Right click unmount (umount) of loop device fails

[Daniel Harvey]

Binary package hint: nautilus

I have the following loop based filesystem in /etc/fstab

/media/usbdisk/.fs.ext3 /media/usbdisk/fs ext2 defaults,noauto,loop=/dev/loop4,user,exec 0 0

Once mounted, this appears on my desktop and within nautilus "Computer".

When I right click on the volume and select "Unmount Volume", the operation fails with the message

    "Unable to unmount the selected volume."

with the details

    "umount: /dev/loop4 not mounted"
    "Error: umount failed"

Note that the graphical icon in nautilus is correctly labelled "fs", but the umount appears to attempt to unmount the loop device.

Note that the command "umount /media/usbdisk/fs" works.

[Sebastien Bacher (seb128)]

Thank you for your bug. What version of Ubuntu do you use?

[Daniel Harvey (daniel.harvey)]

Apologies, I've upgraded to edgy. The install was up to date when the bug was reported.

[Sebastien Bacher (seb128)]

Could you gives extra details on the configuration you use? What is /media/usbdisk? a mounted device?

[Daniel Harvey (daniel.harvey)]

Yes, /media/usbdisk is a mounted USB device, and the mount point is a directory 'fs' within this.

I've done some more checking and I don't believe this is related to the problem. The problem appears to be related to mount/umount and the use of loop devices.

My mount line represents the following:

/media/usbdisk/.fs.ext3 --> /dev/loop4 --> /media/usbdisk/fs ext2
file containing EXT3 filesystem --> loop device --> mounted EXT3 filesystem

The problem is that in the past, "umount /dev/loop4" worked, and this is the command that the Gnome interface is executing.

My setup is as follows:

daniel@elvandar:~$ dpkg -S /bin/umount
diversion by loop-aes-utils from: /bin/umount
diversion by loop-aes-utils to: /bin/umount.orig
mount, loop-aes-utils: /bin/umount

daniel@elvandar:~$ dpkg -l mount loop-aes-utils

||/ Name Version Description
+++-==============-==============-============================================
ii loop-aes-utils 2.12r-11 Tools for mounting and manipulating filesyst
ii mount 2.12r-11ubuntu Tools for mounting and manipulating filesyst

So, perhaps the problem is loop-aes-utils?

[Sebastien Bacher (seb128)]

Does "umounrt /dev/loop4" work correctly now then?

[Sebastien Bacher (seb128)]

No reply, closing. Feel free to reopen with the asked informations if you still get the bug

[Daniel Harvey (daniel.harvey)]

Still a problem. Re-opening, see updated comments.

[Daniel Harvey (daniel.harvey)]

I passed this over the linux crypto list as it may have related to the loop-aes code. Comment received from Jari Ruusu <email address hidden> detailed below. I think that the problem can be confirmed that umount parameter needs to match mount.

In this case, option (3) below is used in which case the loop device is set up by the mount command. This means that "/dev/loop4" was *not* mounted and should not be un-mounted. Specifically, nautilus should executed "umount /media/usbdisk/fs" not "umount /dev/loop4".

--

> My fstab mount line represents the following:
>
> /media/usbdisk/.fs.ext3 --> /dev/loop4 --> /media/usbdisk/fs ext2
> file containing EXT3 filesystem --> loop device --> mounted EXT3
> filesystem

That is journaling file system on file backed loop.
loop-AES README section 2.2.

> The problem is that in the past, "umount /dev/loop4" worked, but NOT any
> more.

There are three ways to mount loop devices:

1) Do loop setup/teardown manually:

   losetup -e AES128 -K foo.gpg /dev/loop4 /dev/hda999
   mount -t ext3 /dev/loop4 /mnt
   umount /mnt (or umount /dev/loop4 )
   losetup -d /dev/loop4

2) Let mount/umount do loop setup/teardown for you:

   mount -t ext3 /dev/hda999 /mnt -o loop=/dev/loop4,encryption=AES128,gpgkey=foo.gpg
   umount /mnt (or umount /dev/hda999 )

3) The fstab way, mount/umount do loop setup/teardown for you:

   /etc/fstab line:
    /dev/hda999 /mnt ext3 defaults,noauto,loop=/dev/loop4,encryption=AES128,gpgkey=foo.gpg,user=daniel 0 0

   mount /mnt
   umount /mnt (or umount /dev/hda999 )

> However mount shows:
>
> /media/usbdisk/.fs.ext3 on /media/usbdisk/fs type ext2
> (rw,nosuid,nodev,loop=/dev/loop4,user=daniel)

Looks like you used method (1) earlier and are now using method (3). umount
needs mountpoint directory or backing device that was used at mount time. If
you didn't mount /dev/loop4 device directly, then you should not expect
"umount /dev/loop4" to work either.

Try "umount /media/usbdisk/fs" or "umount /media/usbdisk/.fs.ext3"

[Sebastien Bacher (seb128)]

likely an upstream bug, would be nice to send it on bugzilla.gnome.org, the desktop team is overworked and not likely to work soon on this one

[Daniel Harvey (daniel.harvey)]

This problem no longer occurs in Gutsy Tribe 5. Suggest closing.

[Leann Ogasawara (leannogasawara)]

I'm closing this report per the last comment. Thanks.

[Zippex Linux Developer (zippex)]

Really me, and a lot of my co workers have this problem in Hardy