df -h показывает неправильное свободное пространство

Вот мой выход df-h. Здесь /media/Songs использует почти 100% дискового пространства.

root@LAB:~# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1              19G  8.7G  9.2G  49% /
udev                  1.5G  4.0K  1.5G   1% /dev
tmpfs                 596M  960K  595M   1% /run
none                  1.5G  1.5M  1.5G   1% /run/shm
/dev/sda7              99G   32G   63G  34% /media/Softs
/dev/sda6              99G   90G  3.6G  97% /media/Films
/dev/sda8             106G   61G   40G  61% /media/Misc
/dev/sda5              99G   94G  4.9M 100% /media/Songs

Вот подробный обзор /media/Songs.

root@LAB:~# du -sch /media/Songs/*
39G /media/Songs/AUDIO
16K /media/Songs/lost+found
55G /media/Songs/Video
93G total
root@LAB:~# 

Мой вопрос: где находится 5 ГБ свободное место?

В G-parted, а также nautilus он показывает 5 ГБ свободного места, но доступное пространство составляет всего 4.9Mb. Почему?

Вот мои данные о системе.

root@LAB:~# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 11.10
Release:    11.10
Codename:   oneiric

root@LAB:~# uname -a
Linux LAB 3.0.0-12-generic #20-Ubuntu SMP Fri Oct 7 14:56:25 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux

root@LAB:~# df -i
Filesystem            Inodes   IUsed   IFree IUse% Mounted on
/dev/sda1            1250928  182541 1068387   15% /
udev                  378633     606  378027    1% /dev
tmpfs                 381366     563  380803    1% /run
none                  381366       9  381357    1% /run/shm
/dev/sda7            6553600   16148 6537452    1% /media/Softs
/dev/sda6            6553600     484 6553116    1% /media/Films
/dev/sda8            6995968    4287 6991681    1% /media/Misc
/dev/sda5            6553600   10857 6542743    1% /media/Songs


root@LAB:~# tune2fs -l /dev/sda5
tune2fs 1.41.14 (22-Dec-2010)
Filesystem volume name:   Songs
Last mounted on:          /media/Songs
Filesystem UUID:          191fe922-ed45-431f-9ae6-4ab1247701d9
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
Filesystem flags:         signed_directory_hash 
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              6553600
Block count:              26214400
Reserved block count:     1310720
Free blocks:              1311973
Free inodes:              6542744
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      1017
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         8192
Inode blocks per group:   512
Flex block group size:    16
Filesystem created:       Sun Jul 17 16:06:42 2011
Last mount time:          Thu Nov 17 02:36:00 2011
Last write time:          Thu Nov 17 02:36:00 2011
Mount count:              1
Maximum mount count:      35
Last checked:             Thu Nov 17 02:35:20 2011
Check interval:           15552000 (6 months)
Next check after:         Tue May 15 02:35:20 2012
Lifetime writes:          98 GB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:           256
Required extra isize:     28
Desired extra isize:      28
Journal inode:            8
Default directory hash:   half_md4
Directory Hash Seed:      dc98c454-9826-4f42-ad66-3fb7a1941526
Journal backup:           inode blocks