Greyhole shouldn't be available when shares are on a non-Linux-formatted partition
Non-Linux-formatted partitions (like NTFS or FAT) can't handle symlinks, and since symlinks are created in the shared directories by Greyhole, it just won't work with such partitions.
You probably want to stop the user from being able to use the storage pool page when /var/hda/files is not Linux-formatted.
And stop the user from being able to check 'Uses Pool' if the share is not Linux-formatted.
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