
> +        return 0;
> +
>      /* See if we're only looking for a specific volume */
>      if (data != NULL) {
>          vol = data;
> 

ACK

(but I'll let someone else ACK and push since I haven't historically pushed
contributer patches)

- Cole