Comment 5 for bug 363271

As a sanity check, I've reconfirmed the problem on a jaunty/ext4/amd64 system. When I select 'fsck' from the recovery menu, I am told: "mount: / is busy" (at the bottom of the screen, it goes away very quickly as the menu seems to refresh immediately after fsck errors out. When I select a root shell prompt and try "mount -o ro,remount /" I receive the same message: "mount: / is busy"

ski@portege:~$ dpkg -l | grep friendly-recovery
ii friendly-recovery 0.2.8.1 Make recovery more user-friendly

Attached is a log of what happens when I tinker a bit to try to umount other filesystems to see if that helps (short version: it doesn't).

... And here's some tune2fs -l output (from the system booted multi-user, forgot to include it in the log above)
ski@portege:~$ sudo tune2fs -l /dev/disk/by-label/root #multi-user boot
tune2fs 1.41.4 (27-Jan-2009)
Filesystem volume name: root
Last mounted on: <not available>
Filesystem UUID: b25363cd-d0c0-4d6b-ad32-efada5d29825
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: 1313280
Block count: 5242880
Reserved block count: 262160
Free blocks: 1928070
Free inodes: 1153802
First block: 0
Block size: 4096
Fragment size: 4096
Reserved GDT blocks: 1022
Blocks per group: 32768
Fragments per group: 32768
Inodes per group: 8208
Inode blocks per group: 513
Flex block group size: 16
Filesystem created: Sun Aug 16 18:01:52 2009
Last mount time: Wed Oct 14 20:45:34 2009
Last write time: Wed Oct 14 20:45:34 2009
Mount count: 20
Maximum mount count: 28
Last checked: Mon Oct 5 04:32:13 2009
Check interval: 15552000 (6 months)
Next check after: Sat Apr 3 04:32:13 2010
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
First orphan inode: 3865
Default directory hash: half_md4
Directory Hash Seed: 802ed7e2-cde7-4eef-8bdf-72922e387abc
Journal backup: inode blocks