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

cameracommand linelinuxmountusb

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') ***

Best Answer

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
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