ZFS does not correctly import by label

[Ben RUBSON]

> On 16 Aug 2016, at 11:09, Ben RUBSON <ben.rubson at gmail.com> wrote:
> 
> Hello,
> 
> Sounds like ZFS does not correctly import cache and spares by label.
> 
> Example :
> 
> # zpool add home cache label/G12000KU2RVJAch
> # zpool add home spare label/G1207PFGPTKDXhm 
> # zpool status home
>  (...)
>  home                       ONLINE       0     0     0
>    mirror-0                 ONLINE       0     0     0
>      label/G1203PGGLJWZXhm  ONLINE       0     0     0
>      label/G1204PHKXHJ2Xhm  ONLINE       0     0     0
>  (...)
>  logs
>    mirror-2                 ONLINE       0     0     0
>      label/G12000KU2RVJAlg  ONLINE       0     0     0
>      label/G12010KU22RVAlg  ONLINE       0     0     0
>  (...)
>  cache
>    label/G12000KU2RVJAch    ONLINE       0     0     0
>  spares
>    label/G1207PFGPTKDXhm    AVAIL
> 
> # zpool export home
> # zpool import -d /dev/label/ home
> # zpool status home
>  (...)
>  home                       ONLINE       0     0     0
>    mirror-0                 ONLINE       0     0     0
>      label/G1203PGGLJWZXhm  ONLINE       0     0     0
>      label/G1204PHKXHJ2Xhm  ONLINE       0     0     0
>  (...)
>  logs
>    mirror-2                 ONLINE       0     0     0
>      label/G12000KU2RVJAlg  ONLINE       0     0     0
>      label/G12010KU22RVAlg  ONLINE       0     0     0
>  (...)
>  cache
>    da5p7                    ONLINE       0     0     0
>  spares
>    da4p1                    AVAIL
> 
> # uname -v
> FreeBSD 10.3-RELEASE-p7 #0: Thu Aug 11 18:38:15 UTC 2016     root at amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC 

I just tested my pool under FreeBSD 11-RC1, the issue does not occur, cache and spares are correctly imported by label.
Could it be possible to backport required changes to 10.3 ?

Many thanks !

Ben