illumos gate

Actually it's mount2zhandle that is failing (returning NULL)

1. dtrace -n 'pid$target::mount2zhandle:return { ustack(); trace(arg1); }' -c 'zoneadm -z stat install'
   dtrace: description 'pid$target::mount2zhandle:return ' matched 1 probe
   CPU ID FUNCTION:NAME
   3 77414 mount2zhandle:return
   zoneadm`mount2zhandle+0x2e
   zoneadm`create_zfs_zonepath+0x2b
   zoneadm`install_func+0x484
   zoneadm`parse_and_run+0x3c
   zoneadm`main+0x3c1
   zoneadm`_start+0x83
   0
   ERROR: the zonepath must be a ZFS dataset.
   The parent directory of the zonepath must be a ZFS dataset so that the
   zonepath ZFS dataset can be created properly.
   dtrace: pid 28482 has exited

and thus path2name and create_zfs_zonepath fail. This comment is interesting: http://src.illumos.org/source/xref/illumos-gate/usr/src/cmd/zoneadm/zoneadm.c#3504

However the ipkg brand common.ksh (which admittedly is not part of gate) assumes that zoneadm creates the dataset successfully, which is why the error happens.

mount2zhandle just calls zfs_iter_root with http://src.illumos.org/source/xref/illumos-gate/usr/src/cmd/zoneadm/zfs.c#match_mountpoint - I'm not familiar with libzfs but perhaps this needs further investigation: I don't see why the pool's root would need to be mounted here.

zoneadm creates a ZFS dataset for the zone based on the zone's zonepath attribute.
Since a zonepath is a pathname, it has to first work out if there is a suitable parent dataset and it does this by iterating datasets from the root.

However, if it finds an unmounted dataset, it stops iterating, which is wrong.

It doesn't have to be the root of the pool that is not mounted, any dataset above the zone root parent directory is enough.

bloody# zfs list -r rpool/xxx
rpool/xxx                                       61.6M  43.2G   192K  none
rpool/xxx/zones                                 61.4M  43.2G   192K  /z

bloody# zadm show sparse zonepath
"/z/sparse" 

bloody# zoneadm -z sparse install
ERROR: the zonepath must be a ZFS dataset.
The parent directory of the zonepath must be a ZFS dataset so that the
zonepath ZFS dataset can be created properly.

With the proposed patch:

bloody# /tmp/zoneadm -z sparse install
A ZFS file system has been created for this zone.

       Image: Preparing at /z/sparse/root.

With this patch I've installed a number of zones with different zonepath attributes under mounted and non-mounted datasets. All now work successfully.