Remove Kernel Lock from Unmounted Mass Storage USB Device from the Command Line in Linux

Question

I've searched high and low, and can't figure this one out. I have a older Olympus Camera (2001 or so). When I plug in the USB connection, I get the following log output:

$ dmesg | grep sd
[20047.625076] sd 21:0:0:0: Attached scsi generic sg7 type 0
[20047.627922] sd 21:0:0:0: [sdg] Attached SCSI removable disk

Secondly, the drive is not mounted in the FS, but when I run gphoto2 I get the following error:

$ gphoto2 --list-config

*** Error ***              
An error occurred in the io-library ('Could not lock the device'): Camera is already in use.
*** Error (-60: 'Could not lock the device') ***       

What command will unmount the drive. For example in Nautilus, I can right click and select "Safely Remove Device". After doing that, the /dev/sg7 and /dev/sdg devices are removed.

The output of gphoto2 is then:

# gphoto2 --list-config
/Camera Configuration/Picture Settings/resolution                              
/Camera Configuration/Picture Settings/shutter
/Camera Configuration/Picture Settings/aperture
/Camera Configuration/Picture Settings/color
/Camera Configuration/Picture Settings/flash
/Camera Configuration/Picture Settings/whitebalance
/Camera Configuration/Picture Settings/focus-mode
/Camera Configuration/Picture Settings/focus-pos
/Camera Configuration/Picture Settings/exp
/Camera Configuration/Picture Settings/exp-meter
/Camera Configuration/Picture Settings/zoom
/Camera Configuration/Picture Settings/dzoom
/Camera Configuration/Picture Settings/iso
/Camera Configuration/Camera Settings/date-time
/Camera Configuration/Camera Settings/lcd-mode
/Camera Configuration/Camera Settings/lcd-brightness
/Camera Configuration/Camera Settings/lcd-auto-shutoff
/Camera Configuration/Camera Settings/camera-power-save
/Camera Configuration/Camera Settings/host-power-save
/Camera Configuration/Camera Settings/timefmt

Some things I've tried already are sdparm and sg3_utils, however I am unfamiliar with them, so it's possible I just didn't find the right command.

Update 1:

# mount | grep sdg
# mount | grep sg7
# umount /dev/sg7
umount: /dev/sg7: not mounted
# umount /dev/sdg
umount: /dev/sdg: not mounted
# gphoto2 --list-config

*** Error ***              
An error occurred in the io-library ('Could not lock the device'): Camera is already in use.
*** Error (-60: 'Could not lock the device') ***       

Answer 1

Quick and Dirty Method

For a brute force disable of all active mass storage devices:

rmmod usb_storage

Prevent Any Device from Loading usb_storage Module

I found the following link, basically asking the same question as this. If you want to prevent the kernel from auto-mounting using usb_storage:

echo "blacklist usb_storage" | sudo tee /etc/modprobe.d/blacklist-usb-storage.conf

Prevent Single Device from Loading usb_storage Module

Instead of disabling all devices, you can target a specific device to ignore using udev rules. There is a specific example here.

I spent a lot of time trying to get this to work in Ubuntu 10.04, but it looks like this functionality was disabled in newer versions of udev.

"Safely Remove Disk" Unbind/Unclaim Source Code

The last post on this thread worked like a charm.

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <linux/ioctl.h>
#include <linux/usbdevice_fs.h>

int main(int argc, char**argv)
{
   struct usbdevfs_ioctl command;
   int ret;
   int fd;
   int i;
   if (argc>1) {
      fd = open(argv[1],O_RDWR);
      if (fd<1){
         perror("unable to open file");
         return 1;
      }
      for (i=0;i<255;i++){ // hack: should fetch how many interface there is.
         command.ifno = i;
         command.ioctl_code = USBDEVFS_DISCONNECT;
         command.data = NULL;
         ret = ioctl(fd, USBDEVFS_IOCTL, &command);
         if(ret!=-1)
            printf("un claimed interface %d %d\n",i,ret);
      }
   }else {
      printf ("usage: %s /dev/bus/usb/BUS/DEVICE\n",argv[0]);
      printf("Release all interfaces of this usb device for usage in virtualisation\n");
   }
}

Simple Script for Binding / Unbinding Device

The previous example is an interesting case, but I also found a much simplified method. You can use the usb-storage driver interface for binding and unbinding devices.

The following command worked, just like the source code from above:

echo -n "1-2.4:1.0" | sudo tee unbind    

Answer 2

First, run mount as root. This should list all mounted filesystems. If /dev/sdg and /dev/sg7 are not in the list, then the camera is no longer mounted.

If the camera is still mounted, you can unmount it with the command umount (note the missing 'n'). An example would be umount /dev/sg7 or umount /dev/sdg.

If the camera has mounted filesystems, then you can probably just browse to the photos in Nautilus. The output of mount will tell you where the devices are mounted to in the filesystem - just browse to the folder and start looking around for the photos.

Answer 3

Are you using Ubuntu? There is talk of a bug in 8.10, and while I'm not sure if this is fixed in the latest version, there is a workaround which might let you do... whatever it is you're trying to do (since you aren't just downloading pictures). :P

Answer 4

I do this in a script:

# If camera is mounted we need to unmount it
export CAMERA_MOUNT_POINTS=`gvfs-mount -l | grep gphoto2 | sed 's/.*\(gphoto2.*\)$/\1/' | uniq 2> $LOG_FILE`
for CAMERA_MOUNT_POINT in $CAMERA_MOUNT_POINTS
do
    echo Unmounting mounted camera from $CAMERA_MOUNT_POINT.
    gvfs-mount -u $CAMERA_MOUNT_POINT &> $LOG_FILE
done

I am not sure this is what you need, but it might be, since I've had similar problems.

EDIT: To explain a little: gvfs-mount -l lists mounted stuff The rest of that line cleans the output to produce just a list of mounted cameras (and pipes errors to a log file). Then the loop unmounts all cameras.