libvolume_id: narrow down ufs detection

[Andriy Gapon]

I think that libvolume_id should compare fs size to provider size similarly to
what geom_label does and for the same reasons. With geom providers stacked upon
each other current libvolume_id may see the same fs on multiple volume-like devices.

An example:
o ad6s1a and ad10s1a comprise a geom_mirror named 'bootgm'
o there is a UFS on bootgm and it is labeled as 'bootfs'

Snippets from lshal output:
=======================
udi = '/org/freedesktop/Hal/devices/volume_label_bootfs_0'
  block.device = '/dev/ad6s1a'  (string)
  block.is_volume = true  (bool)
  block.major = 0  (0x0)  (int)
  block.minor = 92  (0x5c)  (int)
  block.storage_device = '/org/freedesktop/Hal/devices/pci_8086_2922_storage_0'
(string)
  info.capabilities = {'block', 'volume'} (string list)
  info.category = 'volume'  (string)
  info.interfaces = {'org.freedesktop.Hal.Device.Volume'} (string list)
  info.parent = '/org/freedesktop/Hal/devices/volume_part2_size_6440361984_0'
(string)
  info.product = 'bootfs'  (string)
  info.subsystem = 'block'  (string)
  info.udi = '/org/freedesktop/Hal/devices/volume_label_bootfs_0'  (string)
  org.freedesktop.Hal.Device.Volume.method_argnames = {'mount_point fstype
extra_options', 'extra_options', 'extra_options'} (string list)
  org.freedesktop.Hal.Device.Volume.method_execpaths = {'hal-storage-mount',
'hal-storage-unmount', 'hal-storage-eject'} (string list)
  org.freedesktop.Hal.Device.Volume.method_names = {'Mount', 'Unmount', 'Eject'}
(string list)
  org.freedesktop.Hal.Device.Volume.method_signatures = {'ssas', 'as', 'as'}
(string list)
  volume.block_size = 512  (0x200)  (uint64)
  volume.fstype = 'ufs'  (string)
  volume.fsusage = 'filesystem'  (string)
  volume.fsversion = '2'  (string)
  volume.ignore = false  (bool)
  volume.is_disc = false  (bool)
  volume.is_mounted = false  (bool)
  volume.is_mounted_read_only = false  (bool)
  volume.is_partition = false  (bool)
  volume.label = 'bootfs'  (string)
  volume.mount.valid_options = {'ro', 'noexec', 'noatime'} (string list)
  volume.mount_point = ''  (string)
  volume.num_blocks = 4194304  (0x400000)  (uint64)
  volume.size = 2147483648  (0x80000000)  (uint64)
  volume.uuid = ''  (string)
===============================
udi = '/org/freedesktop/Hal/devices/volume_label_bootfs'
  block.device = '/dev/ufs/bootfs'  (string)
  block.is_volume = true  (bool)
  block.major = 0  (0x0)  (int)
  block.minor = 112  (0x70)  (int)
  block.storage_device = '/org/freedesktop/Hal/devices/pci_8086_2922_storage'
(string)
  info.capabilities = {'block', 'volume'} (string list)
  info.category = 'volume'  (string)
  info.interfaces = {'org.freedesktop.Hal.Device.Volume'} (string list)
  info.parent = '/org/freedesktop/Hal/devices/volume_size_2147483136'  (string)
  info.product = 'bootfs'  (string)
  info.subsystem = 'block'  (string)
  info.udi = '/org/freedesktop/Hal/devices/volume_label_bootfs'  (string)
  org.freedesktop.Hal.Device.Volume.method_argnames = {'mount_point fstype
extra_options', 'extra_options', 'extra_options'} (string list)
  org.freedesktop.Hal.Device.Volume.method_execpaths = {'hal-storage-mount',
'hal-storage-unmount', 'hal-storage-eject'} (string list)
  org.freedesktop.Hal.Device.Volume.method_names = {'Mount', 'Unmount', 'Eject'}
(string list)
  org.freedesktop.Hal.Device.Volume.method_signatures = {'ssas', 'as', 'as'}
(string list)
  volume.block_size = 512  (0x200)  (uint64)
  volume.fstype = 'ufs'  (string)
  volume.fsusage = 'filesystem'  (string)
  volume.fsversion = '2'  (string)
  volume.ignore = false  (bool)
  volume.is_disc = false  (bool)
  volume.is_mounted = true  (bool)
  volume.is_mounted_read_only = false  (bool)
  volume.is_partition = false  (bool)
  volume.label = 'bootfs'  (string)
  volume.mount.valid_options = {'ro', 'noexec', 'noatime'} (string list)
  volume.mount_point = '/.bootdir'  (string)
  volume.num_blocks = 4194303  (0x3fffff)  (uint64)
  volume.size = 2147483136  (0x7ffffe00)  (uint64)
  volume.uuid = ''  (string)
=============================

I think that UFS on the first volume should not be reported.

-- 
Andriy Gapon